The URL can be used to link to this page

Browse Search

Home My WebLink About20194017.tiffUSE BY SPECIAL REVIEW (USR) APPLICATION North Weld Landfill, Unit 2 Weld County, Colorado Prepared By: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 Prepared For: Waste Management Disposal Services of Colorado, Inc. North Weld Landfill 40000 Weld County Road 25 Ault, CO 80610 December 21, 2016 1538880 Golder Associates Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation December 2016 1538880 Table of Contents 1.0 2.0 2.A 2.B 2.C 2.D 2.E 2.F 2.G 2.H 2.1 2.J 2.K 2.L 2.M 2.N 2.N.1 2.N.2 2.N.3 2. N .4 2.N .5 2.O 2.P 2.O 2.R 3.0 3.A 3.B 3.C 3.D 3.E 3.F USE BY SPECIAL REVIEW APPLICATION FORM I DETAILED DESCRIPTION OF THE PROPOSED OPERATION AND USE 3 Proposed Use 3 N eed for Use 4 Types of Existing Uses on Surrounding Properties 4 Distance of Proposed Use to Residential Structures in Each Direction 4 Maximum Number of Users, Patrons, Members, and Buyers 5 N umber of Employees, Number of Shifts, and Hours of Operation 5 Type of Water Source for Proposed Use 5 Access Route to be Utilized for Proposed Use 5 Type, Size, Weight, and Frequency of Vehicular Traffic Associated with Proposed Use 6 Type of Sewage Facilities for Proposed Use 6 Description of Proposed Fire Protection Measures Associated with Proposed Use 6 Types and Maximum Number of Animals to be Concentrated on the USR Area 7 Type and Size of Any Waste, Stockpile, or Storage Areas Associated with Proposed Use 7 Type of Storm Water Retention Facilities Associated with Proposed Use 8 General Concept 8 Variance Request 8 Run-on Diversion 9 Temporary Surface Water Management 9 Runoff Control and Management 9 Time Schedule and Method of Removal and Disposal of Debris, Junk, and Other Wastes Associated with Proposed Use 9 Proposed Landscaping Plans and Erosion Control Measures Associated with Proposed Use 10 Reclamation Procedures to be Employed upon Cessation of U S R Activity 10 Time Table Showing Periods of Time Required for Construction and Start-up of Proposed Use 11 WRITTEN MATERIALS AND SUPPORTING DOCUMENTS 12 Statement Demonstrating Need for Facility Within Proposed Area of Service 12 Statement Explaining How Proposal is Consistent with Weld County Code, Chapter 22 12 Statement Explaining How Proposal is Consistent with Intent of District in which Use is Located 13 Statement Explaining What Efforts Have Been Made, in the Location Decision for the Proposed U se, to Conserve Productive Agricultural Land in the Agricultural Zone District 13 State Explaining There is Adequate Provision for the Protection of the Health, Safety►, and Welfare of Inhabitants of the Neighborhood and County 13 Statement Explaining the Uses Permitted Will be Compatible with Existing Surrounding Land Uses 13 i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwif unit 2 usr 21 decl6.docx Golder Associates December 2016 ii 1538880 3.G Statement Explaining Proposed Use will be Compatible with Future Development of Surrounding Area as Permitted by Existing Zone and with Future Development as Projected by the Comprehensive Plan of the County or Adopted Master Plans of Affected Municipalities 14 3.H Statement Explaining USR Area is not Located in Flood Plain, Geologic Hazard, and Weld County Airport Overlay District Area 14 3.1 Proof that Water Supply will be Available which is Adequate in Terms of Quantity, Quality, and Dependability 14 3.J Copy of Deed or Legal Instrument Identifying Applicant Interest in Property Under Consideration 14 3.K Noise Report 14 31 L Soils Report 15 3.M Affidavit and Certified List of Names, Addresses, and Corresponding Parcel Identification Numbers of Owners of Property Within 500 feet of Property Being Considered 15 3.N Drainage Report 15 3.O Traffic Study 15 3.P Waste Handling Plan 15 3.Q Dust Abatement Plan 15 3.R Flood Hazard Development Permit 15 3.S Geologic Hazard Development Permit 15 List of Figures Figure 1 Figure 2 Figure 3 Figure 1 Figure 2 Figure 3 Site Vicinity Map (11 x 17) Site Plan with Unit 2 Subgrade Topography (11 x 17) Site Plan with Site -wide Final Cover Topography (11 x 17) Site Vicinity Map (22 x 34) Site Plan with Unit 2 Subgrade Topography (22 x 34) Site Plan with Site -wide Final Cover Topography (22 x 34) List of Appendices Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Statement of Water Supply Property Deed NRCS Custom Soils Resource Report Affidavit of Interested Land Owners Surface Estate Drainage Report Transportation Impact Study Dust Abatement Plan (excerpted from EDOP) Waste Handling Plan (excerpted from EDOP) i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.dacx Golder Associates SOLID WASTE DISPOSAL SITES USE BY SPECIAL REVIEW APPLICATION Department of Planning Services 1555 N 17th Ave Greeley CO 80631 Phone (970) 353-6100 x3540 Fax (970) 304-6498 FOR PLANNING DEPARTMENT USE RECEIPT # /AMOUNT # f$ APPLICATION RECEIVED BY DATE RECEIVED: CASE # ASSIGNED: PLANNER ASSIGNED: Parcel Number 0707-07-0-00-008, 0707-07-0-00-009, and 0707-07-0-00-045 (12 digit number - found on Tax I.D. information, obtainable at the Weld County Assessor's Office, or www.co.weld.co.us) (Include all lots being included in the application area. If additional space is required, attach an additional sheet) TO BE COMPLETED BY APPLICANT: (please print or type, except for necessary signature). I (we), the undersigned, hereby request a hearing before the Weld County Planning Commission and Weld County Board of County Commissioners concerning the proposed Use by Special Review Permit on the following described unincorporated area of Weld County, Colorado: Parts of the SW 1/4, NW1/41 SE 114, and NE 1/4 LEGAL DESCRIPTION OF SPECIAL REVIEW PERMIT AREA: (see warranty deeds for exceptions) Section 7 T 7 N, R 66W. LEGAL DESCRIPTION of contiguous property owned which Special Review Permit is proposed: Section T N, R W. Property Address (if available) 40000 County Road 25 Weld, CO 80610 PRESENT ZONE Ag OVERLAY ZONES none TOTAL ACREAGE 490 PROPOSED LAND USE Solid waste disposal EXISTING LAND USE Solid waste disposal and cropland SURFACE FEE f PROPERTY OWNERS) OF AREA PROPOSED FOR THE USE BY SPECIAL REVIEW PERMIT: Name: Waste Management Disposal Services of Colorado Inc. Address: 40000 County Road 25 City: Ault Home Telephone: Business Telephone: 970-686-2800 Zip: 80610 Name: Address: City: Zip: Home Telephone: Business Telephone: APPLICANT OR AUTHORIZED AGENT (if different than above): Name: Address: City: - Zip: Home Telephone: Business Telephone: List the owner(s) and/or lessees of mineral rights on or under the subject properties of record. Name: Anadarko Land Corp. Address: PO Box 173779 City: Denver Zip: 80217 I hereby depose and state under the 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 knowledge. Signature: Owner or A. . ized Agent 10 , ;-r-.: c T pl AIN+► g-- December 2016 3 1538880 2.0 DETAILED DESCRIPTION OF THE PROPOSED OPERATION AND USE 2.A Proposed Use The North Weld Landfill (NWLF) is located at 40,000 Weld County Road 25 near the intersection of Weld County Road 25 and Colorado State Highway 14 (co-signed with Weld County Road 82) within unincorporated Weld County (the County), Colorado. The site is approximately nine miles east of Interstate Highway 25 (1-25) and five miles west of the Town of Ault. NWLF is owned and operated by Waste Management Disposal Services of Colorado, Inc. (WMDSC). Waste Services Corporation (later merged with Waste Management, Inc.) received a Certificate of Designation (CD) from the Weld County Board of County Commissioners on June 27, 1990, authorizing the development of the first four phases of NWLF (Phases 1, 2, 3A, and BB), which provide approximately 122 acres of waste disposal area. This disposal area is referred to as Unit 1. A USR permit (USR-895) for solid waste disposal within Unit 1 was adopted by the Weld County Board of County Commissioners on November 14, 1990. The remaining permitted disposal capacity in Unit 1 is projected to be consumed by 2021. WMDSC is proposing to further develop the NWLF site by adding an additional 155 acres of waste disposal area, hereinafter referred to as Unit 2. The Unit 2 waste disposal footprint will be contiguous to the north of the existing Unit 1 waste disposal footprint and will piggyback over the existing northern side slope of the Unit 1 waste disposal area. The waste disposal footprint of Unit 2 maintains the minimum offset of 175 feet from the property boundary. The development of Unit 2 at the NWLF site will allow for existing site facilities and infrastructure to remain and continue to support the operation of the facility. No additional structures, sanitary systems, or lighting is anticipated as part of the Unit 2 development unless additional site infrastructure is necessary to meet future site needs. WMDSC will continue to own and maintain approximately 185 acres of adjacent buffer property surrounding the Unit 1 and Unit 2 waste disposal areas. The Unit 2 waste disposal area will be designed, constructed, and maintained with engineered containment systems that meet current Colorado Department of Public Health and Environment (CDPHE) Regulations, including the same liner system previously approved by CDPHE and WCDPHE and constructed for the Unit 1 waste disposal area, a composite liner with a high -density polyethylene (HDPE) geomembrane below permanent leachate collection system sumps, and a water balance final cover. Unit 2 will consist of two primary waste disposal phases; these phases will be further subdivided into modules to limit the area of exposed liner and active waste disposal area open at one time. Module development is expected to proceed from west to east with temporary leachate collection sumps constructed at the downgradient (i.e., east) end of modules until ultimate build -out of each phase when permanent leachate collection sumps will be constructed along the eastern boundary of each phase. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 4 1538880 Removal of leachate from leachate collection sumps (both temporary and permanent) will be performed on an as needed basis with the typical leachate management strategy to apply the leachate within the constructed waste disposal limits (i.e., within lined areas of the landfill) to manage fugitive dust. 2.B Need for Use NWLF has served the Northern Front Range Service Area (NFRSA), which includes the cities, towns, and surrounding rural communities of Central and Northern Weld and Eastern Larimer Counties in Colorado and Southern Laramie County in Wyoming, since 1992. The remaining permitted disposal capacity in Unit 1 is projected to be consumed by 2021. Further development of the NWLF site is necessary to continue to meet the solid waste disposal needs of the NFRSA that are currently met by the facility. 