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Home My WebLink About20200738.tiffUSE BY SPECIAL REVIEW (USR) APPLICATION FOR PLANNING DEPARTMENT USE: AMOUNT $ APPLICATION RECEIVED BY DATE RECEIVED: CASE # ASSIGNED: PLANNER ASSIGNED: PROPERTY INFORMATION (Attach additional sheets if necessary.) Proposed use: 115 -kV Transmission Line, Substation, and Staging Areas Is the property currently in violation? M No / ❑ Yes Violation Case Number: Site Address: Multiple - see application Parcel Number: 0 2 0 9. 1 1. 0 _ 0 0_ 0 0 4 Legal Description: Multiple - see application Substation Parcel Section: , Township N, Range W Zoning District: A Acreage: 10 Within subdivision? El No / II Yes Townsite? El No / ❑ Yes If yes, subdivision or townsite name: Floodplain O No / ❑ Yes Geological Hazard © No / ❑ Yes Airport Overlay O No / 0 Yes PROPERTY OWNER(S) (Attach additional sheets if necessary.) Name: Substation Parcel Owner - Loyd Farms Company: Phone #: 970-895-2289 Street Address: 66732 County Road 87 Email: dan@loydfarms.com City/State/Zip Code: Grover, CO 80729 Name: Transmssion Line Easement Owners - provided in attached spreadsheet Company: Phone #: Street Address: City/State/Zip Code: Email: APPLICANT/AUTHORIZED AGENT (Authorization must be included if there is an Authorized Agent.) Name: Joel K. Bladow Company: Tri-State Generation and Transmission Association, Inc. Phone #: 303-254-3655 Email: jbladow@tristategt.org Street Address: 1100 W. 116th Avenue City/State/Zip Code: Westminster, CO 80234 I (We) hereby depose and state under penalties of perjury that all statements, proposals, and/or plans submitted with or contained within the application are true and correct to the best of my (our) knowledge. All fee owners of the property must sign this application. If an Authorized Agent signs, an Authorization Form signed by all fee owners must be included with the application. If the fee owner is a corporation, evidence must be included indicating the signatory has the legal authority to sign for the corporation. Print 10/25/2019 iift etc( Da a Signature Date Print "Joel K. Bladow, as Senior Vice President Transmission, signing in said capacity for and on behalf of Tri-State Generation and Transmission Association, Inc. 9 6� M 'Abk �8Sroptii) DEPARTMENT OF PLANNING AND BUILDING DEPARTMENT OF PUBLIC HEALTH AND ENVIRONNMENT 1555 NORTH 17TH AVENUE GREELEY, CO 80631 AUTHORIZATION FORM FOR BUILDING, PLANNING AND HEALTH DEPARTMENT PERMITS AND SERVICES Legd Sys Dan ryod of Lyod Farms, I, (We), (Owner — please print) , give permission to Denise Gibbons (Applicant/Agent — please print) to apply for any Planning, Building or Health Department permits or services on our behalf, for the property located at: the intersection of WCR 130 and 71 near the town of Grover all of 63.00 Legal Description: of Section Township N, Range W Subdivision Name: 11 11 N/A Property Owners Information: 970-895-2289 Phone: Applicant/Agent Contact Information - 303 -254-3229 Phone: E-mail: E -Mail: Lot dan@loydfarms.com Block dgibbons@tristategt.org Email correspondence to be sent to: Owner I _I Applicant/Agent Postal service correspondence to be sent to: (choose only one) Owner Additional Info: Tri-State Generation and Transmission Association. Inc. Both Applicant/Agent 1100 W. 116th Avenue, Westminster, CO 80234 Owner Signature. Owner Signature: Date: — Date: 7/29/2019 5 NA 1041 USE BY SPECIAL REVIEW (USR) PROCEDURAL GUIDE MAJOR FACILITY OF A PUBLIC UTILITY DEPARTMENT OF PLANNING SERVICES 11555 N. 17TH AVENUE, GREELEY, CO 80631 www.weldgov.com 1970-400-6100 1 FAX 970-304-6498 Note: This form is for uses falling under Weld County Code Chapter 21, Areas and Activities of State Interest, Article III, Major Facilities of a Public Utility. Note: A pre -application conference with the Department of Planning Services is required prior to the submittal of this application. Please submit a Pre -Application Request form. (Available at www.weldgov.com>departments>planninq and zoninq>land use applications.) APPLICATION SUBMITTAL REQUIREMENTS X A copy of the pre -application meeting minutes provided by Planning Services. X Application form. (See attached). X Authorization form, if applicable. (See attached). NA Incorporation documents if the owner is a business entity (LLC, etc.), or trust documents. X Completed Questionnaire. (See attached). See Appendix E X A certified list of names, addresses and the corresponding Parcel Identification Number(s) assigned by the County Assessor of the owners of property (the surface estate) within 1,320 feet of the property, except for transmission line projects, for which surface property owners for 500 feet on either side of the centerline of the proposed alignment, and to interest holders (excluding mineral interests) in any real property proposed to be physically disturbed or crossed by the activity or development which is the subject of the application. The source of such list shall be the records of the County Assessor, or an ownership update from a title or abstract company or attorney, derived from such records or from the records of the County Clerk and Recorder. If the list was assembled from the records of the County Assessor, the applicant shall certify that such list was assembled within 30 days of the application submission date. (See attached affidavit form.) See Appendix F X The names and addresses of any owner, operator, or user of any irrigation ditch, lateral, or pipeline that traverses the property, if applicable. See page 25 A copy of an agreement with the mineral owners associated with the subject property, if applicable. Such agreement shall stipulate that the oil and gas activities on the subject property have been adequately incorporated into the design of the site or shall provide written evidence that an adequate attempt has been made to mitigate the concerns of the mineral owners on the subject property. X A copy of the most recent deed to the property and, if the applicant is not the property owner, evidence of interest in the subject land held by the applicant, such as a lease agreement, trust documents, Statement of Authority, or similar evidence. See Appendix H X A Certificate of Conveyances (Chain of Title) form provided by the Department of Planning Services and completed by a Title Insurance or Abstract Company. The date of certification of the form must be within 30 days of the date of application. (See attached COC cover sheet.) See Appendix G X A signed Statement of Taxes from the County Treasurer showing no delinquent property taxes for the area referred to in the application materials. See Appendix G NA A copy of a document showing evidence of adequate water supply (e.g., well permit or letter from water district). NA A copy of a document showing evidence of adequate methods of sewage disposal (e.g., on -site wastewater treatment system (OWTS) (septic)) permit). Continued on the next page. 10/25/2019 1 NA A signed Notice of Inquiry from a municipality or municipalities if the site is located within an Intergovernment Agreement (IGA) boundary or a Coordinated Planning Agreement (CPA) boundary, if applicable. X A drainage report, preliminary drainage study, or drainage narrative, as determined by Public Works. (See attached Questionnaire.) See Appendix A NA A traffic study or traffic narrative including a traffic control plan, as determined by Public Works. (See attached Questionnaire.) NA A sign plan detailing type, size and number of desired signs with images following the standards set forth in Chapter 23, Article IV, Division 2 and Appendices 23-C through E, if applicable. NA A nuisance abatement plan, if applicable. NA A landscape and screening plan, if applicable. NA A decommissioning plan, if applicable. Adequate financial assurance to cover the decommissioning of the facility may be required as a condition of approval. NA A draft emergency incident action plan, if applicable. NA A noise study including a noise abatement plan documenting the methods to be utilized to meet the applicable noise standard, if applicable. X A soil report of the site prepared by the Natural Resource Conservation Service or by a soils engineer or scientist. In those instances when the soil report indicates the existence of moderate or severe soil limitations for the uses proposed, the applicant shall detail the methods to be employed to mitigate the limitations. See Appendix D NA Community meeting sign -in sheet, minutes, and summary (optional). X The application fee ($10,000). Note: Fees are non-refundable and due when the application is determined to be complete. Fees are set by the Board of County Commissioners. County Staff is not authorized to negotiate fees and cannot, under any circumstance, waive, reduce, or amend the fees set forth in the Weld County Planning Fee Schedule. NA Investigation fee, due only if this is a violation case. (50% of the application fee.) X The planned access to the project site and the means the applicant intends to use to obtain a legal right to utilize such access, including copies of any access or right-of-way agreements which have been entered into by the date of the application for such access. X The names and addresses of persons or entities with an interest in any real property proposed to be physically disturbed or crossed by the activity or development which is the subject of the application, excluding mineral interests but including those holding mortgages, judgments, liens, easements, contract rights, rights -of -way, reservations, exceptions or other encumbrances, at least to the extent shown in the records of the County Clerk and Recorder or of which applicant has actual knowledge. See Appendix F NA The names and addresses of mineral interest holders with an interest in any real property proposed to be physically disturbed or crossed by the activity or development which is the subject of the application in the case of projects to be constructed more than 10 feet below the surface. excluding foundation structures for above -ground transmission lines, at least to the extent shown in the records of the County Clerk and Recorder and County Assessor. In addition, the applicant shall provide a certificate stating the process by which the applicant compiled such information, when such information was compiled and the steps which were taken to ensure the accuracy of the information. The County will require that the information be compiled and verified in a manner reasonably designed to ensure the accuracy of such information, but shall not require the use of title insurance or attorney's title opinions. The County will require that the last search for such information have been updated no later than 10 days before the date that the application is submitted, and that such information be updated again no later than 10 days before the public hearing on the application. Continued on the next page. 10/25/2019 2 x 1041 USR map. The applicant shall submit the draft map for preliminary approval to the Department of Planning Services in electronic (.pdf) format. Upon approval, the applicant shall submit a 24" x 36" map on Mylar. (See attached for map requirements.) x A sketch or map showing the following: If a power plant is proposed, the area within 10 miles from the site. X For transmission lines, provide a map showing all existing transmission lines (115 kV or greater) for a distance of 2 miles beyond any reasonable alternative studied. For upgrades of existing transmission lines (115 kV or greater), provide a sketch showing all existing transmission lines and pipelines within 1 mile on either side of the proposed alignment. For all other major facilities of a public utility, provide a sketch showing the area within 5 miles of the site. Indicate any floodplains, if required. x A map showing each existing major facility of a public utility within the County of the type proposed for development, if required. X If required, identify and locate on a map of appropriate scale the juxtaposition of any of the following features present in the proposed development or activity and its vicinity, and detail the potential impact of the proposal upon each feature: X Marshlands and wetlands. Groundwater recharge areas, if applicable. Potential natural hazards. Forests and woodlands. Critical wildlife habitat. Public outdoor recreation areas. Unique areas of geologic, historic or archeological importance ********** 10/25/2019 3 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Appendix E: USR Questionnaire Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Planning Questions 1. Explain, in detail, the proposed use of the property. Include, at a minimum, the following: a. Type of use for which the application is being made. The application is for a Major Facility of a Public Utility or Public Agency. consisting of a substation. transmission line. and construction staging area. b. Current or previous use of the land, if any. Current land uses include agricultural operations, electric transmission, oil and gas production and storage, and residential. c. Include a statement delineating the need for the proposed use. Tri-State is obligated to provide reliable, efficient, cost -based, wholesale power to our Member Systems. One of our Members. High West. has received formal requests for service for several large industrial loads associated with oil and gas facilities. d. Describe the uses surrounding the site and explain how the proposed use is compatible with them. Surrounding uses are agricultural operations, oil and gas development. and rural residences. The proposed land use is commonly located in agricultural areas and is compatible with the existing surrounding land uses. Major facilities of public utilities are uses that are allowed by special review within the Agricultural Zone District e. Describe the proximity of the proposed use to residential structures. There are two residences within 500 feet. and seven residences within '/2 mile. There are no residences directly adjacent to the Substation site. but one residence one mile to the east. f. Describe the hours and days of operation (e.g. Monday thru Friday 8:00 a.m. to 5:00 p.m.). One 10 -hour shift per day (5-7 days per week) would be worked during construction: the facilities would be monitored remotely during operation, 24 hours/day, 365 days/year. g. Describe the number of shifts and the maximum number of employees per shift. The maximum number of construction workers at any one time would be approximately 50. The Project would generate infrequent trips to the transmission line and substation during operations with the line being inspected annually and for occasional maintenance The substation would be visited one to two times per month. Describe the maximum number of users, patrons, members, buyers, or other visitors that the use by special review facility is designed to accommodate at any one time. Not applicable. Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application i. List the types and maximum numbers of animals to be on the site at any one time (for dairies, livestock confinement operations, kennels, etc.). Not applicable. j• List the types and numbers of operating and processing equipment to be utilized. The 20 miles of transmission line would consist of approximately 110-130 structures. The structures would be a mixture of wood and steel pole construction spaced approximately 700- 1.000 feet apart. The transmission line would have three conductors (single -circuit configuration). an overhead optical ground wire for internal Tri-State communications, and one shield wire. Steel transmission poles would be set in concrete foundations. The Lloyd Sisson Substation is designed as a single 115 -kV bay to a dual voltage 34.5 -12.47 -kV distribution bank with four feeders at each distribution voltage. Ultimately the substation is laid out for a future four breaker 115 -kV ring bus and an additional eight feeders of distribution. The initial build out will consist of (4) 115 -kV switches. (1) 115 -kV circuit switcher. a 115/34.5 -kV 30/40/50 megavolt ampere (MVA) transformer, a 34.5/12.47 -kV transformer along with distribution voltage switches. meters and electrical equipment. Site preparation at the substation will include grading, fencing. grounding, and construction foundations. k. List the types, number, and uses of the proposed structures to be erected. Approximately 110-130 transmission line structures would be used to transmit electricity over the 115 -kV transmission lines_ I. Describe the size of stockpile, storage, or waste areas to be utilized, if any. The Project also includes a construction staging area used for the duration of construction to store equipment and stage construction located at the existing Keota Substation and at the proposed Lloyd Sisson Substation. The staging areas will have two construction trailers on -site for approximately 11 months. multiple storage containers, and other associated equipment. m. Describe the method and time schedule of removal or disposal of debris, junk and other wastes associated with the proposed use. Enclosed containment would be provided for all trash. All construction waste. including trash and litter, garbage. other solid waste. petroleum products. and other potentially hazardous materials would be removed from the site and transported to a disposal facility authorized to accept such materials. n. Include a timetable showing the periods of time required for the construction of the operation. Milestone Date Weld County Permit Granted 1Q 2020 Easement Acquisition 1Q -2Q 2020 Construction Begins Summer 2020 In Service 1Q 2021 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application o. Describe the type of lot surface propose and the square footage of each type (e.g. asphalt, gravel, landscaping, dirt, grass, buildings). The land cover underneath the transmission line would remain unchanged Within the fenced substation area, the ground vegetation would be removed and replaced with a gravel base Approximately 2 acres of the 7.5 -acre site would be covered with rock surface and/or road base. The remaining space. including the detention pond would be returned to native grasses. The proposed types of lot surface are summarized below. Area Type Area (Sq. Yards) Area (Acres) 3' Thick Surface Washed Rock Surface Aggregate 8,893 1 84 12" Thick Class 5 Base Material Driveway 472 0 10 Total Area 9,365 1_94 P. q. How many parking spaces are proposed? How many handicapped (ADA) parking spaces are proposed? No parking spaces are proposed for this project. Vehicles will park inside the substation fence during inspections and maintenance. Vehicles will park at the staging area or on the transmission line right-of-way during construction. Describe the proposed screening for all parking and outdoor storage areas. No screening is being proposed for the staging area due to its proximity to an existing substation and its distance from any residences. r. Describe the existing and proposed landscaping for the site. Existing landscape consists of native vegetation and agricultural crops. No landscaping is proposed in association with construction of the transmission line or substation_ s. Describe the type of fence or other screening proposed for the site. The substation will be fenced with a chain -link security fence to prevent public access t. Describe reclamation procedures to be employed as stages of the operation are phased out or upon cessation of the Use by Special Review activity. Tri-State will exercise care to preserve the natural landscape and will conduct its construction operations so as to prevent any unnecessary destruction, scarring, or defacing of the natural surroundings in the vicinity of the work. Mitigation practices described in Appendix C of the Weld County 1041 Application will be implemented to minimize impacts to environmental resources. Except where clearing is required for permanent works or excavation operations, all trees. native shrubbery. and vegetation will be preserved and protected from damage by the construction operations and equipment. Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application On completion of the work, all work areas except existing access roads and substation site would be revegetated as soon as practical using a landowner approved seed mixture. Alternatively, in areas where mutually agreed to by Tri-State and landowner, the ground shall be scarified or left in a condition that would facilitate natural revegetation. provide for proper drainage. and prevent erosion. Site -specific revegetation measures would be developed after consultation with the landowner u. Describe the proposed fire protection measures. The proposed Project is located in Pawnee Fire Protection District. All applicable fire laws and regulations. as outlined in the Colorado Revised Statutes (CRS) 31-16-601, would be observed during the construction period. Tri-State would advise construction personnel of their responsibilities under the applicable fire laws and regulations. including taking practical measures to report and suppress fires. 2. Explain how this proposal is consistent with the Weld County Comprehensive Plan. The Weld County Code. Chapter 22. Comprehensive Plan. has been reviewed and the proposed substation and transmission line are consistent with the intent of the Comprehensive Plan, including Land Use. Environmental Resources. and Natural Resources. The proposed substation and transmission line are located in the Agriculture Zone. Although the transmission line is not an agricultural use, it is a land use that is commonly located in agricultural areas and does not conflict with the goals outlined in the Comprehensive Plan. Ground disturbance for transmission lines is generally limited to the area immediately around the base of each pole. The Lloyd Sisson Substation would occur on lands removed from agricultural. but agricultural practices could continue on adjacent lands. Impacts to environmental resources such as air. water. waste, noise, and public health would be minimal and limited to the construction period (see Sections 21-3-330.B.5.g. 21 3-330.B.12. and 21 3- 330.B.15). Mitigation practices described in Appendix C of this Weld County 1041 Application would be implemented to minimize impacts to environmental resources. Natural resources such as sensitive wildlife areas. recreation areas, and mineral and energy resources would not be impacted by the proposed Project. Affects to and proposed mitigation for sensitive wildlife are described in the Wildlife and Critical Wildlife Habitat section and Appendix C of this Weld County 1041 Application. No parks, open space or recreation areas are located near the Project No oil and gas wells and associated facilities occur within 200 feet of the proposed transmission line and substation. Detailed design of the transmission lines will ensure that poles are located to avoid any impact on oil and gas facilities. 3. Explain how this proposal is consistent with the intent of the zone district in which it is located. (Intent statements can be found at the beginning of each zone district section in Article III of Chapter 23.) The proposed Project is located within the Agricultural Zone District. Major facilities of public utilities may be constructed. operated. and maintained in the Agricultural Zone District upon approval of a Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application permit in accordance with the requirements and procedures set forth in Article II, Division 4 of Chapter 23 of the Weld County Code. Major facilities of a public utility are also subject to the provisions of section 23-4-420. This section of the code states that the applicant shall have the burden of proof to demonstrate that there is a need for the facility within the proposed area of service; this is discussed in the Purpose and Need section of this Weld County 1041 Application. 4. Explain how this proposal will be compatible with future development of the surrounding area or adopted master plans of affected municipalities. This proposal will allow for the continued growth and support of oil and gas operations within the county. as well as provide continued electric reliability for surrounding residential and agricultural uses. 5. Explain how this proposal complies with Article V and Article XI of Chapter 23 if the proposal is located within any Overlay Zoning District (Airport, Geologic Hazard, or Historic Town sites Overlay Districts) or a Special Flood Hazard Area identified by maps officially adopted by the County. The Project does not occur within any Overlay District Area identified by the County. 6. If the proposed use is to be located in the A (Agricultural) Zone District, explain your efforts to conserve prime agricultural land in the locational decision for the proposed use. One soil type (157 acres) along the transmission line is designated as Farmland of Statewide Importance Two soil types (16_4 acres) are designated as Prime Farmland, if irrigated. However, placement of the transmission line structures would not preclude the use of farmland under the suspended transmission line. and only a small portion of the soils in the 100 -foot right-of-way would be disturbed for the Project (approximately 2.5 acres of permanent disturbance for the transmission line). Additionally, transmission structures will be designed to accommodate agricultural operations, to the extent feasible. based on discussions with the landowners_ The 7.5 acre Substation site is considered Farmland of Statewide Importance. but is only a small subdivision of a larger 627 -acre parcel that continues to be farmed. See Section 21 -3 -330.B.15 —Hydrologic. Atmospheric. Geologic. Pedologic, Biotic, Visual, and Noise Impacts. 7. Explain whether this proposal interferes with the protection of health, safety and welfare of the inhabitants of the neighborhood and the County. All Tri-State electric facilities are designed, constructed. operated, and maintained to meet or exceed all applicable standards of design and performance set forth in the National Electrical Safety Code (NESC 2012). See also Section 21-3-330.B.5.g—Hazards and Emergency Procedures. Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Environmental Health Questions 1. What is the drinking water source on the property? If utilizing a drinking water well include either the well permit or well permit application that was submitted to the State Division of Water Resources. If utilizing a public water tap include a letter from the Water District, a tap or meter number, or a copy of the water bill. Not applicable. The use being permitted includes a transmission line and substation, which do not require water service. Bottled water will be used during construction. 2. What type of sewage disposal system is on the property? If utilizing an existing septic system provide the septic permit number. If there is no septic permit due to the age of the existing septic system, apply for a septic permit through the Department of Public Health and Environment prior to submitting this application. If a new septic system will be installed, please state "a new septic system is proposed." Only propose portable toilets if the use is consistent with the Department of Public Health and Environment's portable toilet policy. Not applicable. The use being permitted includes a transmission line and substation, which do not require sewer service. Portable toilets will be used during construction 3. If storage or warehousing is proposed, what type of items will be stored? There would be temporary storage of construction materials and equipment at the proposed staging areas. 4. Describe where and how storage and/or stockpile of wastes, chemicals, and/or petroleum will occur on this site. Materials would be temporarily stored at the staging areas during construction, but there would be no stockpile of wastes on site Dumpsters would be provided for construction waste and would be emptied on a regular or as -needed basis. There will be no permanent storage on site. Enclosed containment would be provided for all trash. All construction waste, including trash and litter. garbage. other solid waste. petroleum products. and other potentially hazardous materials would be removed to a disposal facility authorized to accept such materials. 5. If there will be fuel storage on site, indicate the gallons and the secondary containment. State the number of tanks and gallons per tank. No bulk fuel storage will occur on site. The only hazardous chemicals expected to be used on site are those found in diesel fuel, gasoline. coolant (ethylene glycol), and lubricants in machinery. 6. If there will be washing of vehicles or equipment on site, indicate how the wash water will be contained. Not applicable. 7. If there will be floor drains, indicate how the fluids will be contained. Not applicable. Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application 8. Indicate if there will be any air emissions (e.g. painting, oil storage, etc.). Construction activities associated with the project would generate less than significant amounts of emissions. There would be no long-term air quality effects associated with routine operation and maintenance of the substation and transmission line. . 9. Provide a design and operations plan if applicable (e.g. composting, landfills, etc.). Not applicable. 10. Provide a nuisance management plan if applicable (e.g. dairies, feedlots, etc.). Not applicable. 11. Additional information may be requested depending on type of land use requested. Noted. Public Works Questions 1. Include a traffic narrative with the information below. A traffic impact study may be required. Improvements to adjacent streets/roads may be necessary to provide adequate safe and efficient transportation to and from the site. An Improvements Agreement may be required. a. The projected number of vehicle trips (average per day, maximum per day, peak hour data) to and from the site and the type of vehicles (passenger, semi -truck, etc.). The projected number of vehicle trips to and from the site will vary based on the phase of construction. On average, there will be 30 trips per day, with a maximum of 45. All trips are expected to occur within the work hours of 7 AM to 7 PM. b. Describe how many roundtrips/day are expected for each vehicle type: Passenger Cars/Pickups, Tandem Trucks, Semi-Truck/Trailer/RV (Roundtrip = 1 trip in and 1 trip out of site). The typical construction personnel and equipment, including the average and maximum number of trips per vehicle type. is summarized below for the construction line. Activity Number of Persons Equipment Duration of Construction Trips (Average/Max) Substation 6 -12 6-12 pickup trucks 4 concrete trucks 1 flatbed 18 wheeler 16 weeks 3 weeks 1 month 4-6 roundtrips per day 2 -10 roundtrips per day 1-2 roundtrips per day Foundations 8 1 pressure digger 4-5 concrete trucks 3-4 pickup trucks 1 tractor/trailer 2 flatbed trailers 1 loader 1 mobile crane 1-2 dump trucks 5 weeks 1 round trip per week 4-5 round trips per day 12-16 round trips per day 4-6 round trips per day 1 round trip per day 1 round trip per day 1 roundtrip per day 4-6 round trips per day Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Activity Number of Persons Equipment Duration of Construction Trips (Average/Max) Structure Assembly and Erection 25-30 3-4 bucket trucks 3 digger derricks 1 boom truck 2 mobile crane 6 pickup trucks 3 flatbed trailers 2-3 tractor/trailers 8 weeks 3-4 round trips per day 3 round trips per day 1 round trip per day 2 round trips per week 20 round trips per day 1 round trip per day 8-12 round trips per day Wire Installation 25-30 6 pickup trucks 2 drum pullers 2 tensioners 3 bucket trucks 1 helicopter (maybe needed) 8 weeks 20 round trips per day 2 round trips per week 2 round trips per week 3 round trips per day Cleanup 8 1 bobcat 5-6 pickups 4 weeks 1 round trip per day 20 round trips per day Total 33-38 N/A 22 weeks 30 average/45 max c. Describe the expected travel routes for site traffic. Access to the proposed Lloyd Sisson Substation, the transmission line. and the Keota Substation will generally occur along Interstate 25, Highway 14, and County Roads 77 and 89. Highway 85 could also be used, as well as County Road 71 into Wyoming. d. Describe the travel distribution along the routes (e.g. 50% of traffic will come from the north, 20% from the south, 30% from the east, etc.). During construction, it is expected that approximately 60 percent of the traffic will come from the Denver Metro Area along 1-25 and Highway 85, Highway 14 and County Roads 77 and 89. Approximately 30 percent of the traffic could come from Wyoming along County Road 71. and the remainder could come from miscellaneous routes. possibly from Sidney. Nebraska along 1-80. e. Describe the time of day that you expect the highest traffic volumes to and from the site. One 10 -hour shift per day would be worked during construction; the site would be monitored remotely during operation. The highest traffic volumes would be expected when construction personnel are entering the site in the morning and exiting the site in the evenings. 2. Describe where the access to the site is planned. Existing access to the Keota Substation would be used to access the staging area. A new access road would be required off of County Road 130 for the Lloyd Sisson Substation. Tri-State will submit Access Road Permit applications where required and will comply with all County design standards. E-8 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application 3. Drainage design: Design and construction of a detention pond as described in an approved Drainage Report is required unless the project falls under an exception to stormwater detention requirements per code. (See below.) Does your site qualify for an exception to stormwater detention? If so, describe in a drainage narrative the following: The Project does not qualify for an exception to stormwater detention. A Drainage Report is provided as Appendix A. 4. If your site does not qualify for an exception, the following applies: a. A Drainage Report summarizing the detention pond design with construction drawings and maintenance plan shall be completed by a Colorado Licensed Professional Engineer and adhere to the drainage related sections of the Weld County Code. Noted, see Appendix A b. The Drainage Report must include a certification of compliance, which can be found on the Public Works website, stamped and signed by the PE. Noted. see Appendix A. c. See the attached Drainage Report Review Checklist. Noted. see Appendix A. Building Questions 1. List the type, size (square footage), and number of existing and proposed structures. Show and label all existing and proposed structures on the USR drawing. Label the use of the building and the square footage. No buildings are proposed and there are no existing structures on the property. An electric equipment enclosure (EEE) will be installed within the substation to store control, relay, and metering equipment. These EEEs are constructed from pre-engineered metal panels, structural metal framing or poured concrete. They contain wiring methods and electrical equipment that is concealed or inaccessible for inspection. These structures are often delivered with a UL Certificate of Inspection ensuring compliance with the National Electric Code (NEC) The International Building Code (IBC), which has been adopted by Weld County, exempts electrical equipment enclosures from building permits: Section [A] 105.23... "a permit shall not be required for the installation. alteration or repair of generation, transmission. distribution or metering or other related equipment that is under the ownership and control of public service agencies by established right". 2. Explain how the existing structures will be used for this USR. There are no existing structures on the property proposed for the substation. The existing Keota Substation property will be used for construction staging. The proposed transmission line will follow the existing 345 -kV transmission line, but will occur in its own right-of-way and on its own structures. E-9 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application 3. List the proposed use(s) of each structure. See answer to numbers 1 and 2 above. 10/24/2019 Tax Account Summary Account Id R0108886 Parcel Number 020911000004 Owners LOYD FARMS Address 66732 COUNTY ROAD 87 GROVER, CO 80729-9476 Sites Address Legal 8099 ALL 11 1 l 63 (16R4S) Inquiry As Of Payment Type 10/24/2019 First L#) Full Total Due $0.00 Value L Area Id Mill Levy 1204 - 1204 35.2910000 Actual Assessed AG -DRY FARM LAND - 4127 61,900 17,950 AG -GRAZING LAND - 4147 3,979 1,150 Total Value 65,879 19,100 Taxes $674.06 Tax Account <br> The amount of taxes due on this page is based on last year's property value assessment. httpsi/www.weldtax.com/treasurer/treasurerweblaccount.jsp?account=R0108886 1/1 Weld County Treasurer Account R0108886 Parcel Number 020911000004 LOYD FARMS 66732 COUNTY ROAD 87 GROVER, CO 80729-9476 Sitas Address Legal Description 8099 ALL 11 11 63 (16R4S) y Code AG -DRY FARM LAND - 4127 AG -GRAZING LAND - 4147 Payments Received Net Vantage Check Number 00050010 Payments Applied Year Charges 2018 Tax Receipt Date Feb 26, 2019 Receipt Number 2019-02-26-10-15389 Payer Actual Assessed Year Area fill Levy 61,900 17,950 2018 1204 35.291 3,979 1,150 2018 1204 35.291 Multi -Account Payment Billed Prior Payments New Payments $674.06 $0.00 $674.06 Balance $0.00 $674.06 $0.00 Balance Due as of Feb 26, 2019 $0.00 Thank you for your payment. All payments made by check are subject to final bank clearance. Account Balance Sorted by area showing outstanding tax charges (does not show interest or other fees) running over a subset of accounts No Delinquent Accounts for the year 2018 <publicwebuser> @ Oct 24. 2019 12:15:59 PM Weld County Treasurer Page 1 of 1 TRI-STATE GENERATION & TRANSMISSION, INC. LLOYD SISSON SUBSTATION DRAINAGE REPORT USR19-0070 February 18. 2020 Prepared by: nk — — IMPS— an a - -- -- — — — - c ..: sNs tar a • Ar DEL-MONT CONSULTANTS, INC. ENGINEERING • SURVEYING 125 Colorado Ave. • Montrose, CO 81401 • (970) 249-2251 • (970) 249-2342 FAX www.del-mont.com • serviceOdel-mont.com Lloyd Sisson Substation Drainage Report TRI-STATE GENERATION & TRANSMISSION, INC. LLOYD SISSON SUBSTATION DRAINAGE REPORT U S R 19-0070 ENGINEER'S CERTIFICATION I David Schieldt, Consultant Engineer for Tri-State Generation and Transmission, understand and acknowledge that the applicant is seeking land use approval of the case and parcel described within this document. I have designed or reviewed the design for the proposed land use set for in the application. I hereby certify, on behalf of the applicant, that the design will meet all applicable drainage requirements of the Weld County Code with the exception of the variances described (No variances for this application). This certification is not a guarantee or warranty either expressed or implied. David Schieldt Registered Professional Engineer State of Colorado No. 47195 COUNTY ACCEPTANCE This report has been reviewed and found to be in general compliance with the Weld County Engineering and Construction Guidelines. The accuracy and validity of the engineering design. details, dimensions, quantities, and concepts in this report remains the sole responsibility of the professional engineer whose stamp and signature appear hereon: Accepted by: County Engineer Date DM's Lloyd Sisson Substation Drainage Report TABLE OF CONTENTS 1.0 General Location and Description 1.1 Site Location 1.2 Site Description 2.0 Drainage Basins and Sub -Basins 2.1 Existing Drainage Sub -Basins 2.2 Proposed Drainage Sub -Basins 3.0 Drainage Design Criteria 3.1 Methodology 3.2 Land Cover Hydrologic Properties 3.3 Weighted Design Values 4.0 Drainage Facility Design 4.1 Historical Drainage 4.2 Proposed Drainage 5 Conclusions 5.1 Drainage Concept 5.2 Compliance with the Weld County Code 6.0 References Appendix A — Appendix B — Appendix C Appendix D Site Maps & Design Drawings NRCS Soils Report — Site Specific Physical Design Properties — SWMM Modeling Results DMCLloyd Sisson Substation Drainage Report 1-1 1-1 1-1 2-1 2-1 2-1 3-1 3-1 3-1 3-1 4-1 4-1 4-1 5-1 5-1 5-1 6-1 1 0 General Location and Description Tri-State Generation and Transmission (TSGT) in coordination with Del -Mont Consultants, Inc. (DMC) is in the process of designing a new substation yard. The scope of work includes the construction of the substation yard. driveway, detention pond and swales, installation of new perimeter and property fence. and the addition of high voltage electrical equipment and facilities. The purpose of this report is to present the findings from the hydrologic and hydraulic analyses that were performed on the existing property as well as present the results from a detailed analysis performed on the proposed improvements to the property. 1.1 Site Location The proposed substation yard is located on a 7.5 -acre parcel owned by TSGT, situated in the SE 1/4 of Section 11, Township 11 North, Range 63 West, 6th Principal Meridian in Weld County. Colorado. The substation site is accessed from County Road 130 approximately 430' west of County Road 71. 1.2 Site Description The site naturally drains from northwest to southeast and is currently covered in native grasses. weeds. and agricultural crops. There are currently no features on the site to provide water quality or quantity treatment for discharge from the site. Site layout details will be discussed in more detail in Section 2. There are currently no developments on or near the site. No wetlands are present on the site and the site is not located within a floodplain. nA A ' Lloyd Sisson Substation Drainage Report 1-1 2.0 Drainage Basins and Sub -Basins The property functions overall as one drainage basin flowing to the east, towards the intersection of CR130 and CR71, ultimately ending up in Little Crow Creek. Proposed conditions produce several smaller sub -basins and will be discussed in detail in the following sections. 2.1 Existing Drainage Sub -Basins The existing site is comprised of one overall drainage basin: Existing Site. The entire property discharges southeasterly. A map illustrating the delineation of the existing property can be found in Appendix A. There is currently no development present on the neighboring properties located to the north and west of the substation. Table 2-1 presents the existing basin and its corresponding acreage. Table 2-1: Existing Basin Acreages Sub -Basin Total Area (Acres) Existing Site 7.5 2.2 Proposed Drainage Sub -Basins The proposed conditions will produce several different sub -basins. The proposed site is divided into three different sub -basins; Sub -Yard. West Area, and East Area. A map illustrating the delineation of the sub -basins can be found in Appendix A. The Sub -Yard contains the majority of the entrance driveway, the substation yard that is scheduled to be built. and the detention pond. The Western Area and Eastern Areas contain swales that will route any run-on from the neighboring property around the substation site. returning to historical discharge patterns. Table 2-2 presents the proposed sub -basins. their corresponding acreages. and their percentage of the overall site. Table 2-2: Proposed Sub -Basin Acreages Sub -Basin Total Area (Acres) % of Total Area Sub -Yard 2.32 31% West Area 2.00 27% East Area 3.16 42% Lloyd Sisson Substation Drainage Report 2-1 3.0 Drainage Design Criteria 3.1 Methodology The hydrologic/hydraulic analysis of the site was performed using the Autodesk Storm and Sanitary analysis utilizing the SWMM engine platform model for a 10 -year, 1 -hour rainfall event of 1.38 total inches and a 100 -year. 1 -hour rainfall event of 2.82 total inches. The Curve Number method of determining rainfall losses due to infiltration was used. Runoff for all site conditions was computed for both the 10 -year and 100 -year, 1 -hour storms. Rainfall depths were obtained for the region from NOAA Atlas 14, Volume 8. Version 2 and rainfall distribution curves were developed using a 1 -hour rainfall distribution. Modeling results are presented in Appendix D. The Urban Drainage Detention Basin Design Workbook was utilized to determine the required water quality capture volume (WQCV) and to design the outlet structure. The spreadsheets/worksheets can be found in Appendix C and are discussed in more detail in Section 4.0. Soil data was obtained from a USDA Soils Report and gives a hydrologic soil group B for the site. The soils report is included in Appendix B. The described methods/tools used in the analysis. are in accordance with Weld County's Engineering and Construction Guidelines. 3.2 Land Cover Hydrologic Properties Curve numbers and corresponding Manning's N values. for hydrologic soil group B. were assigned to the various land cover types found on the project, both existing and proposed. and are presented in Table 3-1. Table 3-1: Land Cover Hydrologic Properties Land Cover Type Curve Number Manning's N Pasture or Range Land. Fair Condition (Existing Site) 69 0.15 Open Graded Aggregate Topping Over Compacted Base (Substation Yard) 85 0.024 Compacted Base Material (Driveways) 85 0.024 Pavement/Concrete 98 0.015 3.3 Weighted Design Values Utilizing the land cover hydrologic properties presented above. a weighted curve number and Manning's N value was calculated for each of the sub -basins. presented in Section 2.0 to be used for analysis. Table 3-2 presents the weighted design values for existing conditions and Table 3-3 presents the weighted design values for proposed conditions. Detailed calculations can be found in Appendix C. 3-1 Lloyd Sisson Substation Drainage Report Table 3-2: Existing Sub -Basin Weighted Design Values Sub -Basin Total Area (Acres) Weighted Manning's N Weighted Curve Number Existing Site 7.48 0 144 69.8 Table 3-3: Proposed Sub -Basin Weighted Design Values Sub -Basin Total Area (Acres) Weighted Manning's N Weighted Curve Number Sub -Yard 2.32 0.050 88.1 West Area 2.00 0.145 69.7 East Area 3.16 0.137 70.7 Lloyd Sisson Substation Drainage Report 4.0 Drainage Facility Design 4.1 Historical Drainage Per Weld County requirements. the historical discharge rate from the 10 year — 1 -hour storm shall be utilized to determine the allowable discharge from the detention pond for the 100 year — 1 -hour storm for the proposed improvements. Values presented in Table 3-2 were used in the model to calculate a historical discharge rate for the existing property. Table 4-1 presents the discharge rate for the existing property for both the 10 -year and 100 -year 1 - hour storm events as well as a theoretical discharge for the proposed substation basin based on percentage of the total acreage. This flow rate for the Sub basin is the target flow rate to be used to design the proposed pond and outlet structure. Table 4-1: Existing Property Discharge Values Sub -Basin 10 -Year Discharge (CFS) 100 -Year Discharge (CFS) Existing Site 2.24 8.07 Sub (31% of Total) 0.69* 2.50 *Design flow rate for discharge pond for 100 -year event. 4.2 Proposed Drainage Values presented in Table 3-3 were utilized in the model to calculate the runoff for the proposed conditions. The Urban Drainage Detention Basin Design Workbook was utilized to determine the WQCV in conjunction with the model to size the detention pond. Once the pond was sized, the Urban Drainage Detention Basin Design Workbook was utilized to estimate required orifice sizes in the outlet structure to provide water quality treatment. The model was then used to verify all design elements of the pond and the outlet structure to ensure the pond not only retained the correct WQCV but to also discharge at or less than the required 10 -year historic discharge rate presented in Table 4-1 as well as drain the pond in less than the allowable time per State Requirements. The spreadsheet showing the detailed calculations can be found in Appendix C. The design of the outlet structure is detailed in the grading drawings. The proposed detention pond was designed to provide water quality treatment as well as detain the 100 -year storm event for the ultimate buildout of the yard while maintaining the required 1 -foot of freeboard prior to passing through the overflow weir. The proposed detention pond stage -storage curve is presented in Table 4-2. Table 4-2: Detention Pond Stage -Storage Table Elevation Surface Area (Sq. Ft.) 5242.61 0 5243.0 947 5244.0 11,502 5245.0 14,485 5246.0 17,736 DM Lloyd Sisson Substation Drainage Report 4-1 The model of the proposed site conditions was utilized to calculate discharge flow rates from the outlet structure in order to size the pond discharge culvert. Table 4-3 presents the hydraulic capacity of the culvert and the required capacity to discharge flow from the outlet structure for both the 10 -year and 100 -year events. A larger pipe than needed was selected to reduce the amount of discharge the emergency weir will need to carry in the event of large back-to-back storms. The design of the driveway culvert was also analyzed to pass the flow from the west basin to the southeast corner of the property. Detailed design of the pipes is provided in Appendix A. Table 4-3: Outlet Pipe Hydraulic Capacity (100 -year event) 7 Drainage Feature Pipe Diameter (in) Total Capacity (cfs) Required Flow Capacity (cfs) Remaining Capacity (cfs) Pond Outlet 12 2.18 0.20 1.98 Driveway Culvert 15 3.96 1.82 2.14 Table 4-4 presents the discharge rates for the proposed sub -basins for both the 10 -year and 100 -year 1 -hour storm events prior to detention. This discharge value represents the flow rate that the pond is receiving. The discharge from the pond and other basins (total discharge from site) is summarized in Table 5-1. Table 4-4: Proposed Sub -Basin Discharge Values (Pre -Detention) Sub -Basin 10 -Year Discharge (CFS) 100 -Year Discharge (CFS) Sub -Yard 5.33 12.68 West Area 0.20 1.82 East Area 0.57 3.15 Utilizing the flow rates presented above, the model was utilized to analyze the flow path of water through the piping and pond system. With the installation of the outlet structure, the pond was designed to pass both the 10 -year and 100 -year events. treat the required WQCV, and slowly release the water in the required length of time after the end of an event set forth by the County/State. The entire substation yard drains to the pond and the discharge rate leaving the pond is presented in Table 5-1. Pond drain down curves for both storm events are found in Appendix C. The intercept swale routing water around the northern end of the substation was also analyzed for adequate capacity. The contributing areas to the swales are native land. The contributing area to the north swale is approximately 10 acres. The capacity of the north swale as designed is approximately 24 cfs. The area would generate approximately 10.7 cfs for the 100 -year event. Required channel capacity is 1.33xflow rate or approximately 14.3 cfs. The capacity of the swale is adequate and can easily pass the 100 -year flow rate, meeting County regulations. 'k'J Lloyd Sisson Substation Drainage Report 4-2 5.0 Conclusions 5.1 Drainage Concept The drainage design has been prepared using sound engineering judgement and practices and will provide an effective means of controlling runoff on the project site as well as protect the site from damage. The design has been completed according to Weld County Standards and will result in no downstream impacts to any people or structures. Historic flow paths, discharge rates, and water quality have been maintained or improved. 5.2 Compliance with the Weld County Code Per Weld County requirements, the historical discharge rate from the 10 -year — 1 -hour storm shall be utilized to determine the allowable discharge rate for the 100 -year 1 -hour storm for the proposed improvements. To demonstrate compliance with this requirement, both the existing and proposed conditions were combined into one overall sub -basin. Table 5-1 presents the overall discharge rates for the overall basin as well as the individual basins. Table 5-1: Overall Sub -Basin Discharge Values (Post Detention) Basin 10 -Year (CFS) Discharge 100 -Year Discharge (CFS) Existing Proposed Existing Proposed Sub -Yard (Pond Outlet) 2.24 0.08 8.07 0.20* West Area 0.20 1.82 East Area 0.57 3.15 Total 2.24 0.85 8.07 5.17 *Discharge from the pond discharge structure is less than the required 10 -year flow rate of 0.69 cfs The pond outlet structure was sized according to County Standards so that the proposed condition 100 -year discharge rate is less than the required discharge rate from the 10 -year, 1 -hour storm event, resulting in compliance with County requirements. The detention pond was also sized according to County requirements to treat the WQCV. detain the 100 -year event, maintain 1 foot of freeboard. and maintain historical discharge patterns resulting in no downstream impacts. The emergency overflow weir has been designed according to County requirements and sizing calculations can be found in Appendix C. Weir details can be found in the grading/drainage design drawings. Inspections of the pond and outlet structure will be conducted by the owner on an annual basis as well as after large storm events. If deficiencies are identified or if maintenance is required, maintenance of the outlet structure will be performed by the owner of the property in an effort to return the structure to its original level of functionality. Maintenance may involve cleaning of sediment and debris from the facility. maintaining vegetation growth around the structure. and performing any additional maintenance required. iTh?s, IC Lloyd Sisson Substation Drainage Report 5-1 6.0 References NOAA Atlas 14, Volume 8, Precipitation -Frequency Atlas of the United States. U.S. Department of Commerce. 2013. United States Department of Agriculture Natural Resources Conservation Service. Web Soil Survey Urban Drainage and Flood Control District. Detention Basin Design Workbook. Version 3.07, February 2017. Urban Drainage and Flood Control District. Urban Storm Drainage Criteria Manual, Volume 1-3, June 2001. Weld County Engineering and Construction Guidelines. April 2012. Updated July 2017 6-1 Lloyd Sisson Substation Drainage Report Appendix A Site Maps & Design Drawings ,J Lloyd Sisson Substation Drainage Report Summary Runoff Tables basing Dean ►onl Eonulbuluy NN Runoff Peak 10.yas tent Runoff Peak 100 -yeas Lawns lens) loh) 4th) 1 /.N 1.24 LO7 noised Onipv Pont Corolitbuting Ants RTRTaff Peak 10 Mal twat Runoff PM 100year Event Ours) KM (ch) I P.N 0.0 5.7) 5.17 1 2J1 _ 12.55 PROPOSLO CUtvlal ou0004T0 wax CONTOUR POOPOSLO IRILR1tlDN?E CONTOUR PROPOSER O1o111NCE 4014,111 PROPOSED tOT ILOw ARROW A DEL. -MOAT CONSULTANTS, INC. likaufI•I•c • •LS.I ri.0 FCC...,... e (imams,. • $.n manor.. 8 i i ii o I 1' r Y i 1 i DRAINAGE BASIN DELINEATION 1 Appendix C Site Specific Physical Design Properties Lloyd Sisson Substation Drainage Report Lloyd Sisson Substation Drainage Design Existing Conditions Total Area Area Name (sfl (acres) Flow Length Width (A/L) Slope (%) Existing Site 325950 7.48 500 651.9 1 Land Cover Type Curve Number Mannings N D -Store Pervious Pasture or Range Land, Fair Condition 69 0.15 0.15 Open Graded Aggregate Topping Over Compacted Base 85 0.024 0.1 Compacted Base Material 85 0.024 0.05 Pavement/Concrete 98 0.015 0.05 Roughness Coefficient and Curve Number Analysis Existing Site Description County Roads Native Total Area (ac) Weighted Manning's 'n' Weighted Curve Number Dstore Pervious (in) Total Area lac) 0.37 711 7.48 0.144 69.79 0.15 Manning's'n' 0.024 0.15 sum Weighted An 0.0088 1.0672 1.0760 0.143803405 gri A• N 85 31.2798 69 490.9201 522.2000 69.78686915 Lloyd Sisson Substation Drainage Design Proposed Conditions Total Area Area Name (sf) (acres) Flow Length Width (AA) Slope (%) Sub Yard & Pond West East 101059.2 87120 137649.6 2.32 2.00 3.16 150 500 500 673.728 174.24 275.2992 1.2 1.00 1.00 Land Cover Type Curve Number Mannings N D -Store Pervious Pasture or Range Land, Fair Condition 69 0.15 0.15 Open Graded Aggregate Topping Over Compacted Base 85 0.024 0.1 Compacted Base Material 85 0.024 0.05 Pavement/Concrete 98 0.015 0.05 Roughness Coefficient and Curve Number Analysis Sub -Yard & Pond Description Substation Yard/Driveway Pond Area Total Area (ac) Weighted Manning's'n' Weighted Curve Number Dstore Pervious (in) Total Area lac) 1.84 0.48 2.32 0.050 88.12 0.10 Manninc's'n' 0.024 0.15 sum Weighted A_n 0.0441 0.0723 0.1164 0.050176689 cM A•CN 85 156.2314 100 48.1983 204.4298 88.11627244 West Area Description Driveway/County Roads Native Total Area (ac) Weighted Manning's 'n' Weighted Curve Number Dstore Pervious (in) Total Area lac) 0.08 1.92 2.00 0.145 69.67 0.15 Mannlna's'n' 0.024 0.15 sum Weighted Asn 0.0020 0.2874 0.2894 0.144706612 A•CN 85 7.1419 69 132.2025 139.3444 69.67217631 East Area Description Driveway/County Roads Native Total Area (ac) Weighted Manning's'n' Weighted Curve Number Dstore Pervious (in) Total Area lac) 0.33 2.83 3.16 0.137 70.68 0.15 Mannin['s'n' 0.024 0.15 sum Weighted Mn 0.0079 0.4244 0.4323 0.13680772 �N A• N 85 28.1226 69 195.2111 223.3337 70.6752101 DETENTION BASIN STAGE -STORAGE TABLE BUILDER Up -Detention, Version 3.07 (February 2017) Prgea: Lind Olron Ilueaaean Bann D: Detention Pond T I ••••••sMi •ar IOW ••e t-' ens SEWN 00111m MIX Example larlt Conlquratron (Retention Pond) Reputed Volune Calddnlon Sidtl se Type • Welshed Mee • Wdenh•d Length • WMlMod Sip • Wsonad lnpenaauenaa • Peceeepa 143..,.. Sail (heap A • Pnontapl t%3eilooc Sol Onap B • Peceeyt IAafd. pc SW Ooup CD • Dewed WOCV One Ins • town%b 14e Rend Op01 • %a Ipt Wow Oink Capin Volume (WO(.YI • Enna Ulen Rinse Wane ELM) • 27r Rnd Vilna fPt • 083n.)• Spa Pura *Lima (P1 • 1.11 n.)• 101n Rural Volume (Pt • 1.36 n.1 • 2Syr Runde VoYna (P1 • 1.67 n.) • 501. Reef Win 191 • 22...e • 10D.c Rua/ Wire (Pt • Wn.l• 5009 Rnd Won Pt • 176 n.) • hOawe 2F Da .1a, Nina • A1Vaus Se Daraa flew • +tpPaaee 104 Caner. Vibes • fpvannat• 254 Diemen VSme a acsaana. 5611 Delrtun *auntie • Appna.nra t0pge Da unlbn Volume • EDE 222 ]60 0.012 67207 0.0% —a 6 en 0.0% CO Slag►Storape Cakullabon bay I Votes ONOCV) • bn2Vain* (106ye• 2v.t1• Selma ISwe 3 Snaps Nina *Ord • Tan Cent n Ban Viler • Sid Sinew's Wens 1SV) • and Ssahepr Dap, 0601• Teal kiratkle Ninon Dupe Ot, .4 • D•en of Incur Channel Oi _) • Sip d Te,Me Chancel (S•r) • Slope d Men Ban Sees (Ss, a • Ben t. in.4o-tWd, Ranh Pt%) • Intl Suchepr Mm l.4µ1 Ssltay. Vain Lange 0.,.) Ssdnnit Vane Ndfh ,W,..) Den of ban Fka (Kw.1 Lint d San Asa (Land Width d San Fba OMa•1 • Area d Ban Flow Ai") • Vine d San Plow Noma) • Den d Mtn Bain Kwn•) • Lange of Men San 0.µ,J • Wed► d MW Ban Myra) Aiwa d Men Saw (A,...L Witty d Man San Na•d CadOded Total Saw Vans 141„1 01141 0129 0.073 0.106 0.151 0140 0.307 0306 02]0 00M 0006 0.130 0.175 0.197 0233 wen weed 3I r.d J.e O.e.na• aches 4• e••w.e•at• mated aches acre(eat inches acrNeM e c hs 4004001 Mats acmes nine :seed adne sawed mine an:wrd Ace -1W weed aS S 414.1•.1 arisen OS 1.11 127 220 2413 171 0eph Mcrenes • n• 1 S. • Swept Top of Wcropod S4 cm OpOW anyeds Wet II 000 Lee 14 10 nil DP nag On rid M,a n•: 0 Me Skin van Heel &MO VCiltit 010 147 0.022 175 0.001 1,06 11.002 14.466 17,736 0.264 6194 0145 0733 19.402 0.445 0.407 35.513 0215 130 • - I - 10695- Pod (D Olen if oan• San 10100011 11 16141 1331 DETENTION BASIN STAGE -STORAGE TABLE BUILDER UD-0etenbon, Version 1.07 (February 2017] 5 0 0O0 :x — •"4th (el awI li lei —leer no 0I Ix 4 00 0 432 038 ono G :% -a.. (.eed —VoVnw.1..411 11136 • Pad UD DMaMMndun, Saab 1DlR01; 11'.10 M1 Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (February 2017) Project: Lloyd Sisson Substation Basin ID: Detention Pond 'n'-2z euav �v MAMMAL .oa ZONE a ZONE I toNE ZONE I MO r-1 MRCSs Example Zone Configuration (Retention Pond) 1aoVwi ownce User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration 8MP) Underdrain Orifice Invert Depth =F Underdrain Orifice Diameter N/A N/A Zone 1 (WQCV) :one 2 (100 -year) Zone 3 Stage (ft) Zone Volume (ac -ft) Outlet Type 0.86 0.041 Orifice Plate 1 71 0.192 Weu&Pipe (circular) ft (distance below the filtration media surface) inches 0.233 Total Calculated Parameters for Underdrain Underdrain Orifice Area = N/A ft' Underdrain Orifice Centroid = N/A feet User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Invert of Lowest Orifice = Depth at top of Zone using Orifice Plate = Orifice Plate: Orifice Vertical Spacing = Orifice Plate: Orifice Area per Row = 0.00 2.00 6.00 0.36 ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches sq. Inches (diameter = 11/16 inch) User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Stage of Orifice Centroid (fl) Orifice Area (sq. inches) Stage of Orifice Centroid (R) Orifice Area (sq. inches) Calculated Parameters for Plate Wq Orifice Area per Row = 2.500E-03 ft' Elliptical Half -Width = Elliptical Slot Centroid = Elliptical Slot Area = N/A N/A N/A feet feet ft' Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row S (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) 0.00 0.50 1.00 1.50 0.36 0.36 0.36 0.36 Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) User Input: Vertical Orifice (Circular or Rectangular) Invert of Vertical Orifice = Depth at top of Zone using Vertical Orifice = Vertical Orifice Diameter = Not Selected Not Selected N/A N/A N/A ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches Calculated Parameters for Vertical Orifice Vertical Orifice Area = Vertical Orifice Centroid = Not Selected Not Selected N/A N/A ft2 feet User Input: Overflow Weir (oropbox) and Grate (Flat or Sloped) Overflow Weir Front Edge Height, Ho = Overflow Weir Front Edge Length = Overflow Weir Slope = Horiz. Length of Weir Sides = Overflow Grate Open Area % _ Debris Clogging %_ Zone 2 Weir Not Selected 2.00 4.00 0.00 0.00 70% 50% ft (relative to basin bottom at Stage = 0 ft) feet H.V (enter zero for flat grate) feet %, grate open area/total area User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Depth to Invert of Outlet Pipe = Circular Orifice Diameter = Zone 2 Circular Not Selected User Input: Emergency Spillway (Rectangular or Trapezoidal) Spliway Invert Stage= Spillway Crest Length = Spillway End Slopes Freeboard above Max Water Surface = ft (distance below basin bottom at Stage = 0 ft) inches ft (relative to basin bottom at Stage = 0 ft) feet H,V feet Calculated Parameters for Overflow Weir Height of Grate Upper Edge. HI = Over Flow Weir Slope Length = Grate Open Area / 100-yr Orifice Area = Overflow Grate Open Area w/o Debris = Overflow Grate Open Area w/ Debris = Zone 2 Weir Not Selected 200 0.00 0.00 0.00 feet feet should be> 4 It' ft' Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Outlet Orifice Area = Outlet Orifice Centroid = Half -Central Angle of Restrictor Plate on Pipe = Zone 2 Circular Not Selected N/A N/A Calculated Parameters for Spillway Spillway Design Flow Depth= feet Stage at Top of Freeboard = feet Basin Area at Top of Freeboard = acres ft2 feet radians Routed Hydrograph Results Design Storm Return Period One -Hour Rainfall Depth (in) Calculated Runoff Volume (acre -ft) OPTIONAL Override Runoff Volume (acre -ft) Inflow Hydrograph Volume (acre -ft) Predevelopment Unit Peak Flow. q (ck/aae) Predevelopment Peak Q (cfs) Peak Inflow 0 (cfs) Peak Outflow Q (cfs) Ratio Peak Outflow to Predevelopment Q Structure Contoing Flow Max Velocity through Grate I (fps) Max Velocity through Grate 2 (fps) Time to Drain 97% of Inflow Volume (rows) Time to Drain 99% of Inflow Volume (hours) Maximum Ponding Depth (R) Area at Maximum Ponding Depth (acres) Maximum Volume Stored tacre-R) WQCV EURV 2 Year 5 Year 10 Year 25 Year SO Year 100 Year 500 Year 0.53 1.07 0.83 111 1.38 1.82 2.20 2.63 3.78 0.041 0 129 0.073 0.106 0.151 0.240 0.307 0.396 0.620 0.040 0.129 0.073 0.105 0.150 0.239 0.306 0.395 0.620 0 00 0.00 0.01 0 02 0.18 0.67 0.99 1 41 2.41 0.0 0.0 0.0 0.0 0.4 1.5 2.3 3.3 5.6 0.8 2.4 1.4 1.9 2.7 4.3 5.5 7.1 11.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0 6 3.4 N/A N/A N/A 0.7 01 0.0 0.0 0.2 0.6 Plate Plate Plate Plate Plate Plate Plate Overflow Grate 1 Overflow Grate 1 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 38 77 55 68 83 107 >120 >120 >120 40 81 59 72 89 >120 >120 >120 >120 0.83 1.30 1.04 1.20 1.38 1.70 1.93 2.12 2.42 0.13 0.24 0.18 0 22 0.26 0 28 0.30 0.31 0.33 0.037 0.122 0.070 0 099 0.145 0 229 0.297 0.358 0.455 Detention Basin Outlet Structure Design JD -Detention. Version 3.07 (February 2017) 12 scan RI O J 8 4 2 1 TIME (tut( 0: 10 -SOOrR — IOoYR - AYR 2SM - Ion �SYR — n —EIMV FMK cv 0.5 • 0 0.1 10 DRAIN TIME (hr) 100 AREA Ift^2], VOLUME Ift^3] 40,000 35,000 30.000 25.000 20000 15,000 10,000 5.000 User Area (ft"2( Interpolated Area (ft"2( • Summary Area (tt"2( Volume (ft"3f - • ♦ - • Summary Volume [ft"3( Outflow (cfsl • • • • • Summary Outflow (cfsl 0 57 00 5 -A -V -D Chart Axis Override minimum hound marimum bound X-axis 1 50 3X PONDING DEPTH (ft] Lett V -Axis Right V -Axis 25.00 •S0 D 5. ti. Detention Basin Outlet Structure Design Time Interval 4.62 mm Hydropraph Constant 1.082 'Ju:fcow rydr Jggraph '. or kbuuk fLenarr- Storm Inflow Hydrographs UD-Detention, Version 3.07 (February 2017) The uses can override the calculated inflow hydrographr. horn this, workbook worth inflow IN drographs developed in a separate program SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK TIME WQCV Itfs! EURV [cis] 2 Year Icfsl 5 Year jcfsj 10 Year (cis; 25 Year [chi 50 Year (cfs! 100 Year ;cis] 500 Year jets! 0.00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.0U 0.00 coo 0.04:37 0.00 0.00 0.00 0.00 0.00 U. W 0.00 0.00 0.00 0:09:14 0.00 coo coo 0.00 0.00 0.00 0.00 0.07 0.00 0.13:52 0.04 0 11 0.06 0.09 0 13 0.20 0 25 0.32 0.49 01829 009 029 0.17 024 033 052 0.67 0.86 133 0.23.06 0.24 0 74 0.41 0.61 0 86 1.35 1.77 2.20 3.47 0:27:43 0.65 2 03 1.17 1.67 2 35 3.71 4.72 6.06 9.39 0:32:20 0.75 2.37 1.35 194 2.74 4.34 5 55 7.15 1114 036:58 0.71 2 25 1 28 1 84 2 61 4.13 5.28 6 81 10.63 0 41.35 0.64 204 1.16 1 67 2.37 3.76 4 81 6 20 9.68 0:46:12 0 56 1 81 1.03 1 48 2 10 3.34 4 28 5.52 864 0.50:49 0.48 154 0.87 1.26 1.79 2.86 3.67 4.75 7.46 0.55:26 0.42 1.35 0.76 1.10 1.57 2,50 3.21 4.15 6.50 1.00:04 0.38 1 22 0.69 099 1 42 2.26 290 3.75 5 89 1.04:41 0 30 0.99 0 56 080 1 15 1.85 238 3.08 486 1:09:18 0.24 080 0.44 0.65 093 150 193 251 397 1.13:55 0.17 0.59 0.33 0 48 0.70 1.13 1 47 1 91 3.05 1.18:32 011 0.43 0.23 034 0.50 0.83 1.08 1.41 2.2/ 1:23:10 0.09 0.32 0.17 0.26 0.37 0.61 079 1.03 1.65 1:27:47 0.07 0.25 0.14 0.20 0.29 0.48 0.61 0.80 1.28 1.32 24 0.06 0 21 011 0 17 0.24 0.39 0 51 0.66 1.05 1:37:01 0.05 018 0.10 014 0.21 0.33 0.43 0.56 0.89 1:41:38 0.05 0.16 0.09 0.13 0.18 0.29 0.38 0.49 0.78 :46:16 0.04 014 0.08 0.11 0.16 0.27 034 0.45 0.70 1.50:53 0.04 0 13 0.07 0 11 0.15 0.25 0 32 0 41 0.65 1.55:30 003 010 005 008 011 0.18 023 0.30 048 2:00.07 0.02 0.07 0.04 006 008 0.13 0.17 0.22 0.35 2:04:44 0.02 0.05 0.03 004 0.06 0.10 0.12 0.16 0.26 2:09:22 0.01 0.04 0.02 0 03 004 0.01 0.09 0.12 0.19 2:13.59 0.01 003 0.01 002 0.03 0.05 0.06 0.08 0.13 2'18-36 0.01 0.02 0.01 0.01 0.07 0.04 0.05 0.06 0.10 2:23:13 0.00 0.01 0.01 0 01 0.01 0.02 0.03 0.04 0.07 2:2750 0.00 0.01 0.00 0.01 0.01 0.02 0.02 0.03 0.04 2:3228 0.00 0.00 000 000 001 001 0.01 0.02 0.03 2:3705 0.00 000 0.00 000 000 0.00 001 0.01 0.01 2:41:42 0.00 000 0.00 000 000 0.00 000 000 000 2.46.19 000 0.00 0.00 000 0.00 000 0.00 0.00 0.00 2:50:56 0.00 0.00 0.00 0 W 0.00 0. W 0.00 000 0.00 255:34 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 3 00.11 0.00 000 000 000 0.00 0.00 000 0.00 0.00 3.04.48 coo a oo o.00 0 co 000 000 000 0.00 000 3.09:25 0.00 000 0.00 0.00 0.00 0.00 000 0.00 0.00 3 14:02 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 3:18:40 0.00 000 0.00 0.00 000 0.00 0.00 000 0.00 3.23 17 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3 27 54 0.00 000 000 0.00 0.00 0.00 0.00 0.00 0.00 3:32:31 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 3 37.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 341:46 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 3:46:23 0.00 0.00 0.00 000 0.00 000 0.00 000 0.00 3:51 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:55:37 0.00 000 000 0.00 0.00 000 000 000 0.00 4:00:14 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 4.04:52 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:09:29 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:14:06 000 000 0.00 000 0.00 0.00 0.00 0.00 0.00 4.18:4 3 0.00 000 000 000 0.00 0.00 0.00 0.00 0.00 4:23:20 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 4:2758 000 0.00 0.00 000 000 0.00 0.00 0.00 0.00 4 32 35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 4.3 7.12 0.00 0 o0 0.00 0.00 0. W 0.00 000 0. W 0.00 4:41.49 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 4:46.26 000 0.00 0.00 000 0.00 0.00 000 000 000 4.51.04 000 000 0.00 000 0.00 0.00 000 000 0.00 4 55.41 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 5:00:18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:04.55 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 5:09:32 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 14:10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 000 5 18 47 0.00 0.00 0.00 000 000 0.00 0.00 0.00 0.00 5 23.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:28:01 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 5.32.38 0.00 000 0.00 000 0.00 0.00 000 0.00 000 Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (Februar1 2011) Summary Stage -Area -Volume -Discharge Relationships The user can create a summary, S -A -V -D by entering the desired stage increments and the remainder of the table will populate automabcally The user should graphically compare the summary S -A -V -D table to the full S -A -V -D table in the chart to confirm it captures all key transition points. KMe -Stays Oe+nlotlae Stag Ie. Am Mee Istre+1 Volume , tr 31 Volume 'ec-r.' Total Ovelber ktl For best results, include the stages of all grade slope changes (e g. ISV and Floor) from the S-A.V table on Sheet 'Basin' Also include the inverts or a outlets (e.g vertical orifice) overflow grate, and spillway where applicable) Lloyd Sisson Substation Calculated by: David Schieldt Trapezoidal Broad -Crested Weir Sizing Francis Weir Equation: Q=2/3 C1 bV2g H^(3/2) Solve For b: b=Q/(2/3 C1 V2g H^(3/2) ) Variable Input Units Discharge Rate (Q) 12.7 cfs Disharge Coefficient (C1) 0.5 Weir Height (H) 0.5 ft Garvity Constant (g) 32.2 ft/s^2 Width of Weir (b) - Required 13. ft Width of Weir (b) - Provided 15.00 ft Date: 10-08-2019 Appendix D SWMM Modeling Results Lloyd Sisson Substation Drainage Report Lloyd Sisson Substation 10 -Year Event Project Description File Name Project Options Flow Units Elevation Type Hydrology Method EPA SWMM Infiltration Method Link Routing Method Enable Overflow Ponding at Nodes Skip Steady State Analysis Time Periods Analysis Options 19095 Lloyd Sisson Substation.SPF CFS Elevation EPA SWMM SCS Curve Number Kinematic Wave YES NO Start Analysis On Aug 21, 2018 00:00:00 End Analysis On Aug 25. 2018 00:00:00 Start Reporting On Aug 21, 2018 00:00:00 Antecedent Dry Days 0 days Runoff (Dry Weather) Time Step 0 01:00:00 days hh:mm:ss Runoff (Wet Weather) Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds Number of Elements Qty Rain Gages 1 Subbasins 4 Nodes 6 Junctions 4 Outfalls 1 Flow Diversions 0 Inlets 0 Storage Nodes 1 Links 8 Channels 1 Pipes 2 Pumps 0 Orifices 4 Weirs 1 Outlets 0 Pollutants 0 Land Uses 0 Rainfall Details SN Rain Gage Data Data Source Rainfall ID Source ID Type 1 Rain Gage -01 Time Series 10-YR 1 -HR Cumulative Rain Units inches State County Return Rainfall Rainfall Period Depth Distribution (years) (inches) 0.00 Lloyd Sisson Substation 10 -Year Event Subbasin Summary SN Subbasin Area Impervious Weighted Average Equivalent Impervious Pervious Total Total Total Total Peak Time of ID Area Curve Slope Width Area Area Rainfall Infiltration Runoff Runoff Runoff Concentration Number Manning's Manning's Volume Roughness Roughness (ac) (%) (%) (ft) (in) (in) (in) (ac -in) (cfs) (days hh:mm:ss) 1 East 3.16 6.00 70.70 1.0000 275.00 0.0150 0.1430 1.38 1.1710 0.16 0.52 0.57 0 00:41:06 2 Existing 7.48 10.00 69.80 1.0000 652.00 0.0150 0.1440 1.38 1.1260 0.21 1.55 2.24 0 00:40:10 3 SubYard&Ponc 2.32 52.00 88.10 1.2000 1673.00 0.0150 0.0500 1.38 0.3800 0.97 2.25 5.33 0 00:03:53 4 West 2.00 3.00 69.70 1.0000 175.00 0.0150 0 1430 1.38 1.2190 0.12 0.23 0.20 0 00:41:45 Lloyd Sisson Substation 10 -Year Event Node Summary SN Element Element ID Type 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe 5 SE Corner 6 Sisson Pond Junction Junction Junction Junction Outfall Storage Node Invert Elevation (ft) Ground/Rim (Max) Elevation Initial Surcharge Ponded Peak Max HGL Water Elevation Area Inflow Elevation Elevation Attained (ft) (ft) 5073.15 6.00 0.00 5074.00 6.00 0.00 5242.02 5246.00 0.00 5241.87 5070.00 0.00 5241.00 5242.61 5246.00 0.00 (ft) (ft2) (cis) (ft) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.08 0.00 0.08 3.02 0.00 5.33 5073.50 5074.00 5242.15 5242 00 6058.00 5244.13 Max Surcharge Depth Attained (ft) 0.00 0.00 0.00 0.00 Min Freeboard Attained Time of Peak Flooding Occurrence (ft) (days hh:mm) 1.50 1.50 3.85 0.87 0 00:00 0 00:00 0 00:00 0 00:00 Total Total Time Flooded Flooded Volume (ac -in) (min) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Uoyd Sisson Substation 10 -Year Event Link Summary SN Element Element From ID Type gnIet) Node To (Outlet) Node 1 Link -02 Pipe OulieFPipe SE Comer 2 OutletPipe Pipe OutietBoxlnvOut OutletPipe 3 N.ChannelControlling Channel 4 Orifice -01 Orifice 5 Orifice -02 Orifice 6 Orifice -03 Orifice 7 Orifice -04 Orifice 6 Weir -01 War N.ChanStart SissonPond SissonPond SissonPond SissonPond SissonPond N.ChanEnd OutletBoxl nvOut OutietBoxlnvOut OutletBoxlnvOut OutletBo%InvOut OutletBox I nvOut Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported Invert Invert Slope He Roughness Flow Capacity Design Flow Vekodity Depth Depth, Surcharged Condition Elevation Elevation Ratio Total Depth Ratio (ft) (It) ft� (%) 1287.35 5067.89 6058.00 -76.9100 30.00 5242.02 524187 0.5000 100.00 5074.00 5073.50 0.5000 5242.61 5242.02 5242.61 5242.02 5242.61 5242.02 5242.61 5242.02 5242.61 5242.02 in) 0.000 12.000 18.000 0.750 0.750 0.750 1.375 (cs) 0 0150 0.08 0.0150 0.08 0.0320 0.00 0.02 0.02 0.01 0.03 0.00 cfs) 0.00 2.18 23.91 0.00 0.04 0.00 (ft/sec) (ft) 0.00 1.31 0.00 0.00 0.13 0.00 0.00 0.13 0.00 (in) 0.00 0.00 Calculated 0.00 Lloyd Sisson Substation 10 -Year Event Subbasin Hydrology Subbasin : East Input Data Area (ac) 3.16 Impervious Area (%) 6.00 Weighted Curve Number 70.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 275.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 3.16 - 70.70 Composite Area & Weighted CN 3_16 70.70 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1 1710 Total Runoff (in) 0.16 Peak Runoff (ds) 0.57 Weighted Curve Number 70.70 Time of Concentration (days hh:mm:ss) 0 00:41:06 Lloyd Sisson Substation 10 -Year Event Subbasin : East Rainfall Intensity Graph Rainfall On/hr) 3 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 17 1.6 15 14 13 1.2 1.1 1 0.9 0.8 07 0.6 0.5 0.4 0.3 0.2 0.1 0.62 0.6 0.58 056 0.54 0.52 0.5 0.48 0.46 0 44 0.42 0.4 0.38 0.36 034 0.32 0 0.3 c ' 028 CY 0.26 024 0.22 02 0.18 0.16 0.14 0 12 0.1 008 0.06 0.04 0.02 5 10 15 40 45 50 55 Time (hrs) Runoff Hydrograph 65 70 75 80 0 5 10 15 20 25 30 35 40 45 50 55 Time (hrs) 65 70 75 80 85 90 Lloyd Sisson Substation 10 -Year Event Subbasin : Existing Input Data Area (ac) 7.48 Impervious Area (%) 10.00 Weighted Curve Number 69 80 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 652.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1440 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 7.48 - 69.80 Composite Area & Weighted CN 7.48 69.80 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.1260 Total Runoff (in) 0.21 Peak Runoff (cfs) 2.24 Weighted Curve Number 69.80 Time of Concentration (days hh:mm:ss) 0 00:40:10 Lloyd Sisson Substation 10 -Year Event Subbasin : Existing Rainfall Intensity Graph 3.1 3 2.9 2.8 2.7 26 2.5 2.4 2.3 2.2 21 2 1.9 18 17 16 15 14 13 12 11 1 0.9 0.8 07 0.6 0.5 04 03 0.2 0.1 2.4 23 2.2 2.1 2 19 18 17 16. 1.5 14 u 13 12- 1 C 11 1 09 08 0.7 06 05 04 03 02 01 5 10 15 40 45 50 55 Time (hrs) Runoff Hydrograph 70 75 80 85 90 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) 65 70 75 80 85 90 95 Lloyd Sisson Substation 10 -Year Event Subbasin : SubYard&Pond Input Data Area (ac) 2.32 Impervious Area (%) 52.00 Weighted Curve Number 88.10 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.2000 Equivalent Width (ft) 1673.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.0500 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 2.32 - 88.10 Composite Area & Weighted CN 2.32 88.10 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 0.3800 Total Runoff (in) 0.97 Peak Runoff (cfs) 5.33 Weighted Curve Number 88.10 Time of Concentration (days hh:mm:ss) 0 00:03:53 Lloyd Sisson Substation 10 -Year Event Subbasin : SubYard&Pond Rainfall Intensity Graph 3.1 3 2.9 2.8 2.7 26 2.5 2.4 2.3 2.2 2.1 2 1.9 18 1.7 1.6 1.5 14 13 12 11 1 09 0.8 07 0.6 0.5 0.4 0.3 0.2 01 54 52 5 48 46 44 4.2 4 38 3.6 3.4 3.2 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 5 10 15 20 25 30 45 50 Time (hrs) Runoff Hydrograph 70 75 t 0 5 10 15 25 30 35 40 45 50 55 Time (hrs) 70 75 80 85 90 Lloyd Sisson Substation 10 -Year Event Subbasin : West Input Data Area (ac) 2.00 Impervious Area (%) 3.00 Weighted Curve Number 69.70 Conductivity (in/hr) 0.1500 Drying Time (days) TOO Average Slope (%) 1.0000 Equivalent Width (ft) 175.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 2.00 - 69.70 Composite Area & Weighted CN 2.00 69.70 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.2190 Total Runoff (in) 0.12 Peak Runoff (cfs) 0.20 Weighted Curve Number 69.70 Time of Concentration (days hh:mm:ss) 0 00:41:45 Lloyd Sisson Substation 10 -Year Event Subbasin : West Rainfall Intensity Graph Rainfall (in/hr) 3.1 3 2.9 2.8 2.7 26 2.5 2.4 2.3 2.2 2.1 2 19 1.8 1.7 1.6 15 1.4 13 12 1.1 1 0.9 0.8 07 0.6 0.5 0.4 0.3 0.2 0.1 0.21 02 0 19 0.18 0 17 0.16 015 014 0.13 N 012 0.11 C C 01 3 Ce 0.09 008 0.07 0.06 0.05 004 0.03 0.02 0.01 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) Runoff Hydrograph 70 75 85 90 95 5 10 15 25 35 40 45 50 55 Time (hrs) 70 75 80 85 90 Lloyd Sisson Substation 10 -Year Event Junction Input SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum Elevation (Max) (Max) Water Water Elevation Depth Area Pipe Elevation Offset Elevation Depth Cover (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft') (in) 5073.15 5074.00 5242.02 5241 87 6.00 6.00 5246.00 5070.00 -5067.15 -5068.00 3.98 -171.87 0.00 -5073.15 0.00 -5074.00 0.00 -5242.02 0.00 -5241.87 0.00 0.00 0.00 0.00 -6.00 -6.00 -5246.00 -5070.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Junction Results SN Element Peak ID Inflow 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe (cfs) 0.00 0.00 0.08 0.08 Peak Lateral Inflow Max HGL Elevation Attained (cfs) (ft) 0.00 5073.50 0.00 5074.00 0.00 5242.15 0.00 5242.00 Max HGL Max Depth Surcharge Attained Depth Attained (ft) (ft) 0.35 0.00 0.13 0.13 0.00 0.00 0.00 0.00 Min Average HGL Freeboard Elevation Attained Attained (ft) 1.50 1.50 3.85 0.87 (It) 5073.50 5074.00 5242.08 5241.93 Average HGL Time of Time of Total Total Time Depth Max HGL Peak Flooded Flooded Attained Occurrence Flooding Volume Occurrence (ft) (days hh:mm) (days hh:mm) (ac -in) (min) 0.35 0.00 0.06 0.06 0 00:00 0 00:00 0 01:13 0 01:13 0 00:00 0 00:00 0 00:00 0 00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Channel Input SN Element ID Length Inlet Inlet Outlet Outlet Total Average Shape Height Width Manning's Entrance Exit/Bend Additional Initial Flap Invert Invert Invert Invert Drop Slope Roughness Losses Losses Losses Flow Gate Elevation Offset Elevation Offset (ft) (ft) (ft) (ft) (ft) (ft) (%) (f) (ft) (cfs) 1 N.ChannelControlling 100.00 5074.00 0.00 5073.50 0.35 0.50 0.5000 Triangular 1.500 12.000 0.0320 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 10 -Year Event Channel Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 N.ChannelControlling 0.00 0 00:00 23.91 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Pipe Input SN Element Length Inlet Inlet ID Invert Invert Elevation Offset (ft) (ft) (ft) Outlet Invert Elevation (ft) Outlet Total Average Pipe Invert Drop Slope Shape Offset (ft) (ft) (%) 1 Link -02 1287.35 5067 89 -173.98 6058.00 817.00 -990.11 -76.9100 Dummy 2 OutletPipe 30.00 5242.02 0.00 5241.87 0.00 0.15 0.5000 CIRCULAR Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Diameter or Width Roughness Losses Losses Losses Flow Gate Height (in) (in) (cfs) 0.000 0.000 0.0150 0.5000 0.5000 0.0000 0.00 No 12.000 12.000 0.0150 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 10 -Year Event Pipe Results SN Element Peak Time of Design Flow Peak Flow! Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth (cfs) (days hh:mm) (cfs) Ratio (ft/sec) (min) (ft) (min) 1 Link -02 0.08 0 01:13 2 OutletPipe 0.08 0 01:13 0.00 2.18 0.00 0.04 0.00 0.00 0.00 0.00 1.31 0.38 0.13 0.13 0.00 Calculated Lloyd Sisson Substation 10 -Year Event Storage Nodes Storage Node : SissonPond Input Data Invert Elevation (ft) 5242.61 Max (Rim) Elevation (ft) 5246.00 Max (Rim) Offset (ft) 3.39 Initial Water Elevation (ft) 0.00 Initial Water Depth (ft) -5242.61 Ponded Area (ft') 0.00 Evaporation Loss 0.00 Storage Area Volume Curves Storage Curve Lloyd Sisson Pond Stage Storage Storage Area Volume (ft) (ft') (ft') 0 0 0.000 0.39 947 184.67 1.39 11502 6409.17 2.39 14485 19402.67 3.39 17736 35513.17 Lloyd Sisson Substation 10 -Year Event 0 3.4 3.3 - 3.2 3.1 - 3 2.9 2.8 2.7 2.6 - 2.5 - 2.4 - 2.3 - 2.2 2.1 - Co N 1.6 1.5 1.4 1.3 1.2 r 1.1 1 0.9 0.8 0.7 - 0.6 0.5 0.4 0.3 0.2 0.1 0 Storage Area Volume Curves Storage Volume (ft) 5,000 10.000 15.000 20.000 a r • r r • • ; r r 25.000 4 J. • 30.000 r • f " 35.000 0 2.000 4,000 6,000 8,000 10,000 12.000 1.1.000 16.000 Storage Area (ft ) Storage Area — Storage Volume I 3.4 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Lloyd Sisson Substation 10 -Year Event Storage Node : SissonPond (continued) Outflow Weirs SN Element Weir ID Type Flap Gate Crest Elevation (ft) Crest Length Offset (ft) (ft) Weir Total Discharge Height Coefficient (ft) Outflow Orifices 1 Weir -01 Rectangular No SN Element Orifice ID Type 1 Orifice -01 Side 2 Orifice -02 Side 3 Orifice -03 Side 4 Orifice -04 Side Output Summary Results 5244.94 Orifice Flap Shape Gate CIRCULAR No CIRCULAR No CIRCULAR No CIRCULAR No Peak Inflow (cfs) 5.33 Peak Lateral Inflow (ds) 5.33 Peak Outflow (ds) 0.08 Peak Exfiltration Flow Rate (cfm) 0.00 Max HGL Elevation Attained (ft) 5244.13 Max HGL Depth Attained (ft) 1.52 Average HGL Elevation Attained (ft) 5243.20 Average HGL Depth Attained (ft) 0.59 Time of Max HGL Occurrence (days hh:mm) 0 01:13 Total Exfiltration Volume (1000-ft3) 0.000 Total Flooded Volume (ac -in) 0 Total Time Flooded (min) 0 Total Retention Time (sec) 0.00 Orifice Diameter (in) 0.75 0.75 0.75 1.38 2.33 4.00 Circular Rectangular Orifice Height (in) 1.00 3.33 Rectangular Orifice Width (in) Orifice Orifice Invert Coefficient Elevation (ft) 5242.28 5242.78 5243.28 5243.78 0.61 0.61 0.61 0.61 Lloyd Sisson 10 -Year Pond Draindown Curve (— DYipin 100, - SuaunPon01190i4 uuytl &aeon Substation 7014.1 D•06 11 06 28i) 1,60 1.25 Ix 6 0.75 0.60 0.25 OX I 0 10 20 30 40 50 Time (his) 60 70 60 YO Lloyd Sisson Substation 100 -Year Event Project Description File Name Project Options Flow Units Elevation Type Hydrology Method EPA SWMM Infiltration Method Link Routing Method Enable Overflow Ponding at Nodes Skip Steady State Analysis Time Periods Analysis Options 19095 Lloyd Sisson Substation.SPF CFS Elevation EPA SWMM SCS Curve Number Kinematic Wave YES NO Start Analysis On Aug 21. 2018 00:00:00 End Analysis On Aug 25, 2018 00:00:00 Start Reporting On Aug 21. 2018 00:00:00 Antecedent Dry Days 0 days Runoff (Dry Weather) Time Step 0 01:00:00 days hh:mm:ss Runoff (Wet Weather) Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds Number of Elements Qty Rain Gages 1 Subbasins 4 Nodes 6 Junctions 4 Outfalls .1 Flow Diversions 0 Inlets 0 Storage Nodes 1 Links 8 Channels 1 Pipes 2 Pumps 0 Orifices 4 Weirs 1 Outlets 0 Pollutants 0 Land Uses 0 Rainfall Details SN Rain Gage Data Data Source Rainfall ID Source ID Type Rain State County Return Rainfall Rainfall Units Period Depth Distribution (years) (inches) 1 Rain Gage -01 Time Series 100-YR 1 -HR Cumulative inches 0.00 Lloyd Sisson Substation 100 -Year Event Subbasin Summary SN Subbasin ID Area Impervious Area (ac) 1 East 3.16 2 Existing 7.48 3 SubYard&Pont 2.32 4 West 2.00 (%) 6.00 10.00 52.00 3.00 Weighted Average Equivalent Impervious Curve Slope Width Area Number Manning's Roughness (%) 70.70 1.0000 69.80 1.0000 88.10 1.2000 69.70 1.0000 (ft) 275.00 652.00 1673.00 175.00 0.0150 0.0150 0.0150 0.0150 Pervious Total Total Total Total Peak Area Rainfall Infiltration Runoff Runoff Runoff Manning's Volume Roughness 0.1430 0.1440 0.0500 0.1430 Time of Concentration (in) (in) (in) (ac -in) (cfs) (days hh:mm:ss) 2.82 2.82 2.82 2.82 1.8510 1.7960 0.4910 1.9440 0.92 0.98 2.30 0.82 2.91 7.30 5.33 1.65 3.15 8.07 12.68 1.82 0 00:30:52 0 00:30:10 0 00:02:55 0 00:31:21 Lloyd Sisson Substation 100 -Year Event Node Summary SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OuttetBoxlnvOut 4 OutletPipe 5 SE Corner 6 SissonPond Element Type Junction Junction Junction Junction Outfall Storage Node Invert Elevation (ft) Ground/Rim (Max) Elevation Initial Surcharge Ponded Peak Max HGL Water Elevation Area Inflow Elevation Elevation Attained (ft) (ft) 5073.15 6.00 0.00 5074.00 6.00 0.00 5242.02 5246.00 0.00 5241.87 5070.00 0.00 5241.00 5242.61 5246.00 0.00 (ft) (ft') (cfs) (ft) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.20 13.02 0.00 12.68 5073.50 5074.00 5242.23 5242.08 6058.00 5244.97 Max Surcharge Depth Attained (ft) 0.00 0.00 0.00 0.00 Min Freeboard Attained Time of Peak Flooding Occurrence (ft) (days hh:mm) 1.50 1.50 3.77 0.79 0 00:00 0 00:00 0 00:00 0 00:00 Total Total Time Flooded Flooded Volume (ac -in) (min) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Link Summary SN Element D Element From Type (Intel) Node To (Outlet) Node 1 Link -02 Pipe OutietPipe SE Comer 2 OutletFlpe Pipe OutielBmdnvOut OutietPipe 3 N.ChannelControlling Channel N.ChanStart N.ChanEnd 4 Orifice -01 5 Orifice -02 6 Onfice-03 7 Oniice04 8 Vtteir-01 Orifice SissonPond Orifice SissonPond Orifice SissonPond Orifice SissonPond Weir SissonPond OutletBoxinvOut OutletBoxlnvOut OudetBoxinvOut OutletBozlnvOut OutletBoxlnvOut Length Inlet Outlet Invert Invert Elevation Elevation Average Diameter or Manning's Peak Design Flow Peak Flaw! Peak Flow Peak Flow Peak Flow Total Time Reported Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition Ratio Total Depth Ratio ft) 'ft) ,ft) (°%) 1287.35 5067.89 6058.00 30.00 5242.02 5241.87 100.00 5074.00 5073.50 5242.61 5242.02 5242.61 5242.02 5242.61 5242.02 524261 5242.02 5242.61 5242.02 -76.9100 0.5000 0.5000 fn 0.000 12.000 18.000 0.750 0.750 0.750 1.375 (cis) (cis) 0.0150 0.20 0.0150 0.20 0.0320 0.00 0.02 0.02 0.02 0.05 0.09 0.00 2.18 23.91 (11/seci (ftl 0.00 0.00 0.09 1.74 0.00 0.00 0.00 0.21 0.00 0.00 0.21 0.00 On) 0.00 0.00 Calculated 0.00 Lloyd Sisson Substation 100 -Year Event Subbasin Hydrology Subbasin : East Input Data Area (ac) 3.16 Impervious Area (%) 6.00 Weighted Curve Number 70.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 275.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 3 16 - 70.70 Composite Area & Weighted CN 3.16 70.70 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.8510 Total Runoff (in) 0.92 Peak Runoff (cfs) 3.15 Weighted Curve Number 70.70 Time of Concentration (days hh:mm:ss) 0 00:30:52 Lloyd Sisson Substation 100 -Year Event Subbasin : East Rainfall Intensity Graph 6.2 6 5.8 5.6 5.4 52 5 48 4.6 4.4 42 4 3.8 36 34 3.2 3 2.8 26 24 2.2 2 18 16 14 1.2 1 0.8 06 0.4 02 34 32 3 2.8 2.6 24 2.2 2 18 1.6 14 12 0.8 0.6 04- 02 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) Runoff Hydrograph 70 75 80 85 90 95 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) 70 75 80 85 90 95 Lloyd Sisson Substation 100 -Year Event Subbasin : Existing Input Data Area (ac) 7.48 Impervious Area (%) 10.00 Weighted Curve Number 69.80 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 652.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness .0.1440 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (aces) Group Number 7.48 - 69.80 Composite Area & Weighted CN 7.48 69.80 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.7960 Total Runoff (in) 0.98 Peak Runoff (cfs) 8.07 Weighted Curve Number 69.80 Time of Concentration (days hh:mm:ss) 0 00:30:10 Lloyd Sisson Substation 100 -Year Event Subbasin : Existing Rainfall Intensity .9ph 7 6.5 6 55 5 4.5 t c m 35 3 25 2 1.5 0.5 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 3.5 3 l 5 15 1 05 5 10 15 20 25 60 70 75 0 5 10 15 25 40 45 50 55 Time (hrs) Runoff Hydrograph 35 40 45 50 55 Time (hrs) 65 70 75 80 85 90 95 Lloyd Sisson Substation 100 -Year Event Subbasin : SubYard&Pond Input Data Area (ac) 2.32 Impervious Area (%) 52.00 Weighted Curve Number 88.10 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.2000 Equivalent Width (ft) 1673.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.0500 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 2.32 88 10 Composite Area & Weighted CN 2.32 88.10 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 0.4910 Total Runoff (in) 2.30 Peak Runoff (cfs) 12.68 Weighted Curve Number 88.10 Time of Concentration (days hh:mm:ss) 0 00:02:55 Lloyd Sisson Substation 100 -Year Event Subbasin : SubYard&Pond Rainfall Intensity Graph 7 6.5 6 55 5 45 Rainfall (in/hr) w u zit w 0 c 0_ 35 3 2.5 2 1.5 0.5 13.5 13 12.5 12 115 11 10.5 10 95 9 8.5 8 75 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 5 10 15 5 10 15 20 25 70 75 80 85 90 95 0 35 40 45 50 Time (hrs) Runoff Hydrograph 40 45 50 55 Time (hrs) 70 75 80 85 Lloyd Sisson Substation 100 -Year Event Subbasin : West Input Data Area (ac) 2.00 Impervious Area (%) 3.00 Weighted Curve Number 69.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 175.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 2.00 - 69.70 Composite Area & Weighted CN 2.00 69.70 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.9440 Total Runoff (in) 0.82 Peak Runoff (cfs) 1.82 Weighted Curve Number 69.70 Time of Concentration (days hh:mm:ss) 0 00:31:21 Lloyd Sisson Substation 100 -Year Event Subbasin : West Rainfall Intensity Graph 7 65 6 5.5 5 4.5 2.5 "Cl w 0 c CC 2 1.5 0.5 1.9 1.8 1.7 1.6 1.5 14 13 12 11 0.9 08 0.7 06 05 0.4 0.3 0.2 0.1 5 10 15 40 45 50 Time (hrs) Runoff Hydrograph 65 70 75 5 10 15 40 45 50 55 60 65 70 75 80 85 Time (hrs) Lloyd Sisson Substation 100 -Year Event Junction Input SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Invert Ground/Rim Elevation (Max) Elevation (It) (ft) 5073.15 5074.00 5242.02 5241.87 Ground/Rim Initial (Max) Water Offset Elevation (ft) 6.00 -5067.15 6.00 -5068.00 5246.00 3.98 5070.00 -171.87 Initial Water Depth (ft) (ft) 0.00 -5073.15 0.00 -5074.00 0.00 -5242.02 0.00 -5241.87 Surcharge Surcharge Ponded Minimum Elevation Depth Area Pipe Cover (ft) (ft) (ft') (in) 0.00 -6.00 0.00 0.00 0.00 -6.00 0.00 0.00 0.00 -5246.00 0.00 0.00 0.00 -5070.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Junction Results SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Peak Peak Max HGL Max HGL Max Inflow Lateral Elevation Depth Surcharge Inflow Attained Attained Depth Attained (cfs) (cfs) (ft) (ft) (ft) 0.00 0.00 0.20 0.20 0.00 0.00 0.00 0.00 5073.50 5074.00 5242.23 5242.08 0.35 0.00 0.21 0.21 0.00 0.00 0.00 0.00 Min Freeboard Attained (ft) 1.50 1.50 3.77 0.79 Average HGL Elevation Attained (ft) 5073.50 5074.00 5242.12 5241.97 Average HGL Time of Time of Total Total Time Depth Max HGL Peak Flooded Flooded Attained Occurrence Flooding Volume Occurrence (ft) (days hh:mm) (days hh:mm) (ac -in) (min) 0.35 0.00 0.10 0.10 0 00:00 0 00:00 0 01:10 0 01:10 0 00:00 0 00:00 0 00:00 0 00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Channel Input SN Element ID Length Inlet Inlet Invert Invert Elevation Offset (ft) (ft) (ft) 1 N.ChannelControlling 100.00 5074.00 0.00 Outlet Outlet Total Average Shape Height Width Manning's Entrance Exit/Bend Additional Initial Flap Invert Invert Drop Slope Elevation Offset (ft) (ft) (ft) (%) (ft) (ft) Roughness Losses Losses Losses Flow Gate (cfs) 5073.50 0.35 0.50 0.5000 Triangular 1.500 12.000 0.0320 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 100 -Year Event Channel Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 N.ChannelControlling 0.00 0 00:00 23.91 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Pipe Input SN Element Length Inlet Inlet ID Invert Invert Elevation Offset (ft) (ft) (ft) Outlet Outlet Invert Invert Elevation Offset (ft) (ft) 1 Link -02 1287.35 5067 89 -173.98 6058.00 817.00 2 OutletPipe 30.00 5242.02 0.00 5241.87 0.00 Total Average Pipe Drop Slope Shape (ft) (%) -990.11 -76.9100 Dummy 0.15 0.5000 CIRCULAR Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Diameter or Width Roughness Losses Losses Losses Flow Gate Height (in) (in) (cfs) 0.000 0.000 0.0150 0.5000 0.5000 0.0000 0.00 No 12.000 12.000 0.0150 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 100 -Year Event Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 Link -02 0.20 0 01:10 2 OutletPipe 0.20 0 01:10 0.00 0.00 0.00 0.00 0.00 0.00 2.18 0.09 1.74 0.29 0.21 0.21 0.00 Calculated Lloyd Sisson Substation 100 -Year Event Storage Nodes Storage Node : SissonPond Input Data Invert Elevation (ft) 5242.61 Max (Rim) Elevation (ft) 5246.00 Max (Rim) Offset (ft) 3.39 Initial Water Elevation (ft) 0.00 Initial Water Depth (ft) -5242.61 Ponded Area (ftl 0.00 Evaporation Loss 0.00 Storage Area Volume Curves Storage Curve : Lloyd Sisson Pond Stage Storage Storage Area Volume (ft) (ft') (ft') 0 0 0.000 0.39 947 184.67 1.39 11502 6409.17 2.39 14485 19402.67 3.39 17736 35513.17 Lloyd Sisson Substation 100 -Year Event 0 3.4 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 gi 1.7 H 1.6 1.5 1.4 - 1.3 1.2 - 1.1 1- 0.9 -- 0.8 0.7 0.6 0.5 0.4 0.3 0.2 - 0.1 0 Storage Area Volume Curves Storage Volume (ftl 5,000 10.000 15,000 20,000 25,000 30.000 35.000 ✓ 1 L , L r 1 3.4 - -- -3.3 • L r --r -r- L L r ✓ r -r 3.2 3.1 a_ 3 2.9 2.8 2.7 - 2.6 - - 2.5 • . 2.4 - -2.3 r -1.8 r • f fn. r L1 2,0N 4,010 6,000 8.000 10,000 12,000 14,000 16,000 Storage Area (fr9 Storage Area - Storage Volume I 1.6 - 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Lloyd Sisson Substation 100 -Year Event Storage Node : SissonPond (continued) Outflow Weirs SN Element Weir Flap Crest Crest Length Weir Total Discharge ID Type Gate Elevation Offset Height Coefficient (ft) (ft) (ft) (ft) Outflow Orifices 1 Weir -01 Rectangular No 5244.94 2.33 4.00 1.00 3.33 SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient Diameter Height Width Elevation (in) (in) (in) (ft) 1 Orifice -01 Side CIRCULAR No 0.75 5242.28 0,61 2 Orifice -02 Side CIRCULAR No 0.75 5242.78 0.61 3 Orifice -03 Side CIRCULAR No 0.75 5243.28 0.61 4 Orifice -04 Side CIRCULAR No 1.38 5243.78 0.61 Output Summary Results Peak Inflow (cfs) 12.68 Peak Lateral Inflow (cfs) 12.68 Peak Outflow (cfs) 0.20 Peak Exfiltration Flow Rate (cfm) 0.00 Max HGL Elevation Attained (ft) 5244.97 Max HGL Depth Attained (ft) 2.36 Average HGL Elevation Attained (ft) 5243.82 Average HGL Depth Attained (ft) 1.21 Time of Max HGL Occurrence (days hh:mm) 0 01:10 Total Exfiltration Volume (1000 -ft') 0.000 Total Flooded Volume (ac -in) 0 Total Time Flooded (min) 0 Total Retention Time (sec) 0.00 Lloyd Sisson 100 -Year Pond Draindown Curve 25 20 S Is I, 1.0 0,6 00 _ 0 10 m 5.0 Time (his) Drainage Report Checklist Project Name: USR19-0070 Tri-state — Lloyd Sisson Substation The purpose of this checklist is to assist the applicant's Engineer with developing a drainage report that supports the intent of the Weld County Code using commonly accepted engineering practices and methodologies. Is the project in the MS4? =Yes X No If yes. the following requirements Report Content DWeld County Case Number ❑ Certificate of Compliance signed and stamped by a Colorado Licensed PE — See Comment #1 Z Description/Scope of Work ® Location (County Roads, S -T -R) Z Nearby water features and ownership Z Total acres vs. developed acres ❑ Hydrological soil types/maps Z FEMA Flood Zones ❑ Urbanizing or non -urbanizing EZ Methodologies used for report & analysis (full spectrum is not accepted) tease Design Standard used for permanent control measure design in the MS4 Z Discussion of offsite drainage routing Z Conclusion statement indicating that the design will adequately protect public health, safety, and general welfare and have no adverse impacts on public rights -of -way or offsite properties Hydrology and Hydraulic Analysis x Design Storm / Rainfall Information (NOAA Atlas or Local Data) Z Release Rate calculations — See Comment #5 Z Post construction site imperviousness ❑ Hydrologic calculations (historic & developed basins) Z Hydraulic calculations for proposed drainage improvements (swales, culverts. riprap. pond, outlet, spillway, WQCV outlet, etc.) X Detention,WQCV calculations Comments: See next page apply. See Chapter 8, Article IX of the Weld County Code. Construction Drawings Stamped by PE X Engineering scale & north arrow Property lines, rights -of -way, and easements - 1' Contours & elevations (existing & proposed) X Pre- and post -development drainage basins Z Arrows depicting flow direction Time of concentration critical path ,< Drainage design points Improvements labeled = Permanent control measure and associated drainage features labeled 'No Build/No Storage', include design volume Z Cross sections for open channels, profiles for pipes 5< Elevations for inverts, flow lines, top of grates, orifice(s), etc. Pipe specs (size, material, length, slope) K. Outlet and spillway details Maintenance Plan _ Frequency of offsite inspections El Repairs, if needed D. Cleaning of sediment and debris Vegetation maintenance 12 Manufacturer maintenance specifications, if applicable Other Required Documents (If Applicable) 11 Variance Request and documentation explain hardship, applicable code section, and proposed mitigation. Variances will not be granted for the Base Design Standard requirement in the MS4. Department of Public Works I Development Review 1111 H Street. Greeley. CO 80631 I Ph: 970-304-6496 I www.weldgov com/departments/public_works/development_review 2/28/2020 Drainage Report Checklist Del -Mont Consultants response to comments is in Green 1 Please include the Weld County Certificate of Compliance language located at: https://www.weldgov.com/UserFiles/Servers/Server 6/File/Departments/Public%20Works/DevelopmentReview/Certificate%20 of%20Compliance%2008022019. pdf Certificate of Compliance Language added to signature page (page 2) 2 Please sign and stamp the drainage report drawings. Drainage report drawings have been signed and stamped. 3. Please date PE stamps. PE Stamps have been dated 4 Please provide a section in the report on how maintenance of the pond will be addressed in the future. Add pertinent notes to the drainage exhibit for future reference. Maintenance has been addressed in the last paragraph of Section 5.2. 5. Per Appendix D. an impervious value of 10% was used to calculate the historic 1 -hour. 10 -year peak runoff for the Existing" site. Weld County defines historic as an undeveloped site with 2.0% imperviousness. Because your pond is releasing at the conservative rate of 0.20 cfs instead of the calculated rate of 0.69 cfs, and because 0.20 cfs is less than the rate calculated using a 2.0% impervious value for 2.32 acres. no revision to your report is required. For future projects in Weld County. please use 2.0% imperviousness when calculating the historic release rate for detention ponds. No changes required. Design criteria has been noted for future projects. 6. The detention pond outlet pipe must contain a minimum of two concrete cutoff walls embedded a minimum of 18 inches into undisturbed earthen soil. The cutoff walls must be a minimum of 8 inches thick. The outlet pipe bedding material must consist of native earthen soil, not granular bedding material, to at least the first downstream manhole or daylight point." Concrete cutoff walls and details have been added to the drawing set for the pond outlet pipe. 7. Once the revised design and drainage report have been submitted, the County may provide additional comments in addition to the ones listed above. Depending on the complexity of the changes made, a full 28 -day review period may be required. 8 Please provide a written response on how the above comments have been addressed when resubmitting the drainage report. Thank -you. Please see responses in Green. Department of Public Works I Development Review 1111 H Street. Greeley, CO 80631 I Ph: 970-304-6496 I www.weldgov.com/departments/public_works/development_review 2/28/2020 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Appendix B: Tri-State Position Statement on EMF Health Effects TRI-STATE GENERATION AND TRANSMISSION ASSOCIATION, INC. HEADQUARTERS: P.O. BOX 33695 DENVER. COLORADO 80233-0695 303-452-6111 POSITION STATEMENT Electric and Magnetic Fields (EMF) Electric and magnetic fields (EMF) are found wherever there is a flow of electricity. such as in the use of electric lights, appliances. computers. power lines, home wiring and any other devices that carry or use electricity. The Earth itself also creates natural EMF in varying amounts. Therefore. we are all continuously exposed to EMF as a result of living in a society that so heavily relies on the use of electricity as a source of energy. Some members of the public have raised concerns about EMF and health issues. We at Tri- State Generation and Transmission Association are aware of these concerns and we wish to express our position on EMF and our commitment to this matter. Over the past four decades, thousands of scientific studies on EMF have been conducted around the world. This very large body of research has been evaluated by leading public health organizations. such as the World Health Organization (WHO) and the U S. National Institute of Environmental Health Sciences (NIEHS). The WHO currently concludes that "despite extensive research, to date there is no evidence to conclude that exposures to low level electromagnetic fields is harmful to human health." The U.S. NIEHS reached a similar conclusion in an earlier report. finding only "weak" and "marginal" evidence that EMF from electric power could affect health. The U.S. government has not recommended the standards for public exposures to electric power EMF. The WHO has endorsed the exposure limits adopted by the International Commission on Non -Ionizing Radiation (ICNIRP) and the International Committee for Electromagnetic Safety (ICES). These limits are 2.000 mG (ICNIRP) and 9,040 mG (ICES). The EMF levels that members of the public could experience from Tri-State power lines are well below these recommended exposure limits. Tri-State recognizes its responsibility to provide wholesale electric service at the lowest possible cost in a manner that is safe, reliable and environmentally sound. This responsibility includes designing and locating our facilities in accordance with the National Electric Safety Code and applicable federal. state and local regulations. In addition. even though electric power EMF have not been shown to cause adverse health effects, we will continue where reasonable and practicable to design and operate new facilities in a way that will lower EMF from those facilities. Tri-State continues to support credible scientific research on EMF as a sponsor of the EMF research program of the Electric Power Research Institute. We will continue to monitor the results of these and other scientific studies, will provide information about EMF issues to our member systems, our employees and our electric consumers and will respond promptly to inquiries. 11/2019 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application This page intentionally left blank. Appendix C Site Specific Physical Design Properties L1i\AC Lloyd Sisson Substation Drainage Report Lloyd Sisson Substation Drainage Design Existing Conditions Total Area Area Name (se (acres) Flow Length Width (A/L) Slope (%) Existing Site 325950 7.48 500 651.9 1 Land Cover Type Curve Number Mannings N D -Store Pervious Pasture or Range Land, Fair Condition 69 0.15 0-15 Open Graded Aggregate Topping Over Compacted Base 85 0.024 0.1 Compacted Base Material 85 0.024 0.05 Pavement/Concrete 98 0.015 0.05 Roughness Coefficient and Curve Number Analysis Existing Site Description County Roads Native Total Area (ac) Weighted Manning's 'n' Weighted Curve Number Dstore Pervious (in) Total Area (ac) 0.37 7.11 7.48 0.144 69.79 0.15 Mannina's 'n' 0.024 0.15 sum Weighted A'n 0.0088 1.0672 1.0760 0.143803405 A'CN 85 31.2798 69 490.9201 522.2000 69.78686915 Lloyd Sisson Substation Drainage Design Proposed Conditions Total Area Area Name (sf) (acres) Flow Length Width (A/t) Slope (%) Sub Yard & Pond West East 13754E, 6 232 3.5 150 500 673.728 174.24 275.2992 1.2 1.00 1.00 Land Cover Type Curve Number Mannings N D -Store Pervious Pasture or Range Land, Fair Condition 69 0.15 0.15 Open Graded Aggregate Topping Over Compacted Base 85 0.024 0.1 Compacted Base Material 85 0.024 0.05 Pavement/Concrete 98 0.015 0 05 Roughness Coefficient and Curve Number Analysis Sub -Yard & Pond Description Substation Yard/Driveway Pond Area Total Area (ac) Weighted Manning's'n' Weighted Curve Number Dstore Pervious (in) Total Area (ac) 84 2.32 0.050 88.12 0.10 Manning's 'n' 0.024 0.15 sum Weighted A•n 0.0441 0.0723 0.1164 0.050176689 A• N 85 156.2314 100 48.1983 204.4298 88.11627244 West Area Description Driveway/County Roads Native Total Area (ac) Weighted Manning's'n' Weighted Curve Number Dstore Pervious (in) Total Area lac) 0.08 1.92 2.00 0.145 69.67 0.15 Manning's'n' 0.024 0.15 sum Weighted Mn 0.0020 0.2874 0.2894 0.144706612 �N A'CN 85 7.1419 69 132.2025 139.3444 69.67217631 East Area Description Driveway/County Roads Native Total Area (ac) Weighted Manning's'n' Weighted Curve Number Dstore Pervious (in) Total Area (ac) 0.33 2.83 3.16 0.137 70.68 0.15 Manning's 'n' 0.024 0.15 sum Weighted Mn 0.0079 0.4244 0.4323 0.13680772 CN 85 69 A•CN 28.1226 195.2111 223.3337 70.6752101 DETENTION BASIN STAGE -STORAGE TABLE BUILDER UD-0etenDon, Version 3.07 (February 2017) Pt*ct: Lloyd Polo' Lrasaa+ Barn D: Daerdbn Pond -• .w11 t.� T mare a••1 KM IWO D' r•°' Example Zone Configuration (Retention Pond) Required Voting Calculation Sod Bhp Toe• WanMd Area • Wrtnnid Le r • Manned sop. • Wels.hd Inp.rnannae • Prong. tydraopc Sod Group A - Po on ae Nppopc Sol Group B • Peon,. Ipdppc Sol Ormp G1) • Dead WOCV Oran Trio • lac Mon b 14s Rased Dopr • 12sr lops E08 2-12 360 QOt2 5730% 0.0'' 100.0% OD% SO 'UM n pace+ tercet percent peuat note salsa Dar Can Voters (VilOCV) • OOat sweat Eacsa ULar Road Vann (ELR14 • 0.129 acaeter 2yr Rud Kline (Pt • 0.53 n.) • 0.073 acreage! Syr Roca Volume (P1 • 1.11 h) • 0.106 ne s lays Rurd Valens (P1 • I.36 0.) • 0.151 acre4ar 2S, Rind Klnr 4P/ • 132 n.) • 0.240 pair SOY Rhaw 'Elsie Pi • 2.2 n.1 • (1107 reeler 100yr Rod K/nr 97 • 2D al • 0-366 actress SODA Rud Klnr (P1 • 3.79 n.) • 4820 acr•.I.s apnea 2yr DSMcn Vdum. • QOM acrelr arpraanise Syr DdaMon Volume • 0.006 morale,' appraansr toys DSeraon Volume • 0.130 ulcr.aeea Appro.:NM 2Syr Draa,n Velure • 0. 17S /nem aeammaa. SOM De'sate Verses OM dacreae.r appra.nra 103m Cel an Keene • 0233 Ana Staae3toraae Calculation 2aa I Vita (VaDC91 • 0,041 acs►ear 3rsrata (i00y..t-lane I)• 0192 acet.r Selma loe 3 Stage Vans s (QlaaiaO Total Drabs Saw Volum • Pad Saar laaa•i. paV1- 9x11 Ssdhage De. pia)' Tad Arabia Dasami Oat 01. al • Deph d Trade Chanel (M:) • Sao 41 Thais Chad (Sr). w ft Slpsd lam Ban Sala R...)• lies MV Sass Lnl/i-t- Rao 01. %I • Aid Surcharge Ares (4 ,0 Sweeps Kin 1.' (t•n) • SV Wrge Va4hr Width (VV") • Dope d Sean Flow Awn.) Lenin d Bon Flow 0.. an) • PAM d Ban Roar (Wti,X) • Ana d San Roar {kw.) • Kin.. d Ban Fkor M,aw) Da d era flan n P6.,.1 • tsgh d Mon Bean l:-I.rv) • WI01. of ion Ban (W.wvl • a.a of Mtn Bas. tk.,.vl • Van d span Been. C lculoa • Tad Ban v.l..r. (Yin) a.a.r Liter C%e•er •J' Ae.parcn nchea mien naps num . char Woo n orm 033 1.11 1.36 to 2.70 233 3.76 Depth Mcrae • 03 B Slap • Masao Defcrybn Malin 0n Opr nd Owens Siam col to Kwh 011 Are (Ira Cvorntle Arran ha Kin Top of Mlcrcpod 000 0 0.000 0.36 917 0022 175 0.004 13/ 11$03 Q:lf 6294 0146 0.445 0315 2.30 311 to sM 17/36 tun 0.407 19.402 36.513 190115 - Pond lD Odanaan.dam. San 109120/1.. 11 15 AM DETENTION BASIN STAGE -STORAGE TABLE BUILDER UO-Oetenoon, Version 3.07 (February 20171 100 tau 0 )o) I 3: :SLIP On atitw i4l .-4-Noc.- RI —an. 6441 130 400 1 CO 100 snrr nil 100 — an. ipal —Vo1.Iwlaa itl OAP 06u I 0410 0 YE Dom 400 swami 11:16 NA I Detention Basin Outlet Structure Design O UD-Detention, Version 3.07 (February 2017) Project: Lloyd Sisson Substation Basin ID: Detention Pond = woof tare s a zaai tan[ I MO Y IO -V[M Dili u an.rcas Example Zone Configuration (Retention Pond) User Input: Orifice at Underdraln Outlet (typically used to drain WQCV in a Filtration BMP) Underdrain Orifice Invert Depth = Underdrain Orifice Diameter = N/A N/A Zone 1(WQM Ione 2 (100 -year) Zone 3 Stage (ft) Zone Volume (ac -ft) Outlet Type 0.86 0.041 Onfice Plate 1.71 0.192 Weir&Pipe (Circular) ft (distance below the filtration media surface) inches 0.233 Total Calculated Parameters for Underdrain Underdrain Orifice Area = N/A ft: Underdrain Orifice Centroid = N/A feet User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV In a sedimentation BMP) Invert of Lowest Orifice = Depth at top of Zone using Orifice Plate a Orifice Plate: Orifice Vertical Spacing = Orifice Plate: Orifice Area per Row = 0.00 2.00 6.00 0.36 ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches sq. Inches (diameter = 11/16 inch) User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Stage of Orifice Centroid (R) Orifice Area isq- riches) Stage of Orifice Centroid (R) Orifice Area (sq. inches) Calculated Parameters for Plate WQ Orifice Area per Row = Elliptical Half -Width = Elliptical Slot Centroid = Elliptical Slot Area = 2.500E-03 N/A N/A N/A ft' feet feet ft' Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) 0.00 0.50 1.00 1.50 0.36 D.36 0.36 0.36 Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) User Input: Vertical Orifice (Circular or Rectangular) Invert of Vertical Orifice = Depth at top of Zone using Vertical Onfice = Vertical Orifice Diameter = Not Selected Not Selected N/A N/A N/A ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches Calculated Parameters for Vertical Orifice Vertical Orifice Area = Vertical Orifice Centroid = Not Selected Not Selected N/A N/A ft' feet User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Overflow Weir Front Edge Height. Ho = Overflow Weir Front Edge Length = Overflow Weir Slope = Horiz. Length of Weir Sides = Overflow Grate Open Area % Debris Clogging % = Zone 2 Weir Not Selected 2.00 4.00 0.00 0.00 70% 50% ft (relative to basin bottom at Stage = Oft) feet H:V (enter zero for flat grate) feet %, grate open area/total area User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Depth to Invert of Outlet Pipe = Circular Orifice Diameter = Zone 2 Circular Not Selected User Input: Emergency Spillway (Rectangular or Trapezoidal) Spillway Invert Stage= Spillway Crest Length = Spillway End Slopes = Freeboard above Max Water Surface = ft Idsstance below basin bottom at Stage = 0 h 1 inches ft (relative to basin bottom at Stage = 0 ft) feet H:V feet Calculated Parameters for Overflow Weir Height of Grate Upper Edge. H, _ Over Flow Weir Slope Length = Grate Open Area / 100-yr Orifice Area = Overflow Grate Open Area w/o Debris = Overflow Grate Open Area w/ Debris = Zone 2 Weir Not Selected 2.00 0.00 0.00 0.00 eet eet ,hound be ≥ 4 Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Outlet Orifice Area = Outlet Orifice Centroid = Half -Central Angle of Restrictor Plate on Pipe = Zone 2 Circular Not Selected N/A N/A Calculated Parameters for Spillway Spillway Design Flow Depth= feet Stage at Top of Freeboard = feet Basin Area at Top of Freeboard = acres ft' feet radians Routed Hydrograph Results Design Storm Return Period = One -Hour Rental Depth (in) _ Calculated Runoff Volume (ace -ft) OPTIONAL Override Runoff Volume (we -ft) _ Inflow Hydrograph Volume (ace -A) Redevelopment Unit Peak Flow. q (cfs/acre) _ Redevelopment Peak 0 (cfs) _ Peak Inflow 0 (cfs) Peak Outflow 0 fcis) a Ratio Peak Outflow to Redevelopment 0 Structure Cantolltng Flow = Max Velocity through Grate I (fps) Max Velocity through Grate 2 (bps) Time to Drain 97% of Inflow Volume (hours) _ Time to Drain 99% of Inflow Volume (hour) _ Maximum Ponding Depth (It) _ Area at Maximum Ponding Depth (acres) _ Maximum Volume Stored (ace -ft) WQCV EURV 2 Year S Year 10 Year 25 Year 50 Year 100 Year S00 Year 0.53 1.07 0.83 1.11 1.38 1.82 2.20 2.63 3.78 0.041 0.129 0.073 0.106 0.151 0.240 0.307 0.396 0.620 0.040 0.129 0.073 0.105 0.150 0.239 0.306 0.395 0.620 0.00 0.00 0.01 0.02 0,18 0 67 0.99 1.41 2.41 0.0 00 0.0 0.0 0.4 1.5 2.3 3.3 5.6 0.8 2.4 1.4 1.9 2.7 4.3 5.5 7.1 11.1 0.0 0.0 0.0 0.0 0.0 00 0.1 0.6 3.4 N/A N/A N/A 0.7 0.1 0.0 0.0 0 2 0.6 Plate Plate Plate Plate Plate Plate Plate Overflow Grate 1 Overflow Grate 1 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 38 77 55 68 83 107 >120 >120 >120 40 81 59 72 89 >120 >120 >120 >120 0.83 1.30 1.04 1.20 1.38 1.70 1.93 2.12 2.42 0.13 0.24 0.18 0.22 0.26 0 28 0.30 0.31 0.33 0.037 0.122 0.070 0 099 0 145 0 229 0.297 0 358 0.455 Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (februarit2017] 12 3 0 J W 8 0 0: SOOv* IN SOOcf ouT IOOIR IN - — 100nn OOT - son w SOIR OUT nfR N — _ nYR OUT - ion pi _-- 10nn UU1 SYRN STIR OUT - rat IN EWNN - EURV OUT WPC,/ N WOCV OUT 1 TRME DirJ 10 3 X p. n w o • c O 2 2 0 a. 0.5 1 10 0; DRAIN TIME [hr) 100 AREA (k^2L VOLUME (h^3) 40,000 35,000 30.000 25,000 20,000 15,000 I0.000 5.000 User Area (ftn2) interpolated Area [ft^2J ✓ Summary Area [ft^2] Volume [f1"3) Summary Volume )ft^3) Outflow ids] Summary Outflow [Cu)s 2.00 PONDING DEPTH [ft) S -A -V D Chart Axis Override minimum bound maximum bound X-axis Left V -Axis Right V -Axis 2 50 3.00 25.00 20.00 15.00 10.00 5.00 0.00 4.00 Detention Basin Outlet Structure Design Time Interval 4.62 mm Hydrograph Constant 1082 Out -low hydrograph Workbook Filename Storm Inflow Hydrographs UD•Detention, Version 3.07 (February 2017) The user can uvernde the calculated inflow hydrographs from this workbook voth inflow hydrographs developed in a separate program. SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK TIME WQCV (es; EURV Ms' 2 Year (as) 5 Year lets) 10 Year Ids] 25 Year Ecfs) 50 Year Ecfs) 100 Year (cfs) 500 Year )cfsj 000:00 0.00 0.00 0.00 0.00 0.00 0.00 coo o.00 o.00 0:04:37 ow 0.00 o.00 o oo o.00 o.00 0.00 0.00 0.00 0:09:14 0.00 0.00 0.00 000 0.00 0.00 000 000 0.00 0:13:52 0.04 011 0.06 009 0.13 0.20 025 0.32 0.49 018:29 009 029 0.17 024 0.33 0.52 067 086 1.33 0.23.06 0.24 074 0.42 0.61 0.86 1.35 172 2.20 3.47 0:27:43 0.65 2.03 1.17 1.67 2.35 3.71 4.72 6.06 9.39 0:32:20 0 75 2 37 1.35 194 2.74 4.34 5.55 7.15 11.14 0 36.58 0.71 2 25 : 78 : 84 2 61 4 13 5 28 6 81 10.63 0:4135 0.64 204 116 167 237 376 481 620 9.68 0:46:12 0.56 1.81 1.03 1 48 2.10 3 34 4.28 5.52 8.64 0:50:49 0 48 1.54 0.87 1 26 1.79 2.86 3.67 4 75 7.4r, 0:55:26 0.42 1.35 0.76 1.10 157 2.50 3.71 4.15 6.50 1 00:04 0.38 1 22 0.69 0.99 1 42 126 290 3 75 5 89 1:04:41 0.30 0.99 0.56 080 1 15 1.85 238 3.08 486 1.09.18 0 24 0.80 044 0.65 0.93 1.50 1.93 2 51 3.97 1:13.55 0.17 0.59 0.33 0 48 0.70 1.13 1 47 1 91 3.05 1:18:32 0 17 0.43 0.23 034 0.50 0.83 1 08 1 41 2 27 1.23:10 0.09 0.32 0.17 0 26 037 0 61 0.79 1 03 1.65 1:27.47 0.07 0.25 0.14 0.20 0.29 0.48 0.61 0.80 1.28 1:32:24 0.06 0 21 0.11 0 17 0.24 0.39 0.51 0.66 1.05 1:37:01 0.05 018 0.10 014 0.21 0.33 0.43 0.56 0.89 141:38 0.05 0.16 0.09 0.13 0.18 U.29 0.38 0.49 0.78 1.46:16 0.04 0 14 0.08 0 11 0 16 0.27 0.34 0_45 0.70 150:53 0.04 0.13 007 01I 015 025 032 0.41 0-65 1:55:30 a03 0.10 0.05 008 0 it 0.18 0 23 030 0.48 2:00:07 0.02 0 07 0.04 006 0.08 0.13 0.17 0.22 0.35 2:04 44 0.02 0 05 0.03 004 0.06 0.10 0 12 0 16 0 26 2:09:22 0.01 0.04 0.02 003 0.04 0.07 009 012 0.19 2:13.59 0.01 0.03 0.01 002 003 005 006 0.08 013 2.18:36 0.01 0-02 0.01 0.01 0.02 0.04 0.05 0.06 0.10 2:23.13 0.00 0.01 0 01 0.01 0.01 0.02 0 03 0.04 0.07 2'27:50 0.00 0.01 0.00 0.01 0.01 0.02 0.02 0.03 0.04 2 3228 000 000 0.00 0.00 001 001 0.01 0.02 0.03 2:37 OS 0.00 000 0.00 0.00 0.00 0.00 0.01 0.01 0.01 2:41:42 000 000 000 000 000 0.00 000 000 000 2 46.19 0.00 000 0.00 o oo 0.00 0.00 0.00 0.00 0.00 2:50:56 0.00 0.00 U.00 000 0.00 0.00 0.00 0.00 0.00 2:55:34 0.00 000 0.00 000 000 0.00 0.00 0.00 0.00 3.00:11 0.00 000 0.00 003 000 0.00 000 000 0.00 3:434.48 0.00 000 0.00 000 000 0.00 0.00 0.00 0.00 3:09.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:14:02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:18:40 0.00 0.00 0.00 0.00 0-00 coo o.00 0.00 0.00 3:23:17 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 3 27.54 0.00 000 000 000 0.00 0.00 0.00 0.00 0.00 3:32:31 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 000 3:37:08 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:41:46 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:46:23 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 3:51 00 000 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 3:55.37 0.00 000 000 000 0.00 000 0.00 000 0.00 4.00:14 000 000 0.00 000 0.00 0.00 0.00 0.00 0.00 4:04.52 0.00 0.00 0.00 000 0.00 0,00 0.00 0.00 0.00 4 09:29 0.00 0.00 0.00 0.00 0.00 UAO 0.00 0.00 0.00 4:14:06 0.00 0 O0 0.00 0.00 0.00 000 000 0.00 0.00 4.18.43 0.00 000 0.00 000 000 0.00 0.00 000 000 4:I3:20 000 000 0.00 000 003 0.00 0.00 0.00 0.00 4 27:58 0.00 000 0.00 000 000 0.00 0.00 0.00 0.00 32:35 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 4.37:12 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.41:49 000 0.00 0.00 000 0.00 000 000 0.00 0.00 4:46:26 0.00 000 000 0.00 0.00 0.00 0.00 0.00 0.O0 4.51:04 0.00 000 0.00 000 000 000 000 0.00 0.00 4.55.41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:00:18 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 5:04:55 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 5.09:32 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:14:10 0 00 000 0.00 000 0.00 0.00 000 0.00 0.00 5:18:47 000 000 0.00 000 0.00 0.00 0.00 0.00 0.00 5:23.24 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 5:28:01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:32.38 0.00 000 0.00 000 0.00 0.00 000 000 0.00 Detention Basin Outlet Structure Design uD-Detention. Versior 3.07 iFeoruary 2011 Summary Stage -Area -Volume -Discharge Relationships The user can create a summary S -A -V -D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S -A -V -U table to the fug S -A -V -D table in the chart to confirm it captures all key hansnron points. Sue -Swale Descdpb°n Stye In Ana In•ZI Area !well Vohs IRYI Wean. iachl. Toni Outflow lei! For best results, include the stages of all grade slope changes (e.g. ISV and Floor) from the S -A -V table on Sheet 'Basin'. Also include the inverts of all outlets (e g. vertical orifice, overflow grate, and spillway, where applicable). Lloyd Sisson Substation Calculated by: David Schieldt Trapezoidal Broad -Crested Weir Sizing Francis Weir Equation: Q=2/3 C1 bV2g H^(3/2) Solve For b: b=Q/(2/3 Cl V2g H^(3/2) ) Variable Input Units Discharge Rate (0) 12.7 cfs Disharge Coefficient (C1) 0.5 Weir Height (H) 0.5 ft Garvity Constant (g) 32.2 ft/s^2 Width of Weir (b) - Required ft Width of Weir (b) - Provided 15.00 ft Date: 10-08-2019 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application Appendix C: Environmental Protection Measures for Construction Projects Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application This page intentionally left blank. Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application TOPIC No. _ STANDARD ENVIRONMENTAL PROTECTION MEASURES General G-1 The contractor shall comply with all federal, state. and local environmental laws, orders, and regulations. Prior to construction, all supervisory construction personnel will be instructed on the protection of cultural and ecological resources. G-2 Prior to construction. Tri-State shall discuss with the contractor areas of environmental sensitivity within the Project area and. in particular. those areas where a monitor must be present during construction. Access Routes AR -1 No construction activities will be performed during periods when the soil is too wet to adequately support equipment and vehicles If equipment or vehicles create ruts in excess of 4-6 inches deep for a distance of 10 feet on native surface roads, the soil shall be deemed too wet to adequately support construction equipment. If equipment or vehicles create ruts in excess of 1 inch deep on graveled roads, the roads shall be deemed too wet to support construction equipment. AR -2 Only the minimum amount of soils and vegetation necessary for the maintenance of access routes and the safe and reliable operation of the transmission line will be disturbed. If excavation is necessary, topsoil will be conserved and reused as cover on disturbed areas to facilitate re -growth of vegetation. Vegetation will be cleared from those areas necessary to obtain adequate working width and turning radius space for maintenance equipment and allow for the safe operation of the transmission line. AR -3 Water bars on the access roads will be constructed as specified by Tri-State. Water bars will be constructed to: 1) simulate the imaginary contour lines of the slope (ideally with a grade of 1 to 2%): 2) drain away from the disturbed area: and 3) begin and end in vegetation or rock, whenever possible Tri-State to provide specification for water bar construction. Water turn-off bars or small terraces shall be installed across all temporary construction access roads and trails on hillsides to prevent erosion and facilitate natural revegetation of the trails. Aesthetics A-1 The contractor shall exercise care to preserve the natural landscape and shall conduct construction operations so as to prevent any unnecessary destruction. scarring, or defacing of the natural surroundings in the vicinity of the work. Except where clearing is required for permanent works approved temporary or permanent construction roads. staging areas. or excavation operations vegetation shall be preserved and protected from damage by the contractor's construction operations and equipment. A-2 The contractor shall minimize scarring, defacing, damage. or destruction of the natural landscape resulting from construction operations. Any unnecessary or unauthorized damage shall be repaired by the contractor to the satisfaction of Tri-State. A-3 All construction materials. waste. and debris shall be removed from the project area in a timely manner. Burning or burying of waste materials on the right-of-way or at the construction site will not be allowed. All materials resulting from the contractor's clearing operations shall be removed from the right-of-way. A-4 Structures will be located and designed to conform with the terrain and with minimal visual impacts whenever possible Leveling and benching of the structure sites will be done to the minimum necessary to allow structure assembly and erection. Air Quality AQ-1 The contractor shall utilize practicable methods and devices as are reasonably available to control, prevent, and otherwise minimize atmospheric emissions or discharges of air contaminants. AQ-2 Possible construction -related dust disturbance shall be controlled by the periodic application of water to all disturbed areas along the right-of-way and access roads. AQ-3 Vehicles and equipment showing excessive emission of exhaust gases due to poor engine adjustments or other inefficient operating conditions shall not be operated until corrective adjustments or repairs are made. AQ-4 Post seeding mulch will be utilized during reclamation activities to help reduce wind erosion and blowing dust The mulch/stabilization will be performed as soon as possible after completion of project Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application TOPIC No. STANDARD ENVIRONMENTAL PROTECTION MEASURES activities to minimize potential fugitive dust generation as revegetation occurs Biological Resources BR -1 Vegetation shall be preserved and protected from damage by construction operations to the maximum extent practicable. Removal of brush and trees will be limited to those necessary for access and construction There will be no clear cutting within the right-of-way unless specifically approved in writing by Tri-State BR -2 Disturbed areas where vegetation has been removed by construction activities to the extent that the potential for soil erosion is increased to a detrimental level will be subject to seedbed preparation techniques reseeded with an approved seed mixture and mulched (if necessary) during a recognized planting season. Mulching shall be applied only to those areas where potential erosion would prohibit vegetation establishment and growth. BR -3 The contractor shall not cross any wetland and riparian areas (of or relating to. or located on. the banks of a river or stream). except at designated locations designated by Tri-State BR -4 On completion of the work. all work areas, except any permanent access roads/trails, shall be regraded, as required, so that all surfaces drain naturally, blend with the natural terrain, and are left in a condition that will facilitate natural revegetation, provide for proper drainage. and prevent erosion. BR -5 All disturbed areas, except the access route running surfaces, will be reseeded with seed mixes as specified by Tri-State. BR -6 All construction materials and debris shall be removed from the project area BR -7 To preclude avian electrocutions and minimize collision risk. Tri-State will incorporate Avian Protection Plan (APP) guidelines developed by the Avian Power Line Interaction Committee (APLIC 2006) (APLIC and USFWS 2005) to protect birds on power lines. and NESC-specified electric conductor clearances Cultural Resources CR-1 Prior to construction, all supervisory construction personnel will be instructed on protection of cultural resources with reference to relevant laws and penalties. and the need to cease work in the location if cultural resource items are discovered. CR-2 Should any previously unknown historic/prehistoric sites or artifacts be encountered during construction, all land -altering activities at that location will be immediately suspended and the discovery left intact until such time that Tri-State is notified and appropriate measures taken to assure compliance the National Historic Preservation Act and enabling legislation Fire Prevention/Control FP -1 Construction vehicles shall be equipped with government -approved spark arresters. FP -2 The contractor shall maintain in all construction vehicles a current list of local emergency response providers and methods of contact/communication. Hazardous Materials HM -1 Tri-State shall comply with all applicable federal laws and regulations existing or hereafter enacted or promulgated regarding toxic substances or hazardous materials. In any event. Tri-State shall comply with the Toxic Substances Control Act of 1976, as amended (15 U S.C. 2601. et seq.) with regard to any toxic substances that are used, generated by. or stored on the right-of-way or on facilities authorized under this right-of-way grant (See 40 Code of Federal Regulation (CFR), Part 702-799 and especially. provisions on polychlorinated biphenyls. 