2.C Types of Existing Uses on Surrounding Properties NWLF is located in a rural area of unincorporated Weld County. The surrounding properties are primarily zoned agricultural and are used for crop production, with the exception of the Pierce Lateral agricultural canal located immediately to the east, the Belmont Farms residential subdivision located across Colorado State Highway 14 to the southwest, and the Waste Management of Northern Colorado commercial trucking facility (U SR -1627) located immediately northwest of the NWLF site. A number of feedlots and dairy operations are located within two miles of the facility, but all are topographically down slope to the site. 2.0 Distance of Proposed Use to Residential Structures in Each Direction The approximate locations of residential structures located near the NWLF site are shown in Figure 1 and are summarized below (based on aerial imagery): • The Belmont Farms subdivision is located to the southwest of the NWLF site, in the southwest corner of the intersection of Colorado State Highway 14 and Weld County Road 25. The Unit 2 waste disposal footprint will be located more than 0.6 miles from the nearest residential structure within the Belmont Farms subdivision. • A residential structure is located approximately 0.6 miles to the west-southwest of the Unit 2 waste disposal footprint, north of Colorado State Highway 14. • A residential structure is located approximately one mile to the north of the Unit 2 waste disposal footprint, east of Weld County Road 25. • A residential structure is located approximately 0.7 miles to the east -northwest of the Unit 2 waste disposal footprint, east of Weld County Road 27. • A residential structure is located approximately 0.3 miles to the east of the Unit 2 waste disposal footprint, west of Weld County Road 27. • A residential structure is located approximately 0.6 miles to the southeast of the Unit 2 waste disposal footprint, north of Colorado State Highway 14. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 5 1538880 2.E Maximum Number of Users, Patrons, Members, and Buyers The number of customers expected to visit the NWLF facility will depend on market conditions. At this time, the development of Unit 2 is not expected to result in significant differences in the number of people using the site from the current usage. As the service area and surrounding population grows, it is anticipated that the activity level of the facility will increase in similar proportion. The largest category of people using the site on a daily basis are drivers of commercial trucks and other non-commercial customers accessing the site for disposing waste loads and recyclables, which entails checking in at the scale house, unloading the waste or recyclable material in the designated management area, and exiting the site. The number of vehicles bringing waste/recyclable material to the site varies based on seasonal factors, event -based disposal projects, and other factors. Over recent years, waste deliveries have typically ranged between 250 to 500 vehicles per day, although usage has at times and may continue to be outside of this range. 2.F Number of Employees, Number of Shifts, and Hours of Operation Personnel needs at the NWLF facility varies depending on incoming waste volumes as well as other variables. The facility► currently employs a site manager, operations specialist, two scale attendants, five equipment operators, two mechanics, a laborer/spotter, a part-time facility engineer, and a part-time operations manager. Similar staffing levels are anticipated for the operation of Unit 2, generally ranging between 12 and 20 employees. Outsourced laborers will be assigned at the facility for various projects and site maintenance on an as needed basis. No shift work is proposed, although employee start and end times, as well as workdays, may be staggered in order to adequately staff the operating day. The hours of operation of NWLF vary seasonally but generally range from 6:00 a.m. to 6:00 p.m. Monday through Saturday. The facility also periodically operates on Sundays as needed. Hours are subject to change to accommodate operational needs and may be extended to accommodate increased residential and commercial waste volume, clean-up projects, special waste contracts, or other operational variables. Standard hours of operation and all changes in standard operational hours are posted at the entrance to the NWLF site. 2.G Type of Water Source rce for Proposed Use The NWLF site is on the North Weld County Water District municipal water supply network. A letter from the North Weld County Water District documenting their continuing water supply is provided in Appendix A. 2.H Access Route to be Utilized for Proposed Use The NWLF site is accessed via an existing access point from Weld County Road 25 approximately 200 feet north of the intersection of Colorado State Highway 14. Right- and left -turn deceleration and acceleration lanes i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 6 1538880 were constructed along Highway 14 prior to the development of Unit 1 at the NWLF site. NWLF has a special use permit from the Colorado Department of Transportation (CDOT) to allow use of a street sweeper to remove any deposits of soil material on Highway 14 on an as -needed basis. No additional site access infrastructure beyond maintenance of existing roadways and access lanes is anticipated as part of the development of Unit 2. 2.1 Type, Size, Weight, and Frequency of Vehicular Traffic Associated with P roposed Use The largest category of people using the site on a daily basis are drivers of commercial trucks and other non-commercial customers accessing the site for disposing waste loads and recyclables. Historically, the highest traffic volumes have been between 10:00 a.m. and 3:00 p.m. Traffic counts representative of operations at NWLF Unit 1 are provided below: T y pe/Size of Vehicle Typical Per Roundtrips Day Passenger Cars/Pickup Trucks 20-100 Tandem Trucks 200-350 Semi -trucks 30-100 2.J Type of Sewage Facilities for Proposed Use There are currently three permitted septic systems at the NWLF site that are used for management of on -site sewage from the office, shop, and scale house. The existing septic system permit numbers are as follows: • Office: G-19900260 • Shop: G-19920178 • Scale house: SP -0900136 Unless an additional scale house is necessary to meet future site needs, no additional septic systems are anticipated as part of the development of Unit 2. Although originally designed to be managed through the shop septic system, process water from the facility wash pad is segregated and used for dust abatement within the lined limits of the landfill, as permitted. 2.K Description of Proposed Fire Protection Measures Associated with P roposed Use The office, scale house, and maintenance buildings are equipped with suitable fire extinguishers for suppression of any minor fires and for personnel safety. Fire protection for landfill equipment and vehicles is provided by i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 7 1538880 portable fire extinguishers attached to each piece of equipment, vehicle, or machinery and/or automatic fire suppression systems. Operational practices will limit the risk of fire in the landfill. Waste deliveries to the landfill will be checked in accordance with the Waste Identification Plan provided in Appendix H. No burning of waste is permitted at NWLF. Vehicles containing burning materials that would otherwise be accepted at the facility are directed to an inspection area where the vehicle driver can safely extinguish the fire. The vehicle is then directed to an isolated disposal area on site where the individual load can be safely unloaded from the vehicle and inspected by facility personnel. In this manner, NWLF is able to confirm that no burning material remains in the disposed waste. In order to manage accumulation of wind-blown tumbleweeds and prevent them from becoming a nuisance condition, NWLF has received permission from the CDPHE and the Weld County Department of Public Health and Environment (WCDPHE) to burn weeds that have accumulated along internal fence lines and wind screens. NWLF will obtain a case -by -case burn permit from WCDPHE, in consultation with the local fire protection district, and comply with weed -burning restrictions typically in effect within the agricultural district of Weld County. Additional fire protection coverage is available from the Windsor —Severance Fire District via telephone communication. 21L Types and Maximum Number o►f Animals to be Concentrated on the USR Area Not applicable; no animals will be kept or contained at the NWLF site. 21N11 Type and Size o►f Any Waste, Stockpile, or Storage Areas Associated with Proposed Use This USR application is requesting to permit an additional waste disposal unit at the NWLF site. NWLF is a non -hazardous, municipal solid waste landfill (MSWLF) facility that accepts household, municipal, commercial, and industrial solid wastes, as approved. No regulated hazardous wastes, regulated radioactive wastes, or regulated polychlorinated biphenyls (PCB) are accepted by the facility. WMDSC has implemented rigorous waste identification and acceptance programs at NWLF, which are presented in detail in the Waste Identification Plan provided in Appendix H. The purpose of the Waste Identification Plan is to provide procedures to identify and screen wastes, specifically those that may require special handling, to ensure that no regulated hazardous wastes, regulated radioactive wastes, or regulated PCB wastes are accepted at the NW LF facility. Current storage of petroleum and other products for vehicle/equipment maintenance (e.g., diesel fuel, gasoline, lubricants, anti -freeze) in and/or around the maintenance shop is expected to continue. A Spill i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 8 1538880 Prevention, Control, and Countermeasure (SPCC) Plan has been prepared and implemented for the management of the petroleum products. A vehicle/equipment parts storage area is also maintained within the shop. Temporary storage is expected to continue to be provided for customer roll -off containers, Port -0 -Lets, and similar support equipment/containers to the waste industry. Stockpiles of excavated soil will be strategically situated in undeveloped areas of the site, either within future waste limits where stockpiled material may be utilized prior to development or within areas surrounding the ultimate development footprint. 2.N Type of Storm Water Retention Facilities Associated with Proposed Use 2.N.1 Genera! Concept The general concept for management of stormwater for Unit 2 of NWLF will be to divert run-on and manage runoff completely separate from existing Unit 1 stormwater management structures and return flow to historic drainage patterns, to the extent practical. The Unit 2 stormwater management system is briefly summarized herein. Peak flows from the 100 -year, 24 -hour storm event were used to size permanent run-on and runoff channels with one foot (minimum) freeboard. Additional design criteria and details of the stormwater management system are discussed in the Drainage Report provided in Appendix E. 2.14.2 Variance Request As discussed in Section 2.C, the NWLF site is geographically bounded by the manmade Pierce Lateral agricultural canal to the east and by the Colorado State Highway 14 right-of-way to the south. During the development of Unit 1 at the NWLF site, these neighboring property owners informed WMDSC that they were not amenable to receiving discharge from stormwater detention on the NWLF site. Consequently, the CDPHE and the WCDPHE approved the conversion of the previously -designed Unit 1 detention basin to a retention basin. WMDSC re -approached the Pierce Lateral Board of Directors on November 15, 2016, to update them on the Unit 2 development plans and re -gauge their willingness to accept detention discharge from the Unit 2 development. The Board of Directors communicated that they are not interested in receiving any discharge from the NWLF site. A letter from the Pierce Lateral's attorney summarizing their position is included in the Drainage Report provided in Appendix E. Additionally, the concerns CDOT raised in their letter to the NWLF dated August 9, 2000, about detention discharge to the State Highway 14 right-of-way are still applicable to and limit the discharge options from Unit 2 detention. Consequently, WMDSC is again requesting a variance from Article XII, Section 23-12-30, Part D of the Weld County Code to allow on -site retention rather than detention of site runoff; the formal request is presented in the Drainage Report provided in Appendix E. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 9 1538880 2.N.3 bun -on Diversion Surface water run-on from site areas up -gradient of Unit 2 will be diverted around the waste disposal footprint through the construction of a run-on stormwater control channel along the western and northern toe of the landfill perimeter berm. The run-on control channel will concentrate the sheet flow around the waste disposal footprint and then return it to sheet flow through a permanent riprap-lined dissipation basin in the northeast corner of the NWLF site where it will naturally infiltrate into site soils consistent with current drainage patterns. Run-on flow from up -gradient areas will not be allowed to mix with on -site stormwater runoff from the landfill. 2.N.4 Temporary Surface Water Management Surface water within the active landfill will be managed through a series of temporary berms and/or channels that will divert run-on away from the active area and direct runoff toward temporary surface water ponds or the permanent stormwater retention pond. Surface water runoff that is not contact water may be managed via gravity drainage or pumping for use on -site and/or to the stormwater retention pond. 214.5 Runoff Control and Management Permanent surface water structures and erosion control measures will be constructed over the life of Unit 2 to limit stormwater run-on and mange runoff. Perimeter channels adjacent to the waste footprint, bench channels, a downchute channel, and access road grading will be used to control runoff from intermediate - and final -covered areas of Unit 2. All surface water runoff from the landfill is designed to be collected and conveyed to a new stormwater retention pond for Unit 2 runoff to be located southeast of the Unit 2 footprint. The stormwater retention pond will provide up to 77 acre-feet of storage capacity below 1 foot of freeboard (greater than 1.5 times the 24 -hour, 100 -year storm runoff volume from Unit 2), is designed to drain through the pond bottom in less than 72 hours, and includes an emergency spillway capable of conveying the peak discharge from Unit 2 resulting from the 100 -year, 1 -hour storm in accordance with Weld County Code requirements. 2.0 Time Schedule and Method of Removal and Disposal of Debris, Junk, and Other Wastes Associated with Proposed Use This USR application is requesting to permit an additional waste disposal unit at the NWLF site; NWLF is a non -hazardous, MSWLF facility where household, municipal, commercial, and industrial solid wastes are disposed. The Unit 2 waste disposal area will be designed, constructed, and maintained with engineered containment systems that meet current CDPHE Regulations and that reasonably ensure protection of human health and the environment. The CDPHE permitting process for solid waste disposal facilities requires the development and approval of a detailed Engineering Design and Operations Plan (EDOP) that summarizes the engineering design and specifies operational requirements for the facility. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 10 1538880 WMDSC has implemented rigorous waste identification and acceptance programs at NWLF, which are presented in detail in the Waste Identification Plan provided in Appendix H. The purpose of the Waste Identification Plan is to provide procedures to identify and screen wastes, specifically those that may require special handling, to ensure that no regulated hazardous wastes, regulated radioactive wastes, or regulated PCB wastes are accepted at the NWLF facility. If any of these regulated wastes are identified in incoming waste loads, the material is rejected by the facility and will be managed as required by CDPHE Regulations. 2.P Proposed Landscaping Plans and Erosion Control Measures Associated with Proposed Use Screening for the NWLF site is currently provided along the Colorado State Highway 14 by an earthen screening berm and landscaping; maintenance of the screening berm and landscaping will continue through the operation of the Unit 2 waste disposal area. Since Unit 2 is located immediately north of Unit 1, the existing Unit 1 landform will further screen Unit 2 operations from the Highway 14 corridor. Erosion of final cover soils due to rainfall will be mitigated through the grading and construction of stormwater bench channels spaced at approximately 60 -foot intervals (vertically) on the sideslopes of the final waste mass landform. The Construction Quality Assurance (CQA) Plan for the NWLF facility outlines requirements for site construction, including seeding and mulching requirements developed specifically for the site area. 2.O Reclamation Procedures to be Employed upon Cessation of USR Activity A Closure and Post -closure Plan that discusses the design of the final cover and the notifications, schedule, and procedures to be implemented upon closure of the NWLF facility is provided in the EDOP for Unit 2. Final closure activities will include installation of an alternative water balance final cover over any remaining uncapped area(s) of the landfill in accordance with CDPHE guidance and may include removal of site buildings/infrastructure (including fuel tanks), grading disturbed areas to restore pre -development drainage patterns (where practical), and revegetation of all disturbed areas. It is the intent of NWLF to place an environmental covenant (EC) on the property once the facility is closed or develop a Post -closure Care Plan consistent with CDPHE policy on ending post -closure care. The purpose of the EC or post -closure care plan will be to ensure protection of human health and the environment by minimizing the potential for exposure to solid waste that remains in the landfill following closure. This objective will be accomplished by prohibiting those activities that may interfere with the landfill cover or its monitoring or control systems, and by creating a review and approval process to ensure that any such intrusive activities are conducted with appropriate precautions to avoid or eliminate hazards. Following closure, the landfill will most likely serve as open space or some other end use strategy that is protective of human health and the environment for the long term. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.dacx Golder Associates December 2016 11 1538880 .2.R Time Table Showing Periods of Time Required for Construction and Start-up of Proposed Use As discussed in Section 2.A, the NWLF is an existing MSWLF facility currently operating under USR-895. WMDSC plans to further develop the NWLF site by adding the 155 -acre Unit 2 waste disposal area, thus allowing for existing site facilities and infrastructure to remain and continue to support the operation of the facility and continue to meet community needs in the area. As discussed under Section 2.B, the remaining permitted disposal capacity in Unit 1 is projected to be consumed by 2021. Following approval of this USR application by Weld County, WMDSC anticipates that the commencement of the development of Unit 2 (i.e., construction of first waste disposal module) will occur at such time that additional capacity is projected to be required. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.dacx Golder Associates December 2016 12 1538880 3.0 WRITTEN MATERIALS AND SUPPORTING DOCUMENTS 3.A Statement Demonstrating Need for Facility Within Proposed Area of Service NWLF serves the NFRSA, which includes the cities, towns, and surrounding rural communities of Central and Northern Weld and Eastern Larimer Counties in Colorado and Southern Laramie County in Wyoming, since 1992. The remaining permitted disposal capacity in Unit 1 is projected to be consumed by 2021. Further development of the NWLF site is necessary to continue to meet the solid waste disposal needs of the NFRSA that are currently met by the facility. 3.B Statement Explaining How Proposal is Consistent with Weld County Code, Chapter 22 The development of Unit 2 at NWLF will be consistent with the following Goals and Policies set forth in Weld County Code, Chapter 22: ■ A.Goal 1: Respect and encourage the continuation of agricultural land uses and agricultural operations for purposes which enhance the economic health and sustainability of agriculture. • Undeveloped areas of Unit 2 are expected to remain under agricultural production, similar to past management practices during the operation of Unit 1, until such time that development of the land is necessary. ■ A.Goal 4 and UC.Goal 4: Promote a quality environment which is free of derelict vehicles, refuse, lifter, and other unsightly materials. • NW LF fulfills a critical component of northern Weld County's solid waste management needs by providing a dedicated, secure, and environmentally protective regional disposal facility for household, municipal, commercial, and industrial solid wastes while ensuring the long-term protection of public health and the environment. ■ A Goal 8: Ensure that adequate services and facilities are currently available or reasonably obtained to accommodate the requested new land use change for more intensive development. • The development of Unit 2 at the NWLF facility will allow for existing site facilities and infrastructure that were constructed to support the operation of Unit 1 to remain and continue to support the facility. ■ TPD.Goal 2: All facilities in the County which handle, collect, or process waste should maintain an active role in solid waste management resource recovery of such waste. • WMDSC is committed to extending the life of the NWLF facility as long as possible by recycling, proper separation of materials, and effective compaction of waste. Recycling bins are present for glass, newspaper, aluminum, tin, plastic, and cardboard, and appliances and electronic waste (e -waste) are segregated from the waste stream for recycling. ■ F.Goal 1: All final disposal facilities in the County will locate, develop, and operate in a manner that minimizes interference with other agricultural uses, rural settlement patterns, and existing residential communities. • WMDSC owns a total of approximately 490 acres at the NW LF site. The development of Unit 2 at the NWLF facility will minimize additional interference and/or impacts to County agricultural uses by avoiding the land use change of additional agricultural i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 13 1538880 properties within the County for waste disposal purposes. WMDSC DSC is mindful of potential impacts of the continued operation of the NWLF site to its neighboring properties. The lands adjacent to the proposed Unit 2 development are primarily cropland. The closest residential properties are located approximately 0.3 miles to the east and 0.6 miles to the southwest and west of the proposed Unit 2 development footprint. Potential visual impacts are expected to be minimal due to the development of Unit 2 being screened from public view along the Colorado State Highway 14 corridor by the existing Unit 1 landform. Additionally, the closure design for NW LF site ensures that the facility will be left in a condition of good aesthetic appearance with consistent grading to blend with the surrounding topography and without visible differentiation between Units 1 and 2. 