40 CFR 761.1-761.193.). Additionally. any release of toxic substances (leaks. spills. etc ) in excess of the reportable quantity established by 40 CFR. Part 117 shall be reported as required by the Comprehensive Environmental Response. Compensation and Liability Act of 1980. section 102b A copy of any report required or requested by any federal agency or state government as a result of a reportable release or spill of any toxic substance shall be furnished to the authorized officer concurrent with the filing of the reports to the involved federal agency or state government. HM -2 No bulk fuel storage will occur within the project right-of-way. All fuel and fluid spills within this area will be handled in accordance with appropriate state and federal spill reporting and response C-2 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application TOPIC No. STANDARD ENVIRONMENTAL PROTECTION MEASURES requirements The contractor shall notify Tri-State of any spills so appropriate notifications can be made to regulatory authorities HM -3 Any waste generated as a result of the proposed action will be properly disposed of in a permitted facility. Solid waste generated during construction and periodic maintenance periods will be minimal. All hazardous materials will be handled in accordance with applicable local, state. and federal hazardous material statues and regulations. Land Use LU-1 All activities associated with the construction. operation, and maintenance of the transmission line will take place within the authorized limits of the transmission line right-of-way and access routes Additional access routes or cross-country travel will not be allowed outside of the authorized routes prior to review and approval by Tri-State. LU-2 The contractor shall maintain all fences, brace panels, and gates during the construction period Any fence, brace panel, or gate damaged during construction will be repaired immediately by the contractor to appropriate landowner or agency standards as determined by the authorized officer LU-3 The contractor shall eliminate. at the earliest opportunity, all construction ruts that are detrimental to agricultural operations and/or hazardous to movement of vehicles and equipment. Such ruts shall be leveled. filled, and graded. or otherwise eliminated in an approved manner. Damage to ditches tile drains, culverts, terraces, local roads, and other similar land use features shall be corrected as necessary by the contractor. The land and facilities shall be restored as nearly as practicable to their original condition LU-4 Structure foundation holes will not be left open overnight and will be covered. Covers will be secured in place and will be strong enough to prevent livestock, wildlife, or the public from falling. Noise N-1 Construction vehicles and equipment shall be maintained in proper operating condition and shall be equipped with manufacturers' standard noise -control devices or better (e.g., mufflers, engine enclosures). Noxious Weeds NW -1 To minimize introduction of noxious weed seed sources to the project area. the following measures will be performed. All heavy equipment utilized during construction will be washed prior to departure from the equipment storage facility_ Washing of equipment prior to transport from one work site to another is not recommended. as on -site washing of equipment increases the chance of weed seed dispersal by drainage of water off of the site. across an area greater than the size of the work site. Equipment will have accumulations of mud 'knocked off instead. This method promotes containment of weed seeds on the work site. All seed mixes and mulch used for reclamation activities will be certified weed -free. Soils and Geology S-1 The contractor shall mitigate soils compacted by movement of construction vehicles and equipment by 1) loosened and leveled harrowing or disking to approximate pre -construction contours and 2) reseeding with certified weed -free grasses and mulched (except in cultivated fields). The specific seed mix(s) and rate(s) of application will be determined by Tri-State. S-2 Movement of construction vehicles and equipment shall be limited to the right-of-way and approved access routes. S-3 Excavated material not used in the backfilling of poles shall be spread around each pole. evenly spread on the access routes in the immediate vicinity of the pole structure or transported off site to a Tri-State-approved disposal location Disturbed areas shall then be regraded to approximate pre - construction contours and reseeded as specified in S-1. S-4 Topsoil will be removed, stockpiled, and re -spread at temporarily disturbed areas not needed for maintenance access Traffic T-1 The contractor shall make all necessary provisions for conformance with federal, state. and local traffic safety standards and shall conduct construction operations so as to offer the least possible obstruction C-3 Lloyd Sisson 115kV Transmission Line Project Weld County USR and 1041 Application TOPIC No. STANDARD ENVIRONMENTAL PROTECTION MEASURES and inconvenience to public traffic. Water Quality and Erosion WQ-1 Construction activities shall be performed by methods that prevent entrance or accidental spillage of solid matter. contaminants debris, and other objectionable pollutants and wastes into flowing streams or dry water courses. lakes. and underground water sources Such pollutants and wastes include but are not restricted to, refuse. garbage. cement. concrete, sanitary waste, industrial waste. radioactive substances, oil and other petroleum products, aggregate processing tailings. mineral salts, and thermal pollution WQ-2 Dewatering work for structure foundations or earthwork operations adjacent to. or encroaching on. streams or water courses shall not be performed without prior approval by Tri-State and appropriate state agencies. Water and eroded materials will be prevented from entering the streams or watercourses by constructing intercepting ditches. bypass channels. barriers. settling ponds, or other approved methods. WQ-3 Borrow pits shall be so excavated that water will not collect and stand therein. Before being abandoned, the sides of borrow pits shall be brought to stable slopes. with slope intersections shaped to carry the natural contour of adjacent, undisturbed terrain into the pit or borrow area, giving a natural appearance Waste piles shall be shaped to provide a natural appearance WQ-4 Excavated material or other construction materials shall not be stockpiled or deposited near or on stream banks, lake shorelines, or other water course perimeters where they can be washed away by high water or storm runoff or can in any way encroach upon the water source itself. WQ-5 Waste waters from construction operations shall not enter streams water courses or other surface waters without use of such turbidity control methods as settling ponds, gravel -filter entrapment dikes, approved flocculating processes that are not harmful to fish, recirculation systems for washing of aggregates, or other approved methods. Any such waste waters discharged into surface waters shall be essentially free of settleable material. Settleable material is defined as that material that will settle from the water by gravity during a 1 -hour quiescent period. WQ-6 A Storm Water Management Plan shall be developed. if required. to address all construction and reconstruction activities The plan shall conform with all U S. Environmental Protection Agency and Best Management Practices requirements Appendix D SWMM Modeling Results Lloyd Sisson Substation Drainage Report Lloyd Sisson Substation 10 -Year Event Project Description File Name Project Options Flow Units Elevation Type Hydrology Method EPA SWMM Infiltration Method Link Routing Method Enable Overflow Ponding at Nodes Skip Steady State Analysis Time Periods Analysis Options 19095 Lloyd Sisson Substation.SPF CFS Elevation EPA SWMM SCS Curve Number Kinematic Wave YES NO Start Analysis On Aug 21, 2018 00:00:00 End Analysis On Aug 25, 2018 00:00:00 Start Reporting On Aug 21, 2018 00:00:00 Antecedent Dry Days 0 days Runoff (Dry Weather) Time Step 0 01:00:00 days hh:mm:ss Runoff (Wet Weather) Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds Number of Elements Qty Rain Gages . 1 Subbasins 4 Nodes 6 Junctions 4 Outfalls 1 Flow Diversions 0 Inlets . 0 Storage Nodes 1 Links 8 Channels 1 Pipes 2 Pumps _0 Orifices 4 Weirs 1 Outlets 0 Pollutants 0 Land Uses 0 Rainfall Details SN Rain Gage Data Data Source Rainfall ID Source ID Type Rain Units State County Return Rainfall Rainfall Period Depth Distribution (years) (inches) 1 Rain Gage -01 Time Series 10-YR 1 -HR Cumulative inches 0.00 Lloyd Sisson Substation 10 -Year Event Subbasin Summary SN Subbasin Area Impervious Weighted Average Equivalent Impervious Pervious Total Total Total Total Peak Time of ID Area Curve Slope Width Area Area Rainfall Infiltration Runoff Runoff Runoff Concentration Number Manning's Manning's Volume Roughness Roughness (ac) (%) (%) (ft) 1 East 3.16 2 Existing 7.48 3 SubYard&Pont 2.32 4 West 2.00 6.00 10.00 52.00 3.00 70.70 6980 88.10 69.70 1.0000 1.0000 1.2000 1.0000 275.00 652.00 1673.00 175.00 0.0150 0.0150 0.0150 0.0150 0.1430 0.1440 0.0500 0.1430 (in) (in) (in) (ac -in) (cfs) (days hh:mm:ss) 1.38 1.38 1.38 1.38 1.1710 1.1260 0.3800 1.2190 0.16 0.21 0.97 0.12 0.52 1.55 2.25 0.23 0.57 2.24 5.33 0.20 0 00:41:06 0 00:40:10 0 00:03:53 0 00:41:45 Lloyd Sisson Substation 10 -Year Event Node Summary SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe 5 SE Corner 6 SissonPond Element Type Junction Junction Junction Junction Outfall Storage Node Invert Elevation Ground/Rim (Max) Elevation Initial Surcharge Ponded Peak Max HGL Water Elevation Area Inflow Elevation Elevation Attained (ft) (ft) (ft) 5073.15 6.00 5074.00 6.00 5242.02 5246.00 5241.87 5070.00 5241.00 5242.61 5246.00 0.00 0.00 0.00 0.00 0.00 (ft) (ft') (cfs) (ft) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.08 0.00 0.00 0.08 3.02 0.00 5.33 5073.50 5074.00 5242.15 5242.00 6058.00 5244 13 Max Surcharge Depth Attained (ft) 0.00 0.00 0.00 0.00 Min Freeboard Attained (ft) 1.50 1.50 3.85 087 Time of Total Total Time Peak Flooded Flooded Flooding Volume Occurrence (days hh:mm) (ac -in) (min) 0 00:00 0.00 0.00 0 00:00 0.00 0.00 0 00:00 0.00 0.00 0 00:00 0.00 0.00 0.00 0.00 Loyd Sisson Substation 10 -Year Event Link Summary SN Element ID Element From Type (ntit) Node To (Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Row/ Peak Flow Peak Flow Peak Fow Total Time Reported Node Invert Invert Slope He Roughness Row Capacity Design Flow Velocity Depth Depth' Surcharged Condbon Elevation Elevation Raba Taal Depth Ratio (ft) (ft; in cis) (cs) (ftlsec) (A) (nan) 0.00 0.00 Calculated 0.00 1 Link -02 Pipe 2 OutletPipe Pipe 3 N.ChannelContrding Channel 4 Orifice -01 5 Orifice -02 6 Orifice -03 7 Orifice -04 8 Weir -01 Orifice Orifice Orifice Orifice Weir OutietPipe OutletBoxtnvOut N.ChanStart SissonPond SissonPond SissonP od SissonPond SissonPond SE Corner 1287.35 5067.89 OuttetPipe 30.00 5242.02 N.ChanEnd 10000 507400 OutletBoxInvOut OutletBoxlnvOut OudetBrndnvOut OutletBoxl nvOut OutletBoxinvOut 5242.61 5242.61 5242.61 5242.61 5242.61 6058.00 -76.9100 5241.87 0.5000 5073.50 0.5000 5242.02 5242.02 5242.02 5242.02 5242.02 0 000 12.000 18.000 0.750 0.750 0.750 1.375 0.0150 0.08 0.0150 0.08 0.0320 0.00 0.02 0.02 0.01 0.03 0.00 0.00 2.18 23.91 0.00 0.04 0.00 0.00 1.31 0.00 0.00 0.13 0.00 0.00 0.13 0.00 Lloyd Sisson Substation 10 -Year Event Subbasin Hydrology Subbasin : East Input Data Area (ac) 3.16 Impervious Area (%) 6.00 Weighted Curve Number 70.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 275.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve SoilSurface Description (acres) Group Number 3.16 - 70.70 Composite Area & Weighted CN 3.16 70.70 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.1710 Total Runoff (in) 0.16 Peak Runoff (cfs) 0.57 Weighted Curve Number 70.70 Time of Concentration (days hh:mm:ss) 0 00:41:06 Lloyd Sisson Substation 10 -Year Event Subbasin : East Rainfall Intensity Graph Rainfall (inlhr) 3 _ 2.9 2.8 2.7 2.6 2.5 2.4 23 2.2 2.1 2 1.9 1.8 1.7 1.6 15 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 - 02 01 0.62 _ 0.6 0.58 056 0.54 0 52 0.5 048 0.46 -) 0 44 0.42 0.4 0.38 0.36- 034 0.32 0 0.3 0.28 0.26- 0.24 0.22 0.2 0.18 0.16 0.14 121 0.1 008 0.06 0.04 0.02 5 10 15 25 40 45 50 Time (hrs) Runoff Hydrograph 70 75 80 85 90 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) 70 75 80 85 90 Lloyd Sisson Substation 10 -Year Event Subbasin : Existing Input Data Area (ac) 7.48 Impervious Area (%) 10.00 Weighted Curve Number 69.80 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 652.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1440 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 7.48 - 69.80 Composite Area & Weighted CN 7.48 69.80 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.1260 Total Runoff (in) 0.21 Peak Runoff (ds) 2.24 Weighted Curve Number 69.80 Time of Concentration (days hh:mm:ss) 0 00:40:10 Lloyd Sisson Substation 10 -Year Event Subbasin : Existing Rainfall Intensity Graph Rainfall (in/hr) 31 3 29 2.8 2.7 26 2.5 24 23 2.2 2.1 2 1.9 18 17 1.6 1.5 14 13 1.2 11 1 09 0.8 07 0.6 0.5 04 03 0.2 01 2.4 2.3 2.2 21 2 1.9 1.8 1.7 1.6 1.5 14 u 1.3 '- 1.2 O 3 11 Lt 1 0.9 0.8 0.7 0.6 05 0.4 0.3 0.2 0.1 C t0 lr 20 25 30 60 70 75 80 85 90 95 0 20 25 30 35 40 45 50 55 Time (hrs) Runoff Hydrograph 35 40 45 50 55 Time (hrs) 65 70 75 80 85 Lloyd Sisson Substation 10 -Year Event Subbasin : SubYard&Pond Input Data Area (ac) 2.32 Impervious Area (%) 52.00 Weighted Curve Number 88.10 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.2000 Equivalent Width (ft) 1673.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.0500 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Descnption (aces) Group Number 2.32 - 88.10 Composite Area & Weighted CN 2.32 88.10 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 0.3800 Total Runoff (in) 0.97 Peak Runoff (cfs) 5.33 Weighted Curve Number 88.10 Time of Concentration (days hh:mm:ss) 0 00:03:53 Lloyd Sisson Substation 10 -Year Event Subbasin : SubYard&Pond Rainfall Intensity Graph Rainfall (in/hr) u w 0 c 3 0_ 3.1 3 2.9 2.8 2.7 26 2.5 2.4 2.3 2.2 21 2 1.9 1.8 1.7 1.6 1.5 1.4 13 12 1.1 1 09 0.8 07 0.6 0.5 0.4 03 0.2 01 54 52 5 48 46 44 4.2 4 38 36 3.4 3.2 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 5 10 15 20 25 30 35 40 45 50 Time (hrs) Runoff Hydrograph 70 75 80 85 90 95 5 10 15 35 40 45 50 55 Time (hrs) 70 75 80 65 90 Lloyd Sisson Substation 10 -Year Event Subbasin : West Input Data Area (ac) 2.00 Impervious Area (%) 3.00 Weighted Curve Number 69.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 175.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 2.00 - 69.70 Composite Area & Weighted CN 2.00 69.70 Subbasin Runoff Results Total Rainfall (in) 1.38 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.2190 Total Runoff (in) 0.12 Peak Runoff (cfs) 0.20 Weighted Curve Number 69.70 Time of Concentration (days hh:mm:ss) 0 00:41:45 Lloyd Sisson Substation 10 -Year Event Subbasin : West Rainfall Intensity Graph Rainfall (in/hr) 31 3 2.9 28 2.7 26 2.5 2.4 2.3 2.2 21 2 19 1.8 1.7 16 1.5 14 13 12 11 1 09 0.8 07 0.6 0.5 0.4 03 0.2 01 0.21 0.2 0.19 0.18 0 17 0.16 0.15 0.14 0.13 012 11 0.1 Cr 0.09 008 0.07 0.06 0.05 004 0.03 002 0.01 5 10 15 25 30 35 40 45 50 Time (hrs) Runoff Hydrograph 65 70 75 80 85 90 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) 70 75 Lloyd Sisson Substation 10 -Year Event Junction Input SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Invert Ground/Rim Elevation (Max) Elevation (ft) (ft) 5073.15 5074.00 5242.02 5241.87 6.00 6.00 5246.00 5070.00 Ground/Rim Initial (Max) Water Offset Elevation (ft) (ft) (It) -5067.15 -5068.00 3.98 -171.87 0.00 -5073.15 0.00 -5074.00 0.00 -5242.02 0.00 -5241.87 Initial Surcharge Surcharge Ponded Minimum Water Elevation Depth Area Pipe Depth Cover (ft) (ft) (ft2) (in) 0.00 -6.00 0.00 -6.00 0.00 -5246.00 0.00 -5070.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Junction Results SN Element Peak ID Inflow 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Peak Max HGL Max HGL Max Lateral Elevation Depth Surcharge Inflow Attained Attained Depth Attained (cfs) (cfs) (ft) (ft) (ft) 0.00 0.00 0.08 0.08 0.00 0.00 000 0.00 5073.50 5074.00 5242.15 5242.00 0.35 0.00 0.13 0.13 0.00 0.00 0.00 0.00 Min Freeboard Attained (ft) 1.50 1.50 3.85 0.87 Average HGL Elevation Attained (ft) 5073.50 5074.00 5242.08 5241.93 Average HGL Time of Time of Depth Max HGL Peak Attained Occurrence Flooding Occurrence (ft) (days hh:mm) (days hh:mm) 0.35 0 00:00 0 00:00 0.00 0 00:00 0 00:00 0.06 0 01:13 0 00:00 0.06 0 01:13 0 00:00 Total Total Time Flooded Flooded Volume (ac -in) (min) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Channel Input SN Element ID Length Inlet Inlet Outlet Outlet Total Average Shape Height Width Manning's Entrance Exit/Bend Additional Initial Flap Invert Invert Invert Invert Drop Slope Roughness Losses Losses Losses Flow Gate Elevation Offset Elevation Offset (ft) (ft) (ft) (ft) (ft) (ft) (%) (ft) (ft) (cfs) 1 N.ChannelControlling 100.00 5074.00 0.00 5073.50 0.35 0.50 0.5000 Triangular 1.500 12.000 0.0320 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 10 -Year Event Channel Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 N.ChannelControlling 0.00 0 00:00 23.91 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 10 -Year Event Pipe Input SN Element Length Inlet ID Invert Elevation (ft) (ft) Inlet Outlet Outlet Total Average Pipe Invert Invert Invert Drop Slope Shape Offset Elevation Offset (ft) (ft) (ft) (ft) (%) 1 Link -02 1287.35 5067.89 -173.98 6058.00 817.00 -990.11 -76.9100 Dummy 2 OutletPipe 30.00 5242.02 0.00 5241.87 0.00 0.15 0.5000 CIRCULAR Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Diameter or Width Roughness Losses Losses Losses Flow Gate Height (in) (in) (cfs) 0.000 0.000 0.0150 0.5000 0.5000 0.0000 0.00 No 12.000 12.000 0.0150 0.5000 0.5000 0.0000 0.00 No Lloyd Sisson Substation 10 -Year Event Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 Link -02 2 OutletPipe 0.08 0 01:13 0.00 0.00 0.00 0.00 0.00 0.00 0.08 0 01:13 2.18 0.04 1.31 0.38 0.13 0.13 0.00 Calculated Lloyd Sisson Substation 10 -Year Event Storage Nodes Storage Node : SissonPond Input Data Invert Elevation (ft) 5242.61 Max (Rim) Elevation (ft) 5246.00 Max (Rim) Offset (ft) 3.39 Initial Water Elevation (ft) 0.00 Initial Water Depth (ft) -5242.61 Ponded Area (ft9 0.00 Evaporation Loss 0.00 Storage Area Volume Curves Storage Curve : Lloyd Sisson Pond Stage Storage Storage Area Volume (ft) (ft') (ft') 0 0 0.000 0.39 947 184.67 1.39 11502 6409.17 2.39 14485 19402.67 3.39 17736 35513.17 Lloyd Sisson Substation 10 -Year Event 0 3.4 3.3 - 3.2 - 3.1 - 3 - 2.9 - 2.8 2.7 2.6 2.5 2.4 2.3 - 2.2 2.1 - 2 1.9 1.8 - • 1.7 - Y N 1.6 1.5 1.4 1.3 1.2 1.1 0.6 0.5 0.4 0.3 0.2 0.1 0 Storage Area Volume Curves Storage Volume (ft') 5.000 10,000 15.000 20,000 25,000 30.000 35,000 r r 1 • { • r •r- 1 • • 0 2,000 4.000 6,000 8.000 10.000 12,000 14.000 16.000 Storage Area (ft) Storage Area — Storage Volume I 3.4 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 1.7 1.6 -1.5 -1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Lloyd Sisson Substation 10 -Year Event Storage Node : SissonPond (continued) Outflow Weirs Outflow Orifices SN Element Weir Flap ID Type Gate 1 Weir -01 Rectangular No SN Element Orifice Orifice ID Type Shape Crest Elevation (ft) 5244.94 Flap Gate Crest Length Offset (ft) (ft) 2.33 4.00 Circular Rectangular Orifice Diameter (in) Orifice Height (in) Weir Total Discharge Height Coefficient (ft) 1.00 3.33 Rectangular Orifice Width (in) Orifice Orifice Invert Coefficient Elevation (ft) 1 Orifice -01 Side 2 Orifice -02 Side 3 Orifice -03 Side 4 Orifice -04 Side Output Summary Results CIRCULAR No CIRCULAR No CIRCULAR No CIRCULAR No Peak Inflow (cfs) 5.33 Peak Lateral Inflow (cfs) 5.33 Peak Outflow (cfs) 0.08 Peak Exfiltration Flow Rate (cfm) 0.00 Max HGL Elevation Attained (ft) 5244.13 Max HGL Depth Attained (ft) 1.52 Average HGL Elevation Attained (ft) 5243.20 Average HGL Depth Attained (ft) 0.59 Time of Max HGL Occurrence (days hh:mm) 0 01:13 Total Exfiltration Volume (1000-ft3) 0.000 Total Flooded Volume (ac -in) 0 Total Time Flooded (min) 0 Total Retention Time (sec) 0.00 0.75 0.75 0.75 1.38 5242.28 5242.78 5243.28 5243.78 0,61 0.61 0.61 0.61 Lloyd Sisson 10 -Year Pond Draindown Curve (- opts Wit • SS$anfbnd t 19005 Lloyd Solon Sutstatun 2Otu-t0.Oe II 05 25) 130 1.25 1.00 '0.75 050 0.25 0 10 20 30 40 50 Time (ha) 50 70 50 00 Lloyd Sisson Substation 100 -Year Event Project Description e Name 19095 Lloyd Sisson Substation.SPF Project Options Flow Units Elevation Type Hydrology Method EPA SWMM Infiltration Method Link Routing Method Enable Overflow Ponding at Nodes Skip Steady State Analysis Time Periods Analysis Options CFS Elevation EPA SWMM SCS Curve Number Kinematic Wave YES NO Start Analysis On Aug 21, 2018 00:00:00 End Analysis On Aug 25, 2018 00:00:00 Start Reporting On Aug 21. 2018 00:00:00 Antecedent Dry Days 0 days Runoff (Dry Weather) Time Step 0 01:00:00 days hh:mm:ss Runoff (Wet Weather) Time Step 0 00:05:00 days hh:mm:ss Reporting Time Step 0 00:05:00 days hh:mm:ss Routing Time Step 30 seconds Number of Elements Qty Rain Gages .. 1 Subbasins 4 Nodes 6 Junctions 4 Outfalls 1 Flow Diversions 0 Inlets ... 0 Storage Nodes 1 Links 8 Channels 1 Pipes 2 Pumps 0 Orifices 4 Weirs 1 Outlets 0 Pollutants 0 Land Uses 0 Rainfall Details SN Rain Gage ID Data Data Source Source ID Rainfall Type Rain Units State County Return Rainfall Rainfall Period Depth Distribution (years) (inches) 1 Rain Gage -01 Time Series 100-YR 1 -HR Cumulative inches 0.00 Lloyd Sisson Substation 100 -Year Event Subbasin Summary SN Subbasin ID Area Impervious Area (ac) 1 East 3.16 2 Existing 7.48 3 SubYard&Ponc 2.32 4 West 2.00 (%) 6.00 10.00 52.00 3.00 Weighted Average Equivalent Curve Slope Width Number 70.70 69.80 88.10 69.70 1.0000 1.0000 1.2000 1.0000 275.00 652.00 1673.00 175.00 Impervious Area Manning's Roughness 0.0150 0.0150 0.0150 0.0150 Pervious Total Total Total Total Peak Area Rainfall Infiltration Runoff Runoff Runoff Manning's Volume Roughness 0.1430 0.1440 0.0500 0.1430 Time of Concentration (in) (in) (in) (ac -in) (cfs) (days hh:mm:ss) 2.82 2.82 2.82 2.82 1.8510 1.7960 0.4910 1.9440 0.92 0.98 2.30 0.82 2.91 7.30 5.33 1.65 3.15 8.07 12.68 1.82 0 00:30:52 0 00:30:10 0 00:02:55 0 00:31:21 Lloyd Sisson Substation 100 -Year Event Node Summary SN Element ID 1 N.ChanEnd 2 N.ChanStart 3 OutietBoxlnvOut 4 OutletPipe 5 SE Corner 6 SissonPond Element Type Junction Junction Junction Junction Outfall Storage Node Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Elevation Elevation Attained Depth Attained (ft) (ft) (ft) (ft) (ft') (cfs) (ft) (ft) 5073.15 6.00 0.00 5074.00 6.00 0.00 5242.02 5246.00 0.00 5241.87 5070.00 0.00 5241.00 5242.61 5246.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.20 13.02 0.00 12.68 5073.50 5074.00 5242.23 5242.08 6058.00 5244.97 0.00 0.00 0.00 0.00 Min Freeboard Attained (ft) 1.50 1.50 3.77 0.79 Time of Total Total Time Peak Flooded Flooded Flooding Volume Occurrence (days hh:mm) (ac -in) (min) 0 00:00 0 00:00 0 00:00 0 00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Link Summary SN Element Element From ID Type (inlet) Node To (Outlet) Node Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Fl w! Peak Flow Peak Flaw Peak Flow Total Time Repoded Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition Elevation Elevation Ratio Total Depth Ratio (ft) (ft) ft) (°%) (in (c (ct) (ft/sec) ft) (mn) a00 0.00 Calculated 0.00 1link-02 Pipe 2 OutletPipe Pipe 3 N.ChannelControlling Channel 4 Orifice -01 Orifice 5 Orifice -02 Orifice 6 Onfice-03 Orifice 7 Onfice-04 Orifice 8 Weir -01 Illleir 0 Ou1etBaodnvOut N.ChanShart SissonPond SissonPond SissonPond SissonPond SissonPond SE Corner OutletPipe N.ChanEnd OutletBoxinvOut OutletBoxlnvOut OutldBoxlnvOut OudetBaodnvOut OutletBoxkuOut 1287.35 5067.89 30.00 524202 100.00 5074.00 5242.61 5242.61 5242.61 5242 61 5242.61 6058.00.76.9100 5241.87 0.5000 5073.50 0.5000 5242.02 5242.02 5242.02 5242.02 5242.02 0.000 12.000 18.000 0.750 0.750 0.750 1.375 0.0150 020 0.0150 020 0.0320 ON 0.02 0.02 0.02 0.05 0.09 02 2.18 23.91 0.00 0.09 0.00 0.00 1.74 0.00 ON 0.21 0.00 02 0.21 ON Lloyd Sisson Substation 100 -Year Event Subbasin Hydrology Subbasin : East Input Data Area (ac) 3.16 Impervious Area (%) 6.00 Weighted Curve Number 70.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 275.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 3.16 - 70.70 Composite Area & Weighted CN 3 16 70.70 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.8510 Total Runoff (in) 0.92 Peak Runoff (cfs) 3.15 Weighted Curve Number 70.70 Time of Concentration (days hh:mm:ss) 0 00:30:52 Lloyd Sisson Substation 100 -Year Event Subbasin : East Rainfall Intensity Graph Rainfall (in/hr) ut w u ••••- 0 Et 62 6 5.8 5.6 5.4 5.2 5 4.8 4.6 4.4 4.2 4 38 36 3.4 3.2 3 2.8 2.6 2.4 2.2 2 18 16 14 1.2 1 0.8 0.6 0.4 02 3.4 32 3 2.8 2.6 24 22 2 1.8 1.6 1.4 1.2 08 0.6 0.4 0.2 i 0 5 10 15 20 25 30 40 45 50 55 Time (hrs) Runoff Hydrograph 70 75 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) 70 75 Lloyd Sisson Substation 100 -Year Event Subbasin : Existing Input Data Area (ac) 7.48 Impervious Area (%) 10.00 Weighted Curve Number 69.80 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 652.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.1440 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve SoiUSurface Descripbon (acres) Group Number 7 48 - 69.80 Composite Area & Weighted CN 7.48 69.80 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1.7960 Total Runoff (in) 0.98 Peak Runoff (cfs) 8.07 Weighted Curve Number 69.80 Time of Concentration (days hh:mm:ss) 0 00:30:10 Lloyd Sisson Substation 100 -Year Event Subbasin : Existing Rainfall Intensity Graph Rainfall (in/hr) 5 w w 0 c Cr 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 0.5 8.5 8 75 7 6.5 6 5.5 5 4.5 4 3.5 3 25 2 15 0.5 0 5 10 15 30 40 45 50 Time (hrs) Runoff Hydrograph 0 5 10 15 20 25 30 45 50 Time (hrs) 70 75 Lloyd Sisson Substation 100 -Year Event Subbasin : SubYard&Pond Input Data Area (ac) 2.32 Impervious Area (%) 52.00 Weighted Curve Number 88.10 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.2000 Equivalent Width (ft) 1673.00 Impervious Area Manning's Roughness 0.0150 Pervious Area Manning's Roughness 0.0500 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve Soil/Surface Description (aces) Group Number 2.32 - 88.10 Composite Area & Weighted CN 2.32 88.10 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 0.4910 Total Runoff (in) 2.30 Peak Runoff (cfs) ...12.68 Weighted Curve Number 88.10 Time of Concentration (days hh:mm:ss) 0 00:02:55 Lloyd Sisson Substation 100 -Year Event Subbasin : SubYard&Pond Rainfall Intensity Graph 45 Rainfall (in/hr) 3.5 3 2.5 15 u5 13.5 13 12.5 12 115 11 105 10 95 9 8.5 8 75 7 6.5 6 5.5 5 45 4 3.5 3 2.5 2 1.5 1 0.5 n 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 Time (hrs) 5 13 15 20 25 30 35 60 0 Runoff Hydrograph 40 45 50 55 Time (his) 70 75 80 85 90 95 Lloyd Sisson Substation 100 -Year Event Subbasin : West Input Data Area (ac) 2.00 Impervious Area (%) 3.00 Weighted Curve Number 69.70 Conductivity (in/hr) 0.1500 Drying Time (days) 7.00 Average Slope (%) 1.0000 Equivalent Width (ft) 175 00 Impervious Area Manning's Roughness 0 0150 Pervious Area Manning's Roughness 0.1430 Curb & Gutter Length (ft) 0.00 Rain Gage ID Rain Gage -01 Composite Curve Number Area Soil Curve SoiUSurface Description (acres) Group Number 2.00 - 69.70 Composite Area & Weighted CN 2.00 69.70 Subbasin Runoff Results Total Rainfall (in) 2.82 Total Runon (in) 0.00 Total Evaporation (in) 0.0000 Total Infiltration (in) 1 9440 Total Runoff (in) 0.82 Peak Runoff (cfs) 1.82 Weighted Curve Number 69.70 Time of Concentration (days hh:mm:ss) 0 00:31:21 Lloyd Sisson Substation 100 -Year Event Subbasin : West Rainfall Intensity Graph 7 6.5 6 55 5 4.5 Rainfall (in/hr) 3.5 3 2.5 2 1.5 0.5 19 18 17 1.6 1.5 14 1.3 12 1.1 1 0.9 08 0.7 06 0.5 0.4 0.3 - 0.2 0.1 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) Runoff Hydrograph 65 70 75 0 5 10 15 35 40 45 50 Time (hrs) 70 75 Lloyd Sisson Substation 100 -Year Event Junction Input SN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe Elevation Offset Elevation Depth Cover (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft2) (in) 1 N.ChanEnd 5073.15 6.00 -5067.15 0.00 -5073.15 0.00 -6.00 0.00 0.00 2 N.ChanStart 5074.00 6.00 -5068.00 0.00 -5074.00 0.00 -6.00 0.00 0.00 3 OutletBoxlnvOut 5242.02 5246.00 3.98 0.00 -5242.02 0.00 -5246.00 0.00 0.00 4 OutletPipe 5241.87 5070.00 -171.87 0.00 -5241.87 0.00 -5070.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Junction Results SN Element Peak ID Inflow 1 N.ChanEnd 2 N.ChanStart 3 OutletBoxlnvOut 4 OutletPipe Peak Max HGL Max HGL Max Lateral Elevation Depth Surcharge Inflow Attained Attained Depth Attained (cfs) (cfs) (ft) (ft) (ft) 0.00 0.00 0.20 0.20 0.00 0.00 0.00 0.00 5073.50 5074.00 5242.23 5242.08 0.35 0.00 0.21 0.21 0.00 0.00 0.00 0.00 Min Freeboard Attained (ft) 1.50 1.50 3.77 0.79 Average HGL Elevation Attained (ft) 5073.50 5074.00 5242.12 5241.97 Average HGL Time of Time of Depth Max HGL Peak Attained Occurrence Flooding Occurrence (ft) (days hh:mm) (days hh:mm) 0.35 0.00 0.10 0.10 0 00:00 0 00:00 0 01:10 0 01:10 0 00:00 0 00:00 0 00:00 0 00:00 Total Total Time Flooded Flooded Volume (ac -in) (min) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Channel Input SN Element ID 1 N.ChannelControlling Length Inlet Inlet Outlet Outlet Total Average Shape Invert Invert Invert Invert Drop Slope Elevation Offset Elevation Offset (ft) (ft) (ft) (ft) (ft) (ft) (%) 100.00 5074.00 0.00 5073.50 0.35 0.50 0.5000 Triangular Height Width Manning's Entrance Exit/Bend Additional Initial Flap Roughness Losses Losses Losses Flow Gate (ft) (ft) (cis) 1.500 12.000 0.0320 0.5000 0.5000 0.0000 000 No Lloyd Sisson Substation 100 -Year Event Channel Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 N.ChannelControlling 0.00 0 00:00 23.91 0.00 0.00 0.00 0.00 0.00 Lloyd Sisson Substation 100 -Year Event Pipe Input SN Element Length Inlet ID Invert Elevation (ft) (ft) 1 Link -02 2 OutletPipe Inlet Outlet Outlet Total Average Pipe Invert Invert Invert Drop Slope Shape Offset Elevation Offset (ft) (ft) (ft) (ft) (%) 1287.35 5067.89 -173.98 6058.00 817.00 -990.11 -76.9100 Dummy 30.00 5242.02 0.00 5241.87 0.00 0.15 0.5000 CIRCULAR Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Diameter or Width Roughness Losses Losses Losses Flow Gate Height (in) (in) (cfs) 0.000 0.000 0.0150 0.5000 0.5000 0.0000 0.00 No 12.000 12.000 0.0150 0.5000 0,5000 0.0000 0.00 No Lloyd Sisson Substation 100 -Year Event Pipe Results SN Element Peak Time of Design Flow Peak Flow! Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition Occurrence Ratio Total Depth Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min) 1 Link -02 2 OutletPipe 0.20 0 01:10 0.00 0.00 0.00 0.00 0.00 0.00 0.20 0 01:10 2.18 0.09 1.74 0.29 0.21 0.21 0.00 Calculated Lloyd Sisson Substation 100 -Year Event Storage Nodes Storage Node : SissonPond Input Data Invert Elevation (ft) 5242.61 Max (Rim) Elevation (ft) 5246.00 Max (Rim) Offset (ft) 3.39 Initial Water Elevation (ft) 0.00 Initial Water Depth (ft) -5242.61 Ponded Area (ft') 0.00 Evaporation Loss 0.00 Storage Area Volume Curves Storage Curve : Lloyd Sisson Pond Stage Storage Storage Area Volume (ft) (ft') (ft3) 0 0 0.000 0.39 947 184.67 1.39 11502 6409.17 2.39 14485 19402.67 3.39 17736 35513.17 Lloyd Sisson Substation 100 -Year Event 0 3.4 3.3 3.2 3.1 3 2.9 2.8 2.1 2.6 2.5 2.4 2.3 2.2 2.1 7 1.9 1.8 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Storage Area Volume Curves Storage Volume (ftl 5.000 10.000 15.000 20.000 0 2.000 4.000 6.000 8.000 10,000 12.000 14.000 16.000 Storage Area (ft=) 25.000 — Storage Area — Storage Volume I 30,000 - 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 - 2.5 2.4 2.3 2.2 - 2.1 2 -1.9 -1.8 -1.7 1.6 -1.5 1.4 - 1.3 1.2 1.1 1 0.9 - 0.8 0.7 0.6 -0.5 0.4 0.3 0.2 0.1 0 Lloyd Sisson Substation 100 -Year Event Storage Node : SissonPond (continued) Outflow Weirs SN Element Weir Flap Crest Crest Length Weir Total Discharge ID Type Gate Elevation Offset Height Coefficient (ft) (ft) (ft) (ft) Outflow Orifices 1 Weir -01 Rectangular No 5244.94 2.33 4.00 1.00 3.33 SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient Diameter Height Width Elevation (in) (in) (in) (ft) 1 Orifice -01 Side CIRCULAR No 0.75 5242.28 0.61 2 Orifice -02 Side CIRCULAR No 0.75 5242.78 0.61 3 Orifice -03 Side CIRCULAR No 0.75 5243.28 0.61 4 Orifice -04 Side CIRCULAR No 1.38 5243 78 0.61 Output Summary Results Peak Inflow (cfs) 12.68 Peak Lateral Inflow (cfs) 12.68 Peak Outflow (cfs) 0.20 Peak Exfittration Flow Rate (dm) 0.00 Max HGL Elevation Attained (ft) 5244.97 Max HGL Depth Attained (ft) 2.36 Average HGL Elevation Attained (ft) 5243.82 Average HGL Depth Attained (ft) 1.21 Time of Max HGL Occurrence (days hh:mm) 0 01:10 Total Exfiltration Volume (1000 -ft') 0.000 Total Flooded Volume (ac -in) 0 Total Time Flooded (min) 0 Total Retention Time (sec) 0.00 Lloyd Sisson 100 -Year Pond Draindown Curve 25- 20 a 1 1.0 D 10 �o 40 60 Time (In) t •1 d TRI STATE J N S/TF HEREFORD am GROVER VICINITY MAP N.T.S, Generation and Transmission Association, Inc. Lloyd Sisson Substation Construction of a New Substation including Grading, Drainage, and Surface Improvements Weld County, Colorado Construction Plans prepared in cooperation with: rDEL-MONT CONSULTANTS, INC. ENGINEERING V SUR V LYING �� /i II/Aft 125 Colorado Ave V *entrant CO 81401 V(970) 249-2251 (970) 249-2342 FAX ILA / V ■,....si wow SI-rton com t semceeON-mon corn 1 I I 7 LLOYD SISSON SUBSTATION COVER SHEET 0 ZO ZW Qg a4 -bo oz zt A a'- UU O win M Q I- ti a O g i- 1ii4 'if:" Q IY F- 8 I 72-g`: Il 8 0: gi ., 'Y. 221.09 Mr 51142-A-01-001 j I I 2 a I PAIN WIII3I.\NIP/r[I GENERAL NOTES' S. 3 1 I a I THE OWNER (TSGT) WILL PROVIDE THE CONTRACTOR waif DOCUMENTATION NECESSARY TO RECOVER IHE SURVEY MONUMENTS TO ESTABLISH HORIZONTAL AND VERTICAL CONTROL. THE CONTRACTOR IS RESPONSIBLE FOR C00RDNAION Of CONSTRUCTION STAKING WITH THE RESIDENT PROJECT REPRIS(NIAIN( 2 THE CONTRACTOR SHALL SCHEDULE WORK SUCH THAT Ent DURAION Of IMPACT TO ADJACENT PUBLC ROADS AUTO PLIERS -Or • WAY IS YTwMZCD TABLE Or ESTIMATED QUANTITIES 3 7 H CONTRACTOR IS R(S'OAISIBLL ION INSURING THAI IT'S PERSONNEL AND SLIBCONTRAC IDA PERSONNEL ARE AWARE Of PROPIN W( TY PROC( DUNES UMT NO 00 UNIT NAM( MO D(SCAMITON OF CONSIRLC/ON AtSI IL• UNIT W Of UNITS UOY Ai^CONSTRUC1 ED NO Of UNITS K Tort CONTRACTOR 5 RESPONSIBLE 1OR OflIAINJNG ALL WATER NECESSARY FOR CONSTRUCTION I Y- E slur•• TOPSOILmamaim w mull LOGITIDR (HARD COMIWICIXM AREA) SE1f C • 5 IHE CONE RAC TOR SHALL INFORM THE OWNER OP ONLY WORK ACTIVITIES THIS I M-i EAunIIDN (Lit -sou 'AIUMI) 110 K It -Alb ON ORMMY I KIMO Kaman 7I C ANO LOCATIONS IN GENERAL DAILY PLANNING SWNL MCLUDE A 0SCUSSON Of SPECIFIC SAFETY MEASURES TO BC TAKEN DURING THE 3 r -1 dOM NOU5L NC COMPACT IYMNMMMII •I3• DAY'S WORK • v-• OYI0( PROCItS AND CdIMCI TIRING WwYAC[ ARO WM-WXWACt STL41L ('MO. MN(WW. • fore OMSTIUCcdN MOAT T•.m7 N SHALL 6 Tn( CONT RAC TOR SHALL COOPERATE WITH 1HE OWNER AND THE T(SiwG LABORATORY TO IACILI TAT OWNERS S r•! EMMMIMNi COMPACTED . COMPLETE. PLACE (COMLLrI Pe PLACE .OINK) PM C MANAGEMENT AND QUALITY CONTROL Of THE PROJECT CONSTRICTION O M-i ft IMO ea r no all) CUES S SASE WORN ('SAD MU) COMPACTED. COMRnE IN NACI 1110 C 7 THE CALL WORKS CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING HS OWN PROJECT OrIICE. TOILET P r-) An Are flaw. J' Ye RNITIA(X AOGRO•IT (YARD RATA) Caen. w RATE H1 C FACILITIES AND ALL OTHER NECESSARY BUILDINGS OR SHELTERS. THE OWNER WILL NOT PROVIDE ANY FACILITIES TO THE I ••• SCORT SAC PITAL1 I3• TIIC ROOM) Cuts S Mat swim. (DIMAN. MU) CLIMCIED. CONNETR. IN RAC( 156 C CONTRACTOR DURING CONSTRUCTOR ALL FACILITIES AND SERVICES FOR THE RESIDENT PROJECT RETNtESENTATNE(RPR) SHALL BE PROVIDED BY THE CALL WORKS CONTRACTOR AND SHALL BE I M-• 1- Craw INK FCC RITH 3-iTIWO NOSH S. CONRETL. w PLACE (WtSTATIOTI YARD) 1137 LI SUBSIDIARY 10 THE VARIOUS BID ITEMS ON THIS PROJECT THE CONTRACTOR SHALL PROVIDE LOCKABLE AND 10 M -IC 30 CNA* LRAM CATE (1 TS' snot GARES). COVLCTL. W NACI I U SEPARATE OFFICE SPACE FOR THE RPR, FAX MACHINE WITH SUPPLIES AND DEDCATED SERVICE. COPY MACHINE AND SUPPLIES. OFFICE DESK. FILING CABINE IS, DRAFTING TABLE. MEETING TABLE. CHAIRS. INTRANC( STEPS. IT V-11 3' o Loa aim CAR COPIPL[TI, is RIO 1 a AIR CONDITIONING/HEATING MO INSIDE TOILET TOILET FACILITIES SHALL BE MAINTAINED IN WORKING CONDITION 11 s-11 4 TNL. •-S1RNO MD TEAM. COMLE1I. w RACE XOM V BY THE CORNEAL to. Al µt TIMES II v- El •' P'tMOM1(0 MACH OVAL COl•S[11. W PUCE !7D U B INC CONE RAC TOR'S PROJECT MANAGER SHALL ATTEND ALE SCHEDULED ROUTINE: PROGRESS MEETINGS DURING I• 0- I• I. NON-PIwORArtD tRrCN •Ill7q COVA[R w MC[ TIM U IHE DURATION OF IEEE PROJECT. ANO PROMO( uPDATED SCHEDULES AS REOUEST(0 WEEKLY PROGRESS MEETINGS ARE MANOAIORY Ti 0- IS TRIM, MAEN INLET AR1IMMY. COLIRltI. ■ PLANT 3 U II WTI U• IIIMORCLO COrCKTI PIN QAVUT. VCLLOMO '1MCC 1ND SURDAS, COMPLETE. Of R/TCI W M 9 1Elf CONTRACTOR SHALE BE RESPONSIBLE FOR LOCATING AND WINKING ALL. EXISTING UNDERGROUND UTILITIES AND SlItucluRt5 THE CONTRACTOR WILL ER RE WILED TO WORK WITH ALL Out CAUTION IN tnE AREAS Or II M -1r I5• RMIrOfCt0 CONOCO PIPE IW11D IND MCIONS, COMPUTE M RACE 1 U IHE LOCATED UNDERGROUND UTILITIES N ORDER 10 AMMO DAMAGING SAC UTILITIES IN THE EVENT Of U11LEly II M-1• ON • I' ROCK MOW IA(l faC ECHANK1 • Cut** OulrNat KRMXM POLO CMR004y pSMLOIE OWYL[N, NI RACE •I M DAMAGE. THE CONTRACTOR SHALL BE RESPONSIBLE TOR INITIATING IMMEDIATE REPAIRS ANO NOTWCATION OF THE PROPER AUTHORITIES AND SMICE (NtOVIDI W5 10 r-IR CONCERTI OUMION ROW WW1 STTAC1tat. COMlln. w RK1 1 a is V -so r no w.FCKTI /MRKNC SIRLOIN OWL COIRCI(. IN PLACE I LS T0. THE CONE RAC TOR SHALL SUBMIT HS CONS IRIJC ION WORK SCMt DULL TO Int OWNER PROJECTING HIS UPCOMING RORK FOR THE NEXT THREE WEEKS IHE OWNER SHALL NEWS INS PLAN WEEKLY WITH THE It M-11 ! Mt UNPRIETE TROLL OstEk. Moot It W Putt IN LI CON? RAC EON SO THAI EVERYONE 5 AWARE Of UPCOMING CONSTRUCTION (VENTS II to -S1 WEAL RK[MNI costa DOOM CONRITI, M RACE 3111 C I I . THE CONTRACTOR SHALL MAINTAIN A CLEAN AND SAFE CONSTRUCTION MORK AREA THE CONTRACTOR SHALL 13 N -I RAMC / Ott RSIOYTOIA I AC PERFORM CLEAT - UP OPERATIONS ON A DAILY BA55 f• it -2 Mum comma WP eRTAWTK/N AUTO W1A11[TMNGt FOR OIIIIATIDM Or MACE I LS 17. 1HE CONTRACTOR SMALL HAVE SUFYCIENI EQUIPMENT AND PERSONNEL ON SITE 10 ACCOMPLISH EFFICIENT AND 1$ •-1 N0MUAIOV I LS PROMPT CONSTRUCTION OF THE VARIOUS WORK ITEMS. INCEUONG WORK ON MORE THAN ONE WORK ITEM r• O-1 0000041410. r LI SZMUL TANEOUSLY 13 NO TRENCHES N OR DIRECTLY ADJACENT TO OPERATIONAL PAVEMENT SHALL REMAIN OPEN OVERNIGHT OR WHEN TTIE CONTRACTOR FRAMES WORK FOR THE DAY IN THE AREA TRENCHES NOT BACK FILLCO MALL BE COVERED WITH STE(t PLATES TO ALLOW FOR SAFE PASSAGES BY VEHICLES ACROSS THE TRENCH. IF APPROVED BY 1HE OWNER I. THE CONTRACTOR SHAH BE RESPONSIBLE FOR RI PAIR Of ANY DAMAGE TO EXISTING IACILIII(S NOT DESIGNATED EON RE CONS RUC TON OR RfPtACEMLNI. AI HIS EXPENSE lb DAMAGE TO (AIMING PAVEMENTS Dui TO MOVING OR USAGE O HEAVY (OUIPM(NI OR tHt TRANSPORT or MATERIALS TO OR ON THE SITE SHALL BE REPAIRED TO EQUAL DR BETTER QUALITY BY ILK CONTRACTOR Al N5 EXPENSE 16 1HE CONE RAC TON SIMU, BE RESPONSIBLE FOR IMMIOIAIL REPAIR OF ANY DAMAGE TO UNDERGROUND CABLES ENCOUNTERE D I J. ALL ABOVE GROUND AND GROUND LEVEL ELECTRICAL REINED APPURTENANCES (II. LIGHTS. CABLE BOXES CABLE AND/OR DUCT MARKERS. TELEPHONE PEDESTALS. UTILITY POLES. CONDUIT. IT[ SHALL 81 PROTECTED AT ALL TIMES ANY DAMAGE DONE 10 SAO APPURTENANCES BY THE CONTRACTOR SEAL BE REPAIRED TO LIKE QUALITY AT inl CONTRACTOR'S EXPENSE. THE REPAIRS SHALL BE PERFORMED 10 THE SATISFACTION OE THE OWNER'S PROJECT MANAGER. AND ANY RESPONSIBLE UTILITY PROVIDER 1B. CORSIRUC TON WORKERS WELL NOT BE ALLOWED TO ESTABLISH OVERNIGHT RESIDENCE ON THE PREMISES. ALL CONSTRUCTION WORKERS SHALL LEAVE THE CONSTRUCTION SITE AT THE END OF THEIR WORK PERIOD 19 WORK CANNOT COMMENCE UNTIL ED APPROPRIATE DEMOBILIZATION NOTES- SHALL J • • n • .• .. I LLOYD SISSON SUBSTATION iii 4V GENERAL NOTES AND CIVIL CONSTRUCTION OUANT1TJE5 TRI-STATE GENERATION Ar TRANSMISSION ASSOC/A nON. INCORPORATED I j t a B t GRADING AN BE CONE AROUND EACH ENO Of CULVERTS D HEADWALLS TO INSURE THAT RUNOFF IS PROPERTY CHANNELED INTO AND OUT OF THE CULVERTS I CONDITIONS OF IHE PROJECT ARCA UPON COMPLETION OF THE JOB SHALL BE AS 0000 AS OR BETTER • A•. 19 1 THE CONTRACTOR'S STORMWATER MANAGEMENT PERIMETER CONTROLS ENCLUOING 1HE STABILIZED I E I.N GRADES AND SLOPES FOR THE [ONSIRUCTpN REPRESENTED N THESE PLANS ARt NECESSARY TO 1 H CONDITIONS PRIOR TO STARTING WORK. IN ADDITION TO THE WORK ITEMS LISTED. CONSTRUCTION ENTRANCE AND DISCHARGE POINT CONTROLS ARE N PLACE PROVIDE COQ THE EFPROPER HCORAGE AND UTILITY Of TEN SIC CONTRACTOR ARtSHACESSAR FOR 192 ALL SAFETY EQUIPME NI FOR PERSONNEL ANO CONSTRUCTION EOUIPMENT IS IN PLACE AND OPERABLE ACCURATE AND CONSISTENT MEASUREMENT OF ELEVATORS TO ACHIEVE THE GRADES NOTED IN THESE PLANS 2 JO usttSSPROJEC ARIA ISAll SE ERE[ Of ANY CONTRACTOR STOCK WI[ Wl[MWS UPON CORRECTOR O THE Joe UNLESS OTHERWISE OKECT[D BY THE OWNER 20A COMPLETE PROJECT SCHEDULE 5 TO BE SUBMTTID WITHIN 10 DAYS Of NOTICE 10 PROCl10 19 RIP RAP MATERIAL AND PLACEMENT SMALL BI IN COMPLIANCE WITH MGT SPECIFICATIONS 3 UPON COMPYITIN Of IHE PROJECT, ALL Or TIII HALM ROUTES SHALL BE PROPERLY CLEANED TO PREVENT AND/OR DADS INHT vE VICE RI NAC DITON REGULAR BETTERE' IC ALL TEMPORARY HAUL ROUT (S 2T IHE CONTRACTOR IS RESPONSIBLE FOR 111E LOCATION AND RESTRIC I EONS FOR SERVICING AND MAINTAINING IS. CONE RAC TOR SHALL REMOVE TOPSOIL IN AREAS DESIGNATED BY MGT AS STOCKPILE LOCATIONS PRIOR ID SHALL BE FOUIPM(NI AND DISPOSAL Of uS0 LUBRCANTS. ITC STOCKPILING MATERIALS OUNR LAIN TOFNSQq SHALL M RE NOV D AND BRpHKyr11 HACK TO ORIGINAL INCIDENTAL CNON BG IIfR ALL RUTTED AREAS SHAM. RI GRADED SMOOTH SEEDING SNLI BI APPLIED AS 14 EROSION CONTROL BLAME IS SHALE O WINTERS CHOICE 010. */ BIOO(GRAOABLE JUTE NETT MFG, OR 4 HI! JOb TRAILER, ALL OF THE CONSTRUCTION EQUIPMENT. AND ANY IACILIIES TEMPORARILY PLACID ON SR E<d8At41C1EFJVT AND GRADING HQTiS• APPROVED EQUAL TOR THE PROJECT 5111 BE REMOVED FROM TN) SITE , (H[( �r ONIGGAC{61D 5AIL TAKE P(LEGU'IIONS TO AVOID DAMAGING EXISTING PAVEMENT NMI MUST REMAIN IN SERVCI DAMAGE MUSI BE REPAIRED Al THE CONTRACTOR'S EXPENSE TOPSOIL NQ1E$; 5 AMYPROPERTIES BELONGING 10 THE OWNER SHALL BE RETURNED TO THE OWNER -C.4 TRI-STATE Cession and lrwwwMM ...o,vnJ 1 Tombola in"( r_ 1 100 W. 116th Ave V.O. Box 33695 Denver. Colorado 80233 303-452-6)11 1 DESIGN CONTOURS ANO SPOT ELEVATIONS SHOWN IN PLANS REPRESENT FINAL FINISHED SURFACE ELEVATIONS I ORGANIC MATERIAL IS PRE SERI IN THE TOP B- Of THE SITE THIS MATERIAL IS NOT CONSIDERED TO BE 0 PROPER DRAINAGE (NO LOCALIZED PONOING) SHALL BE MAINTAINED PRIOR TO. DOING MD AFTER UNLESS OTHERWISE NOTED. ACCEPTABLE AS STRUCTURAL EMBANKMENT EARTHEN MATERIAL WITH ORGANIC CONTAMINATION SHALL BI MOBILIZATION CONSIDERED TOPSOIL 3 ESTIMATED QUANTITIES OF EXCAVATION AND EMBANKMENT IN 1HE.SE PLANS WERE CALCULATED BASED ON THE 1 DEMOBIIIIAIION SHALL BE DONE TO THE SATISFACTION OF THE OWNER REMOVAL O 6' Of TOPSOIL WITH AN ASSUMED SETTLEMENT Of LOX 1 TOPSOIL MATERIAL REMOVED rROM THE CONSTRUCTION AREAS ON THE SITE SHALL BE STOCKPILED ON - SITE FOR RE -USE IN TOPSON PLACEMENT AFTER OVERALL GRADING IS COMPU IE. EXCESS TOPSOIL MATERIAL B DEMOBILIZATION SHALL BE DONE N A MANNER THAI WILL NOT CAUSE ANY INCONVENIENCE TO SITE 4 QUANTITIES Or EXCAVATION AND EMBANKMENT TO BC MEASURED AND PAID FOR WELL fM BASED ON THE PLAN REMAINING AFTER CONSTRUC TON SHALL BE SPREAD OVER BORROW AREAS ON -SITE OR HAULED Off OPERATIONS OR THE CONTINUED CONS IRUC LION Of THE OTHER APPURTENANCES ON THE SITE QUANTITIES ON THIS SHEET THE METHOD OF COMPUTATION FOR QUANTITIES. WAS BASED ON A PRISMODAL VOLUMETRIC COMPUTATION VALSTEO THROUGH AVERAGE END AREA OF CROSS SECTORS WITH ALLOWANCE FOR 3 TOPSOIL SHALL Si KNOW D TO A MINIMUM DEPTH Of B' N THE NEW YARD AREA. FENCE APRONS. POND 9 ANY DAMAGE 10 PROPERTIES DARING Df YOBILIlATADN SMALL. BE REPAIRED AND PALO 100 AT THE MATERIAL ND DEFORMATION THROUGH THE PROCESS Or EXCAVATON APLACEMENT BERM AREA, MD ACCESS ORNE WAYS THE CONTRACTOR SHALL VEINY WITH THE OWNER THAI THE EXPOSED CONTRACTOR'S EXPENSE MAT FRAIL IS AN ACCEPTABLE SUBGRAOE AS NECESSARY AND DIRECTED BY THE OWNER. THE CONTRACTOR 5 EXCAVATED ROCK (6- DIAMETER AND GREATER) MAY BE USED ONLY N LOWER LEVELS OR OUWEN PORTIONS OF SHALL REMOVE ADDITIONAL MAT ERA E TO ESTABLISH AN ACCEPTABLE SUBCRAD( SURFACE TO SAFETY REGULATIONS SHALL BE OBSERVED AT ALL TIMES DURING DEMOBILIZATION. FILLS. NOT LIKELY 10 RECENE TRAF(IC, SUBJECT TO THE OWNER'S APPROVAL THL MAXIMUM ALLOWABLE SITE OF MATERIAL IN THE TOP 6. Of SUBGRADE 5 K' DIAMETER II Tilt COST FOR DE Wound ON SWILL HE CONSIDERED SUBSIOARY 10 THE PAY ITEM FOR MOBILIlATXP. 6 EARTHEN EMBANKMENTS AND TRENCH BACKFILL SHALL BE PLACED IN ACCORDANCE WIT" MGT SPECIFCATIONS I SOIL WRRML- OTHER THAN TOPSOIL rOuND LAO II FOR US IN THE CONSTRUE 1 ON Cif IVRANKM(MIS SHALL SE REMOVED FROM THE SETE Al THE CONTRACTORS EXPENSE B. EXPOSED SUBG*AD( SMALL BE SARIFLED AND RECOMPAC1EO TO THE DEP11T REQUIREMENTS IN THE SOILS REPORT. TYP 0-. PRIOR ID BEGINNING PLACEMENT Of EMBANKMENT LIFTS AND BASE MAIL MAL RECOMPAC TON SHALL COMPLY WITH TIME COMPACTION RLOUR( MC NTS IN THE SOILS REPORT 9 OVERALL EXCAVATION AND EXCAVATION OF THE DETENTION POND ARE INCLUDED N THE UNCLASSIFIED EXCAVATION QUANTITY YMGW A.I 10/23/19 -TIM SIN. SI I 42 - A-0 I -002 Control Point Totals I I I I I I I Pont , cocci Mortising loste1RPli I I I I I 7 A 1 soo, a, ,w,a.so =NM w _ ,sal MS MY - I + t I l • I IOW CPI I104.07* aa07W,J• fi E 1 � I I• I SAGA CRT SWIMS 7, 0•1.7a 1.1064.1.1064.1.7in - � I I I I I ' - f ' 100• CM MINIM s7WW,• +fi a, ..\.(11 231 it 1 I asN0S77 CA wA• ,7, �� -, •o' —' 3.10011.6ills0NJ7.a0 �i _.� . . I111'`�• I�` • 1/ ` I I • 'i1 I //I / /• / I 1 I •Wtwat -OM IMMO I I I ' I, I I I I I I I I I I I I i II I - • I. I I s / \� I I• I I i) • 1 N. N. I I .= I I II I I I I I t - --; -- LLOYD SISSON I11 SUBSTATION IYI I I I kJ 0 JO •o I I • I I I I I I \� I / // I• I I I I I I I I I1 I I I I I I t q • �,— a 4t , . , ... _,.._ ---s\ \ I Q 8 i Ii LEGEND • / I k- - ' I • 1 • 1 1 1 I I N. -- /// / / I I OET(NIIONPOPO I I 1 I I I I I I `•I l I I I 11 I I• I• II I ' I I I I 8. I I I I I I I I I l I I i . ••, , ill. LLOYD SISSON SUBSTATION 5 •� OVERAII SITE PLAN 71W- STATE GENERATION & TRANSMISSION ASSOCIATION, INCORPORATED 1 t 1 !Ii $ ! 1 J - i j - - ETING PROPERTY FENCE IIK ^EXISTINEXISTING I % 1 - / II I I I I • I I I ; OK.,G1 RD POWER t I — - ERIStING ` iSS•.•f ye noon n A-MM,E TO — — — — - — CAGING O CASTING EASEMENTS MIRAGE rLOwLP1E imp. POLE 1� / ,/ 1 -•I [Ass Siva, tog I I I • I I I I t C7tK 11NG GA& LINE saga / T r 1 I I .zz.. ."so PROPOSE PR PROPOSE ADS M17 POW Stag-DRNA PIPE ADS IMP( I •I I \ I 1 I I. I 1 NI/ Sus -DRAIN • / { fa ;f :f:.f ,t:,t: PROPOSE RMRAP / I \ \ I I . I 1 I I I — — —`- — — PROPOSE GR°RAA�M`EREM LINE ARROW / , I , -•-•-•- PROPOSE suastATck rE710E • _ PROPOSE ROPERtt FENCEtorro • — • — • I I• I 1 • Qan STATE Genres ti r"mirw ww�+w a reArlar/0'laor -- 1100 W. 116th Ave P.O. Box 33695 Denver, Colorado 80233 303-452-6111 r.,. t\eai.lw,.“..� •••••••••••%20.1111.1 �•A�� • I • PROPOSE DRAINAGE FLOWLINE / / I I I •'' t K I}1 IS I Tt=.- �� / r /./ , / I I I • 6 - I T R I • I `\ } — — .— a-_� . • P I I NOTE. - — -. 1 THC HOR170NTAl IDEATION TOR THE CONTROL PONT Al THE • _. - . .. .- .- . ,C �. 15 \ I ,fir 1r ( / - \ `._ -� INTERSECTION OF INC TWO MS(UNES K hl{E D. LOCATIONS • • — — -- - - - - - - - - -I- }I� I— -}' — { FOR OTHER CONTROL I•pNiS MAY It ADJUlICO KONG 7H( BASELINE AS NECESSARY TO PROVIOC FOR -- --- —. -- — — — — — — — I I CLEAR LINES OF SIGHT AND TO PROTECT No CONTROL roe 1HE DURATION OF THE PROJECT --------------------------------------------------- 7 SURKYOR SHALL SEI THE CONTROL PO*" OUILO( THE switch-anSECURRY FENCE IN-THE-FRLD. ANO REPORT \ - I swain, •,e W' I COUNTY ROAD 130 - -_ I _ N./ I - THE -� • _-_. . - • -• • • • . - • . -• • •-- �.. COORD•NTES AND ELCRA110NS TO THE OWNER'S . . . . -. . . j AUTHORIZED TECHNICAL REPRESENTATIVE(OAIN) . ' I 'PRELIMINARY . MODE IV -SP 0- - ■' 3. YOM • • 1044In NI M1aHAl0. OI TM 51[11 11Ip-A-01-111 (IS vI Y-0011011 o10111(1 'n 004 Y■RS 0 30 - 1.30 Control Point Table Point 9 P.: Northing Colima Nov C►1 TEN lam 10 31■00440 1001 D t 1164 tor le 1.101011 la 1151 4.l 15SMaS It 130154! 90 100 ON 1544101 51 1115151. la 5000 FPS 15314 11 3}0001/15 / ROp RS' -RAP b • ►' S' t5 SLOIOM 1.7- SEE M■1NIAMN DMAmatSn42-4-01. -All (n SF) ROC4 M-041. 0. • I ID' alai • 10 LOOP. KN•D I I : - SIC ad14444104 DONE 5•c41 511q -A -01-D11 WI SI ) K1tma. POND Km. x( 01tMS 114(1 %I 4.7-A-OI . 011 DETtNiION POND 1' Ya CO•CRTt MCA! C,11NIW I _ (154 I. ) MOO 011.44. ouRt1 SSSI. 1111 3 LOCATIONS SC[ 01IAA5 SAW 11147-a-01.010 O(TCNTOR PON0 WW1 SIOyCTUR SC( 01141.5 %KO 11•47-4-01-01l OO(Y10M Cw(YCCK+ SPl1 TAI MINES 1 Sl Iq-A'01-0n L _ NOTE F $41- F S1. C at i I 10130' y0rl-RR04TTO ` 0* 4.E pV) I � I N \NI F 1 1� I • IDA 7' nab' PROPOxf Muss J CARE /01.01 T :v — 4 / PR0Pat0 WC( ■RUC Lai 2 N F 1U' NTH' 1 I If IHE HORUONTAL LOCATION FOR THE CONTROL POINT At THE INTERSECTION OF THE TWO BASELINES 5 Fgco LOCATIONS FOR OTHER CONTROL POINTS WY 8E AOJUSTEO ALONG HA BASELINE AS NECESSARY TO PROVO( FOR CLEAR LINES OF SIGHT AN0 TO PROTECT THE CONTROL FOR THE OURAION DI THE PROJECT 1 SURVCYOR SNAIL SET THE CONTROL POINTS OutSOI THE SWITCHYARD SECURITY FENCE N-THE-FICLO, MO REPORT THE COORDINATES MO CLEVATOIE 10 THE OWNER'S AUTHORIZED IECHNCAL REPRESENTATIVE (DAlR) I 4 LEGEND • T —rrran- 01=4- :mom -S 4 EXISTING PROPERTY FENCE EXISTING OVERHEAD POWER EXISTING DRANOLI. FLOWUM EXISTING tuna POLE EXISTING OAS TIM PARKER PROPOSE ADS Nil POW SUB-ORAIN PIPE PROPOSE ADS N11 SUB -DRAIN PIPE PROPOSE R P CUTVLRt PROPOSE PROPOS( PROPOSE PROPOSE PROPOSE PROPOSE RIPRAP DRAPING( FLOW ARROW GRADE BREAK LINE SUBSTATION FENCE PROPERTY FENCE DRAINAGE FLOWN( S. I' -1O Earn tot sop re-YP 0. • I' •IIH •O•.RWIs 1,1111E St( YSTNW0N OOMS 5.11(1 SI IA} -S.01 -01I (5,3 SII ■ M' AM 5 JO 0 20 40 'AG AON]CU MI MM+ OAK', A A IE I I 1 I i } } • * • S. 1 Lloyd Sisson Substation I 8 v, S 4 POW N.O I9/21/10 IM S11112 -A -0I-004 g I Qrsla n 4648 ♦♦ut�J ♦ pn n 22 LEGEND Ee6TING NODE CONTOUR EXISTING NTERMEDMTE CONTOUR 5800PROPOSE 040E% CONTOUR 5786 PROPOSE INtERMEDMIE CONTOUR • PROPOSE DRAINAGE rLOWLINE PROPOSE SUBSTATION FENCE PROPOSE PROPERTY FENCE PROPOSE BREAK LINE PROPOSE MARACA FLOW ARROW PROPOSE DRAINAGE. ROW ARROW nnac+•••m••••• PROPOSE ADS N12 PON SUB -DRAIN PIPE PROPOSE ADS Nil SUB-ORMN PIPE •-- PROPOSE WRAP I• -TO fats n Peet 70 v I It 44.16 0 20 40 11.-6' 1106 M-sD rta %PIGEON:0v a toot ON a-160\(1, amnia( la EMIT ICON 0 'P••0/4D LO{Mll IC 44.74_ • —\ `Io tau G UE7 47 74 5246 5246 5245 5241- 5244 5245 to 433 L-5244 w N ♦ V ro at Ka •Z43 1777 • — • r0 M :71 4044 5248 tan • / ro / I0 46 / tiles 7 r10 047 I/ANN I re day i r to 470 _ -•—r. • 7 N 47.14 -6Mt If _ r 4417 11 4' ro 4? 10-s 7 5247 6248 5245 5244 SMISWQN MSS SWOON LOCATIONS 17191 SE7 Let 57142-A-Gt-COI i NI eon flWQ4 KM vat 76a a toot a 40N•04 04 DEo1ElCD $a Ir•ri I)01t d •P41eW76 lOL1YI•t nu a • • 4 P 4 O 0 D 0 0 0 0 s?4 A 64,Mir 1 41,70 41.71 4112 -704 urn n 427$ I I I 1 i 1 I a a gv a vOu oz V Lug. 4, UU Lam I g tic 4.41 10/23/19 D•4 51142 -A -01-00S t 1 •4 M I R I I 3 I 5600 5796 LEGEND .Liana Jasmine m CRISTMG WOE% CONTOUR USING MTERMEDMIC CONTOUR PROPOSED RODE CONTOUR PROPOSED INTERMEDIATE CONIOUR PROPOSED ORAINACC ELOWLINC PROPOSED SUBSTATON FENCE PROPOSED PROPERTY FENCE PROPOSED SNEAK UNt: PROPOSED DRAINAGE PLOW ARROW PROPOSED ADS N17 PERT SUB -DRAM PIPE PROPOSED ADS NI? SUB -DRAIN PPE PROPOSE 0 ROPRAP zor Scale ntea 1D O JU' 4D IW..yu ) I 11 1 :4 ON •!].I0 AN .S)U )1 P •* 4 W.IACE IICY.S),IM /wY I- an N-1) PII1tatARD PPT DII.y..4I Nr I' ADS N -I) PPE Imps GETS).. 4I ter WI 4I4 .SJ.) 41 Iry a LOS N -I) PCWGRAItD M 041.SJOi]O 4 1 WIPACI file .524110 454 I. ADS N -I) PEIWRARD Pot Q11. S)4A W wY I- ADS N -I) POI 4414 00- 5144 03 An/AG OJT .1•7•P -w4 I- Apt N -I) PCI1OLAItO PIPS O.I.)J44 es AN .S)4) O) • 1 t I.IM 1000 .I sr LOS N-1) PVC • oSOI SURFACE ICS •S)LS /s �Y ADS N•1) WHOA RD PO4 Wt.SJ4)SI / T Y ADS N-1) POT Pit OUt.S)43SI Kenn 1114.514* 57 W4 Y ADi ••• I) PCSOIAID PN 0141.5)44 40 d i I J I f i P. 1 Substation 0 0 N_ U 0 -4 I L g I l R 3 F µPG*o _. INo us. 19 S1142 A-01-006 LEGEND (MONO WOEA CONTOUR ONSBTEC NWRNEOMTE CONTOUR 5e ��• PROPOSED WOO CONTOUR 5756 PROPOSED WIERMEDNTE CONTOUR PROPOSED DRAM& EEORENE PROPOSED SUBSTATION RNCE ENSTING IENCE ANEW —C; Nr• oral 5246 5240 •u0a COSMOS It 4331 COUNTY ROAD 130 IY1CN ODa1iiC r0 4300 rrxl YMG• CCNIC•1•A _ teat 1010 '30 a •WO 2 •000 V •1 IS Cis • x• • DDC* -w is V • h u le $ P N u 0+00 a 80 h n u M w A u •1 E5 - u W 0+50 1400 5245 5240 • E 150 I 1 d 1 I 1 1 • •1 n S Lloyd Sisson Substation 4 '• A o In W • a` to • zu • o_ o • � 'us Q V it" ay 0 IA ae 4 I I 1 a t vc* 10/23/19 51142 -A-01 .007 0l / V'�, i J (Y!. -13.a0' 6 CN.-]]4)]]nor_ 6 QM_ Lp i41C., {fy.� '4r loe rya5250 _ 5250 j f I Orr..2 fr.-un.64� 11m . ,y7 t . S 3246 3` ,]. . lum• I..424O Pot 4/E MUCH WU! AMMO Or MAN S WV StIU-M01.010 WE0/50/1 •040 Wry 52.5 r- -4-- 5245 al o+ I I \ • ,. Pt,. •• PIK I I u' A.V. 4 '2 PIPI 2 yY 1 f t 1 1 5240 50 -40 30 06 \ -20 -10 Yard l i. Section 0 10 20 1-1 30 40 50 60 10 60 90 100 1 0 120 ISO 140 150 160 170 160 190 200 210 220 230 240 750 5240 260 770 6250 ,:21-7300,'• t.. -3]4/6 3 - 4 84.1]4 fl•52*a m• N4 .- 5250 Orr --]6 (4.•31•191 m'- . ' • I 04•.4300 tr..324 SO Wt T 0o41r ICI ownS SAW Mttr614 teal n .. . , nw ,_a,<1 scar / i 5245 ] I i _+ _l 5245 �. . __ ____ l___ 5240 5240 -50 -40 -30 a gR�......•,.-1 ip\I -20 - Yard / -= Section 0 .0 20 2-2 30 w 50 60 /0 60 90 IOU I'0 20 30 40 140 'bO / t/0 i 1m ,90 200 2 0 770 230 240 250 160 270 ; LLOYD SISSON SUBSTATION 11) kV SUBSTATION CROSS SECTIONS TRI-STATE GENERA TIQN & TRANSMISSION ASSOCIATION, INCORPORATED • _• i '. • + 5250 044.573 Ono o0 57•• w .. ".; :7 1. 0 X� • 1 .Orr Crr51460t -I]1 W' 1511.. _. 5250 [ •.v 31 • -lag "i - G 3; ~ L7. . ) ; I{ er.It;ar u o WC OUTLET I T4[•it+l ASSEORY awr SIX DEWS WET 511.2-A-01-010 L sISr z 5245 : - - - - - �-- 5248 4 IqH ),1 : �� 0I I I210raancei 5240 50 -40 -30 t r[ n ton -20 -10 0 10 Yard Section 20 3.3 30 40 50 60 70 60 90 100 IT0 170 130 140 150 160 170 180 I90 200 210 228 no TRI-STATE Gw lir and asts w...r Ma sts \Teodoro LanvrC.q.nIt'Off 1100 W. 1160 Ave P.O. Box 33695 Denver, Colorado 80233 303-4S/41II { 70 0 70 40 g1 A. • x ! r 5 On_4ns “, t ••.p24 {6 5250 e 4/u• U)i - a 0 t0! • _6001{ 0401 _6Mi ..- - --- - - .-. .... Ot0'� NS Oa. Scat n feet _..rnmn __ _ 6' PAO --i— W. 44111 Put If T - 51142-A-01-008 NA /11C 70 ' 0 b W I I 5240 5240 -40 -30 -20 -10 0 10 20 30 40 50 60 70 60 90 100 '0 120 130 140 I53 160 110 150 190 200 210 220 730 740 250 760 270 760 790 300 310 370 330 340 350 360 370 380 390 400 •10 47] 430 440 0 OWN LPN FENCE Ss 1' DTP RACE ROVEM GWTUpE SATE Nan 600i 00 APPROVED ECt.1AEWT) WORT ON -WE BOAR011 PATINAE AS f(CESSaf 10 FORM SE9GM0( 10 050E (ELVAIcNS IDEPT T s eta) PER SRGMKATOT 0.1001 REMOVE TOPSOIL EATER (S- W) Y{ fMMMEKNt OAAORO MO TORSOA N01(3 SAKI) S 1142 -A -0I -07 VARTES SET smut 5TI42-A-01-004 ENCORE MUCH FLU urn RIM STµSMTO SURFACE AGCR(aaE REM CRu5NE0 ROOT Ih' ClS. M.1 0REwSO UNUCI RMI R( Dna U.S POET vaiS SEE 51IEO 51147 -A -01 -DOA 3- MIDI Stela AGGREGATE PER SPEOf4TICM 010.17 R- IroCR CLASS S MU MAMMAL PER SROICAION 010.13 SGMPV NO R(CEMPAC1 EI$TRIG MATEMAt (TI TURIS A COMPACTOR PER SPEW0000N 0.10.01) TYPICAL INTERIOR UNDERDRAIN & YARD SECTION NTS 25' KORAN. IY TIXGLIK$6. ROOfMO CLASS S MS( MAI[RMS ALL RUINER DINING SuRC CE PER SPECMCAIOM OIL ID 13 TYPICAL DRIVEWAY SECTION NTS 0161 cROUO.G GRID MOMµ4 fR- OUP (RR M61MAAltON DITAIES - bT DINERS) 1 I n51MTG GROUTO SUN\. WPC A1.0 RICOTIPAtt a,OS(0 t1TSTWG SYBGAAoC (11RCRNESS R PROCTOR PER SPECRIGATON 0 TOOT) CONTROL CANS (IRIS) RR AGGRCGAIE. R ESC WSIALIATON NOTES 1 LA* FARRC W 1REECH POOR 10 PLACEMENT OF AGGREGATE 2 PW ma TO COiACTEO NAME W1ERME µ0R0 TRNNC$ WHERE NEGESSMT OMERLIIP ADSMlC FENCES A MMMYM Of 6' 00 PEA w1NufACtWCR'S R[COYMEICATSI. 3 Af5L1El PCRFOMIEO PIPE TO OLSO* CAAMS INI$ PSWOKAICIVS POI 000.0. 4 MOOSE To OESR? SUMAC( CRAMS ARO IL(RAIONS RIM Ih' MI SMO AGOACGATE PER SPECWCATONS em FORK TO NATII( INTERNE PRIES -6- MN MOIVLL MERCK PIN I.1/1' WE 0Pi • CRUStCO. RAM(D AGGREGATE (pH I SUR6IATOn u10 stoma SECTION SEE Of1ARS 1NESE PLANS NON-MOV(N GEO1al1LE IMOC (NYEEOP( (Wiwi ITOR 0R A PROTtO EOMWtENI) SEE Rs1µIATCN NOTES PERFORATED ADS N-13 CORRUGATED EXTERIOR AND SMOOTH WIEROI • ROBS Of h' PERFORATIONS AT 6. O C. ROTATE P91 IN TRENCH SUCH THAT THE ACTIN( B(TR(EN THE ROOTS Of PERIORAICNS IS AT THE ROTIDS (SE( PMs foe PIPE S17E) TYPICAL PERFORATED TRENCH DRAIN DETAIL NTS - SUSSTATON YARD SITRTACL SEC TON SE( O(TNLS 11415E PLUG if" ADS N-12 PH PIPE OM I IMPORT OM -SITE SELECT B0µµOµ MATERIAL AS IIECESSMT TO Mc.rLL PP( TROTH (DEPTH VMK51 PER SRclIGAIoll 0 1001 3s' (100 I TYPICAL SOLID UNDERDRAIN DRAIN DETAIL NTS ASµ 12- I CARUS. LOONNO CLASS S nu MATa.t 'ALL 0110 DTNPTG SURFACE RR SPEOICATON 01013 6' SUED ENCORE MATteul PEA SPICRCAIOM 061001 1I' (MIN) 4 ,.1 DRIVEWAY CULVERT SECTION RC.P PPE. WE WOES SEE PLAN NIS t Ie d > S I I If •1 f O VT in O O vI� •OO En.< h fa ° a Asko (n Grp zu c r�tu o2 N �� •a2 in U� z0 d0 UU O t -0 In 4 Ill k Ai rn a 0 <am_ N I ��A� .±$1. _r_^ cc 1 Ik s o0 -0 Ors:. a e IMO 1M TO/2J/19 URA 51142-A-01 009 .. ^ \% SI•\wq.rn t I a I 1 d i 40 OCP CLAVEAI— sewn OM ACCA IM MP 14N cPGnA I1 Pt. PUPS (I3.0 WWI NP)P) • (MN)a1 'IN MMES US PUNS 2 1.0•41 RCA 1µ11E0 ENO SECI.0N WM- SORN CE011SIEE (MAC MMMI '704 a APPOa(O EOtW INaN C110µ.0 itCC.4SS PEN PLAYS (1 yip* nu; nP) taws* 011001.0 T IMIN 1 1WC[YESS PEP PLANS (I S.O.. *tut 1YP) op* Spa ROIEAIUE *AVM WRAC. Ha O11 APPAOYEO EOUA& *LTA YA11wS _r_"{ 2 IMNI UI **ANS RCP CULVERT OUTLET DETAIL NIS MNCEO wawa OUMO -M7 CUMO' ST AaI 0111M 00 AM110YC0 EQUAL (MICA& ALL MENCA DAW MaCANKA P0Mn) MCM MKS SCE Assn MOM-11OYEN CEOIEPIU !SIC MOW 17001 DI AD$gtO IOU** 1 (Mn) PVC TRENCH DRAIN OUTLET ASSEMBLY NIS EASrytO 011ptM MICKNEss PER Pt1Yt5 - (1 S.a vAEUI ttP) Hr PREPARED SuaGACC PEP &K M 401E Sral NM POP PUNS f' CLASS 6 IASE Mutt. COMPAC' 10 SSS IOOffO PAOCIOA WU** Ott OCIGN 3' TRICKLE CHANNEL N'S \\_I-OQ€M GCOTEXTU FABRIC AP11W 170N 011 APPPWCO EOua TYPICAL RIP RAP INSTALLATION N)S I -----'3 TYPICAL SWALE SECTION A -A N'S D'SIACI YAPYS Sit 0PADSC PIRA 1 I r r Lloyd Sisson Substation DRAINAGE DETAILS H ztU y4 Q. 'o z? o_ zo UUa Luta tn ea (E7 a e s a P I Mow I 9 w 10/23/12 1W SII42-A-01-010 f 1 i I P t 3 I d NICK CNMMM[NT COLNMCTLO TO 6011 610001E0 IN0CT01 POND !LOON WV YAKS W61N WINS SEC PUN NEIY ttEvAOYN Slse I' Cif.FIN %WKS J SCE CIAINC NAM Ds \ PIKt /NYNI*SCNI CONPACTIO fD ME SID PROVO* TYPICAL POND BERM SECTION N TS "Cis vans VI PAN POND SLOON Mt VAKS DETENTION BERM EMERGENCY WEIR CONCRETE HEADWALL DETAIL NIS NNW, ISO N fAMC OR NH•IDYLO LOtSI _ It. W 6" YIPNNY COIN 41 (DOLS OCPTH VANES MC O*ADNO PLIw5 I" IHAA CONCI lI ,EAOIALI 1A' It. ILCVATON SINS I 40,491,2416, 'teCE IMYPtwtw. CONNCttp 10 en LLDOt'SO PN0CTM WIDTH yM[S SEC PtAH PUdt 6" TOPSO.L silo KR 5PECNCAt10w5 /IDTH vMES SEC RAN NACC 6 TOPSOIL SCCO rim SPLCIIEATO.G TYPICAL POND BERM & OVERFLOW WEIR SECTION N IS PIAct t6' TNCA tWE• 600, I1P-NAP \ ERN ELLVATON 5266 00 N_ PLACL SOHSOHN CEOlti1NC CAINC Ruin i4)N ON APP10YC0 EWNNENI) Ith11NL LPoU.0 4 CT' I'N0 4NL111LLD DETENTION BERM EMERGENCY WEIR DETAIL NIS I'-4 D•.E M11t0 EPIA* ON Ttrt1 5.Dt a 16" Tonal. T I I ft I C O H 1n C O N DETENTION POND DETAILS O 0 In OO h 2W as 6.0 zo I— q0 2s. U0 to 1,3a H I I c -t I I f I g 2 i k f MGw 6.,. 10/15(19 S1142 -A-01-011 4100.10( CON t.I.d6 .ioSltM C►in, KrMIM onto 0011 IMD 1tt•c TUH a...• • .'1.1.1 • MGT MIS NW IANCSS WILL SUPPORT Ka R 0.C1•' . 010'. I• o1. 1D115:1. —ad 1S ; a )) 2210[2) l 0174 00W all. •n- Tat aft: fMMCt run 1 (S (A) 11"0. 11aaa S� MOOR CI Ht • 0a•Iti MMi Can WI jaw • MMo1 • NO CPI% AKA)IIC.4OR t•C• MIA) • 010 SECTION,., "lt wJ ' W 1•A' Wtit. 5744 It '001.1 WII. 070 I) WOcv 074)4/ • I 1% ,tc 7. Dianne' trowel S747 it i I t t WOO Pea 0747 70 OA•1 op .650 574) 01 0_201 000 T100% 1 ••0601 cOM0v000% M0t•IM atilt MONK KNOTTY 114 watt PWt S• racial' ) KO Purl TO CUMCRUI Tr at. Olt Ct14• Igcv Nan tan I •t,t-Shift. MAP. MOTS Mali K STAMISS atilt t.0 Mats K ARAC,fD • I1lRaaf1M1 /IDS MDC t4 lag 0 bit WOMIA IOW 7 ¶Ydim K• OIL. AKA Ml ID• incite ION. MCI Iy44M.i TOIA. Man R•t Wt We .1110 t0 K tAa61t0 If1 M01110 *Ma DIIt4Mt f•MM AIIA tCiS MIA INTO 11 ash] 1 allalDIN1 KMM, Of IMtr, MOMS Nita K 1010 OM 1102 .2500STADC ,4110 110. Il4O .2 20 0OM6TiWI Dr IM( MCI O•14Mt01 Wn. C4allt .. Wilt own MU., K SO*ltD v0i atAA. I11 SIIMI 444D444•1 I.O AO.aO a1.. 1.•1.10 IMD to4A•t 0• 'COMM OCatl KNITS Wlt. CS,lt Om. M tom ntI tIltt MIAWIY a STll. t1111 CURS Wat K .OT tr Mann AMO W. St MT .a•0I• CORD 011• CAAMAMIIC wire OMRt May. K K11CMD M<. Mat 1.41 0a1A1.44 0.41014010 CI goo. Otlac '110•.211 -5m •4 DMW'It1 01 Tit *WIC, PIM -.t•ILR1M4 alt. 0 WIT. CISIII 1044µS WYD 0. 1y4. +•••1D%IAIC HOW •T,. II.O .00 :VMTHO• DI IN MCl ORIFICE PLATE AND TRASH RACK DETAILS AND NOTES I t' a J ORIFICE PLATE DETAIL 41TC I • I. S 1 • r t• CONCRETE OUTLET STRUCTURE TOP VIEW 1100 %MoeT411M 65 CT CIaMMa I.MII IMPACT •110 cant 4 (Cal II WI,. OMPI - . a • pl Ii l,9 11 Id • • • • . • • . • • . • I\ •. II , Y--� �..... I"` — . a_.•• --�� . .-. -s. V • • IS �. • • • • . a - •. . A H 4 I i F. • aOln ION Sal SECTIONm Mfg �d 1 I • L J __ CONCRETE OUTLET STRUCTURE FRONT VIEW I'w TUM(S► sua It M MI TIMMTd IM III 1C40t ail-) NO OS -I ML0 I' GM IIM M lMM, I•n TRCItI au. I. a*A1t •t'. s" MA. .:,IM KWK(M SAM I I•:1't t 'O tt•gg Tan S• a 4_1Q 1.1_,34__ s•rdai-rit— I • ♦ _ Oe s__0➢ -!11_1111. Ray • a?70 •' sTMILSSS Sal, MRASI SCRUM (•lit SOOTY-10r06oM. vti ••t 011 (0004Oa) AJTAt11 attOt to cwI A WAM Il[t. 00M•1 2011010 MO .O6•(tt •Ctla• Asa Ins OT alma M MA. 7 I• la)y • 1)4) I• rif Sat WIN COOT IL AK.IOIII •1 • - 4 S' • 1 WSr40 CUM Y.r A1pt. !we 2444 aMa 004 K MOICI Mq•O -� asUTAMCt Pint 0 K•MI 4 10.a IDw )•(t r Ctt*•A4Q •M 10 OKAWC 41v • )410) I 1' 11 w41t Y,PI MI 1.101 101 1.IY•1Qwt laly - 12311 11 PROFILE 41S I T I. I • Ka.00/40 M ${•R II it (At et 14P L J CONCRETE OUTLET STRUCTURE SIDE VIEW P. t t e I ) I Substation C O N In I t I S I s II.M MGM w •••• to/]y is, S1142 -A•01-011 ' II i I t r I I I I I ; I t I 1 i SYMBOL LEGEND I ,t --„ Noma on". • / I I I > ( 1 / I .... .n rKggM coma wNan I I 10.44% , / .,® I ® KIN 1 I -, I .lb an KMtM. iW ‘ % da ® pW M.t / I ® VS. colt i / J] N. I .,p unarm I I I I I i I +{ 4 Ma1 CID 1 L I ® sons KIIf.tM.t6 IP van n nmrcra i. - - - - - I I II I b I I I I I I VIAta n..Ic p.0/ I I I I �. cow.' *war wt. lours loM sl ,. �I, a I I • COUNTY ROAD 71 17Wt IOW/ I .w.w ,+� •� �, 1 / / I • V 1] I I{ I I I I I I I t I I I ON SUBSTATION 15 IV CONTROL PLAN TrON & TRANSM,SSION INCORPORA TED i w 1; 1/' iff i 1 i! \ \ \\ i- IFS I I I I I I I I I I I I I I ; ' LLOYD S/SS EROSION 41 -STATE GENERA ASSOCLANON, H �J 1 i Ellice._ _. _. . = /I J I IP PROJECT BOUNDARY IP / / I / , / / I / I, I • d \ IT I / l W I I �`-i -------1-1- ----=--Ca 7--�� J COUNTY ROAD 130 _ 1 / 11 - .-.-.-.-•-•- . - .-. -.-. / ; I STORMWATER MANAGEMENT PLAN (SWMP) For Colorado Construction Activities at: Lloyd Sisson Substation Prepared for: 0 TRI-STATE G&T A Touchstone Energy® let Cooperative 1100 W. 116T" AVENUE WESTMINSTER, COLORADO 80234 Prepared by: a a - - -- -- US -- -- - - _...+01 _ — -- - - - - - �S DEL-MONT CONSULTANTS, INC. ENGINEERING v SURVEYING 125 Colorado Ave. • Montrose, CO 81401 • (970) 249-2251 • (970) 249-2342 FAX www.del-mont.com • service®del-mont.com DMC # 19095 Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Table of Contents: 1.0 INTRODUCTION 1 1.1 The National Pollutant Discharge Elimination System (NPDES) Process and Construction Stormwater Management Plan (SWMP) 1 1.2 Project Owner/Operator and Key Personnel 2 2.0 CONSTRUCTION ACTIVITY AND SITE DESCRIPTION 5 2.1 Project Location 5 2.2 Nature and Description of Construction Activities 5 2.3 Proposed Sequence of Activities 5 2.4 Estimation of the Total Area of Disturbance 5 2.5 Existing Soil Conditions 5 2.6 Existing Vegetation and Runoff Characteristics 6 2.7 Potential Pollutants 6 2.8 Allowable Sources of Non-Stormwater Discharges 8 2.9 Receiving Waters 8 2.10 Site Map 8 3.0 CONTROL MEASURES 9 3.1 Structural Measures for Erosion and Sediment Control 9 3.2 Non -Structural CMs for Erosion and Sediment Control 13 3.3 Phased CM Installation 17 3.4 Dedicated Concrete or Asphalt Batch Plants 17 3.5 Vehicle Tracking Control 17 3.6 Waste Management and Disposal (Including Concrete Washouts) 18 3.7 Product Specific Practices 18 3.8 Groundwater and Stormwater Dewatering 19 4.0 FINAL STABILIZATION AND LONG-TERM STORMWATER MANAGEMENT 20 4.1 Temporary Stabilization 20 4.2 Description of Final Stabilization Practices 20 4.3 Final Stabilization Methods 20 4.4 Final Stabilization Achievement 20 5.0 INSPECTION AND MAINTENANCE 22 5.1 Minimum Inspection Schedule 22 5.1.1 Post -storm inspections 22 5.1.2 Inspections at Completed Sites/Areas 22 5.1.3 Winter Conditions Inspections Exclusion 23 5.2 Inspection Requirements 23 5.2.1 Inspection Scope 23 5.2.2 Inspection Reports 23 5.3 Required Actions Following Site Inspections 24 5.4 CM Maintenance 24 5.5 Corrective Actions 25 Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 5.6 SWMP Requirements 25 5.6.1 SWMP Availability 25 5.6.2 SWMP Retention 25 5.6.3 SWMP Amendment 26 5.6.4 Responsive SWMP Changes 26 5.7 RECORD KEEPING 27 6.0 SPILL PREVENTION AND RESPONSE 28 6.1 Introduction 28 6.2 Material Management Practices 28 6.2.1 Good Housekeeping 28 6.3 Product -Specific Practices 29 6.3.1 Flammable and Combustible Liquids and Hazardous Materials 29 6.3.2 Petroleum Products 29 6.4 Spill Control and Cleanup 30 6.5 Spill Reporting 30 6.6 SWMP Modification Procedures Related to Reportable Releases 31 APPENDIX A: Site Maps APPENDIX B: Soil Erosion and Sediment Control (CMs) Details APPENDIX C: Phased CM Implementation APPENDIX D: Inspection Forms APPENDIX E: Spill Report Form APPENDIX F: Permit Application and Permit APPENDIX G: Geotechnical Soils Report Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 1.0 INTRODUCTION 1.1 The National Pollutant Discharge Elimination System (NPDES) Process and Construction Stormwater Management Plan (SWMP) This document establishes a plan to manage the quality of stormwater runoff from construction activities associated with the Lloyd Sisson Substation, Weld County, CO. This project will disturb at least 1 acre or is part of a larger common plan of development, which will disturb more than 1 acre. For construction projects that require the disturbance of more than 1 acre, the U.S. Environmental Protection Agency (USEPA) requires that the project owner or contractor apply for a stormwater permit under the NPDES program. For the purposes of the NPDES program, construction activities are defined as clearing, grubbing, excavating. grading, import and placement of road material, improvements to existing or new drainage, installation of permanent drainage structures, installing landscaping improvements, paving (asphalt or concrete), construction of permanent structures, or any similar activity that causes native / undisturbed areas to be disturbed. This NPDES permit program is administered in Colorado by the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division (Division) under the Colorado Discharge Permit System (CDPS). CDPHE has a general permit for stormwater discharges from construction activities. The Construction Stormwater Permit (COR400000) was renewed and issued on October 31. 2018. and effective on April 2. 2019. This document. including its attachments and appendices comprises the Stormwater Management Plan (SWMP) required by CDPHE's general permit for Stormwater Discharges from Construction Activities. This plan was written in accordance with the guidelines in the Division's Construction Guidance Document: "COR400000 Stormwater Management Plan Guidance". Reference material was used from the Urban Drainage and Flood Control District's Urban Storm Drainage Criteria Manual (V. 3) (updated 11/2010). the EPA "Developing Your Stormwater Pollution Prevention Plan, A Guide for Construction Sites" (May 2007), and the Colorado Department of Transportation (C.D.O.T.) Drainage Design Manual. A permit application for Stormwater Discharges Associated with Construction Activity must be submitted to CDPHE at least 10 days prior to the start of construction, and the applicant must receive written notification that the Division granted permit coverage prior to conducting construction activities. The plan and permit will be available on -site while construction activities are taking place. The USEPA and the State of Colorado have substantial penalties for non-compliance with the permit. Any permit non-compliance constitutes a violation of the Clean Water Act and is grounds for enforcement action including: permit termination: revocation, reissuance, or modifications: or denial of permit renewal application. Individuals responsible for such violations are subject to criminal, civil and administrative penalties. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan The Construction Stormwater Permit only authorizes the discharges of the stormwater and those non-stormwater sources listed in Part 1.A.1. of the Construction Stormwater Permit. The permit does not cover discharges currently covered under an individual permit or a Division Low Risk Discharge Guidance developed in accordance with the Low Risk Discharge Policy (WQCD Policy 27). 1.2 Project Owner/Operator and Key Personnel Owner/Operator: Tri-State Generation and Transmission Association 1100 W. 116th Ave Westminster, CO 80234 Contact for Owner/Operator: Selina Koler Senior Transmission Siting & Environmental Planner Tri-State Generation and Transmission Association 1100 W. 116th Ave Westminster, CO 80234 (303) 229-3207 skoler@tristategt.org The owner is the party that has overall control of the activities and that has funded the implementation of the construction plans and specifications. This is the party with ownership of. a long term lease of. or easements on the property on which the construction activity is occurring. The operator is the party that has operational control over day-to-day activities at the project site which are necessary to ensure compliance with the permit. This party is authorized to direct individuals at a site to carry out activities required by the permit. Tri-State owns/leases the Lloyd Sisson Substation property and has operational control over the activities at the project site. SWMP Administrator/Qualified Stormwater Manager (QSM): Selina Koler Senior Transmission Siting & Environmental Planner Tri-State Generation and Transmission Association 1100 W. 116th Ave Westminster, CO 80234 (303) 229-3207 skoler@tristategt.org Qualified Stormwater Manager: An individual knowledgeable in the principles and practices of erosion and sediment control and pollution prevention, and with the skills to assess conditions at construction sites that could impact stormwater quality and to assess the effectiveness of stormwater controls implemented to meet Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan the requirements of this permit. Tri-State's Stormwater Administrator, Developer, and Inspector are all identified as Qualified Stormwater Managers (QSM). The SWMP Administrator is responsible for developing, implementing. maintaining, and revising the SWMP. This individual serves as the comprehensive point of contact for all aspects of this SWMP. SWMP Administrator/QSM Signature: Name: Title: Date: SWMP Developer/QSM: David Schieldt, P.E. Del -Mont Consultants, Inc. 125 Colorado Ave. Montrose, CO 81401 dschieldt@del-mont.com (970) 249-2251 The SWMP Developer is responsible for developing the SWMP in accordance with the requirements of the General Permit. Critically important in developing the SWMP is to identify all potential sources of pollution which may reasonably be expected to affect the quality of stormwater discharges associated with construction activity, to describe the practices to be used to reduce these pollutants, and to ensure that pollution prevention practices are based on good engineering practices (includes installation, implementation and maintenance requirements). The SWMP Developer is also available to adjust or update the plan as needed during construction. to make field visits and provide recommendations on appropriate Control Measures (CMs) for specific areas of concern or to determine if final stabilization has been achieved, and can help with administration of the plan or with Inactivation. Transfer. or Reassignment of the Permit. SWMP Developer/QSM Signature: SWMP Inspector/QSM Signature: Name: Title: Date Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan The SWMP Inspector is responsible for conducting and documenting required site inspections in accordance with the Permit. The SWMP Inspector must notify the Construction Contractor and the SWMP Administrator immediately if any additional or different CMs are required on the site. if any CMs require maintenance, or if any CM has failed. During construction, the SWMP Inspector will assist the Construction Contractor with implementing and maintaining stormwater controls at the site and the SWMP Administrator with revising the SWMP as needed. Construction Contractor: Name: Company: Address: _ Email: Phone: The Construction Contractor is responsible for installing and maintaining CMs as defined in the SWMP and is responsible for notifying the SWMP Administrator immediately if any CMs fail, require maintenance, or if additional CMs are required. The Construction Contractor will work closely with both the SWMP Inspector and the SWMP Administrator throughout the duration of the project. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 2.0 CONSTRUCTION ACTIVITY AND SITE DESCRIPTION 2.1 Project Location The proposed substation yard is located on a 7.5 -acre parcel owned by TSGT, situated in the SE 1/4 of Section 11, Township 11 North, Range 63 West, 6th Principal Meridian in Weld County, Colorado. The substation site is accessed from County Road 130 approximately 430' west of County Road 71. 2.2 Nature and Description of Construction Activities The scope of this project is to build a new high voltage substation. The construction will include clearing/grubbing substation pad area, grading drainage swales and detention pond, and installation of high voltage electrical equipment. 2.3 Proposed Sequence of Activities Construction Task Planned Start Month/Year Install initial CMs June 2020 Construct Substation Summer -Fall 2020 Remove CMs no longer required Winter 2020 Reclaim and stabilize all disturbed areas Winter 2020 Remove all temporary CMs Winter 2020 Site stabilization Spring 2021 Close Construction Stormwater Permit Spring/Summer 2021 2.4 Estimation of the Total Area of Disturbance The total area of the site is 7.5 acres. The estimated area of the site to be disturbed by all construction -related activities is approximately 4 acres. 2.5 Existing Soil Conditions Consistent with other similar sites in the Weld County area. the Lloyd Sisson Substation site has the sandy soil with varying amounts of gravel, silt, and clay. A Geotechnical Soils Report (see Appendix G) confirms this typical soil and was used to develop and apply appropriate CMs. Engineering judgment and construction experience with local drainage patterns were relied on to develop appropriate CMs to prevent soil erosion and migration. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 2.6 Existing Vegetation and Runoff Characteristics The site naturally drains to the southeast. The natural vegetation consists of native grasses, weeds, and cultivated land. The site is estimated to have 20-50% ground cover prior to construction. The percent density was determined by examining a representative 10'x10' square and determining the plant density within the area. At final stabilization, ground cover should be greater than 70% of the pre -construction cover, 0.70 x 0.20-0.50, or approximately 15-35% vegetation coverage. 2.7 Potential Pollutants The following chart identifies the potential pollutants that need to be addressed per the CDPS General Permit and their applicability to this project. Potential Pollutant Source/Activity Potential Pollutant Potential with this Project? Description of Activities CMs Selected to Control Source All disturbed and stored soils Sediment X Construction of access road Controlled Parking Controlled Site Entrance Designated Staging Area Detention Basins Drainage Swales/Check Dams Dust Control Good Housekeeping Practices Inlet Protection Natural Vegetative Barrier Seeding Silt Fence Straw Bales Straw Wattles (fiber rolls) Surface Roughening Vehicle Tracking Control Vehicle Tracking of Sediments Sediment X Delivery of construction materials: installation of sub -base materials; clearing and grubbing; daily construction traffic; construction of new access roads, excavation and removal of excess materials Controlled Site Entrance Controlled Parking Designated Staging Area Dust Control Tracking Control Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Potential Pollutant Source/Activity Potential Pollutant Potential with this Project? Description of Activities CMs Selected to Control Source Management of Contaminated soils Fuel spill, runoff from contaminated area X On -Site vehicle maintenance & refueling Spill Prevention Plan Loading & Unloading Operations Sediment. runoff from contaminated area X Equipment/material drop off and pick up; portable sanitary delivery & routine cleaning Controlled Site Entrance Designated Staging Area Outdoor storage activities Sediment, Fuel spill, runoff from contaminated area X Construction material storage on -site for the duration of project Controlled Site Entrance Designated Staging Area Spill Prevention Plan Vehicle & equipment maintenance and refueling Fuel spill, runoff from contaminated area X Vehicles & equipment which will remain at the site until work is completed will be maintained and refueled on site: fuels will not be stored on site Controlled Parking Designated Vehicle Fueling and Maintenance Area Spill Prevention Plan Significant dust or particulate generating processes Dust X Construction of new pad area. grading pad, installation of structures Dust Control Routine Maintenance activities involving fertilizers. pesticides, detergents, etc. Nitrogen. phosphorous None Project does not require use of these materials. On site waste management practices Debris. trash X Construction debris; I portable sanitary facilities: personal trash Designated Staging Area Solid Waste Management Concrete truck & equipment washing Concrete waste, concrete wash water Equipment foundations Concrete Washout(s) Dedicated asphalt or concrete batch plants Waste products. runoff from contaminated areas None Project will not require use of dedicated asphalt or concrete batch plants. Non -industrial waste sources Bacteria, parasites. viruses X Portable sanitary facilities; Personal trash and construction debris Designated Staging Area Solid Waste Management Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Potential Pollutant Source/Activity Potential Pollutant Potential with this Project? Description of Activities CMs Selected to Control Source Other areas where spills could potentially occur Runoff from contaminated areas None No other potential sources of pollutant were identified. Irrigation Return Flows Erosion/sedime nt from construction activities None No irrigation return flows expected on this project 2.8 Allowable Sources of Non-Stormwater Discharges Irrigation return flows are not anticipated on this site. When construction activity involving concrete is required. a concrete washout will be installed in a designated area. No other allowable sources of discharge exist on the site. 2.9 Receiving Waters Receiving waters include any classified or unclassified surface water segment (including tributaries) in the State of Colorado into which stormwater associated with construction activities discharges. This includes all water courses, even if they are usually dry. such as borrow ditches, arroyos. and other unnamed waterways. Runoff from the project site flows southeast flowing overland through various drainages ultimately running to Little Crow Creek. Runoff from the substation will flow to the on -site detention pond to provide water quality treatment prior to discharge following historical drainage patterns. There are no stream crossings located within the construction site. There are no discharges to Outstanding Waters. 2.10Site Map The site map (see Appendix A) will show the following per the CDPS Permit: • Construction site boundaries • Flow arrows that depict stormwater flow directions on -site and runoff direction • Entrances and exits (if applicable) • All areas of ground disturbance including areas of cut and fill • Areas used for vehicle parking, storage of building materials, equipment, soil or waste • Locations of concrete washouts • Locations of all structural CMs (including existing CMs) • Locations of all non-structural CMs (including areas that will be subject to re -seeding) • Locations of springs, streams. wetlands, and other surface waters (including areas that require pre-existing vegetation be maintained within 50 feet of a receiving water) • Locations of all stream crossings located within the construction site boundary • Any other factors that are important to the site and/or the SWMP Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 3.0 CONTROL MEASURES 3.1 Structural Measures for Erosion and Sediment Control Structural measures are those physical structures implemented at the site to minimize erosion and sediment transport. The CMs specified for use on the project are described below. Specific locations for CM implementation at the site are indicated on the site map in Appendix A. The installation details for these CMs are provided in Appendix B. This SWMP anticipates that not all of these CMs are going to be used and additional CMs may be added as site conditions change or climatic conditions warrant. If additional CMs are added, description and construction details will be added to Appendix B or to a revision of the Site Map prior to installation. Concrete Washout A concrete washout is used to capture waste water and waste products resulting from the cleaning of concrete equipment. The wash water is alkaline and can contaminate groundwater, increase the pH of receiving waters. clog storm drains. and harm wildlife. Examples of concrete washouts include, but is not limited to, a bermed excavation, a mobile disposal unit, small excavations located near the point of concrete placement, water tight vessels (such as a rigid pre- fabricated impermeable plastic wading pool, stock tanks. small dumpsters. buckets. etc.). and geotextile bags. Control measures designed for concrete washout waste shall be implemented at the project site, and Tri-State will ensure that washing activities do not contribute pollutants to stormwater runoff or receiving waters. Discharges that may reach groundwater will flow through soil that has a buffering capacity prior to reaching groundwater. The concrete washout area shall not be located in an area where shallow groundwater may be present and would result in the soil buffering capacity not being adequate. Hardened concrete wastes on the ground will be picked up daily and disposed of properly Concrete pours will be scheduled so that no pours occur when a storm event is anticipated. No concrete pours will be conducted during storm events. A concrete washout will not be necessary if all washout operations are performed off -site (at the vendor mixing plant for example). Concrete washout will only be allowed in the designated area. For project phases with large amounts of concrete work, concrete washout will be conducted at a dedicated concrete washout pit installed and maintained on the site. For project phases with small amounts of concrete work, the driver will be directed to return to the mixing facility to washout the truck drum or a rigid pre- fabricated impermeable plastic wading pool can be used to contain the washout. If the concrete contractor is able to provide a prefabricated washout container, this will be used in place of constructing one onsite. A concrete washout will be installed or provided prior to any construction activities that include the handling of materials containing cement (e.g. concrete, masonry. etc.). Concrete washouts will Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan be installed per the attached detail ('Concrete Washout Area" CWA-1 through CWA-4 from Urban Drainage and Flood Control District Drainage Criteria Manual Volume 3). The concrete washout will be inspected daily during periods of concrete construction to make sure appropriate access control. tracking and containment is in place. Additionally. the project manager/superintendent will ensure that concrete washing is being conducted only at this designated area and that no damage is present at the washout. For lined washouts. the liner will be inspected for rips. tears. etc. Concrete operations will be suspended until any needed repairs are completed. Maintenance will include the removal of excess material. cleaning, and general structural integrity of the installation as needed. The concrete washout will be cleaned of excess water and solids on a regular basis to maintain its proper function. The washout will be cleaned out when at 75% of capacity (50% if rigid containment is used). The concrete waste will be properly disposed by a qualified contractor. If a water -tight vessel is used to contain concrete washout water, the following management practices will be followed: (1) The CM will be inspected for waterproof integrity prior to each use: (2) The CM will not be filled to more than 50% of capacity with either liquid or solid waste; (3) Immediately after concrete washing is complete. the CM will be covered with a waterproof barrier (4) Upon termination of use of the washout site or when waste reaches 50% capacity. the accumulated waste will be removed from the site and properly disposed. If unlined pits are used to contain concrete washout.. the following management practices will be followed: (1) The use of the washout site must be temporary (less than 1 year): (2) The washout site will not be located in an area where groundwater may be present. such as near natural drainages. springs, or wetlands. or down slope of construction activity where runoff could flow into the washout; (3) Upon termination of use of the washout site. accumulated solid waste. including concrete waste and any contaminated soils, will be removed from the site to prevent on -site disposal of solid waste. The washout will be removed when it is no longer needed. Drainage Swales/Check Dams Drainage swales and check dams may be constructed during the initial stages of new construction to ensure run-on and run-off are managed correctly. Check dams may also be constructed where existing drainage patterns cross onto the site and bring neighboring property run-on into the construction area. Check dams are generally constructed from rock, straw wattles, or straw bales. They are designed to slow water velocity allowing some sediment to settle. Check dams will be used in areas of concentrated flows along drainage swales. The check dam will be installed Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan across the entire width of the drainage swale in order to function properly. The center of the check dam should be lower than the sides. Drainage swales will be installed per the construction drawings and from Standard Plan No. M-208-1, Temporary Erosion Control, from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans. rev 8- 2010. Check dams will be inspected for proper installation and sediment accumulation on the up - gradient side. Accumulated sediment and debris will be removed when the sediment level reaches one-half the height of the CM or at any time that sediment or debris adversely impacts the functioning of the CM. The removed sediment shall be placed with the topsoil stockpile and debris shall be hauled from site and disposed of. Check dam materials will be cleaned and replaced as needed to maintain function and integrity. Inlet/culvert protection Inlet protection consists of a barrier placed in front. around, or immediately up -gradient from the inlet or culvert. The most common forms of inlet protection are straw wattles or straw bales. Inlet protection is designed to slow stormwater flow into the inlet or culvert, allowing sediment time to settle and accumulate on the up -gradient side to the structure. without constricting the inlet throat. As permanent stormwater system inlets are constructed in areas with potential disturbed area run-off or when existing inlets are potentially impacted by construction activity. inlet protection will be installed. Any structure with a potential to receive run-off from non -stabilized surfaces will be treated with an inlet protection CM. Inlet protection will remain in place until all up -gradient areas are stabilized See attached detail for further description and applications (excerpt from Standard Plan No. M-208-1, Temporary Erosion Control, from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans, rev 8- 2010. Inlet protection will be inspected for damage. structural integrity. and proper installation in relationship to the culvert, and accumulated sediment/debris. Maintenance includes repairing or replacing as needed, repositioning the inlet protection and/or removing accumulated sediment. Riprap Rip rap is a layer of rock used to reduce the velocity of stormwater and to trap sediment. It is a permanent CM that is used to line channels, ditches. drainage swales. and at culvert inlets/outlets. The depth of the rip rap should be a minimum of twice the maximum rock diameter. A geotextile fabric can be used to extend the effectiveness of rip rap. See construction drawings regarding specifications of riprap. Sediment Trap Sediment traps are small impoundments which allow sediment to settle out which are generally installed in a drainage way or other point of discharge from a disturbed area. They are formed by excavating an area or by placing an earthen embankment across a low area or drainage swale. Typically, a spillway or outlet is constructed to allow the slow release of stormwater runoff. Sediment traps are commonly used at the outlets of diversion structures. slope drains or any other runoff that discharges waters containing sediment. If detailed engineering drawings specifically are not designed for this project. see attached installation detail and notes (-Sediment Trap- ST -1 through ST -3 from Urban Drainage and Flood Control District Drainage Criteria Manual Volume Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 3). Sediment Traps will be inspected for accumulated sediment, erosion and to ensure effective operation. Silt Fence Silt fence consists of geotextile fabric installed with at least six inches of the fabric entrenched into the soil attached to wooden stakes on the down -gradient side. Wire -backed fence may be used or additional stakes or lathe may be added on the down -gradient side for strengthening the fence around corners or in high wind conditions. Silt fence provides sediment control by reducing water velocity and ponding water to facilitate the deposition of sediment on the up -gradient side of the fence. Silt fence applications include, but are not limited to: project perimeter control, secondary containment. back of curb protection containment for any disturbed or staging area, or around temporary material stockpiles (outer boundary). Silt fence is an optional CM to be used at the discretion of either the construction foreman and/or the SWMP Administrator. When silt fence is used, it will primarily be installed prior to clearing and grubbing operations in a new phase of construction where a sediment control measure is appropriate. Usually other CMs, such as natural vegetative barriers, straw wattles. and rock sediment traps. will be employed before use of silt fence. The primary application for silt fence will be in steeper sections of the project to protect the site from neighboring run-on or to direct project run-off toward a large sediment trap Silt fence will be installed per the attached detail ("Silt Fence" SF -1 through Sf-4 from Urban Drainage and Flood Control District Drainage Criteria Manual Volume 3). Silt fence will be inspected regularly for sediment accumulation one-half the height of the fence. tears or holes in the fabric. broken stakes, and gaps in the fabric or areas where the fabric needs to be re -attached to the wooden stakes. Straw Bales A straw bale should be a minimum of 14" X 18" X 36" and have a minimum mass of 50 pounds. It should be composed of only vegetative matter, except for the binding. The straw bales should be bound by steel wire (minimum 14 -gauge), nylon or polypropylene. Applications include. but are not limited to. check dams in swales, inlet protection, outlet protection, perimeter control. disturbed areas with significant potential for off -site drainage, protection from neighboring site run-on. or during the construction of drainage swales and ditches. Straw bales may also be used as "final discharge check dams" for drainage swales and ditches to slow run-off and collect sediment. Straw bales will be keyed into the soil perpendicular to the run-off flow. Straw bales will be installed per the attached detail (Excerpt from Standard Plan No. M-208-1. Temporary Erosion Control. from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans. rev 8-2010). Straw Wattles (fiber rolls) A straw wattle consists of a net or geotextile fabric filled with straw, excelsior, wood mulch or other fillers. Straw wattles reduce water velocity allowing sediment to accumulate on the up -gradient side of the straw wattle. Applications include. but are not limited to. disturbed areas with significant potential for off -site drainage, protection from neighboring site run-on, during the construction of drainage swales and ditches. slope stabilization. check dams in swales. back of curb protection, or temporary secondary containment for stock piles and materials storage. Straw Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan wattles will be keyed into the soil in a trench a minimum of two inches deep perpendicular to the run-off flow. secured in the trench using stakes, and backfilled on the up -gradient side. When necessary they will be stacked two courses high with joints off -set or overlapped. Straw wattles will be installed per the attached detail (Excerpt from Standard Plan No. M-208-1, Temporary Erosion Control, from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans. rev 8-2010). Straw wattles should be inspected for proper installation. structural integrity and sediment accumulation. A straw wattle that has been flattened out of round may not need to be replaced if they remain sufficiently sound to function appropriately on the up -gradient side of the straw wattle. Topsoil Berm A topsoil berm is a ridge of compacted soil which is used to prevent run-off and sheet flow of stormwater. The minimum height of the berm is 18 inches with side slopes less than 2:1. Topsoil berms shall be used to intercept and divert drainage to a designated outlet point. Topsoil berms will be installed per the attached detail (Excerpt from Standard Plan No. M-208-1, Temporary Erosion Control, from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans. rev 8-2010). Vehicle Tracking Control Vehicle tracking control will consist of an area with a geotextile liner and gravel, metal grate. medium-sized (6" to 12") rough -cut rocks, or asphalt/concrete "rumble strip". Tracking control is designed to cause soil to vibrate off equipment and vehicles as they transition from disturbed soils to paved areas. The vehicle tracking control will remain in place until access to the areas used by the control are stabilized or no longer needed. All appropriate points of ingress and egress. where traffic transitions from a stabilized road surface (e.g. gravel or pavement) to disturbed soil. will have vehicle tracking control installed. Tracking control will be moved or eliminated as on -site conditions and activities change. Tracking control will be inspected for depth of gravel/rock, presence of excess soil, proper usage and the overall general condition. Strict site access will be maintained throughout the project. Once the section is stabilized and surface drainage features are built, tracking pads will be removed in favor of controlled site access. See attached detail for further description and applications (Standard Plan No. M-208-1, Temporary Erosion Control, from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans, rev 8-2010. 3.2 Non -Structural CMs for Erosion and Sediment Control Non-structural practices are those practices which when implemented will minimize erosion and sediment transport. Practices implemented at this site include interim stabilization practices, permanent stabilization practices (see Section 4). site -specific scheduling for implementation of the practices. and site management practices and personnel training. The CMs specified for the project are described below. Specific locations for CM implementation at the site are indicated on the site map in Appendix A. The installation details for these CMs are provided in Appendix B. Additional CMs may be added as site conditions change and will be identified in the "New CMs Added to the Site" form (Appendix C) prior to installation. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Controlled Parking During construction activity. controlled parking areas will be established to allow workers to commute to/from the job site. Limited and designated parking areas will be established for all new phases of construction. This CM is an administrative measure to control access to/from the site. Controlled Site Entrance During construction activity or when construction activity is temporarily left in an intermediate state awaiting final treatment (concrete. finished gravel surface, etc.), controlled access will be established to direct traffic in/out and across/through the areas under construction. Limited access points will be established for all new phases of construction. This CM is an administrative measure to control access to/from the site and to ensure the general public is directed through the construction site via a safe and stabilized route. Designated Staging Area A designated staging area is a specific location on -site for stockpiling/staging materials or staging equipment for use on -site. A stabilized staging area allows for a central location for deliveries and storage of equipment when not in use, and to prevent disturbance of areas not scheduled for construction activities. Stabilized staging areas will be implemented as needed on site and will be located out of areas of active construction activity. If possible, the designated area will be located so it can be utilized during the entire construction period. Stabilized staging areas will be inspected for adequate vehicle tracking control and perimeter control. The staging area will be repaired or modified as needed. No hazardous material will be stored on site. This CM is an administrative measure to control access to/from the site. Designated Vehicle Fueling and Maintenance Area During all active construction phases. vehicle fueling and maintenance will only be conducted in a designated area. Any waste (oil, antifreeze, solvents, etc.) will be disposed according to manufacturer's instructions or Material Safety Data Sheets (MSDS). Vehicles and equipment will be inspected for leaks. Leaks will be repaired on site immediately or the vehicle/equipment will be removed from the site. Spill kits will be readily available. Any spills will be immediately cleaned up and properly dispose as described in Section 6.4. Spill Control and Cleanup. No fuel will be stored on -site. Dust Control Dust control reduces dust generated from disturbed surfaces and wind. To control dust that may be generated at the project site during construction. water will be applied from water trucks as needed. Care will be taken to apply water per industry standard in small volumes and at a low rate to prevent surface runoff. Correct application is just enough water to moisten the surface and calm dust, but not so much as to create standing water and mud. Erosion Control Blankets (ECBs) and Turf Reinforcement Mats (TRMs) ECBs and TRMs are sheets of straw. excelsior, coconut, manmade fiber. or combination thereof, usually contained between layers of netting to provide structural integrity. ECBs and TRMs provide a ground cover that reduces erosive action. TRMs are able to handle higher levels of Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan concentrated flows and are used mainly in channel applications. ECBs and TRMs may be used in conjunction with other velocity reducing CMs. ECB and TRM applications include. but are not limited to. slope and swale protection. See attached detail for further description and applications (Standard Plan No. M-208-1. Temporary Erosion Control. from the Colorado Department of Transportation (CDOT) 2006 M -Standard (Miscellaneous Standard) Plans. rev 8-2010). ECB and TRMs will be inspected for erosion underneath and at the sides, sediment accumulation. rips. tears and other structural problems. Maintenance will include removing sediment (to be placed with topsoil stockpile), re -securing material to ground. and re -trenching at up -gradient portions and sides as needed. Good Housekeeping Practices Good housekeeping will be used to keep potential areas where pollutants exist clean and orderly. Any containers. drums, and bags will be stored away from direct traffic routes to reduce the risk of accidental spills. stacked according to manufacturer's instructions, and stored on pallets or similar items. Materials which require spill containment practices (described in Section 6) shall be stored in close proximity to an appropriately stocked spill response kit. Hazardous materials will not be stored on this site The site will be managed to keep materials, equipment. and portable sanitary facilities (these will additionally be staked to prevent/inhibit tipping) only in designated areas and promptly directing the thorough clean-up of any debris resulting from these operations. Stockpiles will be protected from run-on and run-off with berms. natural vegetative barriers, or structural CMs (straw wattles. straw bales. silt fence. etc.). Mulching Mulching uses materials such as grass, wood chips or fibers. hay. straw or native mowed vegetation to stabilize exposed or recently seeded soil and to reduce stormwater velocity and improve infiltration. It is most effective when used in conjunction with vegetation. Mulching can additionally aid vegetation growth by preventing birds from eating the seeds. retaining moisture. etc. Natural mulches will be used whenever possible. For steep slopes and critical areas. mulch matting with anchoring or matting will be utilized. The SWMP administrator will determine the appropriateness of utilizing mulching throughout the project. See attached detail for further description and applications (Figure C4-2, Mulching, from the Urban Drainage and Flood Control District Drainage Criteria Manual (V.3)). Since subject to erosion. mulched areas will be inspected frequently for effectiveness. Natural Vegetative Barrier A natural vegetative barrier is a preexisting vegetated area that is retained during construction to reduce water velocity and prevent erosion. Natural vegetative barrier provides a barrier zone where sediment is trapped. which reduces sediment discharge off -site. and are encouraged for any perimeter or environmentally sensitive areas. Whenever possible. a natural vegetative barrier will be maintained between the construction area and stormwater drainage areas For best efficiency. buffer strips should be a minimum of 20' in length along the direction of flow; shorter distances should be supplemented with additional CMs. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Perimeter control Perimeter control will control access during construction activity. Perimeter control will consist of various CMs. including, but not limited to controlled parking, controlled site entrances. vehicle tracking control. wire boundary fencing, etc. This CM is an administrative measure to control access to/from the site and to ensure the general public safety. Seeding Seeding involves the mechanical or hand application of specific seed mixes appropriate for the site location and soil type. Seeding provides plant growth to stabilize the soil reducing the likelihood of erosion or sediment transport and provides permanent stabilization. Drilling is the preferred method of seeding. As soon as practical, after the completion of final grading. disturbed surfaces as well as all areas which will not be hard surfaced or graveled, shall be properly prepared and seeded per the recommended seed mix below. To maximize seed germination and to utilize natural precipitation. seeding will normally occur from March to May or September to October. The SWMP Administrator will determine the appropriateness of seeding throughout the project. Seeding may be accompanied by an additional CM, such as mulching or straw mats. to protect the seed and soil from erosion during the germination and growth process. Straw mats will be stapled to the slopes and overlapped. Stockpiled topsoil will be redistributed over areas to be seeded. At the discretion of the SWMP administrator. a soil conditioner (3CY per 1,000 SF) may be rototilled into the top 6" of the topsoil soil before fine grading. The topsoil shall be graded to a reasonably even and smooth surface. Seed shall be uniformly distributed over the area. Drilled seed shall be applied .25 to .5 inches deep in rows spaced no more than 7 inches apart. On slopes steeper than 3:1, seed shall be applied by a mechanical broadcaster or hand broadcast at double the rate required for drill seeding. All seed sown by mechanical broadcasters shall be raked or dragged into the soil to a depth of W. Seed mix to be provided by Contractor to be approved by the owner. All seed must comply with Colorado weed seed guidelines. There should be no prohibited/noxious weed species seeds in the mix. Use certified Pure Live Seed (PLS). Deliver in original unopened containers with seed tags dealers warranty analysis attached. Seeded areas will be inspected every 14 days and after an erosion causing storm event to ensure that the soil stabilization method (e.g. surface roughening. erosion control blankets. etc.) was applied correctly and has not been compromised. The area will also be inspected for erosion and/or sediment deposition. If vegetation does not begin to grow in a seeded area after 4 to 6 weeks, the area will be reseeded, fertilized, and mulched. Maintenance items would include re- grading and seeding bare or areas of thin vegetative growth and/or adding additional CMs as appropriate. Seeded area will be inspected and monitored until the area obtains final stabilization. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan Solid Waste Management To reduce the risk of pollution at the project site. construction wastes require proper management and disposal. This includes location of refuse piles. materials that may be displaced by stormwater, trash disposal and spill prevention. Waste collection will be scheduled to prevent containers from overflowing. Debris stockpiles will be continuously monitored and dispose of properly throughout the construction period. Additionally. waste will be monitored around the site perimeter. The onsite portable sanitary facilities will be staked to prevent tipping and will be monitored and cleaned weekly. Trays can be used to contain spills. Any spills of sewage chemicals will be cleaned up according to Section 6.4. Surface Roughening Surface roughening consists of grooves or tracks installed in the soil surface, perpendicular to the slope. This is a temporary soil stabilization technique that works well in areas that will remain inactive for a short time. It reduces water velocity and promotes infiltration, thus decreasing the potential for erosion to occur. As areas are cleared. surfaces will be left rough to inhibit run-off sheeting from disturbed areas. Where practical, surfaces will be left in a roughened state and slopes will be graded (or "tracked") parallel to the contour to further inhibit sheet flow drainage. Any disturbed areas with no construction activity planned for more than 14 days or longer will be surfaced roughened. See attached detail for further guidance and potential applications ("Surface Roughening" SR -1 through SR -4 from Urban Drainage and Flood Control District Drainage Criteria Manual Volume 3). In areas where it is impractical to apply surface roughening using tracked equipment the surface may be manually raked to create the desired texture. 3.3 Phased CM Installation Phased CMs will be used in conjunction with the installation of permanent structural CMs (rip - rapped outfalls. culvert installations, etc.). Temporary additional sediment control and/or erosion control CMs will be added to the upstream side of the permanent CM. As an example. if new culverts are installed. rip -rapped scour protection will generally be installed at the outlet end. A temporary (phased) sediment control CM (usually straw bales or straw wattles) will be installed on the inlet side to prevent the culvert and the outlet rip -rap from silting in before the upstream ditch/drainage can be stabilized (usually with natural vegetation). Phased CMs can be a combination of both Structural and Non -Structural CMs. Refer to Appendix C for phased CM Installation. 3.4 Dedicated Concrete or Asphalt Batch Plants No onsite concrete or asphalt production will be used for this project unless approved by the owner. All concrete and asphalt will be imported and placed the same day. 3.5 Vehicle Tracking Control Vehicle tracking controls are used to prevent sediment transport from the construction site to paved or permanently graveled roads. These controls are: Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan • Controlled Parking • Controlled Site Entrance • Designated Staging Area • Dust Control • Vehicle Tracking Control. including management of general public traffic 3.6 Waste Management and Disposal (Including Concrete Washouts) On -site waste disposal including personnel trash. construction debris. sanitary wastes, etc. is prohibited. The following practices shall be implemented as directed. Concrete Washout Designated concrete washout(s) will be installed on site during construction phases involving concrete. The location of these washout(s) will be added to the site map. No concrete waste will be discharged directly into the ground without a containment feature. The concrete waste and/or excess wash water will be properly disposed as needed. Additionally. signs will clearly indicate the concrete washout location. Concrete washout water will not be discharged to receiving waters, storm sewer systems or the ground. Portable Sanitary Facilities Portable sanitary facilities will be provided (if necessary) in a convenient. level location away from traffic areas at least three feet from curb flow lines and paved/driving surfaces, storm drains. or retention areas. A qualified contractor will maintain and clean the units. inspect for any deficiencies, and keep the units in good working order. Portable sanitary facilities will be adequately anchored to prevent tipping. The construction contractor will be responsible for ensuring that the units are properly used and maintained. Solid Waste Large amounts of solid waste are not anticipated to be generated during this project. The majority of solid waste will be collected, removed from site. and properly disposed on a daily basis. If dumpsters are needed, they will be installed in a convenient, level location away from traffic areas, storm drains, drainage areas. or retention areas. The dumpsters will be kept off of paved surfaces (to avoid damages to the asphalt) and a qualified contractor will empty the dumpsters. as needed. The site perimeter will be monitored to ensure that all site personnel utilize the proper waste disposal practices and facilities. Hazardous Wastes Fuel and hazardous materials will not be stored at the site. 3.7 Product Specific Practices Due to the chemical makeup of specific products. certain handling and storage procedures are required to promote the safety of personnel and prevent the possibility of pollution. Site personnel Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan will be instructed to follow all directions and warnings for products used on the site. All pertinent information can be found on the Material Safety Data Sheets (MSDS) for each product. The appropriate MSDS will be located with each product container or in a readily accessible central location. 3.8 Groundwater and Stormwater Dewatering Based on the shallow nature of construction, dewatering of groundwater or stormwater is not anticipated on this project. The Division's Low Risk Discharge Guidance for Discharges of Uncontaminated Groundwater to Land allows the discharge of construction dewatering to the ground. under specific conditions. when appropriate control measures are implemented. It does not allow discharge of construction dewatering of non-stormwater to be discharged to the surface waters or to storm sewer systems without separate permit coverage. Although the Construction Stormwater permit does not authorize the conditional discharge of construction dewatering to the ground. discharge of uncontaminated groundwater to land may be covered under the Low Risk Discharge Guidance when all the provisions in the guidance document are adhered to. In all cases when groundwater is encountered. a geotechnical and/or a professional engineer will be consulted before proceeding with the project. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 4.0 FINAL STABILIZATION AND LONG-TERM STORMWATER MANAGEMENT 4.1 Temporary Stabilization Temporary stabilization must be implemented for earth disturbing activities on any portion of the site where ground disturbing construction activity has permanently ceased. or temporarily ceased for more than 14 calendar days. Temporary stabilization methods may include. but are not limited to, tarps. soil tackifier. and hydroseed. The 14 -day schedule may be exceeded when either the function of the specific area of the site requires it to remain disturbed. or. physical characteristics of the terrain and climate prevent stabilization. The constraints necessitating the alternative schedule must be documented. an alternate stabilization schedule provided. and all locations where the alternative schedule is applicable on the site map need to be identified. 4.2 Description of Final Stabilization Practices Final stabilization for disturbed areas of the site will be to return to their original condition or to the improved design (native re -vegetated areas. access roads, gravel yards. drainage basins. etc.) For disturbed areas, temporary CMs will be maintained until the final surface cover is constructed or established. 4.3 Final Stabilization Methods Final stabilization includes those measures taken to control pollutants in stormwater after soil disturbing activities are complete. Practices implemented to achieve final stabilization include: • Preparation of the soil prior to seed application: • Seed mix appropriate for the area will be broadcasted per recommended instructions; • Maintaining appropriate erosion and sediment control CMs until final stabilization is achieved: and • Removal of temporary CMs once work is completed and final stabilization achieved. 4.4 Final Stabilization Achievement Final stabilization of road surface areas and graveled areas will be achieved when the final surface (improved gravel surface. landscaping, etc.) is accepted by the Owner. Final stabilization will be reached when all ground surface disturbing activities at the site have been completed. and for all areas of ground surface disturbing activities where a uniform vegetative cover has been established with an individual plant density of at least 70 percent of pre -disturbance levels. or equivalent permanent, physical erosion reduction methods have been employed. Coverage under the Stormwater Construction Permit may be terminated by the permittee when the entire site has attained final stabilization. all temporary erosion and sediment control measures have been removed. and all components of the SWMP are complete. Vegetative ground cover shall be greater than 70% of the pre -construction cover. 0.70 x 0.2-0.50, or approximately 15-35% Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan vegetation coverage depending on the location, for areas of disturbance that are not hard surfaced. graveled. or landscaped. When the site has attained final stabilization and all temporary erosion and sediment control measures have been removed, the permittee will submit an Inactivation Notice form. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 5.0 INSPECTION AND MAINTENANCE 5.1 Minimum Inspection Schedule A thorough inspection will be conducted within 7 calendar days of the commencement of construction activities, and in accordance with one of the following minimum frequencies: • At least one inspection every 7 calendar days • At least one inspection every 14 calendar days, PLUS post -storm even inspections conducted within 24 hours after the end of any precipitation or snowmelt event that causes surface erosion. Post -storm inspections may be used to fulfill the 14 -day routine inspection requirement. Inspections will be conducted on either the 7 day or 14 day schedule. and may switch between these schedules as appropriate for the site. The inspection frequency will be noted on the inspection reports. There are no discharges to Outstanding Waters: therefore inspections will not be required at least once every 7 days. 5.1.1 Post -storm inspections Post -storm inspections will be conducted within 24 hours after the end of any precipitation or snowmelt event that causes surface erosion. If no construction activities will occur following a storm event. post -storm event inspections will be conducted prior to re -commencing construction activities. but no later than 72 hours following the storm event. The delayed inspection will be documented in the inspection record. 5.1.2 Inspections at Completed Sites/Areas For completed construction sites, an inspection of the site will be made at least once every month until final stabilization is reached. The following must be met in order for the site to be inspected on a monthly basis instead of every 14 days: • All construction activities that will result in surface ground disturbance are completed: • All activities required for final stabilization have been completed, with the exception of the application of seed that has not occurred due to seasonal conditions or the necessity for additional seed application to augment previous efforts; and • The SWMP has been amended to indicate those areas that will be inspected in accordance with the reduced schedule. The reduced frequency schedule also applies to the site or portions of the site where continuing construction activities can be conducted without disturbance of the ground surface. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 5.1.3 Winter Conditions Inspections Exclusion Inspections will not be conducted where construction activities are temporarily halted. snow cover exists over the entire site for an extended period. and melting conditions posing a risk of surface erosion do not exist. The following information will be documented in the inspection record for use of this exclusion: • Dates when snow cover occurred, • Date when construction activities ceased. and • Date melting conditions began. 5.2 Inspection Requirements Inspections should include a visual verification of whether all implemented control measures are in effective operational condition and are working as designed to minimize pollutant discharges. It should be determined if there are new potential sources of pollutants. The adequacy of control measures should be assessed to identify areas requiring new or modified control measures. All areas of non-compliance should be identified and corrective actions implemented. 5.2.1 Inspection Scope The following items will be examined for evidence of, or the potential for, pollutants leaving the construction site boundaries. entering the stormwater drainage system. or discharging to state waters during the inspection and reported on the inspection reports: • Construction site perimeter: • All disturbed areas; • Designated haul routes: • Material and/or waste storage areas that are exposed to precipitation: • Discharge locations; • Locations where vehicles access the site: and • All CMs implemented will be evaluated to ensure that they are maintained and operating correctly 5.2.2 Inspection Reports The inspection report form is located in Appendix D. Inspection reports must identify any incidents of non-compliance with the terms and conditions of the general permit. The inspection records will be retained for three years from the expiration or inactivation of permit coverage. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan The inspection record will note evidence of. or the potential for. pollutants leaving the construction site boundaries. entering the stormwater drainage system. or discharging to state waters. The inspection report will include: • The inspection date: • Name(s) and title(s) of personnel making the inspection; • Weather conditions at the time of inspection: • Phase of construction at the time of inspection; • Estimated acreage of disturbance at the time of inspection; • Location(s) of discharges of sediment or other pollutants from the site: • Location(s) of CMs that need to be maintained: • Location(s) and identification of inadequate control measures • Location(s) and identification of additional control measures needed that were not in place at the time of inspection • Description of the minimum inspection frequency. and any deviations from the minimum inspection schedule: • Identification of control measures observed that require routine maintenance (any control measure that is still operating in accordance with its design and the requirements of the permit. but requires maintenance to prevent a breach of the control measure). • After adequate corrective action(s) have been taken, or where a report does not identify any incidents requiring corrective action the report will contain a signed statement indicating "all corrective action and maintenance items identified during the inspection are complete. and the site is currently in compliance with the permit." 5.3 Required Actions Following Site Inspections CMs will be maintained or replaced in accordance with Sections 5.4 and 5.5 of this SWMP. The SWMP will be updated in accordance with Section 5.6.3. Where site inspections note the need for CM maintenance activities. CMs must be maintained such that the conditions in those sections are met. 5.4 CM Maintenance All erosion and sediment control practices and other protective measures identified in the SWMP will be maintained in effective operating condition in accordance with Section 3.0 and Appendix B. CMs that are not adequately maintained in accordance with good engineering, hydrologic and pollution control practices are considered to be no longer operating effectively and will be modified or replaced. CMs implemented at the site must be adequately designed and maintained to provide control for all potential pollutant sources associated with the construction activity to prevent pollution or degradation of State waters. Where site inspections note the need for CM maintenance activities, CMs will be maintained such as these conditions are met. Maintenance Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan items include. but are not limited to: removal of accumulated sediment, repair or replacement of worn or damaged sections. repositioning to correct placement: and reinstallation of CMs displaced. Accumulated sediment and debris will be removed from a CM when the sediment level reaches one-half the height of the CM (unless otherwise noted in the design drawings or CM detail) or at any time that sediment or debris adversely impacts the functioning of the CM. 5.5 Corrective Actions Adequate site assessment will be performed as part of the comprehensive inspection and maintenance procedures. to assess the adequacy of CMs at the site. and the necessity of changes to those CMs to ensure continued effective performance. When an inadequate control measure is identified, the following corrective action requirements apply: All necessary steps must be taken to minimize or prevent the discharge of pollutants. until a control measure is implemented and made operational and/or an inadequate control measure is replaced or corrected and returned to effective operating condition. • If it is infeasible to install or repair a control measure immediately after discovering the deficiency.. the following information must be documented and kept on record: o Describe why it is infeasible to initiate the installation or repair immediately, and o Provide a schedule for installing or repairing the control measure and returning it to an effective operating condition as soon as possible. If applicable. any unauthorized release or discharge must be removed and properly disposed of. Contaminated surfaces must be cleaned up to minimize discharges of the material in subsequent storm events. 5.6 SWMP Requirements 5.6.1 SWMP Availability The SWMP will be implemented prior to commencement of construction activities. The SWMP will be kept accurate and up-to-date, and will reflect the actual on site ground conditions. Only changes in site conditions that require new or modified CMs need to be addressed in the SWMP. 5.6.2 SWMP Retention A copy of the SWMP must be retained on site unless another location, specified by the permittee. is approved by the Division. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 5.6.3 SWMP Amendment The SWMP will be amended: • When there is a change in design, construction. operation, or maintenance of the site. which would require the implementation of new or revised CMs: or • If the SWMP proves to be ineffective in achieving the general objectives of controlling pollutants in stormwater discharges associated with construction activity: or • When CMs are no longer necessary and are removed. SWMP changes will be made prior to changes in the site conditions. except as noted below under "Responsive SWMP Changes." SWMP revisions may include, but are not limited to: potential pollutant source identification: selection of appropriate CMs for site conditions: CM maintenance procedures; and interim and final stabilization practices. The SWMP changes may include a schedule for further CM design and implementation, provided that, if any interim CMs are needed to comply with the permit. they are also included in the SWMP and implemented during the interim period. For SWMP revisions made prior to or following a change(s) onsite, including revisions to sections addressing site conditions and control measures.. a notation must be included in the plan that identifies; the date of the site change; the control measure removed or modified: the location(s) of those control measures: and any changes to the control measure(s). 5.6.4 Responsive SWMP Changes The majority of SWMP revisions to address changing site conditions can be made immediately with simple field revisions to the SWMP. In the less common scenario where more complex development of materials to modify the SWMP are necessary, SWMP revisions will be made in accordance with the following requirements: • The SWMP will be revised as soon as practicable, but in no case more than 72 hours after the change(s) in CM installation and/or implementation occur at the site, and • A notation must be included in the site map prior to the site change(s) that includes the date of the change(s) in the field. an identification of the CM(s) removed or added. and the location(s) of those CM(s). Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 5.7 RECORD KEEPING Copies of the SWMP, amendments to or changes to the SWMP. inspection records and all other data must be retained by the owner (permittee) for three (3) years after the expiration or inactivation of the permit. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 6.0 SPILL PREVENTION AND RESPONSE 6.1 Introduction This section describes measures to prevent, control. and minimize impacts from a spill of chemical products (hazardous. toxic, or petroleum substances) during construction of this project. This plan identifies the handling. transportation. storage. and disposal procedures for these chemical products and outlines procedures to be followed in the event of a spill. 6.2 Material Management Practices Properly managing these materials on the site will greatly reduce the potential for stormwater pollution. Good housekeeping along with proper use and storage of these construction materials form the basis for proper management of chemical products. 6.2.1 Good Housekeeping The proper use of materials and equipment along with the use of general common sense greatly reduce the potential for contaminating stormwater runoff. The following is a list of good housekeeping practices to be used during the construction project. • Provide secondary containment (or equivalent protection) for any container containing 55 gallons or greater. • Fueling of construction equipment will not be performed within 150 feet of definitive stormwater drainages. • An effort will be made to store only enough product required to do the job. • Materials will be stored in a neat, orderly manner, in appropriate closed containers. in secondary containment and, if possible, under a roof or other enclosure. • Products will be kept in their original containers with the original manufacturer's label. • Substances will not be mixed with one another unless recommended by the manufacturer. • Whenever possible, all of the product will be used up before properly disposing of the container. • Manufacturer's recommendations for proper use of a product will be followed. • If surplus product must be disposed of. local and state recommended methods for proper disposal will be followed. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 6.3 Product -Specific Practices Due to the chemical makeup of specific products. certain handling and storage procedures are required to promote the safety of personnel and prevent the possibility of pollution. Care will be taken to follow all directions and warnings for products used on the site. All pertinent information can be found on the Material Safety Data Sheets (MSDS) for each product. The MSDSs will be located with each product container it represents or in a readily accessible central location. Several product -specific practices are listed in the following sections. 6.3.1 Flammable and Combustible Liquids and Hazardous Materials All products will be stored in tightly sealed containers that are clearly labeled. The containers will be stored in secondary containment, which will be of sufficient size to contain the entire contents of the primary container plus a sufficient quantity for precipitation (a total of approximately 110 percent of the volume of the primary container). The secondary containment will be an impermeable containment basin to prevent any spills or leaks from reaching the ground. The containment may be one of the following or other means that meets the definition of impermeable: 1) a temporary earthen berm lined with 20-m1 plastic. 2) a portable tank or basin, or 3) a galvanized steel trough. After each storm event.. all secondary containment areas will be inspected. If there is no visible sheen on the collected water. it can be pumped or drained to the ground in a manner that does not cause scouring. If a sheen is present. it must be cleaned up using absorbent materials prior to discharging or disposing of the water. The absorbent material will be disposed of properly. 6.3.2 Petroleum Products In addition to the requirements above in Section 6.2.1. petroleum products are required to have some additional procedures for handling and storage to prevent the possibility of pollution. On -site vehicles will be monitored for leaks and receive regular maintenance to reduce the potential for leakage. Bulk fuel or lubricating oil dispensers will have a valve that must be manually held open to allow the flow of fuel. When not in use, the fuel dispensing nozzles and/or associated hoses will be kept inside the containment basin. During fueling operations, personnel will be present at all times to detect and contain spills. If any spills or leaks occur. the activity will be stopped immediately. and the containment and cleanup will begin immediately. In addition. the contractor will follow the procedure listed in Section 6.4. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 6.4 Spill Control and Cleanup In addition to the material management practices discussed in Section 6.2, the following spill control and cleanup practices will be followed to prevent stormwater pollution in the event of a spill: • Spills will be contained and cleaned up immediately after discovery. • Manufacturer's methods for spill cleanup of a material will be followed as described on the material's MSDS. • Materials and equipment needed for cleanup procedures ("spill kits") will be kept readily available on the site. either at an equipment storage area or on contractor's trucks. Equipment to be kept on the site may include but is not be limited to brooms, dust pans. shovels. granular absorbents. sand. sawdust. absorbent pads and socks. plastic and metal trash containers, gloves, and goggles. • Drums containing used clean up materials will be labeled with the contents and date. • Personnel on the site will be made aware of cleanup procedures and the location of spill cleanup equipment. In general. every vehicle with bulk fuel or petroleum lubrication supplies will be outfitted with a spill containment and clean-up kit. • The contractor will be responsible for all cleanup activities in accordance with applicable local, state. and federal regulations. 