3.C Statement Explaining How Proposal is Consistent with Intent of District in which Use is Located The NW LF site is located in an Agricultural Zone District. A solid waste disposal site and/or facility is defined as an acceptable Use by Special Review in an Agricultural Zone District in Section 23-3-40 of the Weld County Code. 3.D Statement Explaining What Efforts Have Been Made, in the Location Decision for the Proposed Use, to Conserve Productive Agricultural Land in the Agricultural Zone District As discussed in Section 3.B, undeveloped areas of Unit 2 are expected to remain under agricultural production, similar to past management practices during the operation of Unit 1, until such time that development of the land is necessary. 3.E State Explaining There is Adequate Provision for the Protection of the Health, Safety, and Welfare of Inhabitants of the Neighborhood and County The development of Unit 2 at NWLF will be regulated under Sections 2 and 3 of the CDPHE "Regulations Pertaining to Solid Waste Sites and Facilities," 6 CCR 1007-2, Part 1 as amended November 17, 2015 (adopted date of Regulations). The CDPHE permitting process for solid waste disposal facilities requires the development and approval of a detailed Engineering Design and Operations Plan (EDOP) that summarizes the engineering design and specifies operational requirements for the facility. Additionally, NWLF regularly monitors site groundwater and landfill gas concentrations at the property boundary in accordance with CDPHE-approved monitoring plans. 3.F Statement Explaining the Uses Permitted Will be Compatible with Existing Surrounding Land Uses The NWLF facility currently contains approximately 122 acres of waste disposal area; Unit 2 will add an additional 155 acres. As discussed in Section 2.C, NWLF is located in rural unincorporated Weld County and the surrounding areas are primarily zoned agricultural and are used for crop production. The final closure design for the NW LF facility includes final slopes that are designed to blend with the surrounding topography. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 14 1538880 3.G Statement Explaining Proposed Use will be Compatible with Future Development of Surrounding Area as Permitted by Existing Zone and with Future Development as Projected by the Comprehensive Plan of the County or Adopted Master Plans of Affected Municipalities As discussed in Section 2.C, NWLF is located in rural unincorporated Weld County and the surrounding areas are primarily zoned agricultural and are used for crop production. The proposed development will not inhibit the ongoing agricultural uses in the surrounding areas. Following the pre -application review meeting for this USR application, the WMDSC corresponded with the Town of Severance and met with the Town of Ault regarding potential parcel annexation; however, no interest in annexation or concerns were expressed by either municipality. 3.H Statement Explaining USR Area is not Located in Flood Plain, Geologic Hazard, and Weld County Airport Overlay District Area The NWLF site is not located within a FEMA regulatory floodplain, area of regulated geologic hazard, or Weld County Airport overlay district area. The nearest regulated areas are as follows: ■ Nearest FEMA regulatory floodplain: Zone A 100 -year floodplain located approximately 300 feet (at its closest) to the northeast -east of the NWLF site along the Coalbank Creek drainage area. ■ Nearest regulated geologic hazard area (ground subsidence hazard area): Located near Firestone, Colorado, approximately 33 miles to the southwest of the NWLF site. ■ Greeley —Weld County Airport: Located approximately 13 miles from the NWLF site. 3.1 Proof that Water Supply will be Available which is Adequate in Terms of Quantity, Quality, and Dependability The NWLF site is on the North Weld County Water District municipal water supply network. A letter from the North Weld County Water District documenting their continuing water supply is provided in Appendix A. 3.J Copy of Deed or Legal Instrument Identifying Applicant Interest in Property Under Consideration A copy of the warranty deed to the NWLF property is provided in Appendix B. 3.K Noise Report The development of Unit 2 at NWLF will be a continuation of ongoing operations at the NWLF site. Through 25 years of operations of Unit 1 at the NWLF site, no noise complaints or concerns have been raised or received. As a result, this requirement was waived by the Department of Planning Services. i:115\153888th040010405 usr permit fnl dec1611538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates December 2016 15 1538880 3.L Soils Report The Natural Resources Conservation Service (NRCS) Custom Soils Resource Report for Weld County, Colorado, Southern Part is provided in Appendix C. 3.M Affidavit and Certified List of Names, Addresses, and Corresponding Parcel Identification Numbers of owners of Property Within 500 feet of Property Being Considered The Solid Waste Disposal Sites Affidavit of Interest Owners Surface Estate and a list of the addresses, property owner, and parcel identification numbers within 500 feet of the NWLF property are provided in Appendix D. 3.N Drainage Report The Drainage Report is provided in Appendix E. 3.O Traffic Study The Transportation Impact Study is provided in Appendix F. 3.P Waste Handling Plan WMDSC has implemented rigorous waste identification, acceptance, and handling programs at NWLF, which are provided in the facility EDOP; applicable provisions are excerpted in Appendix H. 3.O Dust Abatement Plan The Dust Abatement Plan for the NWLF facility is provided in the facility EDOP; applicable provisions are excerpted in Appendix G. 3.R Flood Hazard Development Permit The NWLF site is not located within a FE MA regulatory floodplain; therefore, a Flood Hazard Development Permit is not required. 3.S Geologic Hazard Development Permit The NWLF site is not located within an area of regulated geologic hazard; therefore, a Geologic Hazard Development Permit is not required. i:\1511538880104OO\O405 usr permit fnl dec16\1538880 rpt-fnl nwlf unit 2 usr 21 decl6.docx Golder Associates w a September I I , 201S Weld County Department of Planning 1555 North 17th Street Greeley, CO 80631 RE: North Weld Landfill, Waste Management Disposal Services of Colorado, Inc, WASTE MANAGEMENT 221 S. Mitt Ave.,, Ste 333 Tempe, AZ 85281 This letter shall serve as documentation that William J. Hedberg, in his capacity as Sr. District Manager, is authorized to sign applications and permits for the conduct of business for Waste Management Disposal Services of Colorado, Inc., doing business as North Weld Landfill, in Weld County, Colorado. Respectfully suited, Scott A. Bradley Area Vice President Four Corners Area D 4.4-1- C 0-4_ ase-c.. - t 1# to to 3 o 3- O 0 0 O 0 V a -KZ (i Ai. i cceii Art , g.ec % ! — U I.,'-=" LailetI 3 old La, 4 +P st om' r1 4� loco° 09 recc ^�� t US+GS 7 5 TOPOGRAPHIC QUADRANGLE, SEVERANCE, CO LEGEND - ON -SITE SOILS-+QINEY FINE SANDY LOAM, 3 TO 5 PERCENT SLOPES (NRCS) Ohl -SITE SOILS-OLNEY FINE SANDY LOAM, 1 TO 3 PERCENT SLOPES (MRCS) JPROPERTY BOUNDARY EXISTING ROADS EXISTING STREAMS AND IRRIGATION CHANNELS HALF MILE RADIUS FROM SITE LOCATION OF RESIDENTIAL STRUCTURES WITHIN VILE OF SITE ....r •- ---- 'Ns C) 7 Di c.-. r d(4. r* it war- Pr., IP t, i' 231 pLxer-c eadieffr yi, note, ic 4 7000 40130 (Sn e vut4urtii •sr 20ao.FEET FIGURES I- F"- .ti c .1, • LL L G 4- PJ R� s L ,T n A:. r - U. 414 f. r c a: 4- S: c r i(- h S : 7 r'• DEVELOPMENT STANDARDS: 'tie'SZWELD COUN—Y' ROAD 25 4Iw} l,'F f1 COUNTY .4/" 1 Roan $d 1 , t • -, > '�_.r' r 1 I —y ,'.,;. _...' USR 1527 S I I L UOUNUAHY 4>. '• _ _. WELD COUNTY HOAD 25 - U, T COSIAIL NIG-V/AY14 j BELMONT =ARMS SUBDIVISION LEGEND O ON-SI I L SOILS - OLNLY IN_ SANDY LOAM, 3 I 0 5 PLKCLN I SLOPLS ;NKCSI ON-SITF 5O11 $ - UI NFY =IN= SMIDV I OAM. 1 TO PFRGFNT SI OPF$ INRG$j PROPERT-1 BOUNDARY EXISTING ROADS EXISTING STREAMS AND IRR GATION CHANNELS HALT MILL RADIUS I ROM SIIL LOCATION OF RESIDENTIAL STRUCTURES WITHIN) MILE OF SITE A 2C16-12-21 ISSUED FO4 WELD COUNTY USK DVS DVS .RR !:'E'.1 REV. YYYY-MM•DD DESCRIPTION EDE2IGNED PREPARED RE':'IE4'QED APPROVE D LJS(S 7.5' TOPOGRAPHIC QUADRANGLE. SEVERANCE. CO. U 23O1 1" = 20O0' Ion FEET CLILNI WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC_ CONS.LII TANT OS. COLDER. ASSOCIATES INC. 4-1 UNION BLVD. SUITE 3OC LAKEWOOD. CD USA -1 (31133) 980 11.5.13 awt',.golder.a m USE BY SPECIAL REVIEW LJSR 16-XXXX WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. FOR: NORTH WELD LANDFILL SECTION 7, TOWNSHIP 7 NORTH, RANGE 66 WEST OF THE SIXTH PRINCIPAL MERIDIAN, COUNTY OF WELD, STATE OF COLORADO LEGAL DESCRIPTION: PARTS OF 5'W 114: N'iV' 1!$, SE 114: AND NE 1:4 OF SEC —ION 7, TOWNSHIP 7 NORTH, RANCE fin' WEST OF —HE 6TH P.M. SEE WARRANTY DEEDS FOR EXCEPTIONS. PROPERTY OWNER'S APPROVAL: THE UNDERSIGNED MAJOR PROPERTY OWNER DOES HEREBY AGREE TO THIS SITE SPECIFIC ULVLLOPMLN I P_AN ANU I IL USL BY SF'LCIAL KLi+IL41' ULVLLC*'MLN I S I ANUANUS AS ULSCIiI JLD HLIZLON I S JAY 0 . 2C. WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. PLANNING COMMISSION CERTIFICATE; THIS IS TOCER-IFY THAT TI -E WELD CDLNTY PLANNING COMMISSION HAS CERT1F ED. AN) DOES HEREBY RECOMMEND TO THE BOARD DF COUNTY COMMISSIONERS. WELD COUNTY. COLONAUO. 1O14 I ILIR CONI IRMAIION. APPROVAL ANU ADOP ION II IIS SI I L SI LCII IC ULVLLOPMLN I P_AN AANU UCL LiY SI?LCIALRLVILWAS SHCPA'N ANU ULSCRI13LU HLI4CN I HIS r AY C)F , ?1 CHAIR: WELD COUNTY P_ANNINC COMISSION BOARD OF COUNTY COMMISSIONERS CERTIFICATION: THIS IS TOCER-IFY THAT TI -E BOARD OF COUNTY COMM SSIONERS, WELD CO.JNTY, COLORADO. DOES HEREBY CONFIRM AND ADOPT THIS SITE SPECIFIC DEVELOPMENT PLAN AND JSE BY SPECIAL REVIEW AND DEVELOPMENT STANDARDS AS SHOWN AND DESCRIBED I IERON THIS DAY OF . 2.3 . CH1111i, 601 1.140 01 COUNI Y COMMISSIONLIiS AII_S.I: WELD COUNTv CLERK OF THE BOARD UY: U_F'U 1Y CLLIRK I I HL DOAN.° UA I LO: P RU•J_C I NORTH WELD LANDFILL, UNIT 2 USE BY SPECIAL REVIEW - USR XXXX WELD COUNTY, COLORADO TITI F SITE VICINITY MAP PROJECT NO. 1538880 REV. 1 of3 A SHEET I 11 1" =3[k'P 300 !J� 1 f+ QJ4MFR: IAI{,:H/tiFI .J • '▪ . DISSIPATIOM;$A DRAIN.tC$.'1A.. MJ E.L.6 L.6 STORIsti r / 1r 7. iJARTER CORNIER $EC. 7. N R'6 JV FEET CWaMER: k9IYFi42.-C12Ef of • T IDE :'!EST???Ti A RSA ROWER . HORIT1' EA`,Ek1EN C;'MJFFE: knII;.HAFt .I ._fit-,_• k11.(atRY "0 FT.RCI.A.. WELD CCL'FJT`f. ROAD V ;379 FT EACH SIDE- OF SECTION LINE. OOK St PAGE 273 - I CANNk'InRKK.-FAIA.1;1)9NTF —Rif& I• MCA TWA' FSTCON kl -SEC. 7. T7M )! JMFP: DA,VF-Ft} AJEF 7 • O11?NLH: LA -Mt' U"73tt A -k -N I :t IL'1L fi I ION 1iL,H-fi t A LYNN SCI INLILILH _ SCJLEHOIJSE A 2C16-12-21 ISSUED FUR WELD COUNTY USR DVS DVS JAR E REV. YYYY-MM•D0 DESCRIPTION DE•`=IGNED PREPARED REG APPROVED EXISTI NG UNIT TORMINAT RETENTION POND f1 1(42.2 A I mss• Flr-lis1Te CE I FYIJTIMCa . J(cCRS FRCAA I(715Y: Wt) F!Dct SIh IL IIGI IWAY 14 1l;COIC`i4(4, PAGE .IEFi CI IV ciF THORNTON r 1 i r FR: DRAKE FAMILY kPRTMFRSFIP ROW STATE HIGHWAN 11 iBO )K 1-1 1. =PAGE -197i .f i� f i • 1 :`suIJTH CIJARTFR COR'JFR SF . 7, T7M, PE6'JV Li iN�F!'.iJr:NMI$ E DRAKE L. UFI <F 1=d4'MFF!: PRAKF Fr+6'II V PARTY FR.;?H IP USE BY SPECIAL REVIEW USR 16-XXXX WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. FOR: NORTH WELD LANDFILL SECTION 7, TOWNSHIP 7 NORTH, RANGE 66 WEST OF THE SIXTH PRINCIPAL MERIDIAN, COUNTY OF WELD, STATE OF COLORADO .fie, LEGEND I OW STATE HIGHWAY 11 iBCiOK 1-133, PAGE:)3: (ii FIJT,JRF -COMMFYAM;:= TO HAIJO 17FPr•RTh'1FMT RANIEP('RT1TI(j' TR . E GATE rC)L1TH'.:E:;T FORMER -` .—BE" 7. T7M, RrePti 17YJhER: 'A'ST LLP. Iy.IVNER: HH INC. {lINNER: A.K>, I:1 BRAGDON \ LXISI ING I OPCGRAPIIY (SLL NO I L$ 1, 2. AM) J) 5281- PROPOSED LINER SUOC;RADE - - - PR:lFRTY ROIIh1DARY ---- USR 1527 BOJNJARV FXISTING UNIT I I IMIT OF WASTF X EXISTING FENCE PROPOSED FENCE JNII 2 PLKIMLILKCIIANNL_ UNIT 2 Rl1N-ON DI:IFRSION CHANNFI EXISTING IRRICAT Oh DITCH TW-f I^. NOTES EXISTING RIGHT-OF-WAY LINE PC) I LN I IAL I U I UKL CONVLYANCL EXIST NO ROADS PKOPDSLU FLKIMLILK ROAD S OPF INDICATOR I I:RAINAGF Fl OW) TRAFF C CIRCUiITION EX STING BUILDINGS;APPROX. SIZEj EXISTING MON TORINE WELL LDGATION LIYPORARY'WLLL _OVAI ION FXISTING C;AS PRORF I OC.ATION PROPOSED GAS PROBE LOCATION IAPPROX MATE) EXISTING TOPOGRAPHY S A COMPOSITE OF AEROMETRIC IhC. PHOTOGRAPHY DATED JANJARY26. 20'2 AND MILLER CREEK AERIAL MAPPINC PHOTOGRAPHY DATED I LUHUA-Y 21, 21:15. 2. EXISTING CONTOUR INT=RVA_ IS 2 FEET BASED ON NAVDF.R ELEVATIONS. CL ILN I WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC_ CONS UI TANT GOLDER ASSOCIATES INC. 4-1 UNION BLVD, SUITE 3OC• LAKEWOOD, CD USA -1 (2,D3) 980 6510 weII'.9.galder.com COORDINATE SYSTEM IS N NAD27 STATE PLANE COLORADO NORTH. E+KUJLOI NORTH WELD LANDFILL, UNIT 2 USE BY SPECIAL REVIEW - USR XXXX WELD COUNTY, COLORADO TITLE SITE PLAN WITH SUBGRADE TOPOGRAPHY PROJECT NO. 1538880 REV. A 2 o 3 SHEET 2 C IY LL LL LL U. 4 1 II U. s w LL I- S 0: a r- JE T U. C. L' LL IL IT I:. U. v x I - U. • 4 300 (300 1"- 31.Ii' r OWNER: MICH4EL J MC ' (rr I D ISi'.IPATIi iJ; U4 URA!NAG E:'JJ 40 BI J.;II... Q �;TC.RAG��hR` I \CRTJACIIJAR-ER 11ORNEP. f'' SEC. 7. T7FJy FW1.'4 C.1 14rR: TAKE' RyA'IE1 RP _ OWNER: IAICF-L EL =�'-__ _C 5111; ELD (;oUFar II RCAD ?i 30 FT EACH $ID.E y:F T=EcTIOM LINE. BOCG< 24.0. IrA•' E 273 ()AMER: PA %IA I.flN I L TRGS- N NoRT-I':•I E `T-CORNEr? ZEE. 7, T7N, R.14 FFFT r (j4VNEtl3A+-.ryj.I{.E �.'. FT.'J11IDE':.'E$TE j AREA PO41'ER HORITY EA3EI_1EFJT OWNER: LARRY D. JD I1311---- r,r ..r T4-.'--VE 1 F� �'. J • .� �`lt IT 2 1WA ENT N BU IL' AGE AR �� y5 UV FR ER: Lr'�RR.'F-L7-DEFY' 1'3= - ' J / 1 1 • tJELDCOLJNTv 'DAt. 25 E • 'TIf,.T LINE. BOOK P -E2 a — �t':,'-Ti1E_R RI ....'C",A LWIUk $ JHIUEIDER - . \ ti, `"iC l.-ItHOVSF m'd :rFl ai A 2C16-12-21 ISSUED FUR WELD COUNTY USR DVS DVS JAR REV. YYYY-MM-DD DESCRIPTION DE•`5IGNED PREPARED R=C .4FPROVED �1 EXISTING UNIT 'I I TORMWAT RETENTION POND (42.2 AG_' I:laV-5I r LY.I I ING I:1FIA1TF1•ISI''F {/`,CLSSIIOM Hbvt±r I 7O(il- ,F1, - / 'c J / fir RUA, STATE I IIGI ILVAY 1-I {6JC31C `r77, PAGE 41Q;1 'N ER: CI I Y OF THOR NTON -7- --r" -- wet- lr - L OWNER:DRAKE FAMILY PARTNE7SHIP ER' DRAKE FAI: ILY PAN INERr'HIP Rae? STATE HIEIH'WA' 11 {BOOK 117+1. PAGE li .% ./C CZ'- Jam. E JHAYE 12u I HcJr'.- Lr?':Crl'.NLU PICA. N. r,se�.�r FJ R.'DLKINLS F BRAKE CJ':: STATE HICHY.'AY 14 ;'(BcROK 14,V,. PAGE P:',"! - POTENT L3L FLJTJRE - --C-OMVEYAMCETO7 • I1ADO DEP1LPTMENT or, RAMS PORTATIO'J 85 rif FrEt 11 CE ;ATE EST CORNER L'E; 7; T7N. RCIr5V C!iJNER:'r>,'LT LLF, _CJAIkRE: I -H GROUP INO. L',4VVER-GARY'% kl BRAGJON \ CL ILN I WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC_ COKSIJI TAMT GOLDER ASSOCIATES INC. 1-1 UNION BLVD. SUITE 300 LAKEWOOD, CO USA -1 1323, 980 0510 ua".u.galder.com USE BY SPECIAL REVIEW USR 16-XXXX WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. FOR: NORTH WELD LANDFILL SECTION 7, TOWNSHIP 7 NORTH, RANGE 66 WEST OF THE SIXTH PRINCIPAL MERIDIAN: COUNTY OF WELD: STATE OF COLORADO LEGEND FXISTINC,TOPOGRAPHY I;$FF NO -F$ 1: 2, AND 31 x230- PROPO$FD FIN,AI CI Q$L,RF GRADES - PRQPFRTY RD.JNDARY" - LSR 1x27 BOLNDARY FXISTING I IMlTOF WASTF (UNIT 1) PROPOSED LIA'I-OF WASTE (UN I-2) LJCISI ING I LNCL PROPOSED FENCE -C UNIT I -ERRACE GI IANNEL LNIT 1 PFRIMFTFR CHAMNFI UNIT 2 BENCH CHANNEL IJNII 2 -1LKIML I LRC-ANNLL UNIT 2 RUN-ON DIVERSION CHANNE_ EX STING IRRIGATION DITCH _XISIING KIGI I I -CI -YJAY LIPL POTFNTIAI FIJTIIRF TROPFRTYCON:+FYANCF EXISTING ROADS PROPOSED PCRIMETC z AND ACCESS ROADS p MW -9 TW-D8 NOTES SLOPE INDICATOR (DRAINAGE FLOW) TRAFFIC CIRCULATION EXISTING BUILDINGS (APPROX. SIZEI EX STING MONITORINC WELL LC)CA—ION TEMPORARY WELL LOCATION FXISTING c3A$ PZQSF I (CATION 'ROPOSEDGAS PROBE LOCATION {APPROXIMATE) EXISTING TOPOGRAPHY IS AC0-MIPOSITE OF AEROMETRIC INC. PHOTOGRAPHY JATEO JANUARY26. 2012 AND MILLER CREEK AERIAL GAPPING PHOTOGRAPHY DATED I L3HUARY 21, 22115 2. EXISTING; CONTOUR INTERVAL IS2 FEET BASED ON NAVDR3 ELEVATIONS. 3. COORDINATE SYSTEM IS II\ NAD27 STATE PLANE COLORADO VURTII. HKUJL(..:I NORTH WELD LANDFILL, UNIT 2 USE BY SPECIAL REVIEW - USR XXXX WELD COUNTY, COLORADO TITLE SITE PLAN WITH FINAL COVER TOPOGRAPHY PROJECT NO. 1538880 A 3af3 FIGURE 3 APPENDIX E DRAINAGE REPORT DRAINAGE REPORT North Weld Landfill, Unit 2 Weld County, Colorado 1 Prepared By: Golder Associates Inc. 4730 N. Oracle, Suite 210 Tucson, AZ 85705 Prepared For: Waste Management Disposal Services of Colorado, Inc. North Weld Landfill 40000 Weld County Road 25 Ault, CO 80610 December 21, 2016 1538880 Golder Associates Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation December 2016 1538880 Table of Contents 1.0 CERTIFICATION OF COMPLIANCE 1 2.0 INTRODUCTION 2 3.0 GENERAL LOCATION AND DESCRIPTION 3 3.1 Location 3 3.2 Site History 3 3.3 Description of Property 4 3.4 Description of Project 4 3.4.1 Existing Stormwater Controls for Unit 1 4 3.4.2 Development of Unit 2 5 4.0 DRAINAGE BASINS AND SUB -BASINS 6 4.1 Major Basin Description 6 4.2 Sub -basin Description 6 4.2.1 Run-on Basins 6 4.2.2 Runoff Basins 6 5.0 DRAINAGE DESIGN CRITERIA 7 5.1 Development Criteria Reference and Constraints 7 5.2 Hydrologic Criteria 7 5.3 Hydraulic Criteria 8 6.0 DRAINAGE FACILITY DESIGN 9 6.1 General Concept 9 6.2 Specific Design Details and Compliance with Weld County Code 10 6.2.1 Temporary Surface Water Management 10 6.2.2 Final Stormwater Management System 10 6.2.2.1 Run-on Diversion 10 6.2.2.2 Runoff Control 10 6.2.2.3 Stormwater Retention 11 7.0 CONCLUSIONS 14 7.1 Compliance with Weld County Code 14 7.2 Drainage Concept 14 8.0 REFERENCES 15 i:115\153888O O4M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 ii 1538880 List of Tables Table 1 Table 2 NWLF Site Design Storm Events Open Channel Summary List of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Title Sheet Historic Drainage Basin Run-on Map Fully Developed Drainage Basin Map Final Grading and Stormwater Management Plan, Unit 2 Stormwater Management System Details (1 of 2) Stormwater Management System Details (2 of 2) List of Appendices Appendix A Unit 2 Surface Water Run-on and Runoff Controls Calculations Appendix B Unit Al Surface Water Calculations i:\151153888010400\0404 edop fn! dec161appendix d_drainage report\app d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 1 1538880 1.0 CERTIFICATION OF COMPLIANCE The Weld County Certification of Compliance is included on the following page. As discussed in this Drainage Report, Waste Management Disposal Services of Colorado, Inc. (WMDSC) is requesting a variance from Article XII, Section 23-12-30, Part D of the Weld County Code to allow on -site retention rather than detention of site runoff. A letter from the Pierce Lateral's attorney supporting this request is attached to the Certification of Compliance. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates CERTIFICATION OF COMPLIANCE ENGINEERING DESIGNED TO WELD COUNTY CODE STANDARDS AND CRITERIA Jeffrey Rusch , Consultant Engineer for Waste Management Disposal Services of Colorado, Inc. ("Applicant"), understand and acknowledge that Applicant is seeking land use approval of North Weld Landfill, Unit 2 ("Application") for the property described in the attached Exhibit "A." I have designed or reviewed the design ("Design") for the proposed land use set forth in the Application. I hereby certify, on behalf of Applicant that the Design will meet all applicable drainage requirements of the Weld County Code with the exception of variance(s) described below. This certification is not a guarantee or warranty either expressed or implied. (Engineer's Stamp) Engineer,cord Signature VARIANCE REQUEST 1) Describe the Weld County Code criteria of which a variance is being requested. 2) Describe why it is not possible to meet the Weld County Code. 3) Describe the proposed alternative with engineering rational which supports the intent of the Weld County Code. 1) Requesting variance from Article XII, Section 23-12-30, Part D to allow on -site retention rather than detention of site runoff. 2) The NWLF site is geographically bounded by the manmade Pierce Lateral agricultural canal to the east and the Colorado State Highway 14 right-of-way to the south. During the development of Unit 1 at the NWLF site, these neighboring property owners informed WMDSC that were not amenable to receiving discharge from stormwater detention on the NWLF site. Consequently, the CDPHE and the WCDPHE approved the construction of a retention basin at the NWLF site to manage surface water runoff from the Unit 1 landform. Recently, WMDSC re -approached the Pierce Lateral Board of Directors on November 15, 2016, to update them on the Unit 2 development plans and re -gauge their willingness to accept detention discharge from the Unit 2 develo-pment. The Board of Directors communicated that they are not interested in receiving any discharge from. the NWLF site. A letter from the Pierce Lateral's attorney summarizing their position is provided in this Drainage Report. Additionally, the concerns CDOT raised in their letter to NWLF dated August 9, 2000 about detention discharge to the State Highway 14 right-of- way are still applicable to and limit discharge options from Unit 2 detention. 