6.5 Spill Reporting If a spill occurs. the contractor is responsible for immediately (within 5 to 10 minutes) reporting the spill to the Owners Authorized Technical Representative/Project Manager the Tri-State Environmental Services at (303) 349-7711. Tri-State Environmental Services is responsible for calling all agencies in the event of a spill. If there is a spill of antifreeze. gasoline or oils from personal vehicles. it does not need to be reported to Tri-State's Environmental Services or the SWMP Administrator, but should be documented and kept with the master SWMP. All spills should be documented using the "Spill Report" form provided in Appendix E and a record kept with the master SWMP. Copies of the forms can be found in Appendix E. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan 6.6 SWMP Modification Procedures Related to Reportable Releases If a reportable release occurs, a modification to the SWMP must be made within 14 days. The modification will include: a description of the release. the date of the release. an explanation of why the spill happened, a description of procedures to prevent future spills and/or releases from happening. and a description of response procedures should a spill or release occur again and within 14 days of the release. A written description of the release must be submitted to the permitting authority that includes: a description of the release, including the type of material and an estimated amount of spill. the date of the release: an explanation of why the spill happened: and a description of the steps taken to prevent and control future releases. The SWMP Administrator will submit spill reports to the appropriate agencies. Modifications to the SWMP will be made by the SWMP Administrator. or his designee. and will be documented on the "New CMs Added to the Site" form in Appendix C. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan APPENDIX A: Site Maps Tri-State Generation & Transmission — Lloyd Sisson Substation I II I II I I 1 i { t I _ I I I I I I I j .. , !! I I I I I I I1� II • SYMBOL LEGEND 1‘ / I I I t -,--, CDminamla + / in tit WOW. RMiiEt goon l I II I I I re llama / J® I I { Nor ,1 I _~ a>. star., .w/ • I I I I I I ... VMS Mal / I I I N. kisinRat I t ® µl lliw - — — I fix'. ) UMW .OumilM.a tP ,u ,+ nrtna — ..// / I+I I 10 0 ,a so I 1 I I I I I tali 7116.04•C ND I I I I I { \ / SE main rtr- 1:'. I I I I I I stag mow .aura saw / II I I I I .y ,alrusu 'Oki , 1 / I COUNTY ROAD 71 I I / \\\ � \ e — �\ I I11 /// 11 / t / ` / / I I I I II i I I I I I I I I I I ; • I I I I ; ON SUBSTATION CONTROL PLAN TION B rRANSANSSION INCORPORATED I e ,- i f / I ,I \ I / \\\\ I I l_ !IN I I I i I I I i I I I i I I I i I I I I LLOYD SISSC TRT- S TA rE GENERA ASSOCIA?TON. I I I Ivw I I iiitV �I I I -• J I I I i� I I I . FW- I S T I PROJECTBOUNDARV - iP P // I / / / I / I I { Q [1<;s_ ¢ t _ I I / �\ I + go I 1 1 Ankl !J!T is ; ` A `— I 110W'" L�1 w — — COUNTY ROAD 130 _ ... { 51142-A-01-013 Stormwater Management Plan APPENDIX B: Soil erosion and Sediment Control Measures (CMs) Details Tri-State Generation & Transmission — Lloyd Sisson Substation Check Dams (CD) EC -12 Description Check dams are temporary grade control structures placed in drainage channels to limit the erosivity of stormwater by reducing flow velocity. Check dams are typically constructed from rock, gravel bags, sand bags, or sometimes, proprietary devices. Reinforced check dams are typically constructed from rock and wire gabion. Although the primary function of check dams is to reduce the velocity of concentrated flows, a secondary benefit is sediment trapping upstream of the structure. Appropriate Uses Photograph CD -1. Rock check dams in a roadside ditch. Photo courtesy of WWI... Use as a grade control for temporary drainage ditches or swales until final soil stabilization measures are established upstream and downstream. Check dams can be used on mild or moderately steep slopes. Check dams may be used under the following conditions: • As temporary grade control facilities along waterways until final stabilization is established. • Along permanent swales that need protection prior to installation of a non -erodible lining. • Along temporary channels, ditches or swales that need protection where construction of a non - erodible lining is not practicable. • Reinforced check dams should be used in areas subject to high flow velocities. Design and Installation Place check dams at regularly spaced intervals along the drainage swale or ditch. Check dams heights should allow for pools to develop upstream of each check dam, extending to the downstream toe of the check dam immediately upstream. When rock is used for the check dam, place rock mechanically or by hand. Do not dump rocks into the drainage channel. Where multiple check dams are used, the top of the lower dam should be at the same elevation as the toe of the upper dam. When reinforced check dams are used, install erosion control fabric under and around the check dam to prevent erosion on the upstream and downstream sides. Each section of the dam should be keyed in to reduce the potential for washout or undermining. A rock apron upstream and downstream of the dam may be necessary to further control erosion. Check Dams Functions Erosion Control Yes Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 CD -1 EC -12 Check Dams (CD) Design details with notes are provided for the following types of check dams: • Rock Check Dams (CD -1) • Reinforced Check Dams (CD -2) Sediment control logs may also be used as check dams; however, silt fence is not appropriate for use as a check dam. Many jurisdictions also prohibit or discourage use of straw bales for this purpose. Maintenance and Removal Replace missing rocks causing voids in the check dam. If gravel bags or sandbags are used, replace or repair torn or displaced bags. Remove accumulated sediment, as needed to maintain BMP effectiveness, typically before the sediment depth upstream of the check dam is within '/z of the crest height. Remove accumulated sediment prior to mulching, seeding, or chemical soil stabilization. Removed sediment can be incorporated into the earthwork with approval from the Project Engineer, or disposed of at an alternate location in accordance with the standard specifications. Check dams constructed in permanent swales should be removed when perennial grasses have become established, or immediately prior to installation of a non -erodible lining. All of the rock and accumulated sediment should be removed, and the area seeded and mulched, or otherwise stabilized. CD -2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Check Dams (CD) EC -12 COMPACTED BACKFILL, (1W.) CHANNEL GRADE UPSTREAM AND DOWNSTREAM 1' 6" FLOW MIN. 1' MIN. LENGTH. L TOP OF' CHECK DAM CHECK DAM ELEVATION VIEW 2' 6' D50 = 12" RIPRAP, TYPE M OR TYPE L D50= 9" (SEE TABLE MD -7, MAJOR DRAINAGE, VOL. 1 FOR GRADATION) FLOW -•- 1' MIN. D50 =12" RIPRAP, TYPE NI OR TYPE L D50=9" (SEE TABLE MD -7, MAJOR DRAINAGE, VOL. 1 FOR GRADATION) SECTION A 8' 1 SECTION B CHANNEL GRADE EXCAVATION TO NEAT LINE, AVOID OVER -EXCAVATION, (TYP.) r CHANNEL GRADE EXCAVATION TO NEAT - LINE, AVOID OVER -EXCAVATION (TYP.) SPACING BETWEEN CHECK DAMS SUCH THAT A AND B ARE EQUAL ELEVATION CHANNEL GRADE PROFILE CD 1. CHECK DAM November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 CD -3 EC -12 Check Dams (CD) CHECK DAM INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATION OF CHECK DAMS. -CHECK DAM TYPE (CHECK DAM OR REINFORCED CHECK DAM). -LENGTH (L), CREST LENGTH (CL), AND DEPTH (0). 2. CHECK DAMS INDICATED ON INITIAL SWMP SHALL BE INSTALLED AFTER CONSTRUCTION FENCE, BUT PRIOR TO ANY UPSTREAM LAND DISTURBING ACTIVITIES. 3. RIPRAP UTIUZED FOR CHECK DAMS SHOULD BE OF APPROPRIATE SIZE FOR THE APPUCATION. TYPICAL TYPES OF RIPRAP USED FOR CHECK DAMS ARE TYPE M (D50 12") OR TYPE L (D50 9"). 4. RIPRAP PAD SHALL BE TRENCHED INTO THE GROUND A MINIMUM OF 1'. 5. THE ENDS OF THE CHECK DAM SHALL BE A MINIMUM OF 1' 6' HIGHER THAN THE CENTER OF THE CHECK DAM. f.HFCK DAM MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF THE CHECK DAMS SHALL BE REMOVED WHEN THE SEDIMENT DEPTH IS WITHIN OF THE HEIGHT OF THE CREST. 5. CHECK DAMS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 6 WHEN CHECK DAMS ARE REMOVED, EXCAVATIONS SHALL BE FILLED WITH SUITABLE COMPACTED BACKFILL. DISTURBED AREA SHALL BE SEEDED AND MULCHED AND COVERED WITH GEOTEXTILE OR OTHERWISE STABIUZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGLAS COUNTY. COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CD -4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Check Dams (CD) EC -12 ALTERNATIVE TO STEPS ON BANKS ABOVE CREST: DEFORM GABIONS AS NECESSARY TO ALIGN TOP OF GABIONS WITH GROUND SURFACE: AVOID GAPS BETWEEN GABIONS COMPACTED BACKFILL LENGTH, L MAX. STEP HEIGHT 1'6" 1 CREST LENGTH. CL TYP 0 (1'6" MIN) 1 HOG RINGS (rrP) MIN. BURY DEPTH 1'6" -\ROCK FILLED GABION SECURED TO ADJACENT GABION REINFORCED CHECK DAM ELEVATION VIEW FLOW COMPACTED BACKFILL 3' D50=6" RIPRAP ENCLOSED IN GABION 1'6" 6" MIN. CHANNEL GRADE GEOTEXTILE BLANKET SECTION A REINFORCED CHECK DAM INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATIONS OF CHECK DAMS. -CHECK DAM TYPE (CHECK DAM OR REINFORCED CHECK DAM). -LENGTH (L), CREST LENGTH (CL), AND DEPTH (D). 2. CHECK DAMS INDICATED ON THE SWMP SHALL BE INSTALLED PRIOR TO AN UPSTREAM LAND -DISTURBING ACTIVITIES. 3. REINFORCED CHECK DAMS, GABIONS SHALL HAVE GALVANIZED TWISTED WIRE NETTING WITH A MAXIMUM OPENING DIMENSION OF 4X" AND A MINIMUM WIRE THICKNESS OF 0.10". WIRE "HOG RINGS" AT 4" SPACING OR OTHER APPROVED MEANS SHALL BE USED AT ALL GABION SEAMS AND TO SECURE THE GABION TO THE ADJACENT SECTION. 4. THE CHECK DAM SHALL BE TRENCHED INTO THE GROUND A MINIMUM OF 1' 6". 5. GEOTEXTILE BLANKET SHALL BE PLACED IN THE REINFORCED CHECK DAM TRENCH EXTENDING A MINIMUM OF 1' 6" ON BOTH THE UPSTREAM AND DOWNSTREAM SIDES OF THE REINFORCED CHECK DAM. CD -2. REINFORCED CHECK DAM November 2010 Urban Drainage and Flood Control District CD -5 Urban Storm Drainage Criteria Manual Volume 3 EC -12 Check Dams (CD) REINFORCED CHECK DAM MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF REINFORCED CHECK DAMS SHALL BE REMOVED AS NEEDED TO MAINTAIN THE EFFECTIVENESS OF BMP, TYPICALLY WHEN THE UPSTREAM SEDIMENT DEPTH IS WITHIN ti THE HEIGHT OF THE CREST. 5. REPAIR OR REPLACE REINFORCED CHECK DAMS WHEN THERE ARE SIGNS OF DAMAGE SUCH AS HOLES IN THE GABION OR UNDERCUTTING. 6. REINFORCED CHECK DAMS ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABIUZED AND APPROVED BY THE LOCAL JURISDICTION. 7. WHEN REINFORCED CHECK DAMS ARE REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED, AND COVERED WITH A GEOTEXT1LE BLANKET, OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND CITY OF AURORA, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CD -6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Concrete Washout Area (CWA) MM -1 Description Concrete waste management involves designating and properly managing a specific area of the construction site as a concrete washout area. A concrete washout area can be created using one of several approaches designed to receive wash water from washing of tools and concrete mixer chutes, liquid concrete waste from dump trucks, mobile batch mixers, or pump trucks. Three basic approaches are available: excavation of a pit in the ground, use of an above ground storage area, or use of prefabricated haul - away concrete washout containers. Surface discharges of concrete washout water from construction sites are prohibited. Appropriate Uses ttmuNw nn[nnl I uuu@I Ili: fl ain t , Photograph CWA-1. Example of concrete washout area. Note gravel tracking pad for access and sign. Concrete washout areas must be designated on all sites that will generate concrete wash water or liquid concrete waste from onsite concrete mixing or concrete delivery. Because pH is a pollutant of concern for washout activities, when unlined pits are used for concrete washout, the soil must have adequate buffering capacity to result in protection of state groundwater standards; otherwise, a liner/containment must be used. The following management practices are recommended to prevent an impact from unlined pits to groundwater: • The use of the washout site should be temporary (less than 1 year), and • The washout site should be not be located in an area where shallow groundwater may be present, such as near natural drainages, springs, or wetlands. Design and Installation Concrete washout activities must be conducted in a manner that does not contribute pollutants to surface waters or stormwater runoff Concrete washout areas may be lined or unlined excavated pits in the ground, commercially manufactured prefabricated washout containers, or aboveground holding areas constructed of berms, sandbags or straw bales with a plastic liner. Although unlined washout areas may be used, lined pits may be required to protect groundwater under certain conditions. Do not locate an unlined washout area within 400 feet of any natural drainage pathway or waterbody or within 1,000 feet of any wells or drinking water sources. Even for lined concrete washouts, it is advisable to locate the facility away from waterbodies and drainage paths. If site constraints make these Concrete Washout Area Functions Erosion Control No Sediment Control No Site/Material Management Yes November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 CWA-1 MM -1 Concrete Washout Area (CWA) setbacks infeasible or if highly permeable soils exist in the area, then the pit must be installed with an impermeable liner (16 mil minimum thickness) or surface storage alternatives using prefabricated concrete washout devices or a lined aboveground storage area should be used. Design details with notes are provided in Detail CWA-1 for pits and CWA-2 for aboveground storage areas. Pre -fabricated concrete washout container information can be obtained from vendors. Maintenance and Removal A key consideration for concrete washout areas is to ensure that adequate signage is in place identifying the location of the washout area. Part of inspecting and maintaining washout areas is ensuring that adequate signage is provided and in good repair and that the washout area is being used, as opposed to washout in non -designated areas of the site. Remove concrete waste in the washout area, as needed to maintain BMP function (typically when filled to about two-thirds of its capacity). Collect concrete waste and deliver offsite to a designated disposal location. Upon termination of use of the washout site, accumulated solid waste, including concrete waste and any contaminated soils, must be removed from the site to prevent on -site disposal of solid waste. If the wash water is allowed to evaporate and the concrete hardens, it may be recycled. walb a►t. St.*. •.m AC: `CStR C WASH -OUT Photograph ('WA -2. Prefabricated concrete Washout. Photo Photograph CWA-3. Earthen concrete washout. Photo courtesy of CD(Yf. CWA-2 courtesy of CDOT. Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Concrete Washout Area (CWA) MM -1 1 12" TYP. 1�->4� UNDISTURBED OR 3 COMPACTED SOIL >3 Y _ CONCRETE WASHOUT AREA PLAN COMPACTED BERM AROUND THE PERIMETER CONCRETE WASHOUT SIGN 25 MIN. VEHICLE TRACKING CONTROL (SEE VTC DETAIL) OR OTHER STABLE SURFACE 2% SLOPE 3 i MIN. I 1 >Y4).Y'i>i i/i.Yi, t . >3 8 X 8 MIN. 1 SECTION A j =3 VEHICLE TRACKING CONTROL (SEE VTC - DETAIL ) CWA-1. CONCRETE WASHOUT AREA CWA INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -CWA INSTALLATION LOCATION. 2. DO NOT LOCATE AN UNLINED CWA WITHIN 400' OF ANY NATURAL DRAINAGE PATHWAY OR WATERBODY. DO NOT LOCATE WITHIN 1,000' OF ANY WELLS OR DRINKING WATER SOURCES. IF SITE CONSTRAINTS MAKE THIS INFEASIBLE, OR IF HIGHLY PERMEABLE SOILS EXIST ON SITE, THE CWA MUST BE INSTALLED WITH AN IMPERMEABLE LINER (16 MIL MIN. THICKNESS) OR SURFACE STORAGE ALTERNATIVES USING PREFABRICATED CONCRETE WASHOUT DEVICES OR A LINED ABOVE GROUND STORAGE ARE SHOULD BE USED. 3. THE CWA SHALL BE INSTALLED PRIOR TO CONCRETE PLACEMENT ON SITE. 4. CWA SHALL INCLUDE A FLAT SUBSURFACE PIT THAT IS AT LEAST 8' BY 8' SLOPES LEADING OUT OF THE SUBSURFACE PIT SHALL BE 3:1 OR FLATTER. THE PIT SHALL BE AT LEAST 3' DEEP. 5. BERM SURROUNDING SIDES AND BACK OF THE CWA SHALL HAVE MINIMUM HEIGHT OF 1'. 6. VEHICLE TRACKING PAD SHALL BE SLOPED 2% TOWARDS THE CWA. 7. SIGNS SHALL BE PLACED AT THE CONSTRUCTION ENTRANCE, AT THE CWA, AND ELSEWHERE AS NECESSARY TO CLEARLY INDICATE THE LOCATION OF THE CWA TO OPERATORS OF CONCRETE TRUCKS AND PUMP RIGS. 8. USE EXCAVATED MATERIAL FOR PERIMETER BERM CONSTRUCTION. November 2010 Urban Drainage and Flood Control District CWA-3 Urban Storm Drainage Criteria Manual Volume 3 MM -1 Concrete Washout Area (CWA) CWA MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. THE CWA SHALL BE REPAIRED, CLEANED, OR ENLARGED AS NECESSARY TO MAINTAIN CAPACITY FOR CONCRETE WASTE. CONCRETE MATERIALS, ACCUMULATED IN PIT, SHALL BE REMOVED ONCE THE MATERIALS HAVE REACHED A DEPTH OF 2'. 5. CONCRETE WASHOUT WATER, WASTED PIECES OF CONCRETE AND ALL OTHER DEBRIS IN THE SUBSURFACE PIT SHALL BE TRANSPORTED FROM THE JOB SITE IN A WATER -TIGHT CONTAINER AND DISPOSED OF PROPERLY. 6 THE CWA SHALL REMAIN IN PLACE UNTIL ALL CONCRETE FOR THE PROJECT IS PLACED. 7. WHEN THE CWA IS REMOVED, COVER THE DISTURBED AREA WITH TOP SOIL, SEED AND MULCH OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAIL ADAPTED FROM DOUGLAS COUNTY, COLORADO AND THE CITY OF PARKER, COLORADO, NOT AVAILABLE IN AUTOCAD). NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UOFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. CWA-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 CONCRETE WASHOUT "KIDDIE" POOL N.T.S LIQUID CONCRETE WASHOUT WASTE DRIED CONCRETE WASHOUT WASTE (TYPICAL) • • , a • n 48" "KIDDIE POOL" NOTES: 1. Use only rigid, prefabricated impermeable plastic wading pool. 2. Inspect Containment for waterproof integrity prior to each use. 3. Do not fill Containment more than 50% of capacity with either liquid or solid concrete waste. 4. Immediately after each use, cover the Containment with a waterproof barrier to prevent collection of rain water or snow. 5. Properly dispose of dried concrete waste at a landfill when the project is complete or when waste reaches a 50% capacity. �1G DEL-MONT CONSULTANTS, INC. ENGINEERING • SURVEYING • PLANNING IS CAWS a• Y•ra CO •ie V OM Mal • PIW fl1ilp no N/A ECCD 8� SNS SCALE N.T.S. F4E NAME CONCRETE WASHOUT • KIDDIE POOL BMP DETAIL CONCRETE WASHOUT - "KIDDIE" POOL OW 1O84O N/A DATE ISSUED 5-13-2011 1of1 t _ Inlet Protection (IP) SC -6 Description Inlet protection consists of permeable barriers installed around an inlet to filter runoff and remove sediment prior to entering a storm drain inlet. Inlet protection can be constructed from rock socks, sediment control logs, silt fence, block and rock socks, or other materials approved by the local jurisdiction. Area inlets can also be protected by over -excavating around the inlet to form a sediment trap. Appropriate Uses Install protection at storm sewer inlets that are operable during construction. Consider the potential for tracked -out sediment or temporary stockpile areas to contribute sediment to inlets when determining which inlets must be protected. This may include inlets in the general proximity of the construction area, not limited to downgradient inlets. Inlet protection is not a stand-alone BMP and should be used in conjunction with other upgradient BMPs. Photograph IP-1. Inlet protection for a curb opening inlet. Design and Installation To function effectively, inlet protection measures must be installed to ensure that flows do not bypass the inlet protection and enter the storm drain without treatment. However, designs must also enable the inlet to function without completely blocking flows into the inlet in a manner that causes localized flooding. When selecting the type of inlet protection, consider factors such as type of inlet (e.g., curb or area, sump or on -grade conditions), traffic, anticipated flows, ability to secure the BMP properly, safety and other site -specific conditions. For example, block and rock socks will be better suited to a curb and gutter along a roadway, as opposed to silt fence or sediment control logs, which cannot be properly secured in a curb and gutter setting, but are effective area inlet protection measures. Several inlet protection designs are provided in the Design Details. Additionally, a variety of proprietary products are available for inlet protection that may be approved for use by local governments. If proprietary products are used, design details and installation procedures from the manufacturer must be followed. Regardless of the type of inlet protection selected, inlet protection is most effective when combined with other BMPs such as curb socks and check dams. Inlet protection is often the last barrier before runoff enters the storm sewer or receiving water. Design details with notes are provided for these forms of inlet protection: IP-1. Block and Rock Sock Inlet Protection for Sump or On -grade Inlets IP-2. Curb (Rock) Socks Upstream of Inlet Protection, On -grade Inlets Inlet Protection (various forms) Functions Erosion Control No Sediment Control Yes Site/Material Management No August 2013 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 IP-1 SC -6 Inlet Protection (IP) IP-3. Rock Sock Inlet Protection for Sump/Area Inlet IP-4. Silt Fence Inlet Protection for Sump/Area Inlet IP-5. Over -excavation Inlet Protection IP-6. Straw Bale Inlet Protection for Sump/Area Inlet CIP-l. Culvert Inlet Protection Propriety inlet protection devices should be installed in accordance with manufacturer specifications. More information is provided below on selecting inlet protection for sump and on -grade locations. Inlets Located in a Sump When applying inlet protection in sump conditions, it is important that the inlet continue to function during larger runoff events. For curb inlets, the maximum height of the protective barrier should be lower than the top of the curb opening to allow overflow into the inlet during larger storms without excessive localized flooding. If the inlet protection height is greater than the curb elevation, particularly if the filter becomes clogged with sediment, runoff will not enter the inlet and may bypass it, possibly causing localized flooding, public safety issues, and downstream erosion and damage from bypassed flows. Area inlets located in a sump setting can be protected through the use of silt fence, concrete block and rock socks (on paved surfaces), sediment control logs/straw wattles embedded in the adjacent soil and stacked around the area inlet (on pervious surfaces), over -excavation around the inlet, and proprietary products providing equivalent functions. Inlets Located on a Slope For curb and gutter inlets on paved sloping streets, block and rock sock inlet protection is recommended in conjunction with curb socks in the gutter leading to the inlet. For inlets located along unpaved roads, also see the Check Dam Fact Sheet. Maintenance and Removal Inspect inlet protection frequently. Inspection and maintenance guidance includes: • Inspect for tears that can result in sediment directly entering the inlet, as well as result in the contents of the BMP (e.g., gravel) washing into the inlet. • Check for improper installation resulting in untreated flows bypassing the BMP and directly entering the inlet or bypassing to an unprotected downstream inlet. For example, silt fence that has not been properly trenched around the inlet can result in flows under the silt fence and directly into the inlet. • Look for displaced BMPs that are no longer protecting the inlet. Displacement may occur following larger storm events that wash away or reposition the inlet protection. Traffic or equipment may also crush or displace the BMP. • Monitor sediment accumulation upgradient of the inlet protection. IP-2 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 August 2013 Inlet Protection (IP) SC -6 • Remove sediment accumulation from the area upstream of the inlet protection, as needed to maintain BMP effectiveness, typically when it reaches no more than half the storage capacity of the inlet protection. For silt fence, remove sediment when it accumulates to a depth of no more than 6 inches. Remove sediment accumulation from the area upstream of the inlet protection as needed to maintain the functionality of the BMP. • Propriety inlet protection devices should be inspected and maintained in accordance with manufacturer specifications. If proprietary inlet insert devices are used, sediment should be removed in a timely manner to prevent devices from breaking and spilling sediment into the storm drain. Inlet protection must be removed and properly disposed of when the drainage area for the inlet has reached final stabilization. August 2013 Urban Drainage and Flood Control District IP-3 Urban Storm Drainage Criteria Manual Volume 3 SC -6 Inlet Protection (IP) SEE ROCK SOCK DESIGN DETAIL FOR JOINTING 16" CINDER BLOCKS MIN. 2"x4" WOOD - SECTION A - STUD IP-1. BLOCK AND ROCK SOCK SUMP OR ON GRADE INLET PROTECTION 16" CINDER BLOCKS FLOW --- ROCK SOCKS 2"x4" WOOD STUD CURB INLET BLOCK AND CURB SOCK INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. CONCRETE "CINDER" BLOCKS SHALL BE LAID ON THEIR SIDES AROUND THE INLET IN A SINGLE ROW, ABUTTING ONE ANOTHER WITH THE OPEN END FACING AWAY FROM THE CURB. 3. GRAVEL BAGS SHALL BE PLACED AROUND CONCRETE BLOCKS, CLOSELY ABUTTING ONE ANOTHER AND JOINTED TOGETHER IN ACCORDANCE WITH ROCK SOCK DESIGN DETAIL. r r a CURB SOCK FLOW MINIMUM OF TWO CURB SOCKS APPROX 30 DEG BLOCK AND ROCK SOCK INLET PROTECTION(SEE DETAIL IP -1) IP-2. CURB ROCK SOCKS UPSTREAM OF INLET PROTECTION CURB ROCK SOCK INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL INSTALLATION REQUIREMENTS. 2. PLACEMENT OF THE SOCK SHALL BE APPROXIMATELY 30 DEGREES FROM PERPENDICULAR IN THE OPPOSITE DIRECTION OF FLOW. 3. SOCKS ARE TO BE FLUSH WITH THE CURB AND SPACED A MINIMUM OF 5 FEET APART. 4. AT LEAST TWO CURB SOCKS IN SERIES ARE REQUIRED UPSTREAM OF ON -GRADE INLETS. IP-4 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 August 2013 Inlet Protection (IP) SC -6 INLET GRATE SEE ROCK SOCK DETAIL FOR JOINTING ROCK SOCK IP-3. ROCK SOCK SUMP/AREA INLET PROTECTION ROCK SOCK SUMP/AREA INLET PROTECTION INSTALLATION NOTES 1. SEE ROCK SOCK DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. STRAW WATTLES/SEDIMENT CONTROL LOGS MAY BE USED IN PLACE OF ROCK SOCKS FOR INLETS IN PERVIOUS AREAS. INSTALL PER SEDIMENT CONTROL LOG DETAIL. IL N SF I 0 -n SF _ I SILT FENCE (SEE SILT FENCE DESIGN DETAIL ) IP-4. SILT FENCE FOR SUMP INLET PROTECTION SILT FENCE INLET PROTECTION INSTALLATION NOTES 1. SEE SILT FENCE DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. POSTS SHALL BE PLACED AT EACH CORNER OF THE INLET AND AROUND THE EDGES AT A MAXIMUM SPACING OF 3 FEET. 3. STRAW WATTLES/SEDIMENT CONTROL LOGS MAY BE USED IN PLACE OF SILT FENCE FOR INLETS IN PERVIOUS AREAS. INSTALL PER SEDIMENT CONTROL LOG DETAIL. August 2013 Urban Drainage and Flood Control District IP-5 Urban Storm Drainage Criteria Manual Volume 3 SC -6 SHEET FLOW J 1 I ' K o -.••-••• 1 [ 1 w ROCK FILTER OR ROCK SOCK (USE IF FLOW IS CONCENTRATED) Inlet Protection (IP) SILT FENCE AREA INLET ECB LCONCENTRATED FLOW ECB SILT FENCE I AREA INLET I IP-5. OVEREXCAVATION INLET PROTECTION OVEREXCAVATION INLET PROTECTION INSTALLATION NOTES 1. THIS FORM OF INLET PROTECTION IS PRIMARILY APPLICABLE FOR SITES THAT HAVE NOT YET REACHED FINAL GRADE AND SHOULD BE USED ONLY FOR INLETS WITH A RELATIVELY SMALL CONTRIBUTING DRAINAGE AREA. 2. WHEN USING FOR CONCENTRATED FLOWS, SHAPE BASIN IN 2:1 RATIO WITH LENGTH ORIENTED TOWARDS DIRECTION OF FLOW. 3. SEDIMENT MUST BE PERIODICALLY REMOVED FROM THE OVEREXCAVATED AREA. /77/ / / / /7/ STRAW BALE (SEE STRAW BALE DESIGN DETAIL) I I I I 4 I I 0 I I INLET GRATE IP-6. STRAW BALE FOR SUMP INLET PROTECTION STRAW BALE BARRIER INLET PROTECTION INSTALLATION NOTES 1. SEE STRAW BALE DESIGN DETAIL FOR INSTALLATION REQUIREMENTS. 2. BALES SHALL BE PLACED IN A SINGLE ROW AROUND THE INLET WITH ENDS OF BALES TIGHTLY ABUTTING ONE ANOTHER. IP-6 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 August 2013 Inlet Protection (IP) SC -6 FLOW CULVERT END SECTION ROCK SOCK CULVERT INLET PROTECTION PLAN c 10" MIN. I I OF WATTLE SOCK L D (12" MIN.) rTh CIK _ Y P 1 BACKFILL UPSTREAM ROCK SECTION A KEY IN ROCK SOCK 0" ON BEDROCK, PAVEMENT OR RIPRAP KEY IN ROCK SOCK 2" ON EARTH SECTION B CIP-1. CULVERT INLET PROTECTION CULVERT INLET PROTECTION INSTALLATION NOTES 1. SEE PLAN VIEW FOR -LOCATION OF CULVERT INLET PROTECTION. 2. SEE ROCK SOCK DESIGN DETAIL FOR ROCK GRADATION REQUIREMENTS AND JOINTING DETAIL. CULVERT INLET PROTECTION MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF THE CULVERT SHALL BE REMOVED WHEN THE SEDIMENT DEPTH IS !Y THE HEIGHT OF THE ROCK SOCK. 5. CULVERT INLET PROTECTION SHALL REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS PERMANENTLY STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM AURORA, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. August 2013 Urban Drainage and Flood Control District IP-7 Urban Storm Drainage Criteria Manual Volume 3 SC -6 Inlet Protection (IP) GENERAL INLET PROTECTION INSTALLATION NOTES 1. SEE PLAN VIEW FOR: - LOCATION OF INLET PROTECTION. - TYPE OF INLET PROTECTION (IP.1, IP.2, IP.3, IP.4, IP.5, IP.6) 2. INLET PROTECTION SHALL BE INSTALLED PROMPTLY AFTER INLET CONSTRUCTION OR PAVING IS COMPLETE (TYPICALLY WITHIN 48 HOURS). IF A RAINFALL/RUNOFF EVENT IS FORECAST, INSTALL INLET PROTECTION PRIOR TO ONSET OF EVENT. 3. MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. INLET PROTECTION MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF INLET PROTECTION SHALL BE REMOVED AS NECESSARY TO MAINTAIN BMP EFFECTIVENESS, TYPICALLY WHEN STORAGE VOLUME REACHES 50% OF CAPACITY, A DEPTH OF 6" WHEN SILT FENCE IS USED, OR Y4 OF THE HEIGHT FOR STRAW BALES. 5. INLET PROTECTION IS TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS PERMANENTLY STABILIZED, UNLESS THE LOCAL JURISDICTION APPROVES EARLIER REMOVAL OF INLET PROTECTION IN STREETS. 6. WHEN INLET PROTECTION AT AREA INLETS IS REMOVED, THE DISTURBED AREA SHALL BE COVERED WITH TOP SOIL, SEEDED AND MULCHED, OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO AND CITY OF AURORA, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. NOTE. THE DETAILS INCLUDED WITH THIS FACT SHEET SHOW COMMONLY USED, CONVENTIONAL METHODS OF INLET PROTECTION IN THE DENVER METROPOLITAN AREA. THERE ARE MANY PROPRIETARY INLET PROTECTION METHODS ON THE MARKET. UDFCD NEITHER ENDORSES NOR DISCOURAGES USE OF PROPRIETARY INLET PROTECTION; HOWEVER, IN THE EVENT PROPRIETARY METHODS ARE USED, THE APPROPRIATE DETAIL FROM THE MANUFACTURER MUST BE INCLUDED IN THE SWMP AND THE BMP MUST BE INSTALLED AND MAINTAINED AS SHOWN IN THE MANUFACTURER'S DETAILS. NOTE: SOME MUNICIPAUTIES DISCOURAGE OR PROHIBIT THE USE OF STRAW BALES FOR INLET PROTECTION. CHECK WITH LOCAL JURISDICTION TO DETERMINE IF STRAW BALE INLET PROTECTION IS ACCEPTABLE. IP-8 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 August 2013 Straw Bale Barrier (SBB) SC -3 Description A straw bale barrier is a linear wall of straw bales designed to intercept sheet flow and trap sediment before runoff exits a disturbed area. Appropriate Uses Appropriate uses of properly installed straw bale barriers may include: • As a perimeter control for a site or soil stockpile. • As a sediment control at the toe of an erodible slope. • Along the edge of a stream or drainage pathway to reduce sediment laden runoff from entering the waterway. J r . r— — 1; 1 Photograph SBB-1. Straw bale barrier used for perimeter control. Photo courtesy of Tom Gore. • As part of an inlet protection design in sump conditions (See Inlet Protection BMP). Do not use straw bale barriers in areas of concentrated flow or in areas where ponding is not desirable. Straw bales tend to degrade quickly, so they should generally not be used in areas where longer term disturbance is expected. Due to a history of inappropriate placement, poor installation, and short effective lifespan, the use of straw bales is discouraged or prohibited by some communities. Design and Installation The maximum recommended tributary drainage area per 100 lineal feet of straw bale barrier is 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1; longer and steeper slopes require additional measures. Design details with notes are provided in Detail SBB-1. To be effective, bales must be installed in accordance with the design details with proper trenching, staking, and binding. Jute and cotton string must not be used to bind the straw bale. The bales should be certified weed -free prior to use. Maintenance and Removal Check bales for rotting and replace as necessary. Straw bales degrade, and rotting bales require replacement on a regular basis (as often as every three months) depending on environmental conditions. Check for undercutting, bypassed flows, and displacement. Repair by properly re -installing the straw bale barrier and repairing washouts around the bales. Remove sediment accumulated behind the bale when it reaches one -quarter of the bale height. Remove and properly dispose of the straw bale once the upstream area has been stabilized. Areas of disturbance beneath the bale should be seeded and mulched when the bale is removed. Straw Bale Barrier Functions Erosion Control No Sediment Control Moderate Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 SBB-1 STRAW BALE 18" TYP SC -3 Straw Bale Barrier (SBB) BALE LENGTH 2"X2"X24" STAKE FLOW BACKFILL AND COMPACT EXCAVATED TRENCH SOIL BINDING WIRE OR TWINE L 4" MIN IBALE WIDTH 18" TYP TRENCH FOR STRAW BALE ALE WI0 2"X2"X24" 18 TYP STAKE BACKFILL AND COMPACT EXCAVATED TRENCH SOIL - FLOW 6 MIN I L " MIN SECTION A SBB-1. STRAW BALE SBB-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Straw Bale Barrier (SBB) SC -3 STRAW BALE INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATIONS) OF STRAW BALES. 2 STRAW BALES SHALL CONSIST OF CERTIFIED WEED FREE STRAW OR HAY. LOCAL JURISDICTIONS MAY REQUIRE PROOF THAT BALES ARE WEED FREE. 3. STRAW BALES SHALL CONSIST OF APPROXIMATELY 5 CUBIC FEET OF STRAW OR HAY AND WEIGH NOT LESS THAN 35 POUNDS. 4. WHEN STRAW BALES ARE USED IN SERIES AS A BARRIER, THE END OF EACH BALE SHALL BE TIGHTLY ABUTTING ONE ANOTHER. 5. STRAW BALE DIMENSIONS SHALL BE APPROXIMATELY 36"X 18"X 18'. 6. A UNIFORM ANCHOR TRENCH SHALL BE EXCAVATED TO A DEPTH OF 4". STRAW BALES SHALL BE PLACED SO THAT BINDING TWINE IS ENCOMPASSING THE VERTICAL SIDES OF THE BALE(S). ALL EXCAVATED SOIL SHALL BE PLACED ON THE UPHILL SIDE OF THE STRAW BALE(S) AND COMPACTED. 7. TWO (2) WOODEN STAKES SHALL BE USED TO HOLD EACH BALE IN PLACE. WOODEN STAKES SHALL BE 2"X2"X24". WOODEN STAKES SHALL BE DRIVEN 6" INTO THE GROUND. STRAW BALE MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4 STRAW BALES SHALL BE REPLACED IF THEY BECOME HEAVILY SOILED, ROTTEN, OR DAMAGED BEYOND REPAIR. 5. SEDIMENT ACCUMULATED UPSTREAM OF STRAW BALE BARRIER SHALL BE REMOVED AS NEEDED TO MAINTAIN FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY Y4 OF THE HEIGHT OF THE STRAW BALE BARRIER. 6. STRAW BALES ARE TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 7. WHEN STRAW BALES ARE REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. (DETAILS ADAPTED FROM TOWN OF PARKER, COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District SBB-3 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SC -2 Description A sediment control log is a linear roll made of natural materials such as straw, coconut fiber, or other fibrous material trenched into the ground and held with a wooden stake. Sediment control logs are also often referred to as "straw wattles." They are used as a sediment barrier to intercept sheet flow runoff from disturbed areas. Appropriate Uses Sediment control logs can be used in the following applications to trap sediment: • As perimeter control for stockpiles and the site. ■ As part of inlet protection designs. • As check dams in small drainage ditches. (Sediment control logs are not intended for use in channels with high flow velocities.) • On disturbed slopes to shorten flow lengths (as an erosion control). 4 ”2741,•., �7N • Photographs SCL-1 and SCL-2. Sediment control logs used as 1) a perimeter control around a soil stockpile; and, 2) as a "J -hook" perimeter control at the corner of a construction site. ■ As part of multi -layered perimeter control along a receiving water such as a stream, pond or wetland. Sediment control logs work well in combination with other layers of erosion and sediment controls. Design and Installation Sediment control logs should be installed along the contour to avoid concentrating flows. The maximum allowable tributary drainage area per 100 lineal feet of sediment control log, installed along the contour, is approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1. Longer and steeper slopes require additional measures. This recommendation only applies to sediment control logs installed along the contour. When installed for other uses, such as perimeter control, it should be installed in a way that will not produce concentrated flows. For example, a "J -hook" installation may be appropriate to force runoff to pond and evaporate or infiltrate in multiple areas rather than concentrate and cause erosive conditions parallel to the BMP. Sediment Control Log Functions Erosion Control Moderate Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 SCL-1 SC -2 Sediment Control Log (SCL) Although sediment control logs initially allow runoff to flow through the BMP, they can quickly become a barrier and should be installed is if they are impermeable. Design details and notes for sediment control logs are provided in Detail SCL-1. Sediment logs must be properly trenched and staked into the ground to prevent undercutting, bypassing and displacement. When installed on slopes, sediment control logs should be installed along the contours (i.e., perpendicular to flow). improper installation can lead to poor performance. Be sure that sediment control logs are properly trenched, anchored and tightly jointed. Maintenance and Removal Be aware that sediment control logs will eventually degrade. Remove accumulated sediment before the depth is one-half the height of the sediment log and repair damage to the sediment log, typically by replacing the damaged section. Once the upstream area is stabilized, remove and properly dispose of the logs. Areas disturbed beneath the logs may need to be seeded and mulched. Sediment control logs that are biodegradable may occasionally be left in place (e.g., when logs are used in conjunction with erosion control blankets as permanent slope breaks). However, removal of sediment control logs after final stabilization is typically recommended when used in perimeter control, inlet protection and check dam applications. SCL-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SO. _SO. _SO. 35 DIA FLOW OF SCL (TYP.) COMPACTED EXCAVATED TRENCH SOIL FLOW --- ;, SECTION A 9" DIAMETER (MIN) SEDIMENT CONTROL LOG i\\ SEDIMENT CONTROL LOG ..:.., •:\ •••• 12" OVERLAP (MIN.) 1_ SC -2 1X" x 1 x 18" (MIN) WOODEN STAKE 9" DIAMETER (MIN) SEDIMENT CONTROL LOG NOTE: LARGER DIAMETER SEDIMENT CONTROL LOGS MAY NEED TO BE EMBEDDED DEEPER. >'S CENTER STAKE IN CONTROL LOG 3" 9" DIAMETER (MIN) SEDIMENT CONTROL LOG Y3 DIAM. SCL (TYP.) �1p 1 f,\ 1J" x 1Y2" x 18" (MIN) WOODEN STAKE SEDIMENT CONTROL LOG JOINTS SCL-1. SEDIMENT CONTROL LOG November 2010 Urban Drainage and Flood Control District SCL-3 Urban Storm Drainage Criteria Manual Volume 3 SC -2 Sediment Control Log (SCL) 3" COMPACT= EXCAVATED TRENCH SOIL FLOW -� CENTER STAKE IN CONTRC_ LOG 6' MIN. 9" DIAMETER (MIN) SEDIMENT CONTROL LOG PLACE _OG AGAINST BACK OF CURB Y3 DIAM. SCL (TYP.) SCL-2. SEDIMENT CONTROL LOG AT BACK OF CURB CENTER STAKE r IN CONTROL LOG 9" DIAMETER (YIN) SEDIMENT CONTROL LOG Y3 DIAM. SCL (TvP.) FLOW TREE ,AWN (TYPICAL) sr�VYALK y� ,� ≥, �.y �� < L PLACE CONTROL LOG y�'. ' :� N <��• 'c� /�� AGAINST STJEWALK ;\.\. (t/ /,: SCL-3. SEDIMENT CONTROL LOG AT SIDEWALK WITH TREE LAWN STAKING AT 4' MAX. ON CENTER (TIP 1 VERTICAL SPACING VARIES DEPEND NG 1 ON SLOPE CONTINUOUS SCL AT PERIMETER Oa CONSTRUCTION SITE SCL-4. SEDIMENT CONTROL LOGS TO CONTROL SLOPE LENGTH SCL-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Control Log (SCL) SC -2 SEDIMENT CONTROL LOG INSTALLATION NOTES 1. SEE PLAN VIEW FOR LOCATION AND LENGTH OF SEDIMENT CONTROL LOGS. 2. SEDIMENT CONTROL LOGS THAT ACT AS A PERIMETER CONTROL SHALL BE INSTALLED PRIOR TO ANY UPGRADIENT LAND -DISTURBING ACTIVITIES. 3. SEDIMENT CONTROL LOGS SHALL CONSIST OF STRAW, COMPOST, EXCELSIOR OR COCONUT FIBER, AND SHALL BE FREE OF ANY NOXIOUS WEED SEEDS OR DEFECTS INCLUDING RIPS, HOLES AND OBVIOUS WEAR. 4. SEDIMENT CONTROL LOGS MAY BE USED AS SMALL CHECK DAMS IN DITCHES AND SWALES. HOWEVER, THEY SHOULD NOT BE USED IN PERENNIAL STREAMS OR HIGH VELOCITY DRAINAGE WAYS. 5. IT IS RECOMMENDED THAT SEDIMENT CONTROL LOGS BE TRENCHED INTO THE GROUND TO A DEPTH OF APPROXIMATELY 1S OF THE DIAMETER OF THE LOG. IF TRENCHING TO THIS DEPTH IS NOT FEASIBLE AND/OR DESIRABLE (SHORT TERM INSTALLATION WITH DESIRE NOT TO DAMAGE LANDSCAPE) A LESSER TRENCHING DEPTH MAY BE ACCEPTABLE WITH MORE ROBUST STAKING 6. THE UPHILL SIDE OF THE SEDIMENT CONTROL LOG SHALL BE BACKFILLED WITH SOIL THAT IS FREE OF ROCKS AND DEBRIS. THE SOIL SHALL BE TIGHTLY COMPACTED INTO THE SHAPE OF A RIGHT TRIANGLE USING A SHOVEL OR WEIGHTED LAWN ROLLER. 7. FOLLOW MANUFACTURERS' GUIDANCE FOR STAKING. IF MANUFACTURERS' INSTRUCTIONS 0O NOT SPECIFY SPACING, STAKES SHALL BE PLACED ON 4' CENTERS AND EMBEDDED A MINIMUM OF 6" INTO THE GROUND. 3" OF THE STAKE SHALL PROTRUDE FROM THE TOP OF THE LOG. STAKES THAT ARE BROKEN PRIOR TO INSTALLATION SHALL BE REPLACED. SEDIMENT CONTROL LOG MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF SEDIMENT CONTROL LOG SHALL BE REMOVED AS NEEDED TO MAINTAIN FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY Xi OF THE HEIGHT OF THE SEDIMENT CONTROL LOG. 5. SEDIMENT CONTROL LOG SHALL BE REMOVED AT THE END OF CONSTRUCTION. IF DISTURBED AREAS EXIST AFTER REMOVAL, THEY SHALL BE COVERED WITH TOP SOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM Town OF PARKER. COLORADO. JEFFERSON COUNTY. COLORADO, DOUGLAS COUNTY, COLORADO. AND CITY OF AURORA. COLORADO, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District SCL-5 Urban Storm Drainage Criteria Manual Volume 3 Sediment Trap (ST) SC -8 Description Sediment traps are formed by excavating an area or by placing an earthen embankment across a low area or drainage swale. Sediment traps are designed to capture drainage from disturbed areas less than one acre and allow settling of sediment. Appropriate Uses Sediment traps can be used in combination with other layers of erosion and sediment controls to trap sediment from small drainage areas (less than one acre) or areas with localized high sediment loading. For example, sediment traps are often provided in conjunction with vehicle tracking controls and wheel wash facilities. Design and Installation Photograph ST -1. Sediment traps are used to collect sediment -laden runoff from disturbed area. Photo courtesy of EPA Menu of BMPs. A sediment trap consists of a small excavated basin with an earthen berm and a riprap outlet. The berm of the sediment trap may be constructed from the excavated material and must be compacted to 95 percent of the maximum density in accordance with ASTM D698. An overflow outlet must be provided at an elevation at least 6 inches below the top of the berm. See Detail ST -1 for additional design and installation information. Maintenance and Removal Inspect the sediment trap embankments for stability and seepage. Remove accumulated sediment as needed to maintain the effectiveness of the sediment trap, typically when the sediment depth is approximately one-half the height of the outflow embankment. Inspect the outlet for debris and damage. Repair damage to the outlet, and remove all obstructions. A sediment trap should not be removed until the upstream area is sufficiently stabilized. Upon removal of the trap, the disturbed area should be covered with topsoil and stabilized. Sediment Trap Functions Erosion Control No Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 ST -1 SC -8 Sediment Trap (ST) DUa FLOW RIPRAP, TYPE M (050=12") TYP.SMALLER ROCK SIZE MAY BE ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION TOP OF EARTHEN BERM 2.1 MAX. 2 1 MAX. TRANSITION EXISTING CHANNEL INTO SEDIMENT TRAP 2.1 MAX W 2 1 MAX. L 6" MINIMUM FREEBOARD 1 SEDIMENT TRAP PLAN 6" (CENTER OF RIPRAP 6" LOWER THAN ENDS r 1 '6" MIN. FLOW a 12' MIN. 30" CHANNEL GRADE 2' 6' SECTION A 1'8" f MIN. RIPRAP, TYPE M (D50=12") TYP. SMALLER ROCK SIZE MAY 8E ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION SECTION B ST -1. SEDIMENT TRAP ST -2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Sediment Trap (ST) SC -8 SEDIMENT TRAP INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATION, LENGTH AND WIDTH OF SEDIMENT TRAP. 2. ONLY USE FOR DRAINAGE AREAS LESS THAN 1 ACRE. 3 SEDIMENT TRAPS SHALL BE INSTALLED PRIOR TO ANY UPGRADIENT LAND -DISTURBING ACTIVITIES. 4. SEDIMENT TRAP BERM SHALL BE CONSTRUCTED FROM MATERIAL FROM EXCAVATION. THE BERM SHALL BE COMPACTED TO 95% OF THE MAXIMUM DENSITY IN ACCORDANCE WITH ASTM 0698. 5. SEDIMENT TRAP OUTLET TO BE CONSTRUCTED OF RIPRAP, TYPE M (D50=12") TYP.SMALLER ROCK SIZE MAY BE ALLOWABLE FOR SMALLER TRAPS IF APPROVED BY LOCAL JURISDICTION. 6. THE TOP OF THE EARTHEN BERM SHALL BE A MINIMUM OF 6" HIGHER THAN THE TOP OF THE RIPRAP OUTLET STRUCTURE. 7. THE ENDS OF THE RIPRAP OUTLET STRUCTURE SHALL BE A MINIMUM OF 6" HIGHER THAN THE CENTER OF THE OUTLET STRUCTURE. SEDIMENT TRAP MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE. NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. REMOVE SEDIMENT ACCUMULATED IN TRAP AS NEEDED TO MAINTAIN THE FUNCTIONALITY OF THE BMP, TYPICALLY WHEN THE SEDIMENT DEPTH REACHES )6 THE HEIGHT OF THE RIPRAP OUTLET. 5. SEDIMENT TRAPS SHALL REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION. 6. WHEN SEDIMENT TRAPS ARE REMOVED, THE DISTURBED AREA SHALL 8E COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED IN A MANNER APPROVED BY THE LOCAL JURISDICTION. (DETAILS ADAPTED FROM DOUGLAS COUNTY, COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE 8MP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. November 2010 Urban Drainage and Flood Control District ST -3 Urban Storm Drainage Criteria Manual Volume 3 Silt Fence (SF) SC -1 Description A silt fence is a woven geotextile fabric attached to wooden posts and trenched into the ground. It is designed as a sediment barrier to intercept sheet flow runoff from disturbed areas. Appropriate Uses A silt fence can be used where runoff is conveyed from a disturbed area as sheet flow. Silt fence is not designed to receive concentrated flow or to be used as a filter fabric. Typical uses include: • Down slope of a disturbed area to accept sheet flow. • Along the perimeter of a receiving water such as a stream, pond or wetland. ■ At the perimeter of a construction site. Design and Installation Photograph SF -1. Silt fence creates a sediment barrier, forcing sheet flow runoff to evaporate or infiltrate. Silt fence should be installed along the contour of slopes so that it intercepts sheet flow. The maximum recommended tributary drainage area per 100 lineal feet of silt fence, installed along the contour, is approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no steeper than 3:1. Longer and steeper slopes require additional measures. This recommendation only applies to silt fence installed along the contour. Silt fence installed for other uses, such as perimeter control, should be installed in a way that will not produce concentrated flows. For example, a "J -hook" installation may be appropriate to force runoff to pond and evaporate or infiltrate in multiple areas rather than concentrate and cause erosive conditions parallel to the silt fence. See Detail SF -1 for proper silt fence installation, which involves proper trenching, staking, securing the fabric to the stakes, and backfilling the silt fence. Properly installed silt fence should not be easily pulled out by hand and there should be no gaps between the ground and the fabric. Silt fence must meet the minimum allowable strength requirements, depth of installation requirement, and other specifications in the design details. Improper installation of silt fence is a common reason for silt fence failure; however, when properly installed and used for the appropriate purposes, it can be highly effective. Silt Fence Functions Erosion Control No Sediment Control Yes Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 SF -1 SC -1 Silt Fence (SF) Maintenance and Removal Inspection of silt fence includes observing the material for tears or holes and checking for slumping fence and undercut areas bypassing flows. Repair of silt fence typically involves replacing the damaged section with a new section. Sediment accumulated behind silt fence should be removed, as needed to maintain BMP effectiveness, typically before it reaches a depth of 6 inches. Silt fence may be removed when the upstream area has reached final stabilization. Photograph SF -2. When silt fence is not installed along the contour, a "J -hook" installation may be appropriate to ensure that the BMP does not create concentrated flow parallel to the silt fence. Photo courtesy of Tom Gore. SF -2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Silt Fence (SF) SC -1 SF sc SILT FENCE GEOTEXTILE COMPACTED BACKFI LL FIOW -a EXISTING GROUND 6a MIN AT LEAST 10" OF SILT FENCE "TAIL" SHALL BE BURIED JOIN FIRST ROTATE SECOND POSTS SHALL BE JO NED AS SHOWN, THEN ROTATED 180 DEG. IN DIRECTION SHOWN AND DRIVEN INTO THE GROUND 4MIN 1 x 1 (RECOMMENDED) WOODEN FENCE POST WITH 10' MAX SPACING 18" MIN 36"- 48" TYP. SILT FENCE POSTS SHALL OVERLAP AT JOINTS SO THAT NO GAPS EXIST IN SILT FENC THICKNESS OF GEOTEXTILE HAS BEEN EXAGGERATED, TYP SECTION A SF -1. SILT FENCE November 2010 Urban Drainage and Flood Control District SF -3 Urban Storm Drainage Criteria Manual Volume 3 SC -1 Silt Fence (SF) SILT FENCE INSTALLATION NOTES 1. SILT FENCE MUST BE PLACED AWAY FROM THE TOE OF THE SLOPE TO ALLOW FOR WATER PONDING. SILT FENCE AT THE TOE OF A SLOPE SHOULD BE INSTALLED IN A FLAT LOCATION AT LEAST SEVERAL FEET (2-5 FT) FROM THE TOE OF THE SLOPE TO ALLOW ROOM FOR PONDING AND DEPOSITION. 2. A UNIFORM 6" X 4" ANCHOR TRENCH SHALL BE EXCAVATED USING TRENCHER OR SILT FENCE INSTALLATION DEVICE. NO ROAD GRADERS, BACKHOES, OR SIMILAR EQUIPMENT SHALL BE USED. 3. COMPACT ANCHOR TRENCH BY HAND WITH A "JUMPING JACK" OR BY WHEEL ROLLING. COMPACTION SHALL BE SUCH THAT SILT FENCE RESISTS BEING PULLED OUT OF ANCHOR TRENCH BY HAND. 4. SILT FENCE SHALL BE PULLED TIGHT AS IT IS ANCHORED TO THE STAKES. THERE SHOULD BE NO NOTICEABLE SAG BETWEEN STAKES AFTER IT HAS BEEN ANCHORED TO THE STAKES. 5. SILT FENCE FABRIC SHALL BE ANCHORED TO THE STAKES USING 1" HEAVY DUTY STAPLES OR NAILS WITH 1" HEADS. STAPLES AND NAILS SHOULD BE PLACED 3" ALONG THE FABRIC DOWN THE STAKE. 6. AT THE END OF A RUN OF SILT FENCE ALONG A CONTOUR, THE SILT FENCE SHOULD BE TURNED PERPENDICULAR TO THE CONTOUR TO CREATE A "J -HOOK." THE "J -HOOK" EXTENDING PERPENDICULAR TO THE CONTOUR SHOULD BE OF SUFFICIENT LENGTH TO KEEP RUNOFF FROM FLOWING AROUND THE END OF THE SILT FENCE (TYPICALLY 10' - 20'). 7. SILT FENCE SHALL BE INSTALLED PRIOR TO ANY LAND DISTURBING ACTIVITIES. SILT FENCE MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. SEDIMENT ACCUMULATED UPSTREAM OF THE SILT FENCE SHALL BE REMOVED AS NEEDED TO MAINTAIN THE FUNCTIONALITY OF THE BMP, TYPICALLY WHEN DEPTH OF ACCUMULATED SEDIMENTS IS APPROXIMATELY 6". 5. REPAIR OR REPLACE SILT FENCE WHEN THERE ARE SIGNS OF WEAR, SUCH AS SAGGING, TEARING, OR COLLAPSE. 6. SILT FENCE IS TO REMAIN IN PLACE UNTIL THE UPSTREAM DISTURBED AREA IS STABILIZED AND APPROVED BY THE LOCAL JURISDICTION, OR IS REPLACED BY AN EQUIVALENT PERIMETER SEDIMENT CONTROL BMP. 7. WHEN SILT FENCE IS REMOVED, ALL DISTURBED AREAS SHALL BE COVERED WITH TOPSOIL, SEEDED AND MULCHED OR OTHERWISE STABILIZED AS APPROVED BY LOCAL JURISDICTION. {DETAIL ADAPTED FROM TOWN OF PARKER, COLORADO AND CITY OF AURORA, NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SF -4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Surface Roughening (SR) EC -1 Description Surface roughening is an erosion control practice that involves tracking, scarifying, imprinting, or tilling a disturbed area to provide temporary stabilization of disturbed areas. Surface roughening creates variations in the soil surface that help to minimize wind and water erosion. Depending on the technique used, surface roughening may also help establish conditions favorable to establishment of vegetation. Appropriate Uses Surface roughening can be used to provide temporary stabilization of disturbed areas, such as when revegetation cannot be immediately established due to seasonal planting limitations. Surface roughening is not a stand-alone BMP, and should be used in conjunction with other erosion and sediment controls. Photograph SR -1. Surface roughening via imprinting for temporary stabilization. Surface roughening is often implemented in conjunction with grading and is typically performed using heavy construction equipment to track the surface. Be aware that tracking with heavy equipment will also compact soils, which is not desirable in areas that will be revegetated. Scarifying, tilling, or ripping are better surface roughening techniques in locations where revegetation is planned. Roughening is not effective in very sandy soils and cannot be effectively performed in rocky soil. Design and Installation Typical design details for surfacing roughening on steep and mild slopes are provided in Details SR -1 and SR -2, respectively. Surface roughening should be performed either after final grading or to temporarily stabilize an area during active construction that may be inactive for a short time period. Surface roughening should create depressions 2 to 6 inches deep and approximately 6 inches apart. The surface of exposed soil can be roughened by a number of techniques and equipment. Horizontal grooves (running parallel to the contours of the land) can be made using tracks from equipment treads, stair -step grading, ripping, or tilling. Fill slopes can be constructed with a roughened surface. Cut slopes that have been smooth graded can be roughened as a subsequent operation. Roughening should follow along the contours of the slope. The tracks left by truck mounted equipment working perpendicular to the contour can leave acceptable horizontal depressions; however, the equipment will also compact the soil. Surface Roughening Functions Erosion Control Yes Sediment Control No Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 SR -1 EC -1 Surface Roughening (SR) Maintenance and Removal Care should be taken not to drive vehicles or equipment over areas that have been surface roughened. Tire tracks will smooth the roughened surface and may cause runoff to collect into rills and gullies. Because surface roughening is only a temporary control, additional treatments may be necessary to maintain the soil surface in a roughened condition. Areas should be inspected for signs of erosion. Surface roughening is a temporary measure, and will not provide long-term erosion control. SR -2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Surface Roughening (SR) EC -1 2" TO 4" DEEP SR -1. SURFACE ROUGHENING TRACKING OR IMPRINTING FURROWS 2" TO 4" DEEP WITH 6" MAXIMUM SPACING PARALLEL TO CONTOURS FOR STEEP SLOPES (3:1 OR STEEPER) ROUGHENED ROWS SHALL BE 4" TO 6" DEEP WITH 6" MAXIMUM SPACING PARALLEL TO CONTOURS SR -2. SURFACE ROUGHENING FOR LOW SLOPES (LESS THAN 3:1) November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 SR -3 EC -1 Surface Roughening (SR) SURFACE ROUGHENING INSTALLATION NOTES 1. SEE PLAN VIEW FOR: -LOCATION(S) OF SURFACE ROUGHENING. 2. SURFACE ROUGHENING SHALL BE PROVIDED PROMPTLY AFTER COMPLETION OF FINISHED GRADING (FOR AREAS NOT RECEIVING TOPSOIL) OR PRIOR TO TOPSOIL PLACEMENT OR ANY FORECASTED RAIN EVENT. 3. AREAS WHERE BUILDING FOUNDATIONS, PAVEMENT, OR SOD WILL BE PLACED WITHOUT DELAY IN THE CONSTRUCTION SEQUENCE, SURFACE ROUGHENING IS NOT REQUIRED. 4. DISTURBED SURFACES SHALL BE ROUGHENED USING RIPPING OR TILUNG EQUIPMENT ON THE CONTOUR OR TRACKING UP AND DOWN A SLOPE USING EQUIPMENT TREADS. 5. A FARMING DISK SHALL NOT BE USED FOR SURFACE ROUGHENING. SURFACE ROUGHENING MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACE UPON DISCOVERY OF THE FAILURE. 4. VEHICLES AND EQUIPMENT SHALL NOT BE DRIVEN OVER AREAS THAT HAVE BEEN SURFACE ROUGHENED. 5. IN NON -TURF GRASS FINISHED AREAS, SEEDING AND MULCHING SHALL TAKE PLACE DIRECTLY OVER SURFACE ROUGHENED AREAS WITHOUT FIRST SMOOTHING OUT THE SURFACE. 6. IN AREAS NOT SEEDED AND MULCHED AFTER SURFACE ROUGHENING, SURFACES SHALL BE RE -ROUGHENED AS NECESSARY TO MAINTAIN GROOVE DEPTH AND SMOOTH OVER RILL EROSION. (DETAILS ADAPTED FROM TOWN OF PARKER. COLORADO. NOT AVAILABLE IN AUTOCAD) NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. SR -4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) SIN1-4 Description Vehicle tracking controls provide stabilized construction site access where vehicles exit the site onto paved public roads. An effective vehicle tracking control helps remove sediment (mud or dirt) from vehicles, reducing tracking onto the paved surface. Appropriate Uses Implement a stabilized construction entrance or vehicle tracking control where frequent heavy vehicle traffic exits the construction site onto a paved roadway. An effective vehicle tracking control is particularly important during the following conditions: Photograph VTC-1. A vehicle tracking control pad constructed with properly sized rock reduces off -site sediment tracking. • Wet weather periods when mud is easily tracked off site. • During dry weather periods where dust is a concern. • When poorly drained, clayey soils are present on site. Although wheel washes are not required in designs of vehicle tracking controls, they may be needed at particularly muddy sites. Design and Installation Construct the vehicle tracking control on a level surface. Where feasible, grade the tracking control towards the construction site to reduce off -site runoff. Place signage, as needed, to direct construction vehicles to the designated exit through the vehicle tracking control. There are several different types of stabilized construction entrances including: VTC-1. Aggregate Vehicle Tracking Control. This is a coarse -aggregate surfaced pad underlain by a geotextile. This is the most common vehicle tracking control, and when properly maintained can be effective at removing sediment from vehicle tires. VTC-2. Vehicle Tracking Control with Construction Mat or Turf Reinforcement Mat. This type of control may be appropriate for site access at very small construction sites with low traffic volume over vegetated areas. Although this application does not typically remove sediment from vehicles, it helps protect existing vegetation and provides a stabilized entrance. Vehicle Tracking Control Functions Erosion Control Moderate Sediment Control Yes Site/Material Management Yes November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 VTC-1 SM-4 Vehicle Tracking Control (VTC) VTC-3. Stabilized Construction Entrance/Exit with Wheel Wash. This is an aggregate pad, similar to VTC-1, but includes equipment for tire washing. The wheel wash equipment may be as simple as hand-held power washing equipment to more advance proprietary systems. When a wheel wash is provided, it is important to direct wash water to a sediment trap prior to discharge from the site. Vehicle tracking controls are sometimes installed in combination with a sediment trap to treat runoff Maintenance and Removal Inspect the area for degradation and replace aggregate or material used for a stabilized entrance/exit as needed. If the area becomes clogged and ponds water, remove and dispose of excess sediment or replace material with a fresh layer of aggregate as necessary. With aggregate vehicle tracking controls, ensure rock and debris from this area do not enter the public right-of-way. Remove sediment that is tracked onto the public right of way daily or more frequently as needed. Excess sediment in the roadway indicates that the stabilized construction entrance needs maintenance. Ensure that drainage ditches at the entrance/exit area remain clear. Photograph VTC-2. A vehicle tracking control pad with wheel wash facility. Photo courtesy of Tom Gore. A stabilized entrance should be removed only when there is no longer the potential for vehicle tracking to occur. This is typically after the site has been stabilized. When wheel wash equipment is used, be sure that the wash water is discharged to a sediment trap prior to discharge. Also inspect channels conveying the water from the wash area to the sediment trap and stabilize areas that may be eroding. When a construction entrance/exit is removed, excess sediment from the aggregate should be removed and disposed of appropriately. The entrance should be promptly stabilized with a permanent surface following removal, typically by paving. VTC-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) SM-4 SIDEWALK OR OTHER PAVED SURFACE PUBLIC ROADWAY INSTALL ROCK FLUSH WITH OR BELOW TOP OF PAVEMENT COMPACTED SUBGRADE 50 FOOT (MIN.) 20 FOOT (WIDTH CAN BE LESS IF CONST. VEHICLES ARE PHYSICALLY CONFINED ON BOTH SIDES) zetzNizetzettglitigr 9" (MIN ) UNLESS OTHERWISE SPECIFIED BY LOCAL JURISDICTION, USE CDOT SECT. #703, AASHTO #3 COARSE AGGREGATE OR 6" MINUS ROCK NON -WOVEN GEOTEXTILE FABRIC BETWEEN SOIL AND ROCK UNLESS OTHERWISE SPECIFIED BY LOCAL JURISDICTION, USE CDOT SECT. #703, AASHTO #3 COARSE AGGREGATE OR 6" MINUS ROCK 9,. (MIN.) SECTION A NON -WOVEN GEOTExTILE FABRIC VTC-1. AGGREGATE VEHICLE TRACKING CONTROL November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 VTC-3 SM-4 Vehicle Tracking Control (VTC) PUBLIC ROADWAY NOTE: WASH WATER MAY NOT CONTAIN CHEMICALS OR SOAPS WITHOUT OBTAINING A SEPARATE PERMIT DITCH TO CARRY WASH WATER TO SEDIMENT TRAP OR BASIN 6'7" MIN. REINFORCED CONCRETE RA K (MAY SUBSTITUTE STEEL CATTLE GUARD FOR CONCRETE RACK) DRAIN SPACE SECTION A VTC-2. AGGREGATE VEHICLE TRACKING CONTROL WITH WASH RACK VTC-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Vehicle Tracking Control (VTC) EXISTING PAVED ROADWAY EXISTING PAVED ROADWAY 10% MAX. SPIKES OR STAKES �r r r r r r r rr r r f 1n� TRM END OVERLAP WITH SPIKES OR STAKES SM-4 DISTURBED AREA, CONSTRUCTION SITE, STABIUZED STORAGE AREA OR STAGING AREA 18" MIN CONSTRUCTION MATS, WOVEN OR TURF REINFORCEMENT STRAP MAT (TRM) CONNECTORS CONSTRUCTION MAT END OVERLAP INTERLOCK WITH STRAP CONNECTORS RESTRICT CONST. VEHICLE ACCESS TO SIDES OF MAT CF V4 _ I 20' OR AS REQUIRED TO ACCOMMODATE ANTICIPATED TRAFFIC (WIDTH CAN BE LESS IF V CONST. VEHICLES ARE PHYSICALLY CONFINED ON BOTH SIDES) VTC-3. VEHICLE TRACKING CONTROL W/ CONSTRUCTION MAT OR TURF REINFORCEMENT MAT (TRM) November 2010 Urban Drainage and Flood Control District V"I_C-5 Urban Storm Drainage Criteria Manual Volume 3 SM-4 Vehicle Tracking Control (VTC) STABILIZED CONSTRUCTION ENTRANCE/EXIT INSTALLATION NOTES 1. SEE PLAN VIEW FOR -LOCATION OF CONSTRUCTION ENTRANCE(S)/EXIT(S). -TYPE OF CONSTRUCTION ENTRANCE(S)/EXITS(S) (WITH/WITHOUT WHEEL WASH, CONSTRUCTION MAT OR TRM). 2. CONSTRUCTION MAT OR TRM STABIUZED CONSTRUCTION ENTRANCES ARE ONLY TO BE USED ON SHORT DURATION PROJECTS (TYPICALLY RANGING FROM A WEEK TO A MONTH) WHERE THERE WILL BE LIMITED VEHICULAR ACCESS. 3. A STABIUZED CONSTRUCTION ENTRANCE/EXIT SHALL BE LOCATED AT ALL ACCESS POINTS WHERE VEHICLES ACCESS THE CONSTRUCTION SITE FROM PAVED RIGHT-OF-WAYS. 4. STABILIZED CONSTRUCTION ENTRANCE/EXIT SHALL BE INSTALLED PRIOR TO ANY LAND DISTURBING ACTIVITIES. 5. A NON -WOVEN GEOTEXTILE FABRIC SHALL BE PLACED UNDER THE STABIUZED CONSTRUCTION ENTRANCE/EXIT PRIOR TO THE PLACEMENT OF ROCK. 6. UNLESS OTHERWISE SPECIFIED BY LOCAL JURISDICTION, ROCK SHALL CONSIST OF DOT SECT. #703, AASHTO #3 COARSE AGGREGATE OR 6" (MINUS) ROCK. STABILIZED CONSTRUCTION ENTRANCE/EXIT MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. ROCK SHALL BE REAPPLIED OR REGRADED AS NECESSARY TO THE STABIUZED ENTRANCE/EXIT TO MAINTAIN A CONSISTENT DEPTH. 5. SEDIMENT TRACKED ONTO PAVED ROADS IS TO BE REMOVED THROUGHOUT THE DAY AND AT THE END OF THE DAY BY SHOVELING OR SWEEPING. SEDIMENT MAY NOT BE WASHED DOWN STORM SEWER DRAINS. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UOFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETAILS ADAPTED FROM CITY OF BROOMFELO. COLORADO. NOT AV/WABLE IN AUTOCAD) VTC-6 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC -6 Description Rolled Erosion Control Products (RECPs) include a variety of temporary or permanently installed manufactured products designed to control erosion and enhance vegetation establishment and survivability, particularly on slopes and in channels. For applications where natural vegetation alone will provide sufficient permanent erosion protection, temporary products such as netting, open weave textiles and a variety of erosion control blankets (ECBs) made of biodegradable natural materials (e.g., straw, coconut fiber) can be used. erosion and providing favorable conditions for revegetation. For applications where natural vegetation alone will not be sustainable under expected flow conditions, permanent rolled erosion control products such as turf reinforcement mats (TRMs) can be used. In particular, turf reinforcement mats are designed for discharges that exert velocities and sheer stresses that exceed the typical limits of mature natural vegetation. Photograph RECP-1. Erosion control blanket protecting the slope from Appropriate Uses RECPs can be used to control erosion in conjunction with revegetation efforts, providing seedbed protection from wind and water erosion. These products are often used on disturbed areas on steep slopes, in areas with highly erosive soils, or as part of drainageway stabilization. In order to select the appropriate RECP for site conditions, it is important to have a general understanding of the general types of these products, their expected longevity, and general characteristics. The Erosion Control Technology Council (ECTC 2005) characterizes rolled erosion control products according to these categories: • Mulch control netting: A planar woven natural fiber or extruded geosynthetic mesh used as a temporary degradable rolled erosion control product to anchor loose fiber mulches. • Open weave textile: A temporary degradable rolled erosion control product composed of processed natural or polymer yams woven into a matrix, used to provide erosion control and facilitate vegetation establishment. • Erosion control blanket (ECB): A temporary degradable rolled erosion control product composed of processed natural or polymer fibers which are mechanically, structurally or chemically bound together to form a continuous matrix to provide erosion control and facilitate vegetation establishment. ECBs can be further differentiated into rapidly degrading single -net and double -net types or slowly degrading types. Rolled Erosion Control Products Functions Erosion Control Yes Sediment Control No Site/Material Management No November 2010 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 RECP-1 EC -6 Rolled Erosion Control Products (RECP) ■ Turf Reinforcement Mat (TRM): A rolled erosion control product composed of non -degradable synthetic fibers, filaments, nets, wire mesh, and/or other elements, processed into a permanent, three- dimensional matrix of sufficient thickness. TRMs, which may be supplemented with degradable components, are designed to impart immediate erosion protection, enhance vegetation establishment and provide long-term functionality by permanently reinforcing vegetation during and after maturation. Note: TRMs are typically used in hydraulic applications, such as high flow ditches and channels, steep slopes, stream banks, and shorelines, where erosive forces may exceed the limits of natural, unreinforced vegetation or in areas where limited vegetation establishment is anticipated. Tables RECP-1 and RECP-2 provide guidelines for selecting rolled erosion control products appropriate to site conditions and desired longevity. Table RECP-1 is for conditions where natural vegetation alone will provide permanent erosion control, whereas Table RECP-2 is for conditions where vegetation alone will not be adequately stable to provide long-term erosion protection due to flow or other conditions. RECP-2 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC -6 Table RECP-1. ECTC Standard Specification for Temporary Rolled Erosion Control Products (Adapted from Erosion Control Technology Council 2005) Product Description Slope Applications* Channel Applications* Minimum Tensile Strength Expected Longevity r Maximum Gradient C Factor:" Max. Shear Stress' -4.6 Mulch Control Nets 5:1 (H:V) 5-0.10 @ 0.25 lbs/ft2 5 lbs/ft 5:1 (12 Pa) (0.073 kN/m) Netless Rolled <0.10 @ — 0.5 Ibs/ft2 5 lbs/ft Erosion Control 4:1 (H:V) 4:1 (24 Pa) (0.073 kN/m) Blankets Up to 12 Single -net Erosionmonths Control Blankets & 3:1 (H:V) ≤0.15 @ 1.5 lbs/ft2 50 lbs/ft Open Weave Textiles 3:1 (72 Pa) (0.73 kN/m) Double -net Erosion Control Blankets 2:1 (H:V) _<0.20 @ 2:1 1.75 lbs/ft2 (84 Pa) 75 lbs/ft (1.09 kN/m) Mulch Control Nets 5:1 (H:V) <0.10 @ — 5:1 0.25 lbs/ft2 (12 Pa) 25 lbs/ft (0.36 kN/m) 24 months Erosion Control Blankets & Open <0.25 a 2.00 lbs/ft2 100 lbs/ft Weave Textiles (slowly degrading) 1.5:1 (H:V) 1.5:1 (96 Pa) (1.45 kN/m) 24 months Erosion Control Blankets & Open 1:1 (H:V) <0.25 @ — 2.25 lbs/ft2 125 lbs/ft 36 months Weave Textiles 1:1 (108 Pa) (1.82 kN/m) * C Factor and shear stress for mulch control nettings must be obtained with netting used in conjunction with pre -applied mulch material. (See Section 5.3 of Chapter 7 Construction BMPs for more information on the C Factor.) ' Minimum Average Roll Values, Machine direction using ECTC Mod. ASTM D 5035. 2 C Factor calculated as ratio of soil loss from RECP protected slope (tested at specified or greater gradient, 1-1:V) to ratio of soil loss from unprotected (control) plot in large-scale testing. ' Required minimum shear stress RECP (unvegetated) can sustain without physical damage or excess erosion (> 12.7 mm (0.5 in) soil loss) during a 30 -minute flow event in large-scale testing. 4 The permissible shear stress levels established for each performance category are based on historical experience with products characterized by Manning's roughness coefficients in the range of 0.01 - 0.05. 5 Acceptable large-scale test methods may include ASTM D 6459, or other independent testing deemed acceptable by the engineer. 6 Per the engineer's discretion. Recommended acceptable large-scale testing protocol may include ASTM D 6460, or other independent testing deemed acceptable by the engineer. November 2010 Urban Drainage and Flood Control District RECP-3 Urban Storm Drainage Criteria Manual Volume 3 EC -6 Rolled Erosion Control Products (RECP) Table RECP-2. ECTC Standard Specification for Permanent' Rolled Erosion Control Products (Adapted from: Erosion Control Technology Council 2005) Product Type Slope Applications Channel Applications TRMs with a minimum thickness of inches (6.35 mm) per ASTM D 6525 and UV stability of 80% per ASTM D 4355 (500 hours Maximum Gradient Maximum Shear Stress4'5 Minimum Tensile Strength" 0.5:1 (H:V) 6.0 lbs/ft2 (288 Pa) 125 lbs/ft (1.82 kN/m) 051 HV kN/m) 80 lbs/ft2 384 P 150 lbs/ft (2.19 0.5:1 (H:V) 10.0 lbs/ft2 (480 Pa) 175 lbs/ft (2.55 kN/m) ' For TRMs containing degradable components, all property values must be obtained on the non- degradable portion of the matting alone. 2 Minimum Average Roll Values, machine direction only for tensile strength determination using ASTM D 6818 (Supersedes Mod. ASTM D 5035 for RECPs) 3 Field conditions with high loading and/or high survivability requirements may warrant the use of a TRM with a tensile strength of 44 kN/m (3,000 lb/ft) or greater. 4 Required minimum shear stress TRM (fully vegetated) can sustain without physical damage or excess erosion (> 12.7 mm (0.5 in.) soil loss) during a 30 -minute flow event in large scale testing. 5 Acceptable large-scale testing protocols may include ASTM D 6460, or other independent testing deemed acceptable by the engineer. Design and Installation RECPs should be installed according to manufacturer's specifications and guidelines. Regardless of the type of product used, it is important to ensure no gaps or voids exist under the material and that all corners of the material are secured using stakes and trenching. Continuous contact between the product and the soil is necessary to avoid failure. Never use metal stakes to secure temporary erosion control products. Often wooden stakes are used to anchor RECPs; however, wood stakes may present installation and maintenance challenges and generally take a long time to biodegrade. Some local jurisdictions have had favorable experiences using biodegradable stakes. This BMP Fact Sheet provides design details for several commonly used ECB applications, including: ECB-1 Pipe Outlet to Drainageway ECB-2 Small Ditch or Drainageway ECB-3 Outside of Drainageway RECP-4 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC -6 Staking patterns are also provided in the design details according to these factors: • ECB type • Slope or channel type For other types of RECPs including TRMs, these design details are intended to serve as general guidelines for design and installation; however, engineers should adhere to manufacturer's installation recommendations. Maintenance and Removal Inspection of erosion control blankets and other RECPs includes: • Check for general signs of erosion, including voids beneath the mat. If voids are apparent, fill the void with suitable soil and replace the erosion control blanket, following the appropriate staking pattern. ■ Check for damaged or loose stakes and secure loose portions of the blanket. Erosion control blankets and other RECPs that are biodegradable typically do not need to be removed after construction. If they must be removed, then an alternate soil stabilization method should be installed promptly following removal. Turf reinforcement mats, although generally resistant to biodegradation, are typically left in place as a dense vegetated cover grows in through the mat matrix. The turf reinforcement mat provides long-term stability and helps the established vegetation resist erosive forces. November 2010 Urban Drainage and Flood Control District RECP-5 Urban Storm Drainage Criteria Manual Volume 3 EC -6 Rolled Erosion Control Products (RECP) UNDISTURBED SOIL -\ PERIMETER ANCHOR TRENCH, TYP. JOINT ANCHOR TRENCH, TYP. TOP OF CHANNEL BANK TYPE OF ECB AS INDICATED IN PLAN VIEW. INSTALL IN PIALL DISTURBED AREAS OF STREAMS AND DRAINAGE CHANNELS TO DEPT 0 ABOVE CHANNEL INVERT. ECB SHALL GENERALLY BE ORIENTED PARALLEL TO FLOW DIRECTION (I.E. LONG DIMENSIONS OF BLANKET PARALLEL TO FLOWLINES) STAKING PATTERN SHALL MATCH ECB AND/OR CHANNEL TYPE. ECB-1. PIPE OUTLET TO DRAINAGEWAY JOINT ANCHOR TRENCH, TYP. _ 6" TOPSOIL TYPE OF ECB, INDICATED IN PLAN VIEW ECB SHALL EXTEND TO THE TOP OF THE CHANNEL PERIMETER ANCHOR TRENCH. TYP. COMPACTED SUBGRADE STAKING PATTERN PER MANUFACTURER SPEC. OR PATTERN BASED ON EC8 AND/OR CHANNEL TYPE (SEE STAKING PATTERN DETAIL) ECB-2. SMALL DITCH OR DRAINAGEWAY ANCHOR DETAILS GEOTEXTILE FABRIC OR MAT, TYP. -6-1 3" MIN, TYP. le- MIN, TYP. PERIMETER COMPACTED BACKFILL, "� ANCHOR SINGLE STAKE, TYP. TRENCH EDGE TYP. JOINT ANCHOR TWO OF ADJACENT ROLLS TRENCH EDGES TWO INTERMEDIATE T OOP IDDLE ROLL ANCHOR FROM OF TRENCH i-- 6" FLOW -6-'1 OVERLAPPING JOINT fT 3" MIN. 12" _1 MIN. / WOOD STAKE DETAIL. RECP-6 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 November 2010 Rolled Erosion Control Products (RECP) EC -6 DIVERSION DITCH TYPICALLY AT TOP OF SLOPE PERIMETER ANCHOR TRENCH OR JOINT, TYP. 6 4:1-3:1 SLOPES STAGGER OVERLAPS OVERLAPPING JOINT STAKING PATTERN PER MANUFACTURER SPEC. OR PATTERN BASED ON ECB AND/OR SLOPE TYPE (SEE STAKING PATTERN DETAIL) PERIMETER ANCHOR TRENCH ECB-3. OUTSIDE OF DRAINAGEWAY ROLL L WIDTH W, TYP. STRAW 6' O 0 0 O O w h - 2' STRAW -COCONUT COCONUT OR EXCELSIOR STAKING PATTERNS BY ECB TYPE 3' 6' 0 3:1 —2.1 SLOPES h w LOW FLOW CHANNEL 4' 20" 2' 0 4" ioaii 0 O 0 I O 0 0 I --- 10 000 O 0 0 2:1 AND STEEPER SLOPES - 2' h w HIGH FLOW CHANNEL Y4 W h w STAKING PATTERNS BY SLOPE OR CHANNEL TYPE November 2010 Urban Drainage and Flood Control District RECP-7 Urban Storm Drainage Criteria Manual Volume 3 EC -6 Rolled Erosion Control Products (RECP) EROSION CONTROL BLANKET INSTALLATION NOTES 1. SEE PLAN VIEW FOR: - LOCATION OF ECB. - TYPE OF ECB (STRAW, STRAW -COCONUT, COCONUT, OR EXCELSIOR). -AREA, A, IN SQUARE YARDS OF EACH TYPE OF ECB. 2. 100% NATURAL AND BIODEGRADABLE MATERIALS ARE PREFERRED FOR RECPs, ALTHOUGH SOME JURISDICTIONS MAY ALLOW OTHER MATERIALS IN SOME APPLICATIONS. 3. IN AREAS WHERE ECBs ARE SHOWN ON THE PLANS, THE PERMITTEE SHALL PLACE TOPSOIL AND PERFORM FINAL GRADING, SURFACE PREPARATION, AND SEEDING AND MULCHING. SUBGRADE SHALL BE SMOOTH AND MOIST PRIOR TO ECB INSTALLATION AND THE ECB SHALL BE IN FULL CONTACT WITH SUBGRADE. NO GAPS OR VOIDS SHALL EXIST UNDER THE BLANKET. 4. PERIMETER ANCHOR TRENCH SHALL BE USED ALONG THE OUTSIDE PERIMETER OF ALL BLANKET AREAS. 5. JOINT ANCHOR TRENCH SHALL BE USED TO JOIN ROLLS OF ECBs TOGETHER (LONGITUDINALLY AND TRANSVERSELY) FOR ALL ECBs EXCEPT STRAW WHICH MAY USE AN OVERLAPPING JOINT. 6. INTERMEDIATE ANCHOR TRENCH SHALL BE USED AT SPACING OF ONE-HALF ROLL LENGTH FOR COCONUT AND EXCELSIOR ECBs. 7. OVERLAPPING JOINT DETAIL SHALL BE USED TO JOIN ROLLS OF ECBs TOGETHER FOR ECBs ON SLOPES. 8. MATERIAL SPECIFICATIONS OF ECBs SHALL CONFORM TO TABLE ECB-1. 9. ANY AREAS OF SEEDING AND MULCHING DISTURBED IN THE PROCESS OF INSTALLING ECBS SHALL BE RESEEDED AND MULCHED. 10. DETAILS ON DESIGN PLANS FOR MAJOR DRAINAGEWAY STABILIZATION WILL GOVERN IF DIFFERENT FROM THOSE SHOWN HERE. TABLE ECB-1. ECB MATERIAL SPECIFICATIONS TYPE COCONUT CONTENT STRAW CONTENT EXCELSIOR CONTENT RECOMMENDED NETTING•' STRAWS - 100% - / DouBLENATURAL STRAW- COCONUT 30% MIN 70% MAX _ DOUBLE/ NATURAL COCONUT 100% - - DOUBLE/ NATURAL EXCELSIOR - - 100% DOUBLE/ NATURAL s MAY ONLY BE USED OUTSIDE OF STREAMS AND DRAINAGE CHANNEL. "ALTERNATE NETTING MAY BE ACCEPTABLE IN SOME JURISDICTIONS RECP-8 Urban Drainage and Flood Control District November 2010 Urban Storm Drainage Criteria Manual Volume 3 Rolled Erosion Control Products (RECP) EC -6 EROSION CONTROL BLANKET MAINTENANCE NOTES 1. INSPECT BMPs EACH WORKDAY, AND MAINTAIN THEM IN EFFECTIVE OPERATING CONDITION. MAINTENANCE OF BMPs SHOULD BE PROACTIVE, NOT REACTIVE. INSPECT BMPs AS SOON AS POSSIBLE (AND ALWAYS WITHIN 24 HOURS) FOLLOWING A STORM THAT CAUSES SURFACE EROSION, AND PERFORM NECESSARY MAINTENANCE. 2. FREQUENT OBSERVATIONS AND MAINTENANCE ARE NECESSARY TO MAINTAIN BMPs IN EFFECTIVE OPERATING CONDITION. INSPECTIONS AND CORRECTIVE MEASURES SHOULD BE DOCUMENTED THOROUGHLY. 3. WHERE BMPs HAVE FAILED, REPAIR OR REPLACEMENT SHOULD BE INITIATED UPON DISCOVERY OF THE FAILURE. 4. ECBs SHALL BE LEFT IN PLACE TO EVENTUALLY BIODEGRADE, UNLESS REQUESTED TO BE REMOVED BY THE LOCAL JURISDICTION. 5. ANY ECB PULLED OUT, TORN, OR OTHERWISE DAMAGED SHALL BE REPAIRED OR REINSTALLED. ANY SUBGRADE AREAS BELOW THE GEOTEXTILE THAT HAVE ERODED TO CREATED A VOID UNDER THE BLANKET, OR THAT REMAIN DEVOID OF GRASS SHALL BE REPAIRED, RESEEDED AND MULCHED AND THE ECB REINSTALLED. NOTE: MANY JURISDICTIONS HAVE BMP DETAILS THAT VARY FROM UDFCD STANDARD DETAILS. CONSULT WITH LOCAL JURISDICTIONS AS TO WHICH DETAIL SHOULD BE USED WHEN DIFFERENCES ARE NOTED. (DETNLS ADAPTED FROM DOUGLAS COUNTY. COLORADO AND TOWN OF PARKER COLORADO, NOT AVAILABLE IN AUTOCAD) November 2010 Urban Drainage and Flood Control District RECP-9 Urban Storm Drainage Criteria Manual Volume 3 MULCHING Definition Application of plant residues or other suitable materials to the soil surface. Purposes 1. To prevent erosion by protecting the soil surface from raindrop impact and reducing the velocity of overland flow. 2. To foster the growth of vegetation by increasing available moisture and providing insulation against extreme heat and cold. From: Environmental Protection Agency. 1976 Figure C4 -2 —Mulching From Urban Drainage and Flood Control District Drainage Criteria Manual V.3 Stormwater Management Plan APPENDIX C: Phased CM Implementation Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase r CM Description/Function 1 Installation/Implementation 1 Inspection/Maintenance Install initial CMs Perimeter control Perimeter control serves as erosion and sediment control and, when appropriate, access control during construction activity. At down gradient locations on the perimeter, controls will be installed where overland sheet flow has the potential to leave the site. In up -gradient areas perimeter control may be added to define project boundaries, limit on -site flows or protect off -site features. __ Perimeter control may consist of any number of CMs, including, but not limited to diversion ditch & dike, earthen berms, straw wattles, silt fence, construction fencing, controlled parking, controlled site entrance, vehicle tracking control, etc. See the plan for approximate locations and type proposed for installation. Perimeter control will remain in place until areas up -gradient of controls are stabilized. _ See CM specific discussions for inspection and maintenance issues. Install initial CMs Vehicle tracking control Vehicle tracking control will consist of an area with a geotextile liner and gravel, metal grate, medium-sized (6" to 12") rough -cut rocks, or asphalt/concrete "rumble strip". Tracking control is designed to cause soil to vibrate off equipment and vehicles as they transition from disturbed soils to paved areas. All appropriate points of ingress and egress, from where traffic transitions from a stabilized road surface (e.g.presence gravel or pavement) to disturbed soil, will have a vehicle tracking control installed. Tracking control may be moved or eliminated as on -site conditions and activities change. Tracking control should be inspected for depth of gravel/rock, of excess soil. proper usage and the overall general condition. The most common maintenance items include the removal of accumulated soil and addition of gravel/rock. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase CM _ Description/Function I Installation/Implementation Inspection/Maintenance Install initial CMs Designated Staging Area A stabilized staging area is a specific location on -site to stockpile/stage materials and equipment for use on- site. A stabilized staging area allows a central location for deliveries and storage of equipment when not in use, and to reduce disturbance of areas of the site not scheduled for disturbance through construction activities. _ Stabilized staging areas generally consist of a cleared area of the site with vehicle tracking control and perimeter controls Stabilized staging areas will be implemented as needed on site and will be located out of areas of active construction activity. If possible, the designated area will be located so it can be utilized during the entire construction period. Stabilized staging areas should be inspected for adequate vehicle tracking control and perimeter control. Stabilized staging areas should function as designed or repaired or modified as needed. Initial stages of construction Sediment Trap Sediment traps are small impoundments which allow sediment to settle out which are generally installed in a drainage way or other point of discharge from a disturbed area. They are formed by excavating an area or by placing an earthen embankment across a low area or drainage swale Typically, a spillway or outlet is constructed to allow the slow release of stormwater runoff. Sediment traps are commonly used at the outlets of diversion structures, slope drains or any other runoff that discharges waters containing sediment. Sediment traps will be installed prior to earth disturbing activities in areas where its determined to be needed. Sediment Trap will be inspected for accumulated sediment, erosion and to ensure effective operation Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase I CM Descri Lion/Function j Installation/Implementation 1 Ins ection/Maintenance Initial stages of construction Diversion Ditch Diversion ditches are excavated channels, generally 6"-18" in depth which provide channelization of stormwater runoff for the purpose of directing sediment -laden flows to treatment facilities or interception of potential run-on flows to convey it around the disturbed area. All diversion ditches shall be of the 'unlined' type unless specifically noted on the plan. Diversion ditches will be installed prior to earth disturbing activities in areas indicated on the site map. _ Diversion ditches will be inspected for effectiveness and repaired or modified as necessary. Clearing, Grubbing & Pad Grading Natural Vegetative Barrier A natural vegetative barrier is a preexisting vegetated, landscaped or sod/seed area that is retained to reduce water flow and prevent erosion over disturbed soil. Additionally, natural vegetative barriers provide a barrier zone where overland sheet flow velocity is dissipated and sediment trapped, reducing sediment dischar a off -site. Natural vegetative barriers are encouraged for any perimeter or environmentally sensitive areas. whenever possible, a natural vegetative barrier will be maintained between the construction area and stormwater drainage areas. Inspections include observation for sediment accumulation or erosion to the area. Should damage occur to a vegetative buffer strip a new or additional CM should be considered. Construction of temporary material storage areas, improvement or construction of drainage features if needed Straw Bales A straw bale should be a minimum of 14" X 18" X 36" with a minimum mass of 50 pounds. It should be composed of only vegetative matter, except for the binding The straw bales should be bound by steel wire (minimum 14- gauge), nylon or polypropylene. Applications include check dams in swales, inlet protection: outlet protection, perimeter control, disturbed areas with significant potential for off -site drainage, protection from neighboring site run- on, or during the construction of drains e swales and ditches. The basic installation for a straw bale is to prepare a trench approximately four inches deep, secure the bale in the trench using stakes, and backfilled. _ Straw bales will be inspected for proper installation, structural integrity and sediment accumulation. Straw bales degrade and need to be replaced on a regular basis. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase_ CM Descri Lion/Function Installation/Implementation I Inspection/Maintenance Installation of new culvert if needed Inlet protection Inlet protection consists of a barrier material place in front, around, or immediately up -gradient from the inlet. The most common forms of inlet protection are wire or fabric socks filled with rock or straw wattles Inlet protection is designed to slow stormwater flow into the inlet, allowing sediment time to settle and accumulate on the up -gradient side of the structure. without constricting the inlet throat. Inlet protection will be installed prior to earth disturbing activity. As permanent stormwater system inlets are constructed in areas with potential disturbed area run-off or when existing inlets are potentially impacted by construction activity, inlet protection will be installed If conditions warrant, protection will be provided to prevent sediment from entering the inlet from above or behind the opening. Any structure with a potential to receive run-off from non -stabilized surfaces will be treated with an inlet protection CM. Inlet protection will remain in place until all up -gradient areas are stabilized. Inlet protection will be inspected for damage, structural integrity and need for sediment removal. Maintenance includes repairing or replacing as needed, repositioning the inlet protection and/or removing accumulated sediment. Foundation construction Concrete Wash -Out A concrete wash -out is designed to capture waste water and waste products resulting from the cleaning of concrete equipment. A concrete wash -out may not be necessary if all wash -out operations are performed off -site. A concrete wash -out will be installed or provided prior to any construction activities that include the handling of materials containing cement (e.g. concrete, masonry, etc.). Examples of permanent installations include a bermed excavation, a mobile disposal unit. small excavations located near the point of concrete placement, water tight vessels such as rigid pre -fabricated impermeable plastic pools, stock tanks, small dumpsters, buckets, etc. and geotextile bags. A concrete wash -out should be inspected to make sure appropriate access control, tracking and containment is in place. Maintenance would include the removal of excess material, and general structural integrity of the installation. Concrete wash -outs should be cleaned of excess water and solids when the capacity of the wash -out reaches no more than 50% (5" for rigid "kiddie" pools). Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase CM Description/Function Installation/Implementation Inspection/Maintenance 1 Throughout construction period Dust Control Dust control reduces dust generated from disturbed surfaces and wind. Water will be applied from water trucks as needed. Correct application is just enough water to moisten the surface and calm dust, but not so much as to create standing water and mud. Disturbed areas should be inspected for obvious signs of wind erosion and dust. This CM is implemented as needed. As appropriate during all phases of construction which cause soil disturbances on sloped surfaces Surface Roughening g g Surface roughening consists of grooves or tracks installed in the soil surface, perpendicular to the slope This is a temporary soil stabilization technique that works well in areas that will remain inactive for a short time. Surface roughening works by reducing water velocity and promoting infiltration, thus decreasing the potential for erosion to occur. Any disturbed areas with no construction activity planned for longer than 14 days may be surfaced roughened. Surface roughening may be applied by creating a continuous furrow perpendicular to the slope. This can be done with the teeth on a loader bucket, ripping, disking or plowing equipment. Surface roughening can also be created by running tracked equipment up and down the slope. Inspection of surface roughened areas would include proper implementation, structural integrity and areas of erosion or sediment accumulation. Maintenance for surface roughening would include re - applying the technique or installation of new or additional CMs. All Phases where appropriate to the water volume and velocity Straw Wattles (fiber rolls) Straw wattles consist of a net or geotextile fabric filled with straw, excelsior, wood mulch or other man made fillers. They reduce water velocity allowing sediment to accumulate on the up -gradient side of the wattle. Applications include, but are not limited to, slope stabilization, check dams in swales, back of curb protection and temporary secondary containment for stock piles and materials storage The basic installation for a net wrapped wattle is to prepare a trench approximately three inches deep, secure the wattle in the trench using a stake or landscape pin, and backfill approximately 1/3 of the wattle on the up -gradient side.may Wattles should be installed based on manufacturer's directions. Typical wattle installation details are rovided. Straw wattles should be inspected for proper installation, structural integrity and sediment accumulation. Note: A wattle that has been flattened out of round not need to be replaced if they remain sufficient to function appropriately on the up gradient side of the wattle. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan CMs — Phasing, Implementation and Maintenance Phase CM Description/Function Installation/Implementation I proper Inspection/Maintenance H dams should be inspected installation, structural and accumulated would include or replacing damaged berms and removing sediment. All Phases where appropriate to the water volume and velocity Check Dams Rock check dams will be used in areas of concentrated flows along the swales to slow water velocity to allow sediment to settle and to prevent erosion. Additionally, this may be used in areas where existing drainage patterns cross onto the site and bring neighboring property run-on into the construction area. T The check dam will be installed across the entire width of the swale, with the center of the check dam lower than the sides. Check for integrity sediment. Maintenance repairing rock accumulated Seeding involves the mechanical or As soon as practicable, after the Seed areas should be inspected to hand application of a specific seed mixes appropriate for the site completing of construction activities, soil should be properly prepared and ensure that the straw mat was applied correctly and has not been After location and soil type. Seeding can seeded. The choice of seed mix will compromised. The area should completion of Erosion be used as a permanent or dictate application rates and also be inspected for erosion and construction Control Mats temporary CM. methods. Seeding should always be sediment deposition. activities & Seeding Seeding provides plant growth to accompanied by an additional CM, such as mulching or straw mat to Maintenance items would include re -grading and seeding bare or stabilize the soil reducing the protect the seed and soil from areas of thin vegetative growth likelihood of erosion or sediment erosion during the germination and and/or adding additional CMs as t transport_ g growth process. appropriate. Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan New CMs Added to the Site Use the following space to provide information regarding new CMs added to site Phase CM Description/Function Installation/Implementation Inspection/Maintenance Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan APPENDIX D: Inspection Forms Tri-State Generation & Transmission — Lloyd Sisson Substation IN Summit aSERVICES GROUP StormWater Inspection Report Facility Name Permittee Date of Inspection Weather Conditions Permit Certification # Current Acres Disturbed Phase of Construction Inspector Title Inspector Name Location of SWMP Is the above inspector a qualified stormwater manager? (permittee is responsible for ensuring that the inspector is a qualified stormwater manager) GENERAL NOTES I INSPECTION FREQUENCY I Check the box that describes the minimum inspection frequency utilized when conducting each inspection At least one inspection every 7 calendar days At least one inspection every 14 calendar days PLUS post -storm event inspections •This is a post -storm event inspection within 24 hours after storm. Event Date: Reduced inspection frequency - Include site conditions that warrant reduced inspection frequency • Post -storm inspections at temporarily idle sites (prior to construction/within 72 hours after storm) • Inspections at completed sites/area (at least once every 30 days) • Winter conditions exclusion Have there been any deviations from the minimum inspection schedule? If yes, describe: 0 Summit StormWater Inspection Report INSPECTION REQUIREMENTS RESULT COMMENT Are control measures in effective operational condition and working as designed in the specifications? Are there any new potential sources of pollutants? If answer is yes, list new pollutants in comments. Does the site require any new or modified control measures to minimize pollutant discharges? Are there any areas that require temporary or permanent stabilization? (e.g. slopes, inactive disturbed areas, stockpiles, etc.). Are there any Bulk storage (55 gal. or greater) of petroleum products and other liquid chemicals on site that require secondary containment? Are there any areas of non-compliance with the permit requirements? If answer is yes, implement corrective actions in section below. AREAS TO INSPECT Is there evidence of, or the potential for, pollutants leaving the construction site boundaries, entering the stormwater drainage system or discharging to state waters at the following locations? If "YES" describe discharge or potential for discharge below. Then document related maintenance, inadequate control measures and corrective actions on the approriate subseqent forms. Location Result Description Construction site perimeter All disturbed areas Designated haul routes Material and waste storage areas exposed to precipitation Locations where stormwater has the potential to discharge offsite Locations where vehicles exit the site Other: a Summit SERVICES GROUP StormWater Inspection Report CONTROL MEASURES REQUIRING ROUTINE MAINTENANCE Definition: Any control measure that is still operating in accordance with its design and the requirements of the permit, but requires maintenance to prevent a breach of the control measure. These items are not subject to the corrective action requirements as specified in Part I.B.1.c of the permit. Are there control measures requiring maintenance? If YES, Document below Location Control Measure Maintenance Required Date Observed Date Completed Et Initials 0 Summit StormWater Inspection Report CONTROL MEASURES REQUIRING ROUTINE MAINTENANCE Location Control Measure Maintenance Required Date Observed Date Completed Et Initials SERVICES GROUP ID Summit StormWater Inspection Report INADEQUATE CONTROL MEASURES REQUIRING I CORRECTIVE ACTION Definition: Any control measure that is not designed or implemented in accordance with the requirements of the permit and/or any control measure that is not implemented to operate in accordance with its design. This includes control measures that have not been implemented for pollutant sources. If it is infeasible to install or repair the control measure immediately after discovering the deficiency the reason must be documented and a schedule included to return the control measure to effective operating condition as possible. Are there control measures requiring corrective action? If YES, Document below. Are there additional control measures needed that were not in place at the time of inspection? If YES, Document below. Location Description of Inadequate Control Measure Description of Corrective Action Was deficiency corrected when discovered? YES/NO. If NO provide reason and schedule to correct. Date Observed Date Completed Ex Initials Summit StormWater Inspection Report INADEQUATE CONTROL MEASURES REQUIRING CORRECTIVE ACTION Location Description of Inadequate Control Measure Description of Corrective Action Was deficiency corrected when discovered? YES/NO. If "NO" provide reason and schedule to correct. Date Observed Date Completed 1=t Initials Summit SERVICES GROUP StormWater Inspection Report Has there been an incident of noncompliance requiring 24 -hour notification? If YES, Document Below: INSPECTION CERTIFICATION I certify this inspection is, to the best of my knowledge and belief, true, accurate and complete. I am aware that there are significant penalties for submitting false information. Qualified Stormwater Manager/Inspector (Name, Title, Company Et Signature) Date: COMPLIANCE CERTIFICATON I verify that, to the best of my knowledge and belief, all corrective action and maintenance items identified during the inspection are complete, and the site is currently in compliance with the permit. Qualified Stormwater Manager/Designee (Name, Title, Company Est Signature) Date: Stormwater Management Plan APPENDIX E: Spill Reports Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan t-% TRI-STATE GENERATION AND TRANSMISSION ASSOCIATION, INC. Construction Stormwater Pollution Prevention Spill Report Form Spill Reported By: Phone Number: Details Date Reported: Time: Date of Spill: Time: Name of the Facility: Lloyd Sisson Substation, Weld County. CO Describe Spill Location and Events Leading to Spill: Material Spilled: Source of Spill: AMOUNT OF THE SPILL (GALLONS OR POUNDS): Containment and Cleanup Containment or Cleanup Action: Date and Time Cleanup Completed or Terminated: Description of Materials Contaminated: Label on the Drum of Cleanup Materials: Signed: Contractor Superintendent or Environmental Inspector Tri-State Generation & Transmission — Lloyd Sisson Substation Stormwater Management Plan APPENDIX F: Permit Application and Permit Tri-State Generation & Transmission — Lloyd Sisson Substation STATE OF COLORADO COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT Water Quality Control Division CDPS GENERAL PERMIT STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITY AUTHORIZATION TO DISCHARGE UNDER THE COLORADO DISCHARGE PERMIT SYSTEM (CDPS) In compliance with the provisions of the Colorado Water Quality Control Act, (25-8-101 et seq., CRS, 1973 as amended) and the Federal Water Pollution Control Act, as amended (33 U.S.C. 1251 et seq.; the "Act"), this permit authorizes the discharge of stormwater associated with construction activities (and specific allowable non-stormwater discharges in accordance with Part I.A.1. of the permit) certified under this permit, from those locations specified throughout the State of Colorado to specified waters of the State. Such discharges shall be in accordance with the conditions of this permit. This permit specifically authorizes the facility listed on the certification to discharge in accordance with permit requirements and conditions set forth in Parts I and II hereof. All discharges authorized herein shall be consistent with the terms and conditions of this permit. This permit becomes effective on April 1, 2019, and shall expire at midnight March 31, 2024. Issued and signed this 1st day of November 2018. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT Ellen Howard Kutzer, Permits Section Manager Water Quality Control Division Permit History Originally signed and issued October 31, 2018; effective April 1, 2019. Table of Contents Part I 1 A. COVERAGE UNDER THIS PERMIT 1 1. Authorized Discharges 1 2. Limitations on Coverage 1 3. Permit Certification and Submittal Procedures 2 B. EFFLUENT LIMITATIONS 6 1. Requirements for Control Measures Used to Meet Effluent Limitations 6 2. Discharges to an Impaired Waterbody 9 3. General Requirements 10 C. STORMWATER MANAGEMENT PLAN (SWMP) REQUIREMENTS 11 1. SWMP General Requirements 11 2. SWMP Content 11 3. SWMP Review and Revisions 13 4. SWMP Availability 14 D. SITE INSPECTIONS 14 1. Person Responsible for Conducting Inspections 14 2. Inspection Frequency 14 3. Inspection Frequency for Discharges to Outstanding Waters 15 4. Reduced Inspection Frequency 15 5. Inspection Scope 16 E. DEFINITIONS 17 F. MONITORING 20 G. Oil and Gas Construction 21 Part II: Standard Permit Conditions 22 A. DUTY TO COMPLY 22 B. DUTY TO REAPPLY 22 C. NEED TO HALT OR REDUCE ACTIVITY NOT A DEFENSE 22 D. DUTY TO MITIGATE 22 E. PROPER OPERATION AND MAINTENANCE 22 F. PERMIT ACTIONS 22 G. PROPERTY RIGHTS 22 H. DUTY TO PROVIDE INFORMATION 23 I. INSPECTION AND ENTRY 23 J. MONITORING AND RECORDS 23 K. SIGNATORY REQUIREMENTS 24 PART I Permit No.: COR400000 1. Authorization to Signs 24 2. Electronic Signatures 25 3. Change in Authorization to Sign 25 L. REPORTING REQUIREMENTS 25 1. Planned Changes 25 2. Anticipated Non -Compliance 25 3. Transfer of Ownership or Control 25 4. Monitoring reports 26 5. Compliance Schedules 26 6. Twenty-four hour reporting 26 7. Other non-compliance 27 8. Other information 27 M. BYPASS 27 1. Bypass not exceeding limitations 27 2. Notice of bypass 27 3. Prohibition of Bypass 27 N. UPSET 28 1. Effect of an upset 28 2. Conditions necessary for demonstration of an Upset 28 3. Burden of Proof 28 O. RETENTION OF RECORDS 28 1. Post -Expiration or Termination Retention 28 2. On -site Retention 29 P. REOPENER CLAUSE 29 1. Procedures for modification or revocation 29 2. Water quality protection 29 Q. SEVERABILITY 29 R. NOTIFICATION REQUIREMENTS 29 1. Notification to Parties 29 S. RESPONSIBILITIES 30 1. Reduction, Loss, or Failure of Treatment Facility 30 T. Oil and Hazardous Substance Liability 30 U. Emergency Powers 30 V. Confidentiality 30 W. Fees 30 PART I Permit No.: COR400000 X. Duration of Permit 30 Y. Section 307 Toxics 30 PART I Permit No.: COR400000 Part Note: At the first mention of terminology that has a specific connotation for the purposes of this permit, the terminology is electronically linked to the definitions section of the permit in Part I.E. A. COVERAGE UNDER THIS PERMIT 1. Authorized Discharges This general permit authorizes permittee(s) to discharge the following to state waters: stormwater associated with construction activity and specified non-stormwater associated with construction activity. The following types of stormwater and non-stormwater discharges are authorized under this permit: a. Allowable Stormwater Discharges i. Stormwater discharges associated with construction activity. ii. Stormwater discharges associated with producing earthen materials, such as soils, sand, and gravel dedicated to providing material to a single contiguous site, or within Y4 mile of a construction site (i.e. borrow or fill areas) iii. Stormwater discharges associated with dedicated asphalt, concrete batch plants and masonry mixing stations (Coverage under this permit is not required if alternative coverage has been obtained.) b. Allowable Non-Stormwater Discharges The following non-stormwater discharges are allowable under this permit if the discharges are identified in the stormwater management plan in accordance with Part I.C. and if they have appropriate control measures in accordance with Part I.B.1. i. Discharges from uncontaminated springs that do not originate from an area of land disturbance. ii. Discharges to the ground of concrete washout water associated with the washing of concrete tools and concrete mixer chutes. Discharges of concrete washout water must not leave the site as surface runoff or reach receiving waters as defined by this permit. iii. Discharges of landscape irrigation return flow. c. Emergency Fire Fighting Discharges resulting from emergency firefighting activities are authorized by this permit. 2. Limitations on Coverage Discharges not authorized by this permit include, but are not limited to, the discharges and activities listed below. Permittees may seek individual or alternate general permit coverage for the discharges, as appropriate and available. a. Discharges of Non-Stormwater Page 1 of 33 PART I Permit No.: COR400000 Discharges of non-stormwater, except the authorized non-stormwater discharges listed in Part I.A.1.b., are not eligible for coverage under this permit. b. Discharges Currently Covered by another Individual or General Permit c. Discharges Currently Covered by a Water Quality Control Division (division) Low Risk Guidance Document 3. Permit Certification and Submittal Procedures a. Duty to apply The following activities shall apply for coverage under this permit: i. Construction sites that will disturb one acre or more; or ii. Construction sites that are part of a common plan of development or sale; or iii. Stormwater discharges that are designated by the division as needing a stormwater permit because the discharge: (a) Contributes to a violation of a water quality standard; or (b) is a significant contributor of pollutants to state waters. b. Application Requirements To obtain authorization to discharge under this permit, applicants applying for coverage following the effective date of the renewal permit shall meet the following requirements: i. Owners and operators submitting an application for permit coverage will be co- permittees subject to the same benefits, duties, and obligations under this permit. ii. Signature requirements: Both the owner and operator (permittee) of the construction site, as defined in Part I.E., must agree to the terms and conditions of the permit and submit a completed application that includes the signature of both the owner and the operator. In cases where the duties of the owner and operator are managed by the owner, both application signatures may be completed by the owner. Both the owner and operator are responsible for ensuring compliance with all terms and conditions of the permit, including implementation of the stormwater management plan. iii. Applicants must use the paper form provided by the division or the electronic form provided on the division's web -based application platform when applying for coverage under this permit. iv. The applicant(s) must develop a stormwater management plan (SWMP) in accordance with the requirements of Part I.C. The applicant(s) must also certify that the SWMP is complete, or will be complete, prior to commencement of any construction activity. Page 2 of 33 PART Permit No.: COR400000 v. The applicant(s) must submit a complete, accurate, and signed permit application electronically, by mail or hand delivery to the division at least 10 days prior to the commencement of construction activity except that construction activities that are in response to a public emergency related site shall apply for coverage no later than 14 days after the commencement of construction activities. The provisions of this part in no way remove a violation of the Colorado Water Quality Control Act if a point source discharge occurs prior to the issuance of a CDPS permit. vi. The application must be signed in accordance with the requirements of Part IA. Applications submitted by mail or hand delivered should be directed to: Colorado Department of Public Health and Environment Water Quality Control Division Permits Section, WQCD-PS-B2 4300 Cherry Creek Drive South Denver, CO 80246 vii. The applicant(s) must receive written notification that the division granted permit coverage prior to conducting construction activities except for construction activities that are in response to a public emergency related site c. Division Review of Permit Application Within 10 days of receipt of the application, and following review of the application, the division may: i. Issue a certification of coverage; ii. request additional information necessary to evaluate the discharge; iii. delay the authorization to discharge pending further review; iv. notify the applicant that additional terms and conditions are necessary; or v. deny the authorization to discharge under this general permit. d. Alternative Permit Coverage Division Required Alternate Permit Coverage: The Division may require an applicant or permittee to apply for an individual permit or an alternative general permit if it determines the discharge does not fall under the scope of this general permit. In this case, the Division will notify the applicant or permittee that an individual permit application is required. ii. Permittee Request for alternate permit coverage: A permittee authorized to discharge stormwater under this permit may request to be excluded from coverage under this general permit by applying for an individual permit. In this case, the permittee must submit an individual application, with reasons supporting the request, to the Division at least 180 days prior to any discharge. When an individual permit is issued, the permittee's authorization to discharge under this permit is terminated on the effective date of the individual permit. e. Submittal Signature Requirements Page 3 of 33 PART I Permit No.: COR400000 Documents required for submittal to the division in accordance with this permit, including applications for permit coverage and other documents as requested by the division, must include signatures by both the owner and the operator, except for instances where the duties of the owner and operator are managed by the owner. Signatures on all documents submitted to the division as required by this permit must meet the Standard Signatory Requirements in Part ILK. of this permit in accordance with 40 C.F.R. 122.41(k). i. Signature Certification Any person(s) signing documents required for submittal to the Division must make the following certification: "I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." f. Compliance Document Signature Requirements Documents which are required for compliance with the permit, but for which submittal to the division is not required unless specifically requested by the division, must be signed by the individual(s) designated as the Qualified Stormwater Manager, as defined in Part I.E. i. Any person(s) signing inspection documents required for compliance with the permit must make the following statement: "I verify that, to the best of my knowledge and belief, all corrective action and maintenance items identified during the inspection are complete, and the site is currently in compliance with the permit." g• Field Wide Permit Coverage for Oil and Gas Construction At the discretion of the division, a single permit certification may be issued to a single oil and gas permittee to cover construction activity related discharges from an oil and gas field at multiple locations that are not necessarily contiguous. h. Permit Coverage without Application Qualifying Local Program: When a small construction site is within the jurisdiction of a qualifying local program, the owner and operator of the construction activity are authorized to discharge stormwater associated with small construction activity under this general permit without the submittal of an application to the division. Sites covered by a qualifying local program are exempt from the following sections of this general permit: Page 4 of 33 PART I Permit No.: COR400000 Part I.A.3.a.; Part I.A.3.b.; Part I.A.3.c.; Part I.A.3.d.; Part I.A.3.g.; Part I.A.3.i.; Part I .A. 3. j . ; Part I.A.3.k. 3. k. Sites covered by a qualifying local program are subject to the following requirements: i. Local Agency Authority: This permit does not pre-empt or supersede the authority of local agencies to prohibit, restrict, or control discharges of stormwater to storm drain systems or other water courses within their jurisdiction. ii. Permit Coverage Termination: When a site under a Qualifying Local Program is finally stabilized, coverage under this permit is automatically terminated. iii. Compliance with Qualifying Local Program: Qualifying Local Program requirements that are equivalent to the requirements of this permit are incorporated by reference. Permittees authorized to discharge under this permit, must comply with the equivalent requirements of the Qualifying Local Program that has jurisdiction over the site as a condition of this permit. iv. Compliance with Remaining Permit Conditions. Requirements of this permit that are in addition to or more stringent than the requirements of the Qualifying Local Program apply in addition to the requirements of the Qualifying Local Program. v. Written Authorization of Coverage: The division or local municipality may require any permittee within the jurisdiction of a Qualifying Local Program covered under this permit to apply for, and obtain written authorization of coverage under this permit. The permittee must be notified in writing that an application for written authorization of coverage is required. Permittee Initiated Permit Actions Permittee initiated permit actions, including but not limited to modifications, contact changes, transfers, reassignments, and terminations, shall be conducted following division guidance and using appropriate division -provided forms. j. Sale of Residence to Homeowner Residential construction sites only: The permittee may remove residential lots from permit coverage once the lot meets the following criteria: i. the residential lot has been sold to the homeowner(s) for private residential use; ii. a certificate of occupancy, or equivalent, is maintained on -site and is available during division inspections; iii. the lot is less than one acre of disturbance; iv. all construction activity conducted on the lot by the permittee is complete; v. the permittee is not responsible for final stabilization of the lot; and vi. the SWMP was modified to indicate the lot is no longer part of the construction activity. If the residential lot meets the criteria listed above then activities occurring on the lot are no longer considered to be construction activities with a duty to apply and maintain permit coverage. Therefore, the permittee is not required to meet the final stabilization requirements and may terminate permit coverage for the lot. Page 5 of 33 PART I Permit No.: COR400000 k. Permit Expiration and Continuation of Permit Coverage Authorization to discharge under this general permit shall expire at midnight on March 31, 2024. While Regulation 61.4 requires a permittee to submit an application for continuing permit coverage 180 days before the permit expires, the division is requiring that permittees desiring continued coverage under this general permit must reapply at least 90 days in advance of this permit expiration. The Division will determine if the permittee may continue to discharge stormwater under the terms of the general permit. An individual permit may be required for any facility not reauthorized to discharge under the reissued general permit. If this permit is not reissued or replaced prior to the expiration date, it will be administratively continued and remain in force and effect. For permittees that have applied for continued permit coverage, discharges authorized under this permit prior to the expiration date will automatically remain covered by this permit until the earliest of: i. An authorization to discharge under a reissued permit, or a replacement of this permit, following the timely and appropriate submittal of a complete application requesting authorization to discharge under the new permit and compliance with the requirements of the new permit; or ii. The issuance and effect of a termination issued by the Division; or iii. The issuance or denial of an individual permit for the facility's discharges; or iv. A formal permit decision by the Division not to reissue this general permit, at which time the Division will identify a reasonable time period for covered dischargers to seek coverage under an alternative general permit or an individual permit. Coverage under this permit will cease when coverage under another permit is granted/authorized; or The Division has informed the permittee that discharges previously authorized under this permit are no longer covered under this permit. B. EFFLUENT LIMITATIONS 1. Requirements for Control Measures Used to Meet Effluent Limitations The permittee must implement control measures to minimize the discharge of pollutants from all potential pollutant sources at the site. Control measures must be installed prior to commencement of activities that may contribute pollutants to stormwater discharges. Control measures must be selected, designed, installed and maintained in accordance with good engineering, hydrologic and pollution control practices. Control measures implemented at the site must be designed to prevent pollution or degradation of state waters. a. Stormwater Pollution Prevention The permittee must implement structural and/or nonstructural control measures that effectively minimize erosion, sediment transport, and the release of other pollutants related to construction activity. i. Control Measures for Erosion and Sediment Control Page 6 of 33 PART I Permit No.: COR400000 Control measures for erosion and sediment control may include, but are not limited to, wattles/sediment control logs, silt fences, earthen dikes, drainage swales, sediment traps, subsurface drains, pipe slope drains, inlet protection, outlet protection, gabions, sediment basins, temporary vegetation, permanent vegetation, mulching, geotextiles, sod stabilization, slope roughening, maintaining existing vegetation, protection of trees, and preservation of mature vegetation. Specific non-structural control measures must meet the requirements listed below. Specific control measures must meet the requirements listed below. (a) Vehicle tracking controls shall either be implemented to minimize vehicle tracking of sediment from disturbed areas, or the areas where vehicle tracking occurs shall meet subsection Part I.B.1.a.i(b); (b) Stormwater runoff from all disturbed areas and soil storage areas for which permanent or temporary stabilization is not implemented, must flow to at least one control measure to minimize sediment in the discharge. This may be accomplished through filtering, settling, or straining. The control measure must be selected, designed, installed and adequately sized in accordance with good engineering, hydrologic and pollution control practices. The control measure(s) must contain or filter flows in order to prevent the bypass of flows without treatment and must be appropriate for stormwater runoff from disturbed areas and for the expected flow rate, duration, and flow conditions (i.e., sheet or concentrated flow); (c) Outlets that withdraw water from or near the surface shall be installed when discharging from basins and impoundments, unless infeasible. (d) Maintain pre-existing vegetation or equivalent control measures for areas within 50 horizontal feet of receiving waters as defined by this permit, unless infeasible. (e) Soil compaction must be minimized for areas where infiltration control measures will occur or where final stabilization will be achieved through vegetative cover. (f) Unless infeasible, topsoil shall be preserved for those areas of a site that will utilize vegetative final stabilization. (g) Minimize the amount of soil exposed during construction activity, including the disturbance of steep slopes. ii. Practices for Other Common Pollutants (a) Bulk storage, 55 gallons or greater, for petroleum products and other liquid chemicals must have secondary containment, or equivalent protection, in order to contain spills and to prevent spilled material from entering state waters. (b) Control measures designed for concrete washout waste must be implemented. This includes washout waste discharged to the ground as authorized under this permit and washout waste from concrete trucks and masonry operations contained on site. The permittee must ensure the washing activities do not contribute pollutants to stormwater runoff, or receiving waters in accordance Part I.A.1.b.ii. Discharges that may reach groundwater must flow through soil Page 7 of 33 PART I Permit No.: COR400000 that has buffering capacity prior to reaching groundwater, as necessary to meet the effluent limits in this permit, including Part I.B.3.a. The concrete washout location shall be not be located in an area where shallow groundwater may be present and would result in buffering capacity not being adequate, such as near natural drainages, springs, or wetlands. This permit authorizes discharges to the ground of concrete washout waste. iii. Stabilization Requirements The following requirements must be implemented for each site. (a) Temporary stabilization must be implemented for earth disturbing activities on any portion of the site where ground disturbing construction activity has permanently ceased, or temporarily ceased for more than 14 calendar days. Temporary stabilization methods may include, but are not limited to, tarps, soil tackifier, and hydroseed. The permittee may exceed the 14 -day schedule when either the function of the specific area of the site requires it to remain disturbed, or, physical characteristics of the terrain and climate prevent stabilization. The SWMP must document the constraints necessitating the alternative schedule, provide the alternate stabilization schedule, and identify all locations where the alternative schedule is applicable on the site map. (b) Final stabilization must be implemented for all construction sites. Final stabilization is reached when all ground surface disturbing activities at the construction site are complete; and, for all areas of ground surface disturbing activities, either a uniform vegetative cover with an individual plant density of at least 70 percent of pre -disturbance levels is established, or equivalent permanent alternative stabilization methods are implemented. The division may approve alternative final stabilization criteria for specific operations. (c) Final stabilization must be designed and installed as a permanent feature. Final stabilization measures for obtaining a vegetative cover or alternative stabilization methods include, but are not limited to, the following as appropriate: (1) Seed mix selection and application methods; (2) Soil preparation and amendments; (3) Soil stabilization methods (e.g., crimped straw, hydro mulch or rolled erosion control products); (4) Appropriate sediment control measures as needed until final stabilization is achieved; (5) Permanent pavement, hardscape, xeriscape, stabilized driving surfaces; (6) Other alternative stabilization practices as applicable; Page 8 of 33 (d PART I Permit No.: COR400000 The permittee(s) must ensure all temporary control measures are removed from the construction site once final stabilization is achieved, except when the control measure specifications allow the control measure to be left in place (i.e., bio-degradable control measures). b. Maintenance The permittee must ensure that all control measures remain in effective operating condition and are protected from activities that would reduce their effectiveness. Control measures must be maintained in accordance with good engineering, hydrologic and pollution control practices. Observations leading to the required maintenance of control measures can be made during a site inspection, or during general observations of site conditions. The necessary repairs or modifications to a control measure requiring routine maintenance, as defined in Part I.E., must be conducted to maintain an effective operating condition. This section is not subject to the requirements in Part I.B.1.c. below. c. Corrective Actions The permittee must assess the adequacy of control measures at the site, and the need for changes to those control measures, to ensure continued effective performance. When an inadequate control measure, as defined in Part I.E., is identified (i.e., new or replacement control measures become necessary), the following corrective action requirements apply. The permittee is in noncompliance with the permit until the inadequate control measure is replaced or corrected and returned to effective operating condition in compliance with Part I.B.1. and the general requirements in Part I.B.3. If the inadequate control measure results in noncompliance that meets the conditions of Part II.L., the permittee must also meet the requirements of that section. The permittee must take all necessary steps to minimize or prevent the discharge of pollutants, until a control measure is implemented and made operational and/or an inadequate control measure is replaced or corrected and returned to effective operating condition. If it is infeasible to install or repair of control measure immediately after discovering the deficiency, the following must be documented and kept on record in accordance with the recordkeeping requirements in Part II. (a) Describe why it is infeasible to initiate the installation or repair immediately; and (b) Provide a schedule for installing or repairing the control measure and returning it to an effective operating condition as soon as possible. ii. If applicable, the permittee must remove and properly dispose of any unauthorized release or discharge (e.g., discharge of non-stormwater, spill, or leak not authorized by this permit.) The permittee must also clean up any contaminated surfaces to minimize discharges of the material in subsequent storm events. 2. Discharges to an Impaired Waterbody a. Total Maximum Daily Load (TMDL) If the permittee's discharge flows to or could reasonably be expected to flow to any water body for which a TMDL has been approved, and stormwater discharges Page 9 of 33 PART I Permit No.: COR400000 associated with construction activity were assigned a pollutant -specific Wasteload Allocation (WLA) under the TMDL, the division may: i. ensure the WLA is implemented properly through alternative local requirements, such as by a municipal stormwater permit; or ii. notify the permittee of the WLA and amend the permittee's certification to add specific effluent limits and other requirements, as appropriate. The permittee may be required to do the following: (a) under the permittee's SWMP, implement specific control measures based on requirements of the WLA, and evaluate whether the requirements are met through implementation of existing stormwater control measures or if additional control measures are necessary. Document the calculations or other evidence demonstrating that the requirements are expected to be met; and (b) if the evaluation shows that additional or modified control measures are necessary, describe the type and schedule for the control measure additions or modifications. iii. Discharge monitoring may also be required. The permittee may maintain coverage under the general permit provided they comply with the applicable requirements outlined above. The division reserves the right to require individual or alternate general permit coverage. 