3) The proposed stormwater management system for the Unit 2 development includes a new stormwater retention pond for Unit 2 runoff. The new stormwater retention pond will provide up to 77 acre-feet of storage capacity below 1 foot of freeboard (greater than 1.5 times the 24 -hour, 100 -year runoff volume from Unit 2), is designed to drain through the pond bottom in less than 72 hours, and includes an emergency spillway capable of conveying the peak discharge from Unit 2 resulting from the 100 year, 1 hour storm in_accordance with Weld County Code requirements for retention facilities (Article XII, Section 23-12-90, Part B). I understand properties and and agree the public. that I the understand intention if of this the Code is to variance request reduce is impacts of development approved it is not precedent on neighboring setting and downstream is based on site specific constraints. Planning Director Approval indicated when signed by director or appointee: Planning Director Name Signature 3 Date of approval 1/13/15 irai WILLIAM R. FISCHER MARGARET A. (Meg) BROWN DANIEL K. BROWN BRENT k BARTLETT LISA A. LARSEN SARA J.L. IRBY DONALD E. FRICK ISCHER, BROWN, BARTLETT 1111, ATTORNEYS AT LAW 1319 East Prospect Road Fort Collins, CO 80525 f PC WARD H. FISCHER (1929-1996) WILLIAM H. BROWN (Of Counsel) WILLIAM C. GUNN (Of Counsel) Phone: 970/107.9000 Fax: 970.407.1 055 E-mail: fbg@fbgpc.com Website: www.fhbglaw.com June 5, 2017 Waste Management Bill Hedberg, Senior District Manager Tom Schweitzer 40000 CR 25 Ault, CO 80610 SENT VIA EMAIL AND CERTIFIED MAIL, RE: Expansion of North Weld Landfill and Impact on Pierce Lateral Dear Mr. Hedberg and Mr. Schweitzer: Please be advised that Fischer, Brown, Bartlett & Gunn, P.C. represents the Pierce Lateral Ditch Company (the "Company"). I have been asked to respond on the Company's behalf concerning Waste Management's proposal to expand the North Weld Landfill, which is located adjacent to the Pierce Lateral (the "Ditch"). It is my understanding that representatives of the Pierce Lateral Company met with you and your project consultant on November 15, 2016 to discuss Waste Management's proposed project for adding additional landfill space north of the present facility. The main purpose of the meeting was to discuss the potential impact the expansion of the landfill would have on future storm water runoff into and near the Ditch, and to discuss ways to prevent any damage to the Ditch or injury to the Company's shareholders. As discussed, the typical method of handling storm water discharge involves using a detention pond and releasing the water at specified flow rates in accordance with design standards set forth in the Weld County Code. Alternatively, storm water runoff may be managed and held in a storm water retention structure through a variance from Weld County. Use of a retention pond is how storm water from the existing landfill was addressed in order to protect the Ditch. Under Colorado law, a property owner cannot unilaterally alter historical drainage patterns and drainage structures on the property without permission from the structure owners, including ditch companies, and down -gradient landowners. Specifically, "natural drainage conditions can be altered by an upper [landowner] provided the water is not sent down in a manner or quantity to do more harm than formerly." Hankins v. Borland, 431 P.2d 1007 (Colo. 1967)(Emphasis added). Further, pursuant to Weld County's drainage laws, "use of irrigation ditches for collection and transport of either initial or major storm runoff should be prohibited unless specifically provided in the Weld County master plans or approved byCounty Weld and the ditch owner."' (Article XL Storm Drainage Criteria, Chapter 1, Section 5.5.1). The Company is under no duty to begin accepting storm water from the expanded Landfill, which has the g off of of potential changing the timing, location, and amount of storm water flowing the Landfill in to nto the Ditch, and, which, may be of a quality that could compromise the shareholders' water. The Pierce Lateral is obligated to protect the Ditch, its shareholders, and the public from any harm or injury resulting from use of the Ditch. Notwithstanding the foregoing, the Company's Board of Directors has discussed Waste Management's project and the options presented for preventing storm water from running into the Ditch. Based on initial discussions with you and the Board's review of very reliminar r drawings, the Company supports Waste Management's alternative approach of capturing storm p water in a retention pond, so lonz as no storm water or other runoff from the expanded landfill flows directly into the Ditch and/or is discharged from the pond into the Ditch. The Company's acceptance of the alternative plan is conditioned upon Waste Management's plans and specifications confirming that the timing, location, amount and quality of water that historically into nto the Ditch is not altered in a way to cause harm to the Ditch or the Company's shareholders. To that end, as Waste Management's project moves forward and plans are developed for the proposed pond, the Company requests that its engineers are given the opportunity to review the plans, and that the Company is put on notice and receives copies of such documentation to ensure that the Ditch is protected. me. Thank you. Should you have any questions or concerns, please do not hesitate to contact Regards, Sara J .L. Irby December 2016 2 1538880 2.0 INTRODUCTION This Drainage Report is prepared on behalf of the applicant, WMDSC, in support of a Weld County Use by Special Review (USR) permit application for Unit 2 of the North Weld Landfill (NWLF). The design of the stormwater drainage controls presented herein satisfies applicable design criteria set forth by Section 23, Article XII of the Weld County Code and by Colorado Department of Public Health and Environment (CDPHE) "Regulations Pertaining to Solid Waste Sites and Facilities," 6 CCR 1007-2, Part 1 (Regulations) (CDPHE 2015). WMDSC is proposing to develop Unit 2 of the NWLF facility, which will add an additional 155 acres of waste disposal area to the existing 122 -acre waste disposal footprint at the site, hereinafter referred to as Unit 1. WMDSC owns a total of approximately► 490 acres at the NWLF site, currently consisting of the Unit 1 waste disposal footprint, a Waste Management of Northern Colorado facility (WMNC) permitted under Weld County USR 1527, and adjoining buffer property. The Unit 2 waste disposal area will be located directly north of and contiguous to the existing Unit 1 waste disposal footprint in land that is currently undeveloped and leased for agricultural dry land farming. The current facility infrastructure and support facilities in place for Unit 1 are envisioned to continue to serve the development and operation of Unit 2. No additional site access or operational infrastructure beyond maintenance of existing roadways and access lanes is anticipated as part of the development of Unit 2. Currently, impervious areas of the site comprise approximately 87,500 square feet of paved parking areas and roads. All stormwater runoff from impervious areas and facility structures is and will continue to be managed through existing Unit 1 stormwater management infrastructure. Following closure, the landfill will most likely serve as open space or some other end use strategy that is protective of human health and the environment for the long term; the final disposition of impervious areas and site structures will be determined in conjunction with the development of the end use and post -closure care plan. i:115\15388801040M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 3 1538880 3.0 GENERAL LOCATION AND DESCRIPTION 3.1 Location The NWLF is located at 40,000 Weld County Road 25, near the intersection of Weld County Road 25 and Colorado State Highway 14 (co-signed with Weld County Road 82) within unincorporated Weld County, Colorado. The site is approximately nine miles east of Interstate Highway 25 (1-25) and 5 miles west of the Town of Ault. The Unit 1 and Unit 2 waste disposal areas at NWLF are located in Section 7, Township 7 North, Range 66 West of the Sixth Principal Meridian. Accessibility to NWLF from primary municipalities served by the facility is from Colorado State Highway 14. The property, project site, and surrounding land are zoned (A) Agricultural, and are located in unincorporated Weld County. The site is in an urbanizing area pursuant to the Weld County Code as it is located within 0.25 miles of the annexed Belmont Farms subdivision by the Town of Severance. There are no lakes, streams, or water resource facilities within the property. The NWLF property is bounded by the manmade Pierce Lateral agricultural canal to the east. Existing site access to the NWLF site is from Weld County Road 25 approximately 200 feet north of the intersection of Colorado State Highway 14. No changes or additional infrastructure to the existing site access is anticipated as part of the development of Unit 2. 3.2 Site History Waste Services Corporation received a Certificate of Designation (CD) from the Weld County Board of County Commissioners on June 27, 1990, authorizing the development of the first four phases of NWLF (Unit 1, comprising Phases 1, 2, 3A, and 3B), which provided approximately 122 acres of waste disposal area. A USR permit (USR-895) for solid waste disposal within Unit 1 was adopted by the Weld County Board of County Commissioners on November 14, 1990. Construction of the first disposal module of Unit 1 was completed in December 1991. Site civil improvements were completed in January 1992 and NWLF first received waste on February 3, 1992. Waste Services Corporation merged with an indirect subsidiary of Waste Management, Inc. on July 12, 1991, and changed its name to WMDSC in December 1993. WMDSC continues to be an indirect subsidiary of Waste Management, Inc. In 2006, WMNC allocated approximately 28 acres in the northwest quarter of Section 7, Township 7 North, Range 66 West as a separate USR (USR-1527) for an administrative and maintenance facility for their commercial trucking operations. The CD and USR boundaries for the expanded NWLF facility will exclude the limits of USR-1527. i:115\15388801040M0404 edop fnl dec161appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 4 1538880 3.3 Description of Property The NWLF site is approximately 490 acres in size and is owned by WMDSC. The site is topographically characterized as an upland area of relatively uniform slope toward the regional drainage feature (i.e., Coalbank Creek bed) located approximately 0.25 miles east of the NWLF property boundary. The area of the NWLF property where Unit 2 will be developed is topographically bounded by the Weld County Road 25 embankment to the west, a man-made stormwater runoff channel constructed along the USR-1527 boundary to the northwest, the Weld County Road 84 embankment to the north, the man-made Pierce Lateral agricultural canal to the east, and Unit 1 to the south. Natural, pre -development topographic elevations within the Unit 2 area of the NWLF site range from a high of approximately 5,150 feet above mean sea level (ft AMSL) in the southwestern portion of the site to a low of 5,068 ft AMSL near the Pierce Lateral canal to the east. The existing topography within the Unit 2 area is crossed by a few very shallow drainage swales none of which include perennial surface water flow features. The total natural topographic relief across the Unit 2 area is approximately 80 feet, with natural topographic slopes between 1% and 5% and averaging approximately 1.5% to the east. The United States Department of Agriculture (USDA) National Resources Conservation Service (NRCS) designates the surficial soil types at the NWLF site as predominantly Olney fine sandy loam (NRCS 2016) at varying slopes between 1% and 5%. Olney fine sandy loam soils are classified under Hydrologic Soil Group B and are generally well drained with moderately low runoff potential, and moderately► high to high capacity to transmit water. The Custom Soil Resource Report for Weld County, Colorado, Southern Part is provided in Appendix A. 3.4 Description of Project 144 Existing stormwater Controls for Unit I The existing stormwater management system design for Unit 1 is presented in the Updated Design and Operations (D&O) Plan for the North Weld Sanitary Landfill originally prepared by Rust Environment & Infrastructure, Inc. in January 1996 and later revised by WMDSC in November 1997. The hydrologic and hydraulic calculations have been subsequently revised several times to better accommodate site conditions. Design calculations for the stormwater controls for Unit 1 are provided in Appendix D of this Drainage Report to allow this report to encompass stormwater management for the full NWLF site. Surface water runoff from final closure landfill slopes within Unit 1 and the surrounding run-on areas is collected by permanent perimeter channels and conveyed to a retention pond located in the southeastern corner of the property. The original stormwater management system for Unit 1 included a detention pond with an outlet structure. However, due to concern by the Colorado Department of Transportation (CDOT) regarding discharge of stormwater onto the Colorado State Highway 14 right-of-way, CPDHE requested i:115\15388801040M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 5 1538880 that the detention pond be converted to a retention pond. The modifications to the pond design to allow for stormwater retention are also provided in Appendix D of this Drainage Report for reference. 14.2 Development of Unit 2 The Unit 2 waste disposal area of the NW LF facility will consist of approximately 155 acres of waste disposal footprint located directly north of and contiguous to the existing Unit 1 waste disposal footprint. The waste disposal footprint of Unit 2 includes a minimum offset of 175 feet from the property boundary. The proposed development of Unit 2 will include the 155 -acre landfill, perimeter access roads, stormwater run-on control structures, temporary and permanent stormwater runoff structures, and an approximate 64 -acre stormwater retention pond along the western property boundary. The stormwater controls for Unit 2 were designed to manage the runoff from Unit 2 completely separate from the existing Unit 1 structures. Unit 2 will consist of two primary waste disposal phases, identified as Phases 4 and 5 and shown in Sheet 3 of the Site Development Plans provided in Appendix A of the EDOP. These phases will be further subdivided into modules to limit the area of exposed liner and active waste disposal area open at one time. Run-on and runoff controls will be established and maintained throughout the operation of each phase and module. Module development is expected to proceed from west to east with temporary► leachate collection sumps constructed at the downgradient (i.e., east) end of modules until ultimate build -out of each phase when permanent leachate collection sumps will be constructed along the eastern boundary of each phase. Wherever a module development area will terminate internal to the landfill footprint (i.e., not along the final perimeter), a temporary termination berm will be constructed along the leading edge for containment of waste and leachate and to facilitate tie-in of future cells. Phased construction will progress in this manner until the entire landfill footprint is developed. This method of phased development will limit the amount of active (open) cell area at any given point in the landfill development, minimize leachate generation, and minimize the area requiring stormwater management. i:115\15388801040M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 6 1538880 4.0 DRAINAGE BASINS AND SUB -BASINS 4.1 Major Basin Description As previously discussed, the NWLF is located in a rural area of unincorporated Weld County. The surrounding area is generally used for agricultural farming, including feedlot and dairy operations. Historically►, the average natural slope from northwest to southeast was approximately 3%. The site is situated near a topographic high, such that it receives very little if any surface water run-on from off -site locations. Under current conditions, regional surface water is collected in small reservoirs and deflation basins for agricultural use and distribution through a network of manmade canals. The NWLF site is bounded by the Pierce Lateral agricultural canal, which flows to the south along on the eastern boundary of the NWLF and to the south side of Colorado State Highway 14. The NWLF site is not located within a floodplain or flood hazard area defined by the Federal Emergency Management Agency (FE MA 2016). The nearest FEMA-mapped floodplain is a Zone A 100 -year floodplain located approximately 300 feet (at its closest) to the northeast -east of the site along the Coalbank Creek drainage area. 4.2 Sub -basin Description 4.2.1 Run-on Basins Historically and to the present day, existing stormwater flows across the Unit 2 footprint in a southeasterly direction following existing topographic features. Run-on basins up -gradient of the NWLF waste disposal footprint are bounded by the Weld County Road 25 embankment along the western property boundary, the Weld County Road 84 embankment along the northern property boundary, and a man-made stormwater runoff channel constructed along the boundary of U R-1527 to the northwest. These up -gradient basins are characterized by shallow sheet flow that impact the NWLF waste disposal footprint at several locations along the western and northern boundaries. Sub -basins for the run-on stormwater control design were delineated based on existing topography and ultimate buildout of Unit 2 (conservatively including runoff from the USR-1527 property) and are shown in Figure 2. 4.2.2 Runoff Basins Sub -basins for final closure stormwater management were delineated based on the final closure design of the NWLF facility. Stormwater runoff from Unit 2 and the area where Unit 2 will piggyback over the existing Unit 1 waste footprint will be collected in a network of bench and perimeter channels. The bench channels will discharge to at a single downchute along the eastern side slope of Unit 2, where flow will converge with the perimeter channel flow and ultimately report to the Unit 2 retention pond. Sub -basins for the runoff stormwater control design are shown in Figure 3. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 7 1538880 5.0 DRAINAGE DESIGN CRITERIA The stormwater management system for Unit 2 of NWLF was prepared based on the storm drainage criteria presented in Section 23, Article XII of the Weld County Code and in CDPHE Regulations. The storm event used for the sizing of stormwater management controls was the 100 -year frequency, 24 -hour duration storm event (unless otherwise noted), required by CDPHE Regulations for permanent surface water diversion structures after closure. 5.1 Development Criteria Reference and Constraints There is neither a project master plan nor a regional drainage master plan for the NWLF site. As previously discussed, the initial design of existing stormwater structures for Unit 1 was presented in the Updated Design and Operations (D&0) Plan for the North Weld Sanitary Landfill (revised byWMDSC 1997) and has been subsequently modified (Colder 2010, 2013, and 2016) to accommodate changes in operational development of the site. Historic design calculations for the Unit 1 stormwater controls are provided in Appendix B of this Drainage Report. No run-on diversion or runoff from Unit 2 will be directed to the existing Unit 1 drainage structures. There are no known utilities that cross the NWLF site that are expected to limit the stormwater management system. The gently -sloping topography of the undeveloped NWLF site, with the absence of existing defined drainage features, was considered in preparing the stormwater management system design for Unit 2 and does not pose a significant design constraint. 5.2 Hydrologic Criteria Design rainfall data was obtained from the National Oceanic and Atmospheric Administration's (NOAA) Precipitation Frequency Data Server website. The values, summarized in Table 1 below, were based on NOAA Atlas 14, Volume 8, Version 2.0 (NOAA 2013) and the latitude and longitude of the NWLF site: Table 1: NWLF Site Rainfall Event Data Storm Event Depth (inches) :1.762 -year, 24 -hour 25 -year, 24 -hour 3.38 100 -year, 1 -hour 2.78 100 -year, 24 -hour 4.67 1:115115388801040040404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 8 1538880 Times of concentration were calculated using the methodology described in TR-55 (N RCS 1986) for sheet flow and shallow concentrated flow and via Manning's equation for channel flow. HEC-HMS IBS modeling software (USACE 2013) was used to determine the routing of surface runoff from the delineated drainage basins and the resulting estimated peak flows. 