3. General Requirements a. Discharges authorized by this permit shall not cause, have the reasonable potential to cause, or measurably contribute to an exceedance of any applicable water quality standard, including narrative standards for water quality. b. The division may require sampling and testing, on a case -by -case basis, in the event that there is reason to suspect that the SWMP is not adequately minimizing pollutants in stormwater or in order to measure the effectiveness of the control measures in removing pollutants in the effluent. Such monitoring may include Whole Effluent Toxicity testing. c. The permittee must comply with the lawful requirements of federal agencies, municipalities, counties, drainage districts and other local agencies including applicable requirements in Municipal Stormwater Management Programs developed to comply with CDPS permits. The permittee must comply with local stormwater management requirements, policies and guidelines including those for erosion and sediment control. d. All construction site wastes must be properly managed to prevent potential pollution of state waters. This permit does not authorize on -site waste disposal. e. This permit does not relieve the permittee of the reporting requirements in 40 CFR 110, 40 CFR 117 or 40 CFR 302. Any discharge of hazardous material must be handled in accordance with the division's Noncompliance Notification Requirements (see Part II.L. of the permit). Page 10 of 33 PART I Permit No.: COR400000 C. STORMWATER MANAGEMENT PLAN (SWMP) REQUIREMENTS 1 SWMP General Requirements a. A SWMP shall be developed for each construction site covered by this permit. The SWMP must be prepared in accordance with good engineering, hydrologic and pollution control practices. i. For public emergency related sites a SWMP shall be created no later than 14 days after the commencement of construction activities. b. The permittee must implement the provisions of the SWMP as written and updated, from commencement of construction activity until final stabilization is complete. The division may review the SWMP. c. A copy of the SWMP must be retained onsite or be onsite when construction activities are occurring at the site unless the permittee specifies another location and obtains approval from the division. 2. SWMP Content a. The SWMP, at a minimum, must include the following elements. Qualified Stormwater Manager. The SWMP must list individual(s) by title and name who are designated as the site's qualified stormwater manager(s) responsible for implementing the SWMP in its entirety. This role may be filled by more than one individual. ii. Spill Prevention and Response Plan. The SWMP must have a spill prevention and response plan. The plan may incorporate by reference any part of a Spill Prevention Control and Countermeasure (SPCC) plan under section 311 of the Clean Water Act (CWA) or a Spill Prevention Plan required by a separate CDPS permit. The relevant sections of any referenced plans must be available as part of the SWMP consistent with Part I.C.4. iii. Materials Handling. The SWMP must describe and locate all control measures implemented at the site to minimize impacts from handling significant materials that could contribute pollutants to runoff. These handling procedures can include control measures for pollutants and activities such as, exposed storage of building materials, paints and solvents, landscape materials, fertilizers or chemicals, sanitary waste material, trash and equipment maintenance or fueling procedures. iv. Potential Sources of Pollution. The SWMP must list all potential sources of pollution which may reasonably be expected to affect the quality of stormwater discharges associated with construction activity from the site. This shall include, but is not limited to, the following pollutant sources: (a) disturbed and stored soils; (b) vehicle tracking of sediments; (c) management of contaminated soils; (d) loading and unloading operations; Page 11 of 33 PART I Permit No.: COR400000 (e) outdoor storage activities (erodible building materials, fertilizers, chemicals, etc.); (f) vehicle and equipment maintenance and fueling; (g) significant dust or particulate generating processes (e.g., saw cutting material, including dust); (h) routine maintenance activities involving fertilizers, pesticides, herbicides, detergents, fuels, solvents, oils, etc.; (i) on -site waste management practices (waste piles, liquid wastes, dumpsters); (j) concrete truck/equipment washing, including washing of the concrete truck chute and associated fixtures and equipment; (k) dedicated asphalt, concrete batch plants and masonry mixing stations; (1) non -industrial waste sources such as worker trash and portable toilets. v. Implementation of Control Measures. The SWMP must include design specifications that contain information on the implementation of the control measure in accordance with good engineering hydrologic and pollution control practices; including as applicable drawings, dimensions, installation information, materials, implementation processes, control measure -specific inspection expectations, and maintenance requirements. The SWMP must include a documented use agreement between the permittee and the owner or operator of any control measures located outside of the permitted area, that are utilized by the permittee's construction site for compliance with this permit, but not under the direct control of the permittee. The permittee is responsible for ensuring that all control measures located outside of their permitted area, that are being utilized by the permittee's construction site, are properly maintained and in compliance with all terms and conditions of the permit. The SWMP must include all information required of and relevant to any such control measures located outside the permitted area, including location, installation specifications, design specifications and maintenance requirements. vi. Site Description. The SWMP must include a site description which includes, at a minimum, the following: (a) the nature of the construction activity at the site; (b) the proposed schedule for the sequence for major construction activities and the planned implementation of control measures for each phase. (e.g.: clearing, grading, utilities, vertical, etc.); (c) estimates of the total acreage of the site, and the acreage expected to be disturbed by clearing, excavation, grading, or any other construction activities; (d) a summary of any existing data used in the development of the construction site plans or SWMP that describe the soil or existing potential for soil erosion; Page 12 of 33 PART I Permit No.: COR400000 (e) a description of the percent of existing vegetative ground cover relative to the entire site and the method for determining the percentage; (f) a description of any allowable non-stormwater discharges at the site, including those being discharged under a division low risk discharge guidance policy; (g) a description of areas receiving discharge from the site. Including a description of the immediate source receiving the discharge. If the stormwater discharge is to a municipal separate storm sewer system, the name of the entity owning that system, the location of the storm sewer discharge, and the ultimate receiving water(s); and (h) a description of all stream crossings located within the construction site boundary. vii. Site Map. The SWMP must include a site map which includes, at a minimum, the following: (a) construction site boundaries; (b) flow arrows that depict stormwater flow directions on -site and runoff direction; (c) all areas of ground disturbance including areas of borrow and fill; (d) areas used for storage of soil; (e) locations of all waste accumulation areas, including areas for liquid, concrete, masonry, and asphalt; (f) locations of dedicated asphalt, concrete batch plants and masonry mixing stations; (g) locations of all structural control measures; (h) locations of all non-structural control measures; (i) locations of springs, streams, wetlands and other state waters, including areas that require pre-existing vegetation be maintained within 50 feet of a receiving water, where determined feasible in accordance with Part I.B.1.a.i.(d).; and (j) locations of all stream crossings located within the construction site boundary. viii. Final Stabilization and Long Term Stormwater Management. The SWMP must describe the practices used to achieve final stabilization of all disturbed areas at the site and any planned practices to control pollutants in stormwater discharges that will occur after construction operations are completed. Including but not limited to, detention/retention ponds, rain gardens, stormwater vaults, etc. ix. Inspection Reports. The SWMP must include documented inspection reports in accordance with Part ID. 3. SWMP Review and Revisions Page 13 of 33 PART I Permit No.: COR400000 Permittees must keep a record of SWMP changes made that includes the date and identification of the changes. The SWMP must be amended when the following occurs: a. a change in design, construction, operation, or maintenance of the site requiring implementation of new or revised control measures; b. the SWMP proves ineffective in controlling pollutants in stormwater runoff in compliance with the permit conditions; c. control measures identified in the SWMP are no longer necessary and are removed; and d. corrective actions are taken onsite that result in a change to the SWMP. For SWMP revisions made prior to or following a change(s) onsite, including revisions to sections addressing site conditions and control measures, a notation must be included in the SWMP that identifies the date of the site change, the control measure removed, or modified, the location(s) of those control measures, and any changes to the control measure(s). The permittee must ensure the site changes are reflected in the SWMP. The permittee is noncompliant with the permit until the SWMP revisions have been made. 4. SWMP Availability A copy of the SWMP must be provided upon request to the division, EPA, and any local agency with authority for approving sediment and erosion plans, grading plans or stormwater management plans within the time frame specified in the request. If the SWMP is required to be submitted to any of these entities, the submission must include a signed certification in accordance with Part I.A.3.e., certifying that the SWMP is complete and compliant with all terms and conditions of the permit. All SWMPs required under this permit are considered reports that must be available to the public under Section 308(b) of the CWA and Section 61.5(4) of the CDPS regulations. The permittee must make plans available to members of the public upon request. However, the permittee may claim any portion of a SWMP as confidential in accordance with 40 CFR Part 2. D. SITE INSPECTIONS Site inspections must be conducted in accordance with the following requirements. The required inspection schedules are a minimum frequency and do not affect the permittee's responsibility to implement control measures in effective operating condition as prescribed in the SWMP. Proper maintenance of control measures may require more frequent inspections. Site inspections shall start within 7 calendar days of the commencement of construction activities on site. 1. Person Responsible for Conducting Inspections The person(s) inspecting the site may be on the permittee's staff or a third party hired to conduct stormwater inspections under the direction of the permittee(s). The permittee is responsible for ensuring that the inspector is a qualified stormwater manager. 2. Inspection Frequency Page 14 of 33 PART Permit No.: COR400000 Permittees must conduct site inspections in accordance with one of the following minimum frequencies, unless the site meets the requirements of Part ID.3 a. At least one inspection every 7 calendar days. Or b. At least one inspection every 14 calendar days, if post -storm event inspections are conducted within 24 hours after the end of any precipitation or snowmelt event that causes surface erosion. Post -storm inspections may be used to fulfill the 14 -day routine inspection requirement. c. When site conditions make the schedule required in this section impractical, the permittee may petition the Division to grant an alternate inspection schedule. The alternative inspection schedule may not be implemented prior to written approval by the division and incorporation into the SWMP. 3. Inspection Frequency for Discharges to Outstanding Waters Permittees must conduct site inspections at least once every 7 calendar days for sites that discharge to a water body designated as an Outstanding Water by the Water Quality Control Commission. 4. Reduced Inspection Frequency The permittee may perform site inspections at the following reduced frequencies when one of the following conditions exists: a. Post -Storm Inspections at Temporarily Idle Sites For permittees choosing to combine 14 -day inspections and post -storm -event - inspections, if no construction activities will occur following a storm event, post -storm event inspections must be conducted prior to re -commencing construction activities, but no later than 72 hours following the storm event. The delay of any post -storm event inspection must be documented in the inspection record. Routine inspections must still be conducted at least every 14 calendar days. b. Inspections at Completed Sites/Areas When the site, or portions of a site are awaiting establishment of a vegetative ground cover and final stabilization, the permittee must conduct a thorough inspection of the stormwater management system at least once every 30 days. Post -storm event inspections are not required under this schedule. This reduced inspection schedule is allowed if all of the following criteria are met: i. all construction activities resulting in ground disturbance are complete; ii. all activities required for final stabilization, in accordance with the SWMP, have been completed, with the exception of the application of seed that has not occurred due to seasonal conditions or the necessity for additional seed application to augment previous efforts; and iii. the SWMP has been amended to locate those areas to be inspected in accordance with the reduced schedule allowed for in this paragraph. c. Winter Conditions Inspections Exclusion Page 15 of 33 PART Permit No.: COR400000 Inspections are not required for sites that meet all of the following conditions: construction activities are temporarily halted, snow cover exists over the entire site for an extended period, and melting conditions posing a risk of surface erosion do not exist. This inspection exception is applicable only during the period where melting conditions do not exist, and applies to the routine 7 -day, 14 -day and monthly inspections, as well as the post -storm -event inspections. When this inspection exclusion is implemented, the following information must be documented in accordance with the requirements in Part II: i. dates when snow cover existed; ii. date when construction activities ceased; and iii. date melting conditions began. 5. Inspection Scope a. Areas to be Inspected When conducting a site inspection the following areas, if applicable, must be inspected for evidence of, or the potential for, pollutants leaving the construction site boundaries, entering the stormwater drainage system, or discharging to state waters: i. construction site perimeter; ii. all disturbed areas; iii. designated haul routes; iv. material and waste storage areas exposed to precipitation; v. locations where stormwater has the potential to discharge offsite; and vi. locations where vehicles exit the site. b. Inspection Requirements i. Visually verify whether all implemented control measures are in effective operational condition and are working as designed in their specifications to minimize pollutant discharges. ii. Determine if there are new potential sources of pollutants. iii. Assess the adequacy of control measures at the site to identify areas requiring new or modified control measures to minimize pollutant discharges. iv. Identify all areas of non-compliance with the permit requirements and, if necessary, implement corrective action in accordance with Part IB.1.c. c. Inspection Reports The permittee must keep a record of all inspections conducted for each permitted site. Inspection reports must identify any incidents of noncompliance with the terms and conditions of this permit. Inspection records must be retained in accordance with Part 11.O. and signed in accordance with Part I.A.3.f. At a minimum, the inspection report must include: i. the inspection date; Page 16 of 33 PART I Permit No.: COR400000 ii. name(s) and title(s) of personnel conducting the inspection; iii. weather conditions at the time of inspection; iv. phase of construction at the time of inspection; v. estimated acreage of disturbance at the time of inspection vi. location(s) of discharges of sediment or other pollutants from the site; vii. location(s) of control measures needing maintenance; viii. location(s) and identification of inadequate control measures; ix. location(s) and identification of additional control measures are needed that were not in place at the time of inspection; x. description of the minimum inspection frequency (either in accordance with Part I.D.2., I.D.3. or I.D.4.) utilized when conducting each inspection. xi. deviations from the minimum inspection schedule as required in Part I.D.2.; xii. after adequate corrective action(s) and maintenance have been taken, or where a report does not identify any incidents requiring corrective action or maintenance, the report shall contain a statement as required in Part I.A.3.f. E. DEFINITIONS For the purposes of this permit: (1) Bypass - the intentional diversion of waste streams from any portion of a treatment facility in accordance with 40 CFR 122.41(m)(1)(i) and Regulation 61.2(12). (2) Common Plan of Development or Sale - A contiguous area where multiple separate and distinct construction activities may be taking place at different times on different schedules, but remain related. The Division has determined that "contiguous" means construction activities located in close proximity to each other (within Y mile). Construction activities are considered to be "related" if they share the same development plan, builder or contractor, equipment, storage areas, etc. "Common plan of development or sale" includes construction activities that are associated with the construction of field wide oil and gas permits for facilities that are related. (3) Construction Activity - Ground surface disturbing and associated activities (land disturbance), which include, but are not limited to, clearing, grading, excavation, demolition, installation of new or improved haul roads and access roads, staging areas, stockpiling of fill materials, and borrow areas. Construction does not include routine maintenance to maintain the original line and grade, hydraulic capacity, or original purpose of the facility. Activities to conduct repairs that are not part of routine maintenance or for replacement are construction activities and are not routine maintenance. Repaving activities where underlying and/or surrounding soil is exposed as part of the repaving operation are considered construction activities. Construction activity is from initial ground breaking to final stabilization regardless of ownership of the construction activities. (4) Control Measure - Any best management practice or other method used to prevent or reduce the discharge of pollutants to state waters. Control measures include, but are not limited to, best management practices. Control measures can include other methods such as the installation, operation, and maintenance of structural controls and treatment devices. Page 17 of 33 PART I Permit No.: COR400000 (5) Control Measure Requiring Routine Maintenance - Any control measure that is still operating in accordance with its design and the requirements of this permit, but requires maintenance to prevent a breach of the control measure. See also inadequate control measure. (6) Dedicated Asphalt, Concrete Batch Plants and Masonry Mixing Stations - are batch plants or mixing stations located on, or within Vai mile of, a construction site and that provide materials only to that specific construction site. (7) Final Stabilization - The condition reached when all ground surface disturbing activities at the site have been completed, and for all areas of ground surface disturbing activities where a uniform vegetative cover has been established with an individual plant density of at least 70 percent of pre - disturbance levels, or equivalent permanent, physical erosion reduction methods have been employed. (8) Good Engineering, Hydrologic and Pollution Control Practices: are methods, procedures, and practices that: a. Are based on basic scientific fact(s). b. Reflect best industry practices and standards. c. Are appropriate for the conditions and pollutant sources. d. Provide appropriate solutions to meet the associated permit requirements, including practice based effluent limits. (9) Inadequate Control Measure - Any control measure that is not designed or implemented in accordance with the requirements of the permit and/or any control measure that is not implemented to operate in accordance with its design. See also Control Measure Requiring Routine Maintenance. (10) Infeasible - Not technologically possible, or not economically practicable and achievable in light of best industry practices. (11) Minimize - reduce or eliminate to the extent achievable using control measures that are technologically available and economically practicable and achievable in light of best industry practice. (12) Municipality - A city, town, county, district, association, or other public body created by, or under, State law and having jurisdiction over disposal of sewage, industrial wastes, or other wastes, or a designated and approved management agency under section 208 of CWA (1987). (13) Municipal Separate Storm Sewer System (MS4) - A conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): a) owned or operated by a State, city, town, county, district, association, or other public body (created by or pursuant to State law) having jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes, including special districts under State law such as a sewer district, flood control district or drainage district, or similar entity, or a designated and approved management agency under section 208 of the CWA that discharges to state waters; i. designed or used for collecting or conveying stormwater; ii. are not a combined sewer; and iii. are not part of a Publicly Owned Treatment Works (POTW). See 5 CCR 1002-61.2(62). (14) Municipal Stormwater Management Program - A stormwater program operated by a municipality, typically to meet the requirements of the municipalities MS4 discharge certification. Page 18 of 33 PART Permit No.: COR400000 (15) Operator - The party that has operational control over day-to-day activities at a project site which are necessary to ensure compliance with the permit. This party is authorized to direct individuals at a site to carry out activities required by the permit.(e.g. the general contractor) (16) Owner - The party that has overall control of the activities and that has funded the implementation of the construction plans and specifications. This is the party with ownership of, a long term lease of, or easements on the property on which the construction activity is occurring (e.g., the developer). (17) Permittee(s) - The owner and operator named in the discharge certification issued under this permit for the construction site specified in the certification. (18) Point Source - Any discernible, confined, and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged. Point source does not include irrigation return flow. See 5 CCR 102-61.2(75). (19) Pollutant - Dredged spoil, dirt, slurry, solid waste, incinerator residue, sewage, sewage sludge, garbage, trash, chemical waste, biological nutrient, biological material, radioactive material, heat, wrecked or discarded equipment, rock, sand, or any industrial, municipal or agricultural waste. See 5 CCR 1002-61.2(76). (20) Presentation of credentials - a government issued form of identification, if in person; or (ii) providing name, position and purpose of inspection if request to enter is made via telephone, email or other form of electronic communication. A Permittee's non -response to a request to enter upon presentation of credentials constitutes a denial to such request, and may result in violation of the Permit. (21) Process Water - Any water which, during manufacturing or processing, comes into contact with or results from the production of any raw material, intermediate product, finished product, by product or waste product. (22) Public Emergency Related Site - a project initiated in response to an unanticipated emergency (e.g., mud slides, earthquake, extreme flooding conditions, disruption in essential public services), for which the related work requires immediate authorization to avoid imminent endangerment to human health or the environment, or to reestablish essential public services. (23) Qualified Stormwater Manager - An individual knowledgeable in the principles and practices of erosion and sediment control and pollution prevention, and with the skills to assess conditions at construction sites that could impact stormwater quality and to assess the effectiveness of stormwater controls implemented to meet the requirements of this permit. (24) Qualifying Local Program - A municipal program for stormwater discharges associated with small construction activity that was formally approved by the division as a qualifying local program. (25) Receiving Water - Any classified or unclassified surface water segment (including tributaries) in the State of Colorado into which stormwater associated with construction activities discharges. This definition includes all water courses, even if they are usually dry, such as borrow ditches, arroyos, and other unnamed waterways. (26) Severe Property Damage - substantial physical damage to property, damage to the treatment facilities which causes them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in production. See 40 CFR 122.41(m)(1)(ii). Page 19 of 33 PART I Permit No.: COR400000 (27) Significant Materials - Include, but not limited to, raw materials; fuels; materials such as solvents, detergents, and plastic pellets; finished materials such as metallic products; raw materials used in food processing or production; hazardous substances designated under section 101(14) of CERCLA; any chemical the permittee is required to report under section 313 of Title III of the Superfund Amendments and Reauthorization Act (SARA); fertilizers; pesticides; and waste products such as ashes, slag and sludge that have the potential to be released with stormwater discharges. (28) Small Construction Activity - The discharge of stormwater from construction activities that result in land disturbance of equal to, or greater than, one acre and less than five acres. Small construction activity also includes the disturbance of less than one acre of total land area that is part of a larger common plan of development or sale, if the larger common plan ultimately disturbs equal to, or greater than, one acre and less than five acres. (29) Spill - An unintentional release of solid or liquid material which may pollute state waters. (30) State Waters - means any and all surface and subsurface waters which are contained in or flow in or through this state, but does not include waters in sewage systems, waters in treatment works of disposal systems, waters in potable water distribution systems, and all water withdrawn for use until use and treatment have been completed. (31) Steep Slopes: where a local government, or industry technical manual (e.g., stormwater BMP manual) has defined what is to be considered a "steep slope", this permit's definition automatically adopts that definition. Where no such definition exists, steep slopes are automatically defined as those that are 3:1 or greater. (32) Stormwater - Precipitation runoff, snow melt runoff, and surface runoff and drainage. See 5 CCR 1002-61.2(103). (33) Total Maximum Daily Loads (TMDLs) -The sum of the individual wasteload allocations (WLA) for point sources and load allocations (LA) for nonpoint sources and natural background. For the purposes of this permit, a TMDL is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources. A TMDL includes WLAs, LAs, and must include a margin of safety (MOS), and account for seasonal variations. See section 303(d) of the CWA and 40 C.F.R. 130.2 and 130.7. (34) Upset - an exceptional incident in which there is unintentional and temporary noncompliance with permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventative maintenance, or careless or improper operation in accordance with 40 CFR 122.41(n) and Regulation 61.2(114). F. MONITORING The division may require sampling and testing, on a case -by -case basis. If the division requires sampling and testing, the division will send a notification to the permittee. Reporting procedures for any monitoring data collected will be included in the notification. If monitoring is required, the following applies: 1. the thirty (30) day average must be determined by the arithmetic mean of all samples collected during a thirty (30) consecutive -day period; and 2. a grab sample, for monitoring requirements, is a single "dip and take" sample. Page 20 of 33 PART I Permit No.: COR400000 G. Oil and Gas Construction Stormwater discharges associated with construction activities directly related to oil and gas exploration, production, processing, and treatment operations or transmission facilities are regulated under the Colorado Discharge Permit System Regulations (5 CCR 1002-61), and require coverage under this permit in accordance with that regulation. However, references in this permit to specific authority under the CWA do not apply to stormwater discharges associated with these oil and gas related construction activities, to the extent that the references are limited by the federal Energy Policy Act of 2005. Page 21 of 33 PART II Permit No.: COR400000 Part II: Standard Permit Conditions A. DUTY TO COMPLY The permittee must comply with all conditions of this permit. Any permit noncompliance constitutes a violation of the Water Quality Control Act and is grounds for: a. enforcement action; b. permit termination, revocation and reissuance, or modification; or c. denial of a permit renewal application. B. DUTY TO REAPPLY If the permittee wishes to continue an activity regulated by this permit after the expiration date of this permit, the permittee must apply for and obtain authorization as required by Part I.A.3.k. of the permit. C. NEED TO HALT OR REDUCE ACTIVITY NOT A DEFENSE It shall not be a defense for a permittee in an enforcement action that it would have been necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. D. DUTY TO MITIGATE A permittee must take all reasonable steps to minimize or prevent any discharge in violation of this permit which has a reasonable likelihood of adversely affecting human health or the environment. E. PROPER OPERATION AND MAINTENANCE A permittee must at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) that are installed or used by the permittee to achieve compliance with the conditions of this permit. Proper operation and maintenance also includes adequate laboratory controls and appropriate quality assurance procedures. This provision requires the operation of backup or auxiliary facilities or similar systems which are installed by the permittee only when the operation is necessary to achieve compliance with the conditions of this permit. This requirement can be met by meeting the requirements for Part I.B., LC., and I.D. above. See also 40 C.F.R. 5 122.41(e). F. PERMIT ACTIONS This permit may be modified, revoked and reissued, or terminated for cause. The permittee request for a permit modification, revocation and reissuance, or termination, or a notification of planned changes or anticipated noncompliance does not stay any permit condition. Any request for modification, revocation, reissuance, or termination under this permit must comply with all terms and conditions of Regulation 61.8(8). G. PROPERTY RIGHTS In accordance with 40 CFR 122.41(g) and 5 CCR 1002-61, 61.8(9): 1. The issuance of a permit does not convey any property or water rights in either real or personal property, or stream flows or any exclusive privilege. Page 22 of 33 PART II Permit No.: COR400000 2. The issuance of a permit does not authorize any injury to person or property or any invasion of personal rights, nor does it authorize the infringement of federal, state, or local laws or regulations. 3. Except for any toxic effluent standard or prohibition imposed under Section 307 of the Federal act or any standard for sewage sludge use or disposal under Section 405(d) of the Federal act, compliance with a permit during its term constitutes compliance, for purposes of enforcement, with Sections 301, 302, 306, 318, 403, and 405(a) and (b) of the Federal act. However, a permit may be modified, revoked and reissued, or terminated during its term for cause as set forth in Section 61.8(8) of the Colorado Discharge Permit System Regulations. H. DUTY TO PROVIDE INFORMATION The permittee shall furnish to the division, within a reasonable time, any information which the division may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit, or to determine compliance with this permit. The permittee shall also furnish to the division, upon request, copies of records required to be kept by this permit in accordance with 40 CFR 122.41(h) and/or Regulation 61.8(3)(q). I. INSPECTION AND ENTRY The permittee shall allow the division and the authorized representative, upon the presentation of credentials as required by law, to allow for inspections to be conducted in accordance with 40 CFR 122.41(i), Regulation 61.8(3), and Regulation 61.8(4): 1. to enter upon the permittee's premises where a regulated facility or activity is located or in which any records are required to be kept under the terms and conditions of this permit; 2. at reasonable times to have access to and copy any records required to be kept under the terms and conditions of this permit; 3. at reasonable times, inspect any monitoring equipment or monitoring method required in the permit; and 4. to enter upon the permittee's premises in a reasonable manner and at a reasonable time to inspect or investigate, any actual, suspected, or potential source of water pollution, or any violation of the Colorado Water Quality Control Act. The investigation may include: sampling of any discharges, stormwater or process water, taking of photographs, interviewing site staff on alleged violations and other matters related to the permit, and assessing any and all facilities or areas within the site that may affect discharges, the permit, or an alleged violation. The permittee shall provide access to the division or other authorized representatives upon presentation of proper credentials. A permittee's non -response to a request to enter upon presentation of credentials constitutes a denial of such request, and may result in a violation of the permit. J. MONITORING AND RECORDS 1. Samples and measurements taken for the purpose of monitoring must be representative of the volume and nature of the monitored activity. Page 23 of 33 PART II Permit No.: COR400000 2. The permittee must retain records of all monitoring information, including all calibration and maintenance records and all original strip chart recordings for continuous monitoring instrumentation, copies of all reports required by this permit, and records of all data used to complete the application for this permit, for a period of at least three years from the date the permit expires or the date the permittee's authorization is terminated. This period may be extended by request of the division at any time. 3. Records of monitoring information must include: a. The date, exact place, and time of sampling or measurements; b. The individual(s) who performed the sampling or measurements; c. The date(s) analyses were performed d. The individual(s) who performed the analyses; e. The analytical techniques or methods used; and f. The results of such analyses. 4. Monitoring must be conducted according to test procedures approved under 40 CFR Part 136, unless other test procedures have been specified in the permit. K. SIGNATORY REQUIREMENTS 1. Authorization to Sign: All documents required to be submitted to the division by the permit must be signed in accordance with the following criteria: a. For a corporation: By a responsible corporate officer. For the purpose of this subsection, a responsible corporate officer means: i. a president, secretary, treasurer, or vice president of the corporation in charge of a principal business function, or any other person who performs similar policy- or decision -making functions for the corporation, or ii. the manager of one or more manufacturing, production, or operating facilities, provided, the manager is authorized to make management decisions which govern the operation of the regulated facility including having the explicit or implicit duty of making major capital investment recommendations, and initiating and directing other comprehensive measures to assure long term environmental compliance with environmental laws and regulations; the manager can ensure that the necessary systems are established or actions taken to gather complete and accurate information for permit application requirements; and where authority to sign documents has been assigned or delegated to the manager in accordance with corporate procedures. b. For a partnership or sole proprietorship: By a general partner or the proprietor, respectively; or c. For a municipality, state, federal, or other public agency: By either a principal executive officer or ranking elected official. For purposes of this subsection, a principal executive officer of a federal agency includes i. (i) the chief executive officer of the agency, or Page 24 of 33 PART II Permit No.: COR400000 ii. (ii) a senior executive officer having responsibility for the overall operations of a principal geographic unit of the agency. (e.g., Regional Administrator of EPA) 2. Electronic Signatures For persons signing applications for coverage under this permit electronically, in addition to meeting other applicable requirements stated above, such signatures must meet the same signature, authentication, and identity -proofing standards set forth at 40 CFR § 3.2000(b) for electronic reports (including robust second -factor authentication). Compliance with this requirement can be achieved by submitting the application using the Colorado Environmental Online Service (CEOS) system. 3. Change in Authorization to Sign If an authorization is no longer accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization must be submitted to the division, prior to the re -authorization, or together with any reports, information, or applications to be signed by an authorized representative. L. REPORTING REQUIREMENTS 1. Planned Changes The permittee shall give advance notice to the division, in writing, of any planned physical alterations or additions to the permitted facility in accordance with 40 CFR 122.41(1) and Regulation 61.8(5)(a). Notice is required only when: a. The alteration or addition to a permitted facility may meet one of the criteria for determining whether a facility is a new source in 40 CFR 122.29(b); or b. The alteration or addition could significantly change the nature or increase the quantity of pollutants discharged. This notification applies to pollutants which are subject neither to effluent limitations in the permit, nor to notification requirements under 40 CFR 122.41(a)(1). 2. Anticipated Non -Compliance The permittee shall give advance notice to the division, in writing, of any planned changes in the permitted facility or activity that may result in noncompliance with permit requirements. The timing of notification requirements differs based on the type of non-compliance as described in subparagraphs 5, 6, 7, and 8 below. 3. Transfer of Ownership or Control The permittee shall notify the division, in writing, ten (10) calendar days in advance of a proposed transfer of the permit. This permit is not transferable to any person except after notice is given to the division. Page 25 of 33 PART II Permit No.: COR400000 a. Where a facility wants to change the name of the permittee, the original permittee (the first owner or operators) must submit a Notice of Termination. b. The new owner or operator must submit an application. See also signature requirements in Part ILK, above. c. A permit may be automatically transferred to a new permittee if: i. The current permittee notifies the Division in writing 30 calendar days in advance of the proposed transfer date; and ii. The notice includes a written agreement between the existing and new permittee(s) containing a specific date for transfer of permit responsibility, coverage and liability between them; and iii. The division does not notify the existing permittee and the proposed new permittee of its intent to modify, or revoke and reissue the permit. iv. Fee requirements of the Colorado Discharge Permit System Regulations, Section 61.15, have been met. 4. Monitoring reports Monitoring results must be reported at the intervals specified in this permit per the requirements of 40 CFR 122.41(1)(4). 5. Compliance Schedules Reports of compliance or noncompliance with, or any progress reports on, interim and final requirements contained in any compliance schedule in the permit, shall be submitted on the date listed in the compliance schedule section. The fourteen (14) calendar day provision in Regulation 61.8(4)(n)(i) has been incorporated into the due date. 6. Twenty-four hour reporting In addition to the reports required elsewhere in this permit, the permittee shall report the following circumstances orally within twenty-four (24) hours from the time the permittee becomes aware of the circumstances, and shall mail to the division a written report containing the information requested within five (5) working days after becoming aware of the following circumstances: a. Circumstances leading to any noncompliance which may endanger health or the environment regardless of the cause of the incident; b. Circumstances leading to any unanticipated bypass which exceeds any effluent limitations in the permit; c. Circumstances leading to any upset which causes an exceedance of any effluent limitation in the permit; Page 26 of 33 PART II Permit No.: COR400000 d. Daily maximum violations for any of the pollutants limited by Part I of this permit. This includes any toxic pollutant or hazardous substance or any pollutant specifically identified as the method to control any toxic pollutant or hazardous substance. e. The division may waive the written report required under subparagraph 6 of this section if the oral report has been received within 24 hours. 7. Other non-compliance A permittee must report all instances of noncompliance at the time monitoring reports are due. If no monitoring reports are required, these reports are due at least annually in accordance with Regulation 61.8(4)(p). The annual report must contain all instances of non-compliance required under either subparagraph 5 or subparagraph 6 of this subsection. 8. Other information Where a permittee becomes aware that it failed to submit any relevant facts in a permit application, or submitted incorrect information in a permit application, or in any report to the Permitting Authority, it has a duty to promptly submit such facts or information. M. BYPASS 1. Bypass not exceeding limitations The permittees may allow any bypass to occur which does not cause effluent limitations to be exceeded, but only if it also is for essential maintenance to assure efficient operation. These bypasses are not subject to the provisions of Part II.M.2 of this permit. See 40 CFR 122.41(m)(2). 2. Notice of bypass a. Anticipated bypass. If the permittee knows in advance of the need for a bypass, the permittee must submit prior notice, if possible at least ten days before the date of the bypass. ee 40 CFR 5122.41(m)(3)(i) and/or Regulation 61.9(5)(c). b. Unanticipated bypass. The permittee must submit notice of an unanticipated bypass in accordance with Part II.L.6. See 40 CFR 5122.41(m)(3)(ii) . 3. Prohibition of Bypass Bypasses are prohibited and the division may take enforcement action against the permittee for bypass, unless: i. the bypass is unavoidable to prevent loss of life, personal injury, or severe property damage; Page 27 of 33 PART II Permit No.: COR400000 ii. There were no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance during normal periods of equipment downtime. This condition is not satisfied if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventive maintenance; and iii. proper notices were submitted to the division. N. UPSET 1. Effect of an upset An upset constitutes an affirmative defense to an action brought for noncompliance with permit effluent limitations if the requirements of Part II.N.2. of this permit are met. No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review in accordance with Regulation 61.8(3)(j). 2. Conditions necessary for demonstration of an Upset A permittee who wishes to establish the affirmative defense of upset shall demonstrate through properly signed contemporaneous operating logs, or other relevant evidence that a. an upset occurred and the permittee can identify the specific cause(s) of the upset; b. the permitted facility was at the time being properly operated and maintained; and c. the permittee submitted proper notice of the upset as required in Part II.L.6.(24- hour notice); and d. the permittee complied with any remedial measure necessary to minimize or prevent any discharge or sludge use or disposal in violation of this permit which has a reasonable likelihood of adversely affecting human health or the environment. In addition to the demonstration required above, a permittee who wishes to establish the affirmative defense of upset for a violation of effluent limitations based upon water quality standards shall also demonstrate through monitoring, modeling or other methods that the relevant standards were achieved in the receiving water. 3. Burden of Proof In any enforcement proceeding, the permittee seeking to establish the occurrence of an upset has the burden of proof. O. RETENTION OF RECORDS 1. Post -Expiration or Termination Retention Copies of documentation required by this permit, including records of all data used to complete the application for permit coverage to be covered by this permit, must be Page 28 of 33 PART II Permit No.: COR400000 retained for at least three years from the date that permit coverage expires or is terminated. This period may be extended by request of EPA at any time. 2. On -site Retention The permittee must retain an electronic version or hardcopy of the SWMP at the construction site from the date of the initiation of construction activities to the date of expiration or inactivation of permit coverage; unless another location, specified by the permittee, is approved by the division. P. REOPENER CLAUSE 1. Procedures for modification or revocation Permit modification or revocation of this permit or coverage under this permit will be conducted according to Regulation 61.8(8). 2. Water quality protection If there is evidence indicating that the stormwater discharges authorized by this permit cause, have the reasonable potential to cause or contribute to an excursion above any applicable water quality standard, the permittee may be required to obtain an individual permit, or the permit may be modified to include different limitations and/or requirements. Q. SEVERABILITY The provisions of this permit are severable. If any provisions or the application of any provision of this permit to any circumstances, is held invalid, the application of such provision to other circumstances and the application of the remainder of this permit shall not be affected. R. NOTIFICATION REQUIREMENTS 1. Notification to Parties All notification requirements, excluding information submitted using the CEOS portal, shall be directed as follows: a. Oral Notifications, during normal business hours shall be to: Clean Water Compliance Section Water Quality Control Division Telephone: (303) 692-3500 b. Written notification shall be to: Clean Water Compliance Section Water Quality Control Division Colorado Department of Public Health and Environment WQCD-WQP-B2 4300 Cherry Creek Drive South Denver, CO 80246-1530 Page 29 of 33 PART II Permit No.: COR400000 S. RESPONSIBILITIES 1. Reduction, Loss, or Failure of Treatment Facility The permittee has the duty to halt or reduce any activity if necessary to maintain compliance with the effluent limitations of the permit. It shall not be a defense for a permittee in an enforcement action that it would be necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. T. Oil and Hazardous Substance Liability Nothing in this permit shall be construed to preclude the institution of any legal action or relieve the permittee from any responsibilities, liabilities, or penalties to which the permittee is or may be subject to under Section 311 (Oil and Hazardous Substance Liability) of the CWA. U. Emergency Powers Nothing in this permit shall be construed to prevent or limit application of any emergency power of the division. V. Confidentiality Any information relating to any secret process, method of manufacture or production, or sales or marketing data which has been declared confidential by the permittee, and which may be acquired, ascertained, or discovered, whether in any sampling investigation, emergency investigation, or otherwise, shall not be publicly disclosed by any member, officer, or employee of the Water Quality Control Commission or the division, but shall be kept confidential. Any person seeking to invoke the protection of of this section shall bear the burden of proving its applicability. This section shall never be interpreted as preventing full disclosure of effluent data. W. Fees The permittee is required to submit payment of an annual fee as set forth in the 2016 amendments to the Water Quality Control Act. Section 25-8-502 (1.1) (b), and the Colorado Discharge Permit System Regulations 5 CCR 1002-61, Section 61.15 as amended. Failure to submit the required fee when due and payable is a violation of the permit and will result in enforcement action pursuant to Section 25-8-601 et. seq., C.R.S.1973 as amended. X. Duration of Permit The duration of a permit shall be for a fixed term and shall not exceed five (5) years. If the permittee desires to continue to discharge, a permit renewal application shall be submitted at least ninety (90) calendar days before this permit expires. Filing of a timely and complete application shall cause the expired permit to continue in force to the effective date of the new permit. The permit's duration may be extended only through administrative extensions and not through interim modifications. If the permittee anticipates there will be no discharge after the expiration date of this permit, the division should be promptly notified so that it can terminate the permit in accordance with Part I.A.3.i. Y. Section 307 Toxics If a toxic effluent standard or prohibition, including any applicable schedule of compliance specified, is established by regulation pursuant to Section 307 of the Federal Act for a toxic pollutant which is present in the permittee's discharge and such standard or prohibition is more stringent than any limitation upon such pollutant in the discharge permit, the division Page 30 of 33 PART II Permit No.: COR400000 shall institute proceedings to modify or revoke and reissue the permit to conform to the toxic effluent standard or prohibition Page 31 of 33 Stormwater Management Plan APPENDIX G: Geotechnical Soils Report Tri-State Generation & Transmission — Lloyd Sisson Substation KL E/IVFEL OER Bright People. Right Solutions. GEOTECHNICAL ENGINEERING REPORT LLOYD SISSON SUBSTATION NORTHWEST OF COUNTY ROAD 30 AND COUNTY ROAD 71 WELD COUNTY, COLORADO KLEINFELDER PROJECT #: 20201380.001A SEPTEMBER 13, 2019 Copyright 2019 Kleinfelder All Rights Reserved ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC PROJECT FOR WHICH THIS REPORT WAS PREPARED. k 201201380.001 A/DEN 19R 101024 2019 Kleinfelder a SSW Page i of iii September 13, 2019 www.kleinfelder.com KL E/NFEL DER A Report Prepared for: Tri-State Generation and Transmission Association. Inc. 1100 West 116th Avenue Westminster. CO 80234 GEOTECHNICAL ENGINEERING REPORT LLOYD SISSON SUBSTATION NORTHWEST OF COUNTY ROAD 30 AND COUNTY ROAD 71 WELD COUNTY, COLORADO KLEINFELDER PROJECT #: 20201380.001A Prepared by: Cindy A. Wright. PG* Staff Professional II `Registered in CA Reviewed by: Thomas J. Nevin. PE Principal Geotechnical Engineer KLEINFELDER 1801 California Street. Suite 1100 Denver. Colorado 80202 303.237.6601 FAX: 303.237.6602 September 13. 2019 Kleinfelder Project No. 20201380.001A 201201380.001A/DEN19R101024 Page ii of iii September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KLEINFELDER DER Boot n•ock Rpnr 5&u non, TABLE OF CONTENTS Section Page 1 INTRODUCTION 1 1.1 PURPOSE AND OBJECTIVE 1 1.2 SCOPE OF SERVICES 1 1.3 PROJECT LOCATION AND DESCRIPTION 2 2 FIELD EXPLORATIONS AND LABORATORY TESTING 3 2.1 GENERAL 3 2.2 SUBSURFACE EXPLORATION 3 2.3 LABORATORY TESTING 4 3 SITE CONDITIONS 5 3.1 SITE DESCRIPTION 5 3.2 GEOLOGY 5 3.3 SUBSURFACE CONDITIONS 5 3.4 GROUNDWATER 7 4 CONCLUSIONS AND RECOMMENDATIONS 8 4.1 GENERAL 8 4.2 CONSTRUCTION CONSIDERATIONS 8 4.2.1 Site Preparation and Grading 8 4.2.2 Excavations 9 4.2.3 Structural Fill 9 4.2.4 Compaction Recommendations 10 4.2.5 Substation Yard Surface Preparation 10 4.2.6 Construction in Wet or Cold Weather 11 4.2.7 Construction Testing and Observation 11 4.2.8 Subsurface and Surface Drainage 11 4.3 SHALLOW FOUNDATIONS 11 4.4 DRILLED PIER FOUNDATIONS 13 4.4.1 Axial Capacity 13 4.4.2 Lateral Capacity 14 4.5 GEOLOGIC HAZARDS 16 4.5.1 Seismicity 16 4.5.2 Liquefaction Hazards 17 4.5.3 Corrosivity 17 5 LIMITATIONS 18 FIGURES Figure 1 Exploration Location Plan and Vicinity Map APPENDICES A Boring Logs B Laboratory Test Results C Electrical Resistivity Testing D Important Information About Your Geotechnical Engineering Report 201201380.001A/DEN19R101024 Page iii of iii September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KL E/NFEL DER 1 INTRODUCTION 1.1 PURPOSE AND OBJECTIVE The purpose of this geotechnical engineering report is to summarize geological and geotechnical engineering data obtained from Kleinfelder's recent field exploration for the proposed Lloyd Sisson Substation Project located northwest of the intersection of County Road 130 and County Road 71 in Weld County, Colorado, and to provide geotechnical engineering recommendations for foundation design of the proposed substation. This report includes information obtained from exploratory borings as well as results of laboratory testing of the soil and rock and is based on the request for proposal provided by Tri-State titled Lloyd Sisson Substation Geologic Investigations and Soil Resistivity Testing and Soil Boring Layout. The information within this report will be used by Tri-State Generation and Transmission Association. Inc. (Tri-State) to facilitate the design and construction of the proposed Lloyd Sisson Substation. The geotechnical data provided are subject to the provisions in the Limitations section. In addition, an article prepared by Geoprofessional Business Association (GBA). Important Information about This Geotechnical Engineering Report, has been included in Appendix C. We recommend that all individuals who read the report understand the report limitations along with the included GBA document. 1.2 SCOPE OF SERVICES The scope of service performed for this project included the following: • Coordination and project initialization • Site characterization. including preparation. coordination, and execution of a subsurface exploration program • Electrical resistivity testing • Laboratory testing • Engineering analysis • Report preparation 201201380.001A/DEN19R101024 Page 1 of 19 September 13, 2019 © 2019 Kleinfelder www.kletnfelder.com I KL E/NFEL OER 3,.gnr moo'• NNW SO:0)0M. 1.3 PROJECT LOCATION AND DESCRIPTION The project is located northwest of the intersection of County Road 130 and County Road 71 in Weld County, Colorado (Figure 1). We understand the substation equipment is tentatively designed to be founded on soil -supported slabs. spread footings and drilled piers. Kleinfelder has assumed that small cuts or fills. less than about three feet. may be required for grading. 201201380.001A/DEN19R101024 Page 2 of 19 September 13: 2019 «) 2019 Kleinfelder wvwv.kleinfelder.com KL E/NFEL OER 3.1q,t Proc.:q. q,gnr Sn,ur,o.n 2 FIELD EXPLORATIONS AND LABORATORY TESTING 2.1 GENERAL The geotechnical field exploration was performed on August 29. 2019 and September 12. 2019. This section provides a summary of the subsurface explorations completed as part of this project. 2.2 SUBSURFACE EXPLORATION On August 29. 2019. a total of five borings (B-1 through B-5) were drilled and one test pit (TP-1) was excavated to explore the subsurface conditions at the proposed substation. The Exploration Location Plan and Vicinity Map. Figure 1, shows the approximate boring and test pit locations. The borings were terminated at a depth of approximately 30 to 31 feet beneath the ground surface (bgs). The test pit was excavated to a depth of approximately 6.5 feet bgs. The borings and the test pit were advanced with an all -terrain CME-750 drill rig equipped with solid -stem. continuous -flight auger and a hollow -stem auger. Samples were obtained using the Modified California (2.5 -inch O.D.). and Standard Penetration Test (2 -inch O.D.) samplers. The samplers were driven 12 inches or 18 inches into relatively undisturbed material using a 30 -inch drop of a 140 -pound hammer (ASTM D1586). The samples were packaged and sealed in the field to reduce moisture loss and disturbance. During the exploration. a Kleinfelder geotechnical professional observed drilling and logged the borings and test pit by visually identifying and classifying soils in general accordance with ASTM D2488 and the Unified Soil Classification System (USCS). Upon completion of laboratory testing, soil classifications were further evaluated in general accordance with ASTM D2487 and are presented in the boring logs in Appendix A. The lines defining boundaries between soil types on the logs are based on drill rig observation and interpolation between samples and are therefore approximate. Transitions between soil types may be abrupt or gradual. Electrical resistivity (ER) testing was completed September 12, 2019. Electrical resistivity (ER) testing included two perpendicular electrical resistivity lines (North -South and East-West) that were performed in the proposed substation footprint. The electrical resistivity testing was 201201380.001A/DEN19R101024 Page 3 of 19 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com riN KL E/NFEL DER wghT,►ook R.eM %ownom conducted by Kleinfelder personnel utilizing an AGI Super Sting R1 and the Wenner 4 -pin array method. The tests were performed using array arrangements with probe spacings ranging from 2 to 500 feet. The results of the electrical resistivity tests are presented in Appendix C. 2.3 LABORATORY TESTING Laboratory tests were performed on selected soils and bedrock obtained during the investigation to evaluate their physical and engineering properties. The tests were performed in general accordance with the current ASTM standards. Results of the laboratory tests are included in Appendix B. Selected laboratory results are also summarized in the boring logs (Appendix A). 201201380.001A/DEN19R101024 Page 4 of 19 September 13, 2019 © 2019 Kleinfelder ww v.kleinfelder.com KL E/NFEL DER (4'9!,' People 4.9n1 5.0.0 bey', 3 SITE CONDITIONS 3.1 SITE DESCRIPTION The substation project site is located northwest of the intersection of County Road 130 and County Road 71 in Weld County, Colorado. The proposed substation site is relatively flat, undeveloped agricultural land. At the time of our investigation the surface was covered in low grasses and weeds. The closest structure is a pump jack. tank battery, and associated work pad located southeast of the intersection of County Road 130 and County Road 71 or approximately 700 feet from the project site. The project site is a total of approximately 6.7 acres and the substation is planned to be within a fenced area 350 feet by 300 feet. 3.2 GEOLOGY The geology of the site was evaluated by reviewing published geologic maps. including: Preliminary Geologic Map of the Greely 1°x2° Quadrangle, Colorado and Wyoming, U.S. Geological Survey, Braddock. W.A. and Cole, J.C.. 1978. Local geology at the substation was mapped as the White River Formation of the Oligocene Epoch. The White River Formation is characterized as a light colored, massive, argillaceous and calcareous siltstone interbedded sandstone. conglomerate, and volcanic ash beds. 3.3 SUBSURFACE CONDITIONS The subsurface conditions encountered in the borings were observed to generally consist of sand with varying amounts of gravel. silt, and clay interbedded with lean clay with varying amounts of sand over claystone and siltstone bedrock. Topsoil containing organics was encountered to a depth of up to approximately eight inches. Native soil deposits were encountered from below the topsoil layer to depths ranging from approximately 9 to 14 feet below ground surface (bgs). The soils were comprised of sand with 201201380.001A/DEN19R101024 Page 5 of 19 September 13, 2019 CO 2019 Kleinfelder www.kleinfelder.com KLE/NFELOER Argot People RgAt So:ut.onn varying amounts of clay. silt. and gravel. Borings B-1. B-2, B-4 and B-5 each had a stratum of lean clay soils present with medium plasticity and varying amounts of sand. The sand soils were generally very loose to loose near the surface and increased in relative density to very dense with depth. The clay soils ranged from soft to hard in consistency. The claystone and sandstone bedrock ranged from moderately weathered to slightly weathered and extremely weak to very weak in strength. Five soil and rock samples were selected for shrink/swell testing. In this test the samples are wetted and then surcharge loaded. and then their percentage of shrinkage or swelling is measured. All five samples experienced moderate shrinking or compression under the load. The following table presents the results of this testing. TABLE 1 SHRINK/SWELL TESTING RESULTS Boring and Depth Material Type Surcharge Load Compression B-1. 10 feet Siltstone 1.000 psf' 1.1 Yo B-2, 25 feet Claystone 500 psf 2.4% B-3, 15 feet Claystone 1,000 psf 0.1% B -A, 2.5 feet Sand Lean Clay 500 psf 0.4% B-5, 2.5 feet SanC aYean Clay 500 psf 1.5% 1 Pounds per Square foot (psf) Compressible or Collapse -prone soils can rapidly decrease in volume when wetted. In the high plains of Colorado, development activities typically raise subsurface moisture content by interrupting the natural flow of moisture from the earth to the relatively dry atmosphere. Foundations constructed on expansive or collapse -prone soils can heave or settle in response to the increases in moisture. Typical substation design includes isolated concrete foundations (that are relatively impermeable to air and moisture migration) with a more permeable gravel surface between and surrounding the foundations. Thus. foundations with larger footprints will likely be 201201380.001 A/DEN 19R 101024 © 2019 Kleinfelder Page 6 of 19 September 13, 2019 www.kleinfelder.com KL E/NFEL DER *writ F-# c.'. 4.1hf S.o.0 nee more susceptible to movement. To help reduce the risk of movement. Kleinfelder recommends over -excavation and recompaction of soils below all shallow foundations. as recommended in Section 4 of this report. 3.4 GROUNDWATER Groundwater was not encountered in the borings or test pit during drilling operations to the extents of exploration depths ranging from approximately 6.5 to 31 feet bgs. Soil moisture levels and groundwater levels commonly vary over time depending upon seasonal precipitation, irrigation practices. land use and runoff conditions. The soil moisture and groundwater data in this report pertain only to the locations and time when the borings were drilled. which was during fall. Groundwater may be shallower during spring when runoff is present. 201201380.001A/DEN19R101024 Page 7 of 19 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KL EINPEL DER Rngnt People RAH folutoont 4 CONCLUSIONS AND RECOMMENDATIONS 4.1 GENERAL Based on the subsurface conditions encountered in the borings and our experience with similar projects. it is Kleinfelder's opinion that development of the site as planned is geotechnically feasible. provided the recommendations in this report are incorporated in the design and construction of the project. Due to the presence of near -surface very loose to loose sand and soft clay soils, over -excavation and replacement of these materials will be required to a depth of approximately four feet below the existing ground surface below movement sensitive structures. If movement on the order of one to two inches or more is considered acceptable then complete removal of these very loose to loose sand and soft clay soils will not be required. It is likely that these soils will be unstable under construction traffic and some removal on the order of one to two feet of these materials will likely be required to provide a stable construction platform. Our geotechnical design and construction recommendations for site preparation, foundations. and other related construction topics are provided in the following sections. 4.2 CONSTRUCTION CONSIDERATIONS 4.2.1 Site Preparation and Grading All site preparation and earthwork operations should be performed in accordance with applicable codes. safety regulations and other local. state. or federal guidelines. Prior to site grading or development, the construction area should be stripped of vegetation and deleterious or organic material. Stripping operations should be observed by the geotechnical engineer. and should include removing materials that. in the judgment of the geotechnical engineer. are not suitable for the anticipated loading conditions. 201201380.001A/DEN19R101024 Page 8 of 19 September 13. 2019 CO 2019 Kleinfeider www.kleintelder.coni KL E/NFEL DER 4.2.2 Excavations We anticipate that most excavations can be performed with conventional heavy-duty earthmoving equipment. Groundwater was not observed in the borings at the time of drilling and we do not anticipate that temporary dewatering measures will be required for shallow excavations. All excavations must comply with the applicable local. state. and federal safety regulations. and particularly with the excavation standards of the Occupational Safety and Health Administration (OSHA). Construction site safety. including excavation safety, is the sole responsibility of the Contractor as part of its overall responsibility for the means. methods. and sequencing of construction operations. The actual determination of soil type and required sloping must be made in the field by the contractor's OSHA "competent person". 4.2.3 Structural Fill Structural fill is defined as any fill which will support structural elements. Structural fill will be required for backfill of utilities and for site grading fill. All structural fill must be free of sod, rubbish, topsoil. frozen soil. cobbles. and other deleterious materials. Structural fill materials should consist of a non - expansive, mainly granular material as specified below. On -site soils may be suitable for reuse as structural fill. if they meet the criteria present in Table 2. Import materials can also be used. if desired. TABLE 2 STRUCTURAL FILL CRITERIA GRADATION REQUIREMENTS Standard Sieve Size Percent Passing 3 inch 100 3/4 inch 80 - 100 No. 200 10 - 35 PLASTICITY REQUIREMENTS (ATTERBERG LIMITS) Liquid Limit 30 or less Plasticity Index 12 or less 201201380.001A/DEN19R101024 © 2019 Kleinfelder Page 9 of 19 September 13, 2019 www.kleinfelder.com KL EINFEL DER A sample of any imported fill material should be submitted to the geotechnical engineer for approval and testing at least one week prior to stockpiling at the site. Structural fill should be placed according to the recommendations in Section 4.2.4. 4.2.4 Compaction Recommendations All fill should be moistened, placed in loose lifts of eight inches or less thickness. and compacted to the specifications presented in Table 3. TABLE 3 COMPACTION SPECIFICATIONS Fill Location Material Type Compaction Moisture Content (/o) Site Grading Fill/ Structural Fill Sand. Silty Sand. Clayey Sand. and Structural Fill minimum 95% of maximum dry density (ASTM Method D1557) -2 to +2 of optimum Clay minimum 95% of maximum dry density (ASTM Method D698) 0 to +3 of optimum 4.2.5 Substation Yard Surface Preparation After initial site grading has been completed. the substation yard surface preparation should consist of scarifying the upper eight inches of the subgrade materials. moisture conditioning and compacting the subgrade to the criteria of section 4.2.4. Any areas that appear disturbed or soft should be over -excavated a depth of about two feet and be replaced with well -compacted structural fill. As mentioned previously, near -surface very loose to loose sand and soft clay soils are present at the site. It is likely that these soils will be unstable under construction traffic and some removal on the order of one to two feet of these materials will likely be required to provide a stable construction platform. 201201380.001 A/DEN 19R 101024 © 2019 Kleinfelder Page 10 of 19 September 13. 2019 4wwv. kleinfelder. con' KLE/NFELDER &ngnr wok Right sw.r.own 4.2.6 Construction in Wet or Cold Weather During construction, grade the site such that surface water can drain readily away from the improvement areas. Promptly pump out or otherwise remove any water that may accumulate in excavations or on subgrade surfaces and allow these areas to dry before resuming construction. The use of berms. ditches, and similar means may be used to prevent stormwater from entering the work area and to convey any water off site efficiently. If construction occurs during cold weather, fill and concrete elements should not be constructed on frozen soil. Frozen subgrade soils should be completely removed. or thawed. scarified and re - compacted. The amount of time passing between subgrade preparation and placing fill or concrete should be minimized during freezing conditions to prevent the prepared soils from freezing. Blankets. soil cover or heating as required may be utilized to prevent the subgrade from freezing. 4.2.7 Construction Testing and Observation Fill construction should be observed and tested by Kleinfelder to support our professional opinion as to whether the earthwork does or does not substantially conform to the recommendations in this report. The opinions and conclusions of a geotechnical report are based on the interpretation of a limited amount of information obtained from the field exploration. It is therefore not uncommon to find that actual site conditions differ somewhat from those indicated in the report. Kleinfelder should remain involved throughout the project to evaluate such differing conditions as they appear, and to modify or add to the geotechnical recommendations as necessary. 4.2.8 Subsurface and Surface Drainage Positive drainage away from the structures is essential to the performance of foundations and should be provided during the life of the structures. Surface drainage should be created such that water is diverted off the site and away from equipment foundations. 4.3 SHALLOW FOUNDATIONS The proposed substation equipment may be supported upon isolated spread or strip footing and mat foundations constructed on properly prepared native soils. or structural fill extending to 201201380.001A/DEN19R101024 Page 11 of 19 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KLE/NFELOER Swat Prod* Alert Solutions properly prepared native soils. At the surface in most of the borings there was a very loose to loose or soft layer of soil extending down approximately four feet. For movement sensitive structures. this loose or soft layer of soil must be removed or recompacted according to the recommendations below. If movement on the order of one to two inches or more is considered acceptable then complete removal of these very loose to loose sand and soft clay soils will not be required. It is likely that these soils will be unstable under construction traffic and some removal on the order of one to two feet of these materials will likely be required to provide a stable construction platform. The shallow foundations should be designed and constructed in accordance with the following criteria. • Foundation excavations must be cleaned of all topsoil. non -engineered fill, soft or disturbed soils, construction debris, frozen soil. moisture sensitive soils, or ponded water. All loose or disturbed soils should be completely removed or recompacted to the requirements of structural fill. Cobbles or boulders must be removed from the upper eight inches of the bearing level soils or fill. • Prior to placement of foundation steel. the upper eight inches of the bearing level soils should be scarified. moisture conditioned. and compacted to the specifications of Section 4.2.4. • Foundations prepared in accordance with this report may be designed for an allowable bearing pressure of 2.000 psf. • Foundations may be designed to resist lateral movement with a nominal coefficient of sliding friction of 0.45. and a passive earth pressure calculated as an equivalent fluid density of 400 pcf. The structural engineer should select and apply appropriate factors of safety for lateral resistance parameters. • Footing size should be determined by a structural engineer. As a minimum, we recommend isolated columns be supported on square pads at least 18 inches wide. Continuous strip footings should be at least 16 inches in width. • An allowable modulus of subgrade reaction, Kvi, of 100 pounds per square inch per inch deflection (pci) may be used for design of mat foundations. Kv, refers to a 1 -foot square plate and should be adjusted for actual foundation dimensions using the following equation (B is foundation width in feet): 201201380.001 A/DEN 19R 101024 © 2019 Kleinfelder i`v = Kv1 B ± l 2 2H Page 12 of 19 September 13, 2019 wvw.klewifelder.corn KL E/NFEL DER • Exterior foundations should be protected from frost action. Frost depth at this location is 36 inches. We recommend the footings be protected with at least 36 inches of soil cover. or that which is required by local building codes. whichever is greater. • For slab -on -grade foundations where settlement or heave is not considered critical. these foundations can bear at a depth of at least 12 inches below the surrounding ground surface. 4.4 DRILLED PIER FOUNDATIONS We understand that some structures at the substation may be supported on drilled pier foundations. Tri-State uses the software packages MFAD and LPILE for design. The design parameters provided in the subsequent sections for axial capacity and lateral capacity are for the substation location. 4.4.1 Axial Capacity Table 4 provides ultimate end -bearing and side resistance values for drilled piers within the substation. The design parameters for axial capacity for each transmission line boring (Boring B- 1 to B-6) are provided in the Appendix A. A safety factor value of 3 should be applied to these values when evaluating allowable capacity. TABLE 4 DRILLED PIER CAPACITY SUMMARY FOR THE SUBSTATION MATERIAL LAYER DEPTH (FT) ULTIMATE BEARING CAPACITY (KSF)1 END ULTIMATE SIDE RESISTANCE COMPRESSION (KSF) UPLIFT (KSF) Clay 0 to 4 Neglect Sand 4 to 8 11.0 0.6 0.4 Sand 8 to 10 32.0 1.5 1.1 Stiff Clay w/o Free Water 10 to 14 32.0 2.6 1.8 Bedrock 14 (2) to 31 55.0 4.5 3.2 2012 01380.001 A/DEN 19 R 101024 © 2019 Kleinfelder Page 13 of 19 September 13, 2019 www.kleinfelder.com iCL EINFEL DER a pnt People Right Solutions Notes: (1) Kips per square foot (KSF). (2) Bedrock depth in the exploratory borings varied from 9 to 14 feet. Additional considerations for axial capacity include: • • • • • • • • • Piers should be designed by a qualified structural engineer. Piers should be reinforced their full length. We recommend concrete be designed and placed at a slump between five and seven inches. Pier holes should be cleaned of all loose material and have less than three inches of water in the bottom of the hole at time of concrete placement. If excessive ground water seepage occurs. casing or tremie placement of concrete may be required for proper pier installation. The soil profile in the borings included up to 14 feet of sand soils with gravel present. Caving of pier holes may occur and is more likely for larger diameter holes. Casing should be present on -site if stabilization of holes is required. Concrete placement should occur immediately after pier hole drilling, cleaning. installation of reinforcement and observation. Concrete should be placed in one continuous placement without any cold joints. If casing is used. a positive head of concrete must be maintained above the end of the casing as the casing is withdrawn. A minimum pier diameter of 18 inches is recommended to allow for pier cleaning and observation. Pier caps that overhang the drilled pier should be embedded below frost depth to prevent uplift. The installation of the drilled piers should be observed by a Kleinfelder representative to observe the construction techniques and confirm the subsurface conditions are as anticipated from our exploratory boring. For foundations constructed in accordance to the recommendations presented herein, total foundation settlement should be less than one inch. 4.4.2 Lateral Capacity We understand the computer programs MFAD and LPILE will be used for design of the drilled pier foundations. The unit weight and soil strength data were developed from the results of the 201201380.001 A/DEN 19R 101024 © 2019 Kleinfelder Page 14 of 19 September 13, 2019 www.kleinfelder.coni KL E/NFEL DER \3/4••••.....•••' PFoitr 4ylft Son.rKvn laboratory testing, field exploration. and our experience with similar soils in the area. The modulus of deformation values presented are based on laboratory and field test data and correlated design values published in the 1982 EPRI Design Manual. entitled, "Laterally Loaded Drilled Pier Research. Volume 1: Design Methodology." The following tables present the ultimate soil properties for use with MFAD and LPILE, for design of piers within the substation. TABLE 5 MFAD PARAMETERS FOR DESIGN OF FOUNDATIONS FOR THE SUBSTATION LAYER TYPE LAYER DEPTH (FT) TOTAL WEIGHT UNIT (PCF) DEFORMATION MODULUS (KSI) FRICTION ANGLE (DEGREE) UNDRAINED COHESION (KSF) ULTIMATE ROCK/CONCRE TE STRENGTH (KSF) Clay 0 to 4 Neglect Sand 4 to 8 107 0.63 34 n/a n/a Sand 8 to 10 122 3.07 38 n/a n/a Clay 10 to 14 135 4.00 24 5.900 n/a Weak Rock 14 to 31 135 562 30 8.00 10 201201380.001A/DEN19R101024 Page 15 of 19 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KL E/NFEL OER Right n»ot, &Of Sodurie'n TABLE 6 LPILE PARAMETERS FOR DESIGN OF FOUNDATIONS FOR THE SUBSTATION SOIL MODEL LAYER DEPTH (FT) TOTAL UNIT WEIGHT PC SOIL MODULUS K (PCI) (DEGREES) FRICTION ANGLE STRAIN FACTOR, £so UNDRAINED COHESION (PSF) Stiff Clay w/o Free Water 0 to 4 Neglect Sand 4 to 8 107 130 34 n/a n/a Sand 8 to 10 122 280 38 n/a n/a Stiff Clay w/o Free Water 10 to 14 135 n/a n/a 0.004 5.900 Weak Rock 14 to 31 135 n/a n/a n/a 8.000 4.5 GEOLOGIC HAZARDS 4.5.1 Seismicity Subsurface materials encountered at the substation site and the transmission line to the maximum depth explored of 31 feet, as well as our interpretation of underlying conditions to a depth of 100 feet based on experience and published geology. correspond with 2015 International Building Code (IBC) Site Class D designation. Acceleration coefficients for Site Class D are presented in Table 7. TABLE 7 SEISMIC DESIGN TABLE 7. SEISMIC DESIGN SITE CLASS SEISMIC DESIGN PARAMETERS Ss Si Fa F„ D 0.128 0.049 1.6 2.4 Ss = The mapped spectral accelerations for short periods (U.S. Geological Survey Web Page. 2016) S. = The mapped spectral accelerations for 1 -second period (U.S. Geological Survey Web Page. 2016) F,, = Site coefficient from Table 1613.3.3(1), 2012 IBC F, = Site coefficient from Table 1613.3.3(2), 2012 IBC 201201380.001A/DEN19R101024 Page 16 of 19 © 2019 Kleinfelder September 13, 2019 www.kleinfelder.com KL E/NFEL OER &vat+.004P R,gnr sowt.om 4.5.2 Liquefaction Hazards Earthquake -induced soil liquefaction can be described as a significant loss of soil strength and stiffness caused by an increase in pore water pressure resulting from cyclic loading during shaking. Liquefaction risk is greater in loose to medium -dense, sandy and gravelly soils below the groundwater table. The low magnitude of seismic ground motions indicates the site does not exhibit characteristics consistent with liquefaction risk. It is our opinion that the liquefaction hazard is negligible. 4.5.3 Corrosivity The degradation of concrete or cement grout can be caused by constituents in the soil or groundwater that react with cement. The concentration of water-soluble sulfates in the soils is a good indicator of the potential for chemical attack of concrete or cement grout. Laboratory test results indicate water-soluble sulfate concentrations ranging from 0.001 to 0.011 percent. Based on the sulfate exposure guidance of the American Concrete Institute (ACI) the samples present a Class SO (negligible) sulfate exposure to concrete. ACI has no special cement requirements in Class SO exposure. If there is minimal cost difference between Type I and Type II, use of Type II Portland cement is recommended for additional sulfate resistance of construction concrete. 201201380.001A/DEN19R101024 Page 17 of 19 September 13, 2019 CO 2019 Kleinfelder www.kleinfelder.com KL E/NFEL OEF' 5 LIMITATIONS This work was performed in a manner consistent with that level of care and skill ordinarily exercised by members of Kleinfelder's' profession practicing in the same locality, under similar conditions and at the date the services are provided. Our conclusions, opinions. and recommendations are based on a limited number of observations and data. The scope of services was limited to exploratory borings. laboratory testing. analysis, and preparation of this report. It is likely that subsurface conditions could vary at other locations. It should be recognized that definition and evaluation of subsurface conditions is difficult. Judgments leading to conclusions and recommendations are generally made with incomplete knowledge of the subsurface conditions present due to the limitations of data from field studies. Kleinfelder makes no other representation, guarantee. or warranty. express or implied. regarding the services, communication (oral or written), report. opinion, or instrument of service provided. Kleinfelder offers various levels of investigative and engineering services to suit the varying needs of different clients. Although risk can never be eliminated, more detailed and extensive studies yield more information, which may help understand and manage the level of risk. Since detailed study and analysis involves greater expense. our clients participate in determining levels of service. which provide information for their purposes at acceptable levels of risk. The client and key members of the design team should discuss the issues covered in this report with Kleinfelder, so that the issues are understood and applied in a manner consistent with the owner's budget, tolerance of risk and expectations for future performance and maintenance. Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory tests. and our present knowledge of the proposed construction. It is possible that soil. rock, or groundwater conditions could vary between or beyond the points explored. If soil. rock, or groundwater conditions are encountered during construction that differ from those described herein. the client is responsible for ensuring that Kleinfelder is notified immediately so that we may reevaluate the recommendations of this report. If the scope of the proposed construction changes from that described in this report. the conclusions and recommendations contained in this report are not considered valid unless the changes are reviewed. and the conclusions of this report are modified or approved in writing by Kleinfelder. 201201380.001 A/DEN 19R 101024 Page 18 of 19 September 13, 2019 2019 Kleinfelder vwwv.kleinfelaer.com KL E/NFEL DER a.gnr abae 1.ynt Sonrt oni As the geotechnical engineering firm that performed the geotechnical evaluation for this project, Kleinfelder should be retained to confirm that the recommendations of this report are properly incorporated in the design of this project, and properly implemented during construction. This may avoid misinterpretation of the information by other parties and will allow us to review and modify our recommendations if variations in the soil conditions are encountered. Kleinfelder cannot be responsible for interpretation by others of this report. The scope of services for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil. surface water, or groundwater at this site. This report may be used only by the client and the registered design professional in responsible charge and only for the purposes stated for this specific engagement within a reasonable time from its issuance. but in no event later than two years from the date of the report. 201201380.001A/DEN19R101024 Page 19 of 19 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KLEINFELOER FIGURE 201201380.001A/DEN19R101024 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com LEGEND 9iFV?n1n 10 4c.18 AM PY C'Wr ciht rgisstorpn 1 \Working\_clients\_Automated_Exploration Plans GIS Fit I PATH • S SOIL BORING TEST PIT ELECTRICAL RESISTIVITY TESTING - APPROX. LINE LAYOUT NOTE: BASE MAPPING AND VICINITY MAP CREATED FROM LAYERS COMPILED BY ESRI PRODUCTS AND 2019 MICROSOFT CORPORATION COORDINATE SYSTEM: NAD 1983 2011 STATEPLANE COLORADO NORTH FIPS 0501 Proposed Lloyd Sisson Substation: 350'x300' The information included on this graphic representation has been compiled from a vanety of sources and is subject to change without notice Kleinfelder makes no representations or warranties, express or implied. as to accuracy. completeness tmeliness or nghts to the use of such information This document is not intended for use as a land survey product nor is it designed or intended as a construction design document The use or misuse of the information contained on this graphic representation is at the sole nsk of the party using or misusing the information 0 SITE Air VICINITY MAP age County Road 200 400 1 " = 200 SCALE IN FEET NOT TO SCALE KL E/NFEL OER Bright People. Right Solutions. PROJECT NO 20201380 001A DRAWN BY CWnght CHECKED BY T Nevin DATE 09-08-2019 EXPLORATION LOCATION PLAN AND VICINITY MAP Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado FIGURE 1 KL E/NFEL DER Rngnr Prope Right So+trrom APPENDIX A BORING LOG SHEETS 201201380.001A/DEN19R101024 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com 09/10/2.019 0954 PM BY MPalmer FI('F FILTER C en N O' M SAMPLE/SAMPLER TYPE GRAPHICS MODIFIED CALIFORNIA SAMPLER (2 or 2-1/2 in. (50.8 or 63.5 mm.) outer diameter) STANDARD PENETRATION SPLIT SPOON SAMPLER (2 in. (50.8 mm.) outer diameter and 1-3/8 in. (34.9 mm.) inner diameter) GROUND WATER GRAPHICS WATER LEVEL (level where first observed) WATER LEVEL (level after exploration completion) WATER LEVEL (additional levels after exploration) OBSERVED SEEPAGE NOTES • The report and graphics key are an integral part of these logs. All data and interpretations in this log we subject to the explanations and limitations stated in the report. • Lines separating strata on the logs represent approximate boundaries only. Actual transitions may be gradual or differ from those shown. • No warranty is provided as to the continuity of soil or rock conditions between individual sample locations. • Logs represent general sod or rock conditions observed at the point of exploration on the date indicated. • In general, Unified Soil Classification System designations presented on the logs were based on visual dassification in the field and were modified where appropriate based on gradation and index property testing. • Fine grained soils that plot within the hatched area on the Plasticity Chart, and coarse grained soils with between 5% and 12% passing the No. 200 sieve require dual USCS symbols, ie., GW-GM, GP -GM, GW-GC, GP -GC, GC -GM, SW-SM, SP-SM, SW -SC. SP -SC, SC-SM. • If sampler is not able to be driven at least 6 inches then 50/X indicates number of blows required to drive the identified sampler X inches with a 140 pound hammer falling 30 inches. ABBREVIATIONS WOH - Weight of Hammer WOR - Weight of Rod UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D 2487) COARSE GRAINED SOILS (More than half of material is larger than the #200 sieve) a, w a 0 4- C m 4- m o, (o O a m m 3 0 R L c CO a) 0 kn -J w CLEAN GRAVEL WITH <5% FINES Cu 24 and 1sCcs3 Cu <4 and/ or 1>Cc>3 GRAVELS WITH 5% TO 12% FINES GRAVELS WITH > 12% FINES Cu 24 and 1sCcs3 Cu <4 and/ or 1>Cc>3 •W 1 •'• Dec _ a Qc • 0 0 a1 ( c GW WELL -GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE OR NO FINES GP POORLY GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE OR NO FINES GW-GM WELL -GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE FINES GW-GC WELL -GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE CLAY FINES GP -GM POORLY GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE FINES GP -GC GM GC POORLY GRADED GRAVELS, GRAVEL -SAND MIXTURES WITH LITTLE CLAY FINES SILTY GRAVELS, GRAVEL -SILT -SAND MIXTURES CLAYEY GRAVELS, GRAVEL -SAND -CLAY MIXTURES GC -GM CLAYEY GRAVELS, GRAVEL -SAND -CLAY -SILT MIXTURES 4, a, y a ar c r r `an m H In c O a cn ar W O 0 O E O m U) O z co CLEAN SANDS WITH <5% FINES Cu 26 and 1sCc 3 Cu <6 and/ or 1>Cc>3 V . . • • . ••• • • • • • • • . • •.• • • • • • • �• - SW SP WELL -GRADED SANDS, SAND -GRAVEL MIXTURES WITH LITTLE OR NO FINES POORLY GRADED SANDS. SAND -GRAVEL MIXTURES WITH LITTLE OR NO FINES SANDS WITH 5% TO 12% FINES Cu>6 and 1sCc3 .. • ..•• •• • •• • • • • • SW-SM WELL -GRADED SANDS, SAND -GRAVEL MIXTURES WITH LITTLE FINES SW -SC WELL -GRADED SANDS, SAND -GRAVEL MIXTURES WITH LITTLE CLAY FINES Cu <6 and/ or 1>Cc>3 SANDS WITH > 12% FINES SP-SM POORLY GRADED SANDS, SAND -GRAVEL MIXTURES WITH LITTLE FINES SP -SC POORLY GRADED SANDS, SAND -GRAVEL MIXTURES WITH LITTLE CLAY FINES SM SILTY SANDS, SAND -GRAVEL -SILT MIXTURES SC CLAYEY SANDS, SAND -GRAVEL -CLAY MIXTURES SC-SM CLAYEY SANDS, SAND -SILT -CLAY MIXTURES FINE GRAINED SOILS (Half or more of material is smaller than the #200 sieve) SILTS AND CLAYS (Liquid Limit less than 50) ML INORGANIC SILTS AND VERY FINE SANDS, SILTY OR CLAYEY FINE SANDS, SILTS WITH SLIGHT PLASTICITY �!/ � CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY. GRAVELLY CLAYS. SANDY CLAYS. SILTY CLAYS. LEAN CLAYS f I CL -ML INORGANIC CLAYS -SILTS OF LOW PLASTICITY. GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS. LEAN CLAYS - - OL ORGANIC SILTS & ORGANIC SILTY CLAYS OF LOW PLASTICITY SILTS AND CLAYS (Liquid Limit 50 or greater) MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILT /, CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS A ,tom OH ORGANIC CLAYS & ORGANIC SILTS OF MEDIUM -TO -HIGH PLASTICITY KLE/NFELOER ��1 Bright People. Right Solutions. PROJECT NO.: 20201380.001A DRAWN BY: CHECKED BY DATE: MAP CAW / TJN 9/10/2019 GRAPHICS KEY Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado FIGURE A-1 GRAIN SIZE DESCRIPTION SIEVE SIZE GRAIN SIZE APPROXIMATE SIZE Boulders >12 in. (304.8 mm.) >12 in. (304.8 mm.) Larger than basketball -sized Cobbles 3 - 12 in. (76.2 - 304.8 mm.) 3 - 12 in. (76.2 - 304.8 mm.) Fist -sized to basketball -sized coarse 3/4 -3 in. (19 - 76.2 mm.) 3/4 -3 in. (19 - 76.2 mm.) Thumb -sized to fist -sized Gravel fine #4 - 3/4 in. (#4 - 19 mm.) 0.19 - 0.75 in. (4.8 - 19 mm.) Pea -sized to thumb -sized coarse #10 - #4 0.079 - 0.19 in. (2 - 4.9 mm.) Rock salt -sized to pea -sized O� Sand medium #40 - #10 0.017 - 0.079 in. (0.43 - 2 mm.) Sugar -sized to rock salt -sized o fine #200 - #40 0.0029 - 0.017 in. (0.07 - 0.43 mm.) Flour -sized to sugar -sized • Fines Passing #200 <0.0029 in. (<0.07 mm.) Flour -sized and smaller SECONDARY CONSTITUENT MOISTURE CONTENT CEMENTATION AMOUNT DESCRIPTION FIELD TEST DESCRIPTION FIELD TEST Term of Use Secondary Constituent is Fine Grained Secondary Constituent is Coarse Grained Dry Absence of moisture, dusty. dry to the touch Weakly Crumbles or breaks with handling or slight finger pressure Damp but no Crumbles or breaks Trace 0 <5% <15% Moist visible water Moderately with considerable finger pressure With c5 to <15% c 15 to <30% Visible free water, Will not crumble or Modifier c 15% z30% Wet usually soil is below water table Strongly break with finger pressure CONSISTENCY - FINE-GRAINED SOIL REACTION WITH UNCONFINED HYDROCHLORIC ACID SPT N� Pocket Pen CONSISTENCY - (# blows / ft) (tsf) COMPRESSIVE VISUAL / MANUAL CRITERIA DESCRIPTION FIELD TEST STRENGTH (OO(psf) Very Soft <2 PP < 0.25 <500 Thumb will penetrate more than 1 inch (25 mm). Extrudes between fingers when squeezed. None No visible reaction Thumb will soil about 1 inch mm). Soft 2 - 4 0.25 s PP <0.5 500. 1000 penetrate (25 Remolded by light finger pressure. Some reaction, Medium Stiff 4 - 8 0.5s PP <1 WOO - 2000 Thumb will penetrate soil about 1/4 inch (6 mm). Remolded by strong finger Weals with bubbles forming slowly pressure. Violent reaction, Stiff 8 - 15 1, PP <2 2000 - 4000 Can be imprinted with considerable pressure from thumb. Strong with bubbles forming Thumb will not indent soil but readily indented immediately Very Stiff 15 - 30 2 , PP <4 4000 - 8000 with thumbnail. Hard >30 4 s PP >8000 Thumbnail will not indent soil. FROM TERZAGHI AND PECK 1948, LAMBE AND WHITMAN, 1969, FHWA, 2002. AND ASTM D2488 APPARENT / RELATIVE DENSITY - COARSE -GRAINED SOIL PLASTICITY APPARENT SPT fV,o MODIFIED CA SAMPLER CALIFORNIA SAMPLER RELATIVE DENSITY DESCRIPTION LL FIELD TEST DENSITY (# blows/ft) (# blows/ft) (# blowslft) (%) Non -plastic NP A 1/8 -in. (3 mm.) thread cannot be rolled at any water content. Very Loose <4 <4 <5 0 - 15 Low (L) < 30 The thread can barely be rolled and the lump or thread cannot be formed when dner than the limit. plastic Loose 4 - 10 5 - 12 5 - 15 15 - 35 The thread is easy to roll and not much time is required to Medium Dense 10 - 30 12 - 35 15 - 40 35 - 65 Medium (M) 30 - 50 reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. The lump or thread crumbles when dner than the plastic limit. Dense 30 - 50 35 - 60 40 - 70 65 - 85 It takes considerable time rolling and kneading to reach the Very Dense >50 >60 >70 85 - 100 High (H) ' plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump or thread can be formed without crumbling when dner than the plastic limit. FROM TERZAGHI AND PECK, 1948 STRUCTURE ANGULARITY DESCRIPTION CRITERIA DESCRIPTION CRITERIA Stratified Alternating layers of varying material or color with layers at least 1/4 -in. thick, note thickness. Angular Particles have sharp edges and relatively plane sides with unpolished surfaces. Alternating layers Laminated of varying material or color with the layer less than 1/4 -in, thick, note thickness. Subangular Particles are similar to angular descnption but have rounded edges. Fissured Breaks along definite planes of fracture with little resistance to fracturing. Particles have nearly sides but have well-rounded corners and Slickensided Fracture planes appear polished or glossy. sometimes stnated.edges. Subrounded plane Blocky Cohesive soil that can be broken down into small angular lumps resist further breakdown. Rounded Particles have smoothly curved sides and no edges. which Lensed Inclusion of small pockets of different soils. such as small lenses of sand scattered through a mass of day note thickness. �-- PROJECT NO.. 20201380.001A DRAWN BY MAP CHECKED BY CAW / TJN DATE 9/10/2019 SOIL DESCRIPTION KEY FIGURE /� '; KL E/NFEL DER Tri-State -State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright People. Right Solutions. INFILLING TYPE RELATIVE HARDNESS / STRENGTH DESCRIPTIONS NAME ABBR NAME ABBR GRADE UCS (Mpa) FIELD TEST Albite Al Muscovite Mus R0 Extremely Weak 0.25 - 1.0 Indented by thumbnail Apatite AP None No R1 Very Weak 1.0 - 5.0 Crumbles under firm blows of geological hammer, can be peeled by a pocket knife. Biotite Bi Pynte Py R2 Weak 5.0 - 25 Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with point of geological hammer. Clay a Quartz Qz R3 Medium Strong 25 - 50 Cannot be scraped or peeled with a pocket knife. specimen can be fractured with a single firm blow of a geological hammer. Calcite Ca Sand Sd R4 Strong 50 - 100 Specimen requires more than one blow of geological hammer to fracture it. Chlonte Ch Senate Ser R5 Very Strong 100 - 250 Specimen requires many blows of geological hammer to fracture it. Epidote Ep Silt Si R6 Extremely Strong > 250 Specimen can only be chipped with a geological hammer. Iron Oxide Fe Talc Ta ROCK QUALITY DESIGNATION (RQD! JOINT ROUGHNESS COEFFICIENT (JRC) Manganese Mn Unknown Uk DESCRIPTION RQD (%) 0-2 DENSITY/SPACING OF DISCONTINUITIES Very Poor 0 - 25 DESCRIPTION SPACING CRITERIA Poor 25 - 50 2-4 Unfractured >6 ft. (>1.83 meters) Fair 50 - 75 4 - 6 Slightly Fractured 2 - 6 ft. (0.061 - 1.83 meters) Good 75 - 90 .--- 6 - 8 Moderately Fractured 8 in 2 ft. (203.20 609.60 mm) Excellent - - 90 - 100 - - Highly Fractured 2 - 8 in (50.80 - 203.30 mm) APERTURE 8-10 --_ Intensely Fractured <2 in (<50.80 mm) 10 12 DESCRIPTION CRITERIA [m (mm)1 ADDITIONAL TEXTURAL ADJECTIVES Tight <0.04 (<1) 12 - 14 DESCRIPTION RECOGNITION Open 0.04 0.20 5) - (1 - 16 Pinhole to 0.03 ft. (3/8 in.) (>1 to Pit (Pitted) Wide >0.20 (>5) 10 mm.) openings 16 - 18 Small openings (usually lined with crystals) ranging in diameter from BEDDING CHARACTERISTICS Vug (Vuggy) 0.03 ft. (3/8 to 0.33 ft. in.) 18-20 in.) (4 (10 to 100 mm.) DESCRIPTION Thickness [in (mm)J Cavity An opening larger than 0.33 ft. (4 in.) (100 mm.), size descriptions Very Thick Bedded >36 (>915) 0 5 cm 10 cm are required. and adjectives such as small large. etc.. may be used Thick Bedded 12 - 36 (305 - 915) From Barton and Choubey. 1977 If numerous enough that only thin Moderately Bedded 4 - 12 (102 - 305) ROD Rock -quality designation (ROD) Rough measure of the degree of or fracture Honeycombed walls separate individual pits or wgs, this term further describes Thin Bedded 1 - 4 (25 - 102) jointing in a rock mass, measured as a percentage of the drill core in lengths of 10 cm. or more. the preceding nomenclature to indicate cell-like form. Very Thin Bedded 0.4 - 1 (10 - 25) Small openings in volcanic rocks formed Laminated 0.1 - 0.4 (2.5 - 10) Vesicle (Vesicular)of variable shape and size by entrapped gas bubbles during solidification, Thinly Laminated <0.1 (<2.5) Bedding Planes Planes dividing the individual layers, ADDITIONAL TEXTURAL ADJECTIVES beds. or stratigraphy of rocks. Joint Fracture DESCRIPTION CRITERIA in rock. generally more or less vertical or traverse to bedding. Seam Applies to bedding Unweathered No evidence of chemical / mechanical alternation. nngs with hammer plane with unspecified degree of weather. Slight discoloration on surface, CORE SAMPLER TYPE GRAPHICS Slightly Weathered slight alteration along discontinuities; <10% rock volume altered. CORE SAMPLER '>≤ :±-: EX CORE BARREL (0 846 in. (21.5 mm.) core diameter) Moderately Weathered Discolonng evident, surface pitted and alteration penetration well surface Weathering "halos" belowevident. AQ CORE BARREL (1.067 in. (27.1 mm.) core diameter) HQ CORE SAMPLE (2.500 in. (63.5 mm.) core diameter) 10-50% rock altered. AX CORE BARREL NQ CORE SAMPLE Entire mass discolored: Alteration (1.185 in. (30.1 mm.) core diameter) (1.874 in. (47.6 mm.) core diameter) Highly Weathered pervading most rock, some slight weathering pockets: some minerals may be leached out. BQ CORE BARREL (1.433 in. (36.4 mm.) core diameter) NO RECOVERY CORE SAMPLE Decomposed Rock reduced to soil with relic rock texture/structure. Generally molded by hand. CONTINUOUS CORE SAMPLE (2.000 in. (50.8 mm.) core diameter) NX CORE SAMPLE (2.154 in. (54.7 mm.) core diameter) and crumbled PROJECT NO. 20201380.0o1A DRAWN BY MAP CHECKED BY CAW / TJN DATE 9/10/2019 ROCK DESCRIPTION KEY FIGURE A-3 JCL E/NFEL DER Tri-State. Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright People. Right Solutions. �- - Date Begin - End: 8/29/2019 Drilling Company: Vine Laboratories BORING LOG B-1 Logged By: B. Monterde Drill Crew: Nick & Paul Hor.-Vert. Datum: Not Available Drilling Equipment: CME-750 Hammer Type - Drop: 140 lb. Auto - 30 in. Plunge: -90 degrees Drilling Method: Solid Stem Auger Weather: P. Cloudy Exploration Diameter: 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude 40.93071' Longitude -104.39239' Surface Condition Grass Sample Type Blow Counts(BC) l/ncorr Blows/6 m Recovery (NR=No Recovery) USCS Symbol Water Content (%) Dry Unit Wt. (pcf) Passing #4 (%) Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) a) a) i— To u, c .. o•- - m E Lithologic Descnption Q it _ 5— - ' TOPSOIL -B" Silty SAND (SM) fine-grained sand. light brown, moist very loose 1801 2 12" Poorly Graded SAND with Gravel (SP) fine to — coarse -grained sand, angular to sub -angular gravel, 1802 9 12" 3.6 107.7 pale red and brown moist loose to dense 15" 19.9 Sulfates= 0.006% Lean CLAY with Sand and Gravel (CL) medium plasticity, gray, moist, hard ILBC=10 15 20 /1 10 - - - - 15 -x _ - x x x x x x SILTSTONE tan slightly weathered very weak, weakly cemented, homogeneous BC=17 22 12" 17.1 92.7 Expansion/Compression= Compression= 1.1% under 1 ksf- x x x x x x x x x x x x x x x x x x x x when wetted. x x x x x BC=15 50/5" r 22.5 65 32 6 x x x x x x x x x x x x x x x x x x - 20 J 25— - 30— BC=2O CLAYSTONE tan slightly weathered, extremely 26.0 92.7 37 weak Some cobbles observed in cuttings BC=21 - brown below 25 feet 28.8 88.6 Uric. Comp. Str.= 50/6" - ck, 5:1.50 psi Strain at Failure 4.5% BC=14 29.6 87.4 21 - The boring was terminated at approximately 31 ft. GROUNDWATER LEVEL INFORMATION below ground surface. The boring was backfilled Groundwater was not observed during drilling or after with auger cuttings on August 29, 2019. completion. GENERAL NOTES(-----. PROJECT NO. 20201380.001A DRAWN BY MAP CHECKED BY CAW / TJN DATE 9/10/2019 BORING LOG B-1 BORING PAGE B_ 1 1of1 KL E/NFEL DER Tri-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. Date Begin - End: 8/29/2019 Drilling Company: Vine Laboratories BORING LOG B-2 Logged By: B. Monterde Drill Crew: Nick & Paul Hor.-Vert. Datum: Not Available Drilling Equipment: CME-750 Hammer Type - Drop: 140 lb. Auto - 30 in. Plunge: -90 degrees Drilling Method: Solid Stem Auger Weather: Windy, 69° F Exploration Diameter: 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude. 40.93073° Longitude: -104.39186' Surface Condition: Grass Sample Type Blow Counts(BC) Uncorr Blows/6 in Recovery (NR=No Recovery) USCS Symbol Water Content (%) Dry Unit Wt. (pcf) a , Of C Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) N a) - I To w C Y O 1- Lithdogic Description a_ Qa ipr L TOPSOIL. -8" Sandy Lean CLAY (CL): brown, dry, soft, organics IBC=2 3 12" Sulfates= 0.001% 10 f Silty, Clayey SAND (SC-SM): fine-grained sand, angular gravel, low plasticity, light brown, loose f •BC=3 4 12" SC-SM 5.0 100.9 34 23 6 - fine to coarse -grained sand, pale red medium dense below 7.5 feet 1BC12 20 12" Chattering while dnlling at 8 feet Lean CLAYwith Sand (CL): medium plasticity, light gray. moist hard L BC=15 25 27 18" l 21.4 15- " - _ 20- _ - _ - 25- x x SILTSTONE light gray moderately weathered, extremely weak x x x x BC -20 50/5" 21.0 86.3 Unc. Comp. Str.= qv. 9595 psf x x x x x x x x x x x x x x x x x x x x x x x x BC=23 50/6" Strain at Failure 4.5% x x x x x x x x x x x x x x x x x x x x BC=19 30.6 89.3 Expansion/Compression= — 50/5" CLAYSTONE: brown moderately weathered weak i Compression= 2 4% under 0.5 - ksf when wetted. 30 - calcareous and cobbles at bottom of sample BC=50/5" \- GROUNDWATER LEVEL INFORMATION. The boring was terminated at approximately 30.4 ft Groundwater was not observed during drilling or after below ground surface. The boring was backfilled completion. with auger cuttings on August 29, 2019. GENERAL NOTES PROJECT NO.: 20201380.001A DRAWN BY: MAP CHECKED BY: CAW / TJN DATE: 9/10/2019 BORING LOG B-2 BORING PAGE B-2 1 of 1 KL E/NFEL DER Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. \,..........----......„." HURING/TEST PIT Solt. I nr'; L a c r C c. a a - a. m c • Date Begin - End: 8/29/2019 Drilling Company: Vine Laboratories BORING LOG B-3 Logged By: B. Monterde Drill Crew: Nick & Paul Hor.-Vert. Datum: Not Available Drilling Equipment: CME-750 Hammer Type - Drop: 140 lb. Auto - 30 in. Plunge: -90 degrees Drilling Method: Solid Stem Auger Weather: Not Available Exploration Diameter: 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude 40.93047' Longitude -104.39213° Surface Condition Grass & Weeds Sample Type Blow counts(BC)- Uncorr Blows/6 in Recovery (NR=No Recovery) U E Water Content (%) Dry Unit Wt. (pcf) Passing #4 (%) Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) n' a) H. To ch C,[ - E Lithologic Descnption w ¢ x 5— �. 10-• TOPSOIL -8" Clayey SAND (SC): fine-grained sand. brown. dry, loose calcareous •BC=2 2 Poorly Graded SAND with Gravel and Silt (SP-SM). fine to coarse -grained sand. sub -angular and Chattenng while drilling at 3.5 _ feet sub -rounded gravel light brown. dry. dense LL15 BC=14 21 21 0.8 Sulfates= 0.001% Chattenng while drilling from 6.5., to 8 feet Gravelly SAND with Clay (SP -SC) fine to coarse -grained sand, angular to sub -angular gravel, light brown moist. dense BC=20 22 19 and pink Chattenng while drilling from 9.5.. BC=15 11.7 to 11 feet 32 CLAYSTONE gray. moderately weathered _ 39 extremely weak Chattenng while dnlling at 11.5 _ feet, had to re -drill hole due to collapse Water to hole added 15 — BC=24 24.4 92.2 Expansion/Compression= 22 Compression= 0.1% 1 ksf- under when wetted. 20 — - brown below 20 feet BC=24 25 25 — - calcareous below 25 feet BC=37 23.6 87.6 Unc. Comp. Str.= 50/ % 2770 q„' psf Strain Failure: 9.7% at 30 _ - — BC=19 \ 50/3 1 The boring was terminated at approximately 30.8 ft. GROUNDWATER LEVEL INFORMATION. below ground surface. The boring was backfilled Groundwater was not observed during drilling or after with auger cuttings on August 29 2019 completion GENERAL NOTES �--- PROJECT NO. 20201380.001A DRAWN BY MAP CHECKED BY CAW / TJN DATE 9/10/2019 BORING LOG B-3 BORING PAGE- B_3 1 of 1 KL E/NFEL DER Tn-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. z c C. C IN• cfc Wco CD w N W O 3 N o t a c a o: u o: a o c z 0 Nt cn re L- ra E - E 1 4-- 37 3 LT f - z z Date Begin - End: 8/29/2019 Drilling Company: Vine Laboratories BORING LOG B-4 Logged By: B. Monterde Drill Crew: Nick & Paul Hor.-Vert. Datum: Not Available Drilling Equipment: CME-750 Hammer Type - Drop: 140 lb. Auto - 30 in. Plunge: -90 degrees Drilling Method: Solid Stem Auger Weather: Sunny Exploration Diameter 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude: 40.93023° Longitude: -104.39240' Surface Condition: Grass Sample Type Blow Counts(BC)= Uncorr Blows/6 in Recovery (NR=No Recovery) IogwAS s3sn Water Content (%) Dry Unit Wt. (pct) Passing #4 (%) Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) ti aa, I -- To rn C Y o Lithologic Description Q lo ce 5 7 Sandy Lean CLAY (CL): medium plasticity, light brown, soft r`«< BC=1 2 CL 14.9 83.3 62 33 14 Expansion/Compression= Compression= 0.4% 0.5 Poorly Graded SAND with Gravel and Silt (SP-SM): fine to coarse -grained sand, red dry. very dense under ksf when wetted. pale BC=22 34 47 Chattering while drilling at 2.5 _ feet Sulfates= 0.002% Chattering while drilling at 6 feet BC=30 32 46 10— -x - _x _ 15— _ - _ x x x x x x SILTSTONE: grayish brown, slightly weathered, very weak x x x x BC=19 3,5 11.2 119.1 x x x x x x x x x x x x x x x x x x x x x x x x BC=19 27 x x x x x x x x x x x x x x 20—' - 25— 30 r _ CLAYSTONE: brown, slightly weathered extremely weak. weakly cemented BC=20 29.1 85.0 Unc. Comp. Str.= 55 q,,: 10048 psf Strain at Failure: 6.9% BC=18 Water in sampler 55 BC=31 28.0 88.7 No water in sampler 50/2" / The boring was terminated at approximately 30.7 ft. GROUNDWATER LEVEL INFORMATION: below ground surface. The boring was backfilled Groundwater was not observed dunng drilling or after with auger cuttings on August 29. 2019. completion. GENERAL NOTES. (-----PROJECT NO.: 20201380.001A DRAWN BY: MAP CHECKED BY: CAW I TJN DATE: 9/10/2019 BORING LOG B-4 BORING PAGE B-4 1 of 1 KL E/NFEL DER Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. �� Date Begin - End: 8/29/2019 Drilling Company: Vine Laboratories BORING LOG B-5 Logged By: B. Monterde Drill Crew: Nick & Paul Hor.-Vert. Datum: Not Available Drilling Equipment: CME-750 Hammer Type - Drop: 140 lb. Auto - 30 in. Plunge: -90 degrees Drilling Method: Solid Stem Auger Weather: Windy Exploration Diameter: 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude 40.93023' Longitude -104.39187' Surface Condition Grass Sample Type Blow Counts(BC)= Uncorr Blows/6 in Recovery (NR=No Recovery) USCS Symbol Water Content ((Yu) Dry Unit Wt. (pcf) Passing #4 (%) Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) U) ai i- To cn c Y o Ica E Lithologic Description Qtr _ 5— _ t0- 7Sandy Lean CLAY (CL) light brown dry medium stiff BC=5 5 8" 9.9 94,1 Expansion/Compression= _ Compression= 1.5% under 0.5 SAND with Gravel and Silt (SP-SM) PoorlyAGraded fine to coarse -grained sand, sub -angular tan, ksf when wetted. . gravel. very dense BC=23 26 26 18" 0.8 Chattenng while drilling at 3 feet _ Chattenng while dnlling at 6 feet Silty SAND with Gravel (SM) fine to coarse -grained sand, tan. dry, very dense _ BC=26 26 _ - , BC=22 38 13.7 100.0 Sulfates=0.011% 15- 20J J 25 — 30- _ - CLAYSTONE tan, slightly weathered extremely weak - •BC=22 39 — BC=25 25.8 89.4 Unc. Comp. Str.= 46 q,.. 5589 psf Strain at Failure, 6.4% _ - feet BC=21 - brown below 25 50/6" - ELBC=22 50/5" The boring was terminated at approximately 30.9 ft. GROUNDWATER LEVEL INFORMATION below ground surface. The bonng was backfilled Groundwater was not observed dunng drilling or after with auger cuttings on August 29, 2019 completion. GENERAL NOTES PROJECT NO. 20201380.001A DRAWN BY MAP CHECKED BY CAW / TJN DATE 9/10/2019 BORING LOG B-5 BORING B_5 PAGE. 1 of 1 KL E/NFEL DER Tri-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright People. Right Solutions. Date Begin - Logged By: Hor.-Vert. Datum: Plunge: Weather: End: 8/29/2019 Drilling Company: Crew: Equipment: Method: Diameter: Vine Laboratories Hammer BORING LOG TP-1 B. Monterde Drill Nick & Paul Type - Drop: 140 lb. Auto - 30 in. Not Available Drilling CME-750 -90 degrees Drilling Solid Stem Auger Not Available Exploration 4 in. O.D. Depth (feet) Graphical Log FIELD EXPLORATION LABORATORY RESULTS Latitude. 40.93046' Longitude -104.39168' Surface Condition Grass Sample Type BlowCounts(BC)° Uncorr Blows/6 in Recovery (NR=No Recovery) USCS Symbol Water Content (%) Dry Unit Wt (pcf) Passing #4 (%) Passing #200 (%) Liquid Limit Plasticity Index (NP=NonPlastic) U) TA a) F- as v) C '- o '- .- co -o E Qtr Lithologic Descnption 1 2 3�// 5 TOPSOIL -8" SC 7.7 6.8 1.2 93.5 36 23 9 Test results from bulk sample 0.67 to 6.5 feet _ _ -. — — — . �" Clayey SAND (SC) fine to medium -grained sand, low plasticity brown. dry, loose, trace roots BC -4 5 6— 1 Poorly Graded SAND with Gravel and Silt (SP-SM) fine to medium -grained sand, sub -angular to sub -rounded gravel. light brown and pink. dry loose to medium dense BC=7 5 5 7_ 8- 9- 10- 11- 12- 13- 14- The boring was terminated at approximately 6.5 ft. below ground surface. The boring was backfdled with excavated material on August 29. 2019. GROUNDWATER LEVEL INFORMATION or after Groundwater was not completion. GENERAL NOTES observed during drilling re.--;L �_ PROJECT NO. 20201380.001A DRAWN BY CHECKED BY. DATE. BORING LOG TP-1 BORING T PAGE P-1 1 of 1 EINFEL DER MAP CAW / TJN 9/10/2019 Tri-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright People. Right Solutions. KLE/NFELDER DER alight htopte 4pnt Sok/vont APPENDIX B LABORATORY TEST RESULTS 201201380.001A/DEN19R101024 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com gINT FILE Klt_gnN_master 2020 ;5 . l' . r 1_ Exploration ID Depth (ft-) B-1 B-1 B-1 B-1 B-1 B-1 B-1 B-2 B-2 B-2 B-2 B-2 8-3 B-3 B-3 B-3 B-4 8-4 B-4 B-4 Refer to the Geotech supplemental plates performed above. NP = NonPlastic 5.0 7.5 10.0 15.0 20.0 25.0 30.0 2.5 5.0 11.5 15.0 25.0 5.0 10.0 15.0 25.0 2.5 5.0 10.0 20.0 nical Evaluation for the method Sample Description Water Content (9/a) Dry Unit Wt. (pcf) POORLY GRADED SAND WITH GRAVEL (SP) LEAN CLAY WITH SAND (CL) SILTSTONE 3.6 19.9 17.1 SILTSTONE 22.5 CLAYSTONE 26.0 CLAYSTONE 28.8 CLAYSTONE 29.6 SILTY, CLAYEY SAND (SC-SM) 5.0 LEAN CLAY WITH SAND (CL) 21.4 SILTSTONE 21.0 SILTSTONE 30.6 POORLY GRADED SAND WITH GRAVEL AND SILT (SP-SM) 0.8 CLAYSTONE 11.7 CLAYSTONE 24.4 CLAYSTONE 23.6 SANDY LEAN CLAY (CL) 14.9 SILTSTONE 11.2 CLAYSTONE 29.1 Report or the sed for the testing 107.7 92.7 92.7 88.6 87.4 100.9 86.3 89.3 92.2 87.6 83.3 119.1 85.0 Sieve Analysis (%) M CD C N N R a Atterberg Limits Passing #200 Plastic Limit Additional Tests Sulfates= 0.006% E xpa ns ionlCompression= Compression= 1.1% under 1 ksf when wetted. 65 32 26 6 Unconfined Compressive Strength= q,,: 8350 psf Strain at Failure: 4.5% Sulfates= 0.001% 34 23 17 6 Unconfined Compressive Strength= q,,: 9595 psf Strain at Failure: 4.5% Expansion/Compression= Compression= 2.4% under 0.5 ksf when wetted. Sulfates= 0.001% Expansion/Compression= Compression= 0.1% under 1 ksf when wetted. Unconfined Compressive Strength= q,,: 2770 psf Strain at Failure: 9.7% 62 33 19 14 Expansion/Compression= Compression= 0.4% under 0.5 ksf when wetted. Sulfates= 0.002% Unconfined Compressive Strength= q0: 10048 psf Strain at Failure: 6.9% res.-KLEINFELDER Bright People. Right Solutions. PROJECT NO.: 20201380.001A DRAWN BY MAP CHECKED BY: CAW / TJN DATE. 9/10/2019 LABORATORY TEST RESULT SUMMARY Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado TABLE B-1 gINT FILE KIt_gmt master_2020 PROJECT NUMBER 20201380.001A .!Api �MMAR OFFICE FILTER DENVEf' U) ii; PM B' Exploration ID Depth (ft.) Sample Description Water Content (%) Dry Unit Wt. (pcf) "Mr _M - Sieve Analysis (%) IF Atterberg Limits Passing 3/4" O) C N N R Passing #200 E O tS J Plastic Limit Additional Tests B-4 B-5 B-5 B-5 B-5 TP-1 TP-1 TP-1 30.0 2.5 5.0 10.0 20.0 0.67 - 6.5 1.0 5.0 CLAYSTONE SANDY LEAN CLAY (CL) POORLY GRADED SAND WITH GRAVEL AND SILT (SP-SM) SILTY SAND WITH GRAVEL (SM) CLAYSTONE CLAYEY SAND (SC) CLAYEY SAND (SC) POORLY GRADED SAND WITH GRAVEL AND SILT (SP-SM) 28.0 9.9 0.8 13.7 25.8 7.7 6.8 1.2 88.7 94.1 100.0 89.4 93.5 36 23 14 9 Expansion/Compression= Compression= 1.5% under 0.5 ksf when wetted. Sulfates= 0.011% Unconfined Compressive Strength= q,,: 5589 psf Strain at Failure: 6.4% Refer to the Geotechnical Evaluation Report or the supplemental plates for the method used for the testing performed above. NP = NonPlastic KL E//VFELOER Bright People. Right Solutions. PROJECT NO.: 20201380.001A DRAWN BY MAP CHECKED BY: CAW / TJN DATE: 9/10/2019 LABORATORY TEST RESULT SUMMARY Tn-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado TABLE B-2 PLASTICITY INDEX (PI) N W A (h Q) O a V O O O O O O # p� / .J// / / / / p \\\•9 •P For classification of fine-grained so Is and fine-grained fraction of coarse -grained soils. / / / / / 6 G I / / / / / / / / / / &// / 4, / / / / G'"oc MH or OH / X ML orOL Chart Reference: ASTM O2487 I I 0 10 16 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT (LL) Exploration ID Depth (ft.) Sample Description x #200 ,LL a PI B-1 15 SILTSTONE 65 32 26 6 B-2 5 SILTY. CLAYEY SAND (SC-SM) 34 23 17 6 4 A B-4 2.5 SANDY LEAN CLAY (CL) 62 33 19 14 X TP-1 0.67 - 6.5 CLAYEY SAND (SC) 36 23 14 9 Testing performed in general accordance with ASTM D4318. NP = Nonplastic NM = Not Measured KL E//VFEL Bright People. PROJECT No. 20201380.001A DRAWN BY MAP CHECKED BY: CAW I TJN DATE: 9/10/2019 LIMITS FIGURE B_3 ATTERBERG DER Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado iss� Right Solutions. L. J J w c r. ry� a. a. a: 2 L 2 G C 0 ct ct Ire V scrim L E-: _t 4 w J � 4 P1 EXPANSION/COMPRESSION (%) I I ? W N O ca C7o -! Q) CT W N -s a -A N.) (d a cry O) -1 O3 (D O Compression= 1.1% under 1 ksf when wetted. • 0.1 1 10 STRESS (ksf) • Exploration ID Depth (ft.) Sample Description Initial Water Content (%) Initial Dry Unit Wt. (pcf) Final Water Content (%) Final Dry Unit Wt. (pd) B 1 10 SILTSTONE 92 27.6 92.7 PROJECT NO. 20201380.001A DRAWN BY: MAP CHECKED BY: CAW / TJN DATE: 9/10/2019 DENVER SWELL OF COHESIVE SOILS FIGURE B-4 KL E/NFEL DER Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. ", C 0 m 0 0 N PROJECT NI IMBER 'JELL ISINGLE)i I__KLF_DENVE LIBRARY_2O2, U cr O CI rI z 0 ar a EXPANSION/COMPRESSION (%) I I I I I J J 1 I 1 1 I 1 1 a" co" N � O c0 © v1 0) Cr a W N — a N co a to 0) V 00 (0 O a Compression= 2.4% under 0.5 ksf when wetted. 0.1 1 10 STRESS (ksf) Exploration ID Depth (ft.) Sample Description Initial Water Content (%) Initial Dry Unit Wt. (ixf) Final Water Content (%) Final Dry Unit Wt. (lcf) B-2 25 SILTSTONE 8.9 90.1 27.4 90.1 --- KL .� . DER Solutions. PROJECT NO.: 20201380.001A DRAWN BY: MAP CHECKED BY' CAW / TJN DATE: 9/10/2019 DENVER SWELL OF COHESIVE SOILS FIGURE B_5 E/NFEL Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right EXPANSION/COMPRESSION (%) 1 I 1 1 1 1 1 1 1 1 1 1 1 1 a C) N -+ O co Oo v Q) 61 a W N -+ o N co a CT O) -1 CO CD O Compression= OA% under 1 ksf when wetted. 0 1 1 10 STRESS (ksf) Exploration ID Depth (ft.) Sample Description Initial Water Content (%) Initial Dry Unit Wt. (pct) Final Water Content (%) Final Dry Unit Wt. (pcf) B-3 15 CLAYSTONE 24.4 92.2 28.5 92.2 PROJECT No 20201380.001A DRAWN BY MAP CHECKED BY. CAW / TJN DATE 9/10/2019 DENVER SWELL OF COHESIVE SOILS FIGURE U B-6 KL E/NFEL DER Tn-State. Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County Colorado Bright People. Right Solutions. a u r W ?mnilrin nil c 0 ' rl C 5. X EXPANSION/COMPRESSION (°/0) a co N -a C co 0° v CA Cr A W N a O -+ N GJ ? Cr CA -! CO CD C Compression= 0.4% under 0.5 ksf when wetted. 1 0.1 1 10 STRESS (ksf) Exploration ID Depth (ft.) Sample Description Initial Water Content (%) Initial Dry Unit Wt (pcf) Final Water Content (%) Final Dry Unit Wt. (pcf) B -h 2.5 SANDY LEAN CLAY (CL) 14.9 83.3 34.3 83.3 (----PROJECT No.: 20201380.001A DRAWN BY: MAP CHECKED BY CAW / TJN DATE: 9/10/2019 DENVER SWELL OF COHESIVE SOILS FIGURE B_ 7 KL E/NFEL DER Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright People. Right Solutions. �- • °.)1380.001 A CC w m w Q ce W 2 V' 1f1 a w C; EXPANSION/COMPRESSION r/o) 1 1 I 1 1 1 1 1 1 1 1 A W N — O CID O) -) O) (Ti a ( A) N - O -& NJ W A C1i Q) -I OD CO O i_ Compression= 1.5% under 0.5 ksf when wetted. 0 1 1 10 STRESS (ksf) Exploration ID Depth (ft.) Sample Description Initial Water Content (%) Initial Dry Unit Wt. (pc Final Water Content (%) Final Dry Unit Wt (pcf) B-5 2.) SANDY LEAN CLAY (CL) 9.9 94.1 23.6 94.1 PROJECT NO 20201380.001A DRAWN BY MAP CHECKED BY. CAW / TJN DATE 9/10/2019 DENVER SWELL OF COHESIVE SOILS FIGURE B-8 ( KL EINFEL DER Tri-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County Colorado Bright People. Right Solutions. .--- J LKLLUNC CUM( 0 0 N Z w N tt 11,000 10,000 9.000 U m a. 8.000 U) rn w 1- 7,000 0 w v7 6.000 w cc a_ O 5.000 O a w z 4,000 Z O Z 3.000 D 2,000 1,000 2 4 6 8 10 AXIAL STRAIN (%) Exploration ID Depth (ft.) Sample Description B-1 25 CLAYSTONE Time to Failure (min) Average Rate of Strain to Failure (%/min) Shear StrengthUnconfined (psf) Compressive Strength (psf) a Strain at Failure ( /o) 4.0 1.5 4' _ 8350 4.5 Specimen No. Sample Condition Type Initial Sample Dia. (mm) Initial Height (mm) Initial Height to Diameter Ratio Initial ' Water i Content (%) Initial Dry Unit Wt. (PO(°/Q) Initial Saturation Initial Void Ratio Specific Gravity (Assumed) Passing #200 LL PL PI 1 Intact 48.5 102.4 2.1:1 28.8 38 6 NM 1 NM 2.65 NM NM NM NM Testing performed in general accordance with ASTM D2166. NP = Nonplastic NM = Not Measured KL �.._ PROJECTNO.: 20201380.001A DRAWN BY. CHECKED BY: CAW DATE: 9/10/2019 UNCONFINED COMPRESSIVE STRENGTH FIGURE B_9 E/NFEL People. DER Solutions. MAP i TJN Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright Right 11 10 9,000 tii a 8,000 U) rn w cc 7.000 � w > Ui 6.000 Cl) w cc w 2 5 O O O w z 4.000 i z O Z 3.000 D 2,000 1,000 000 000 000 2 4 6 8 10 AXIAL STRAIN (%) Exploration ID Depth (f..) Sample Description B-2 15 SILTSTONE (min) Time to Failure min Average Rate of Strain to Failure (%/min) Shear Strength (�� Unconfined Compressive Strength (psf) Strain at Failure (°/0) 3.8 1.5 4; i.;.'3 3S 4.5 Specimen No. Sample Condition Type Initial Sample Dia. (mm) Initial Height (mm) Initial Height to Diameter • Ratio Initial Water Content (%) Initial Dry Unit Wt. (pcf) I Initial Saturation (%) Initial Void Ratio Specific Gravity (Assumed) Passing #200 LL PL PI 1 Intact 48 5 9:3 E 2' 0 88 3 NM NV 2.65 NM NM NM NM Testing performed in general accordance with ASTM D2166. NP = Nonplastic NM = Not Measured KL PROJECT NO. 20201380.001A DRAWN BY CHECKED BY CAW DATE UNCONFINED COMPRESSIVE STRENGTH FIGURE B- 1 0 E/NFEL People. DER MAP / TJN 9/10/2019 Tri-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright Right Solutions. 11,000 10,000 9,000 C. in a. 8.000 en rn w 1- 7,000 w > cn 6,000 up w cc a 2 5.000 O 0 0 w Z 4,000 Z O z 3.000 D 2,000 1,000 2 4 6 8 10 AXIAL STRAIN (%) Exploration ID Depth (ft.) Sample Description B-3 25 CLAYSTONE Time to Failure (min) ( Average Rate of Strain to Failure (%/min)(�� Shear Strength Unconfined Compressive Strength (psf) o Strain at Failure (%) 88 ;? 97 Specimen No. Sample Condition Type Initial Sample Dia. (mm) Initial Height (mm) Initial Height to Diameter Ratio Initial Water Content (%) Initial Dry Unit Wt. (pct Initial Saturation (%) Initial Void Ratio Specific Gravity (Assumed) Passingis #200 PL PI 1 Intact 48 5 101.9 2.1:1 23.6 87.6 NM NM 2.65 NM NM NM NM Testing performed in general accordance with ASTM 02166 NP = Nonplastic NM = Not Measured KL \Naime- PROJECT NO.: 20201380.001A DRAWN BY CHECKED BY: CAW DATE: 9/10/2019 UNCONFINED STRENGTH COMPRESSIVE FIGURE B-11 I E/NFEL People. DER MAP / TJN Td -State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright Right Solutions. 11 000 10 000 9.000 C U) a. 8.000 cn 0 w i- 7,000 co > iii 6.000 w a a 2 5,000 O U 0 w z 4,000 I Z O Li Z 3,000 m 2,000 1.000 \\I 2 4 6 8 10 AXIAL STRAIN (%) Exploration ID Depth (ft.) Sample Description 8-4 20 CLAYSTONE Time to Failure (min) Average Rate of Strain to Failure (%/min) Shear Strength (psf) Unconfined Compressive Strength (psf) Strain at Failure (%) 5.8 5024 10048 6.9 Specimen No. Sample Condition Type Initial Sample Dia. (mm) Initial Height (mm) Initial Height to Diameter Ratio Initial Water Content (%) Initial 1 Dry Unit Wt. (pcf) Initial Saturation (%) Initial Void Ratio Specific Gravity (Assumed) Passing #200 LL PL PI 1 Intact 48.8 101.6 2.1.1 29 1 B ^ NM NM 2 65 NM NM NM NM Testing performed in general accordance with ASTM D2166. NP = Nonplastic NM = Not Measured KL PROJECTNO.: 20201380.001A DRAWN BY: CHECKED BY CAW DATE: UNCONFINED STRENGTH COMPRESSIVE FIGURE B-12 E/NFEL People. DER MAP / TJN 9/10/2019 Tri-State: Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County, Colorado Bright '."- Right Solutions. 11,000 10,000 9,000 U) a. 8.000 U Cl) w F- 7.000 w > rn 6.000 Cl) w it a 2 5.000 O U 0 w 4,000 Z Z O z 3 000 D 2.000 1,000 0 al\\1111 2 4 6 8 10 AXIAL STRAIN (°%) Exploration ID Depth (ft.) Sample Description B -S 20 CLAYSTONE Time to Failure (min) Average Rate of Strain to Failure (%/min) Shear Strength (psf) Unconfined Compressive Strength (psf) Strain at Failure (%) 5.0 ' ' .. _ �c,a . _ c SpecNo.imen Sample Condition Type Initial SampDia.le (mm) Initial Height (mm) Initial D ameteHeight � Ratio Initial Water Content (%) Initial UnDit yVt. (PO Initial Saturation (%) Initial Void Ratio Specific Gravity (Assumed) P#200 9 a PL PI 1 Intact 48.8 103.9 2.1 1 25.8 89 4 NM NM 2 F NM NM NM NM Testing performed in general accordance with ASTM D2166 NP = Nonplastic NM = Not Measured PROJECT NO. 20201380.001A DRAWN BY CHECKED BY CAW DATE 9/10/2019 UNCONFINED COMPRESSIVE STRENGTH FIGURE B-13 KL E/NFEL People. DER MAP r TAN Tn-State Lloyd Sisson Substation Northwest Corner of CR 130 and CR 71 Weld County. Colorado Bright �_ Right Solutions. KL E/NFEL DER Bight People. RIM So t.ont APPENDIX C ELECTRICAL RESISTIVITY TESTING 201201380.001 A/DEN 19R 101024 September 13, 2019 © 2019 Kleinfelder www.kleinfelder.com KL E/NEEL DER Bright People. Right Solutions. 1801 California Street. Suite 1100 Denver. CO 80202 Tel: (303) 237-6601 Fax: (303) 237-6602 Project Number Project Name Client 220201380 Lloyd Sisson Substation Tn-State Date and Time Location Test Engineer(s) 9/12/2019 RES 1 DH & TJN Type of Test Weather Surface Conditions 4 -Point Test (Wenner) Sunny Windy, 60° Grass and Silty Sand Equipment Make Model Checked by AGI Super Sting R1 CAW Probe Spacing "A" (feet! Probe depth "B" (inched Apparent Resistance (0) Apparent Resistivity p (D -m) Notes: North - South 2 4&2 11.72 44.89 3 4 & 2 9.885 56.79 5 4 & 2 8.441 80.83 7 4 & 2 6.873 92.14 10 4 & 2 6.593 126.26 20 4 & 2 4.189 160.45 30 12 & 6 2.603 149.55 40 12 & 6 1.526 116.90 50 12 & 6 0.751 71.91 70 12 & 6 0.2179 29.21 100 12 & 6 0.08179 15.66 200 12 & 6 0.02637 10.10 300 12 & 6 0.01824 10.48 500 12 & 6 0.01209 11.58 East - West 2 4 & 2 15.8 60.52 3 4 & 2 12.95 74.40 5 4 & 2 11.95 114.43 7 4&2 10.59 141.97 10 4 & 2 9.533 182.57 20 4 & 2 5.524 211.58 30 12 & 6 3.027 173.91 40 12 & 6 1.659 127.09 50 12 & 6 0.8975 85.94 70 12 & 6 0.2996 40.16 100 12 & 6 0.1122 21.49 200 12 & 6 0.02754 10.55 300 12 & 6 0.01866 10.72 500 12 & 6 0.01251 11.98 Notes: KLE/NFELDER DER Bore swag tot S&ut wn APPENDIX D IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT 201201380.001A/DEN19R101024 September 13. 2019 © 2019 Kleinfelder www.kleinfelder.com Important Information about This Geotechnical-Engineering Report Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you — assumedly a client representative — interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer. Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk -confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil - works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical- engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one - not even you - should apply this report for any purpose or project except the one originally contemplated. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full. You Need to Inform Your Geotechnical Engineer about Change Your geotechnical engineer considered unique, project -specific factors when designing the study behind this report and developing the confirmation -dependent recommendations the report conveys. A few typical factors include: • the client's goals, objectives, budget, schedule, and risk -management preferences; • the general nature of the structure involved, its size, configuration, and performance criteria; • the structure's location and orientation on the site; and • other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities. Typical changes that could erode the reliability of this report include those that affect: • the site's size or shape; • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light -industrial plant to a refrigerated warehouse; • the elevation, configuration, location, orientation, or weight of the proposed structure; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project changes - even minor ones - and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. This Report May Not Be Reliable Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, that it could be unwise to rely on a geotechnical-engineering report whose reliability may have been affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an `apply -by" date on the report, ask what it should be, and, in general, if you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying it. A minor amount of additional testing or analysis - if any is required at all - could prevent major problems. Most of the "Findings" Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site's subsurface through various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing were performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgment to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ - maybe significantly - from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team from project start to project finish, so the individual can provide informed guidance quickly, whenever needed. I r This Report's Recommendations Are Confirmation -Dependent The recommendations included in this report - including any options or alternatives - are confirmation -dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgment and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions revealed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation - dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals' misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a full-time member of the design team, to: • confer with other design -team members, • help develop specifications, • review pertinent elements of other design professionals' plans and specifications, and • be on hand quickly whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction observation. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated -subsurface -conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you've included the material for informational purposes only. To avoid misunderstanding, you may also want to note that "informational purposes" means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report, but they may rely on the factual data relative to the specific times, locations, and depths/elevations referenced. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled "limitations, many of these provisions indicate where geotechnical engineers' responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study - e.g., a "phase -one" or "phase -two" environmental site assessment - differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical- engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk -management guidance. As a general rule, do not rely on an environmental report prepared for a different client, site, or project, or that is more than six months old. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, none of the engineer's services were designed, conducted, or intended to prevent uncontrolled migration of moisture - including water vapor - from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material -performance deficiencies. Accordingly, proper implementation of the geotechnical engineer's recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building -envelope or mold specialists on the design team. Geotechnical engineers are not building - envelope or mold specialists. GEOPROFESSIONAL GEL IS BUSINESS ASSOCIATION Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org Copyright 2016 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA's specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent Hello