5.3 Hydraulic Criteria Run-on from upstream drainage basins will be conveyed in an open channel along the western and northern boundaries of the Unit 2 waste disposal footprint. Peak flows from the 100 -year, 24 -hour storm event, calculated using HEC-HMS S as described in Section 5.2, were used to size the run-on channel with 1 foot of freeboard, exceeding Weld County Code design requirements of conveying the 100 -year, 1 -hour storm event. The run-on channel was designed with three horizontal to one vertical (3H:1 V) side slopes. The concentrated flow from the run-on channel will be returned to natural pre -development sheet flow patterns through a permanent riprap-lined dissipation basin in the northeast corner of the NWLF site and ultimately infiltrate into the surrounding natural soils. Stormwater runoff from the closed landfill will be conveyed in open bench channels along the landfill side slopes or around the landfill perimeter and will be routed to the stormwater retention pond. Runoff bench and perimeter channels were sized for peak flows from a 100 -year, 24 -hour storm event, calculated using HEC-HMS as described in Section 5.2, with 1 foot of freeboard and 3H:1 V (outboard) and 4H:1 V (inboard) side slopes. A stilling basin was designed for the toe of the downchute along the eastern landfill side slope for energy dissipation. The retention pond was designed to store 1.5 times to volume of runoff from the 100 -year, 24 -hour storm event from the ultimate Unit 2 footprint plus 1 foot of freeboard in accordance with Weld County Code requirements. A new access road will be provided near the southwest corner of Unit 2. This access road will cross over two existing drainage facilities within Unit 1 and new conveyance culverts will be provided at these locations. The culverts were designed in accordance with Weld County requirements, with regards to minimum pipe diameter requirements and limiting the design headwater to depth (HW/D) to 1.5 for the 100 -year, 24 -hour storm event. There are no stormwater management manhole inlets or storm sewers at the NWLF site. Various stormwater management structures, such as culverts, check dams, and/or drop structures, may be required throughout the operational life of the facility to address changing conditions through the ongoing development of the site; such stormwater management structures will be designed on an as -needed basis in accordance with Weld County Code requirements. iM5\15388801040M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 9 1538880 6.0 DRAINAGE FACILITY DESIGN 6.1 General Concept The general concept for management of stormwater for Unit 2 of NWLF is to manage the runoff completely separate from the existing Unit 1 structures and return flow to historic drainage patterns, to the extent practical. Additionally, the stormwater management system was designed to retain runoff on site from the developed footprint of the site in order to comply with the requests of the neighboring properties, specifically the Pierce Lateral agricultural canal to the east and CDOT to the south of the NWLF site. Temporary and permanent surface water structures and erosion control measures will be constructed over the life of Unit 2 to manage stormwater run-on, runoff, and contact water (i.e., stormwater runoff that has contacted exposed waste (contact water). Design objectives for the stormwater controls include: • Provide all -season trafficable roads; • Prevent contact water runoff from leaving the active areas of the landfill; • Divert surface water run-on from areas up -gradient of the landfill around the developed footprint and return to historic flow patterns; • Prevent run-on to the active area of the landfill; • Prevent discharge of contact water from the site; and • Control and manage site runoff on site. Components of the stormwater management system for the Unit 2 will include the following: • Run-on diversion channels; • Dissipation basin; • Landfill perimeter and access road channels; • Bench channels; • Downchute channel with stilling basin; • Culverts; and • Retention pond. The locations of the permanent stormwater management structures for Unit 2 are shown in Figure 4. Figures 5 and 6 provide details for the Unit 2 stormwater management structures. For reference, a site -wide site plan with stormwater management structures for the full NW LF site (Units 1 and 2) is shown in Sheet 4B of the Site Development Plans. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 10 1538880 6.2 Specific Design Details and Compliance with Weld County Code 6.2.1 Temporary Surface Water Management Surface water within the active landfill will be managed through a series of temporary berms and/or channels that will divert run-on away from the active area and direct runoff toward temporary surface water ponds or the permanent stormwater retention pond. Surface water runoff that is not contact water may be managed via gravity drainage or pumping for use on site and/or to the stormwater retention pond. Details for the temporary stormwater control structures and other best management practices (BMPs) Ps) will be provided to the CDPHE PH E for informational purposes with the construction packages for each cell prior to construction. Any temporary surface water controls will be designed to handle a 25 -year, 24 -hour storm event. 6.2.2 Final Sformwafer Management System Permanent drainage improvements for the facility► were designed in conformance with the Weld County Code and the Urban Storm Drainage Criteria Manuals (USDCM), Volumes 1, 2, and 3. 6.2.2.1 Run-on Diversion As discussed in Section 3. 3, the NWLF site is located in an upland, topographically high area. As a result, the site received very little if any stormwater run-on from the surrounding areas. Surface water run-on from site areas up -gradient of Unit 2 will be diverted around the waste disposal footprint and returned to historic drainage patterns, to the greatest extent practical. This will be accomplished through the construction of a run-on stormwater control channel along the western and northern toe of the landfill perimeter berm that will concentrate the sheet flow around the waste disposal footprint and then return it to sheet flow through a permanent dissipation basin in the northeast corner of the NWLF site. Run-on flow from up -gradient areas will not be allowed to mix with on -site stormwater runoff from the landfill. The run-on diversion channel will consist of a trapezoidal open channel with 3H:1 V side slopes and a 5 -foot (minimum) bottom width. The channel was designed to control the 100 -year frequency, 24 -hour duration storm event and include a minimum 1 foot of freeboard. The dissipation basin, which will be riprap-lined, will be placed directly downstream of the channel to spread and dissipate the flow prior to discharge as sheet flow onto natural topography. The dissipation basin has been designed to control the runoff from a 100 -year, 24 -hour storm event and reduce the discharge flow velocity to less than 4 feet per second. 6.2.2.2 Runoff Control Perimeter channels adjacent to the waste footprint, bench channels, a downchute channel, and access road grading will be used to control runoff from intermediate- and final -covered areas of Unit 2. All channels were designed to control the 100 -year frequency, 24 -hour duration storm event and include a minimum 1 -foot freeboard. All surface water runoff from the landfill is designed to be collected and report to the Unit 2 stormwater retention pond located southeast of the Unit 2 footprint. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 2ldecl6.docx Golder Associates December 2016 11 1538880 Perimeter channels (Sections 1-3) will be grass -lined trapezoidal open channels with 3H:1V side slopes, 12 -foot (minimum) bottom widths, and 3 -foot (minimum) depths. The perimeter channels will be constructed in segments as the phased development of Unit 2 advances and the perimeter berm is constructed. The bench channels will be grass -lined trapezoidal open channels formed by the construction of 29 -foot -wide benches on landfill side slopes. Across its width an add-on berm will be constructed, creating a trapezoidal channel between the inboard add-on berm side slope (3H:1V) and the coincident final landfill side slope (4H:1 V) and a channel depth of 3 feet. The bench channels will slope longitudinally at approximately 2% across the final cover surface and converge at the downchute channel on the east side of Unit 2. The access road will extend from the west side of Unit 2 to the top deck and will consist of an approximate 2% crowned roadway. The downchute channel will be trapezoidal with 3H:1V sideslopes, a 20 -foot bottom width and 3 -foot depth, and will be lined with either riprap or articulated concrete block (ACB). At the base of the downchute channel, where the flow enters the perimeter channel, a hydraulic stilling (jump) basin will be constructed to dissipate hydraulic energy. The stilling basin will be lined with grouted riprap and include a six -foot -deep concrete cutoff wall at the toe to prevent erosion and/or wash -out. This new access road will cross over two existing Unit 1 drainage facilities: a perimeter channel and a bench channel. The perimeter channel culvert crossing will use a 36 -inch reinforced concrete pipe (RCP), while the bench channel crossing will be an 18 -inch high -density polyethylene pipe (HDPE). Both culverts have been designed to convey the 100 -year, 24 -hour peak discharges reporting to these existing structures, which has been referenced from previous Unit 1 design information (provided in Appendix B). 6.2.2.3 Stormwater Retention As discussed in Section 3.1 of this Drainage Report, the NWLF site is bounded by the man-made Pierce Lateral agricultural canal to the east and the Colorado State Highway 14 right-of-way to the south. During the development of Unit 1 at the NWLF site, these neighboring property owners informed WMDSC that they were not amenable to receiving discharge from stormwater detention on the NW LF site. Consequently, the CDPHE and the WCDPHE approved the conversion of the previously -designed Unit 1 detention basin to a retention basin. WMDSC re -approached the Pierce Lateral Board of Directors on November 15, 2016, to update them on the Unit 2 development plans and re -gauge their willingness to accept detention discharge from the Unit 2 development. The Board of Directors communicated that they are not interested in receiving any discharge from the NWLF site. A letter from the Pierce Lateral's attorney summarizing their position is provided in this Drainage Report. Additionally, the concerns CDOT raised in their letter to NWLF dated August 9, 2000, about detention discharge to the State Highway 14 right-of-way are still applicable to and limit the discharge options from Unit 2 i:115\15388801040M0404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 12 1538880 detention. Consequently, WMDSC is again requesting a variance from Article XII, Section 23-12-30, Part D of the Weld County Code to allow on -site retention rather than detention of site runoff. The perimeter channel (Section 2) will convey stormwater to the 6.7 -acre (77 acre-feet of storage) retention pond though a low-water crossing over the perimeter road. The low-water crossing will transition to channel flow (Section 3) prior to discharging to the retention pond over a riprap apron down the pond side slope. The retention pond was designed to contain 1.5 times the 100 -year frequency, 24 -hour duration storm event runoff from the ultimate Unit 2 buildout and includes a minimum of 1 foot of freeboard. In accordance with Weld County Code, the retention pond capacity will be re-established within 72 hours and an emergency spillway designed to convey the 100 -year, 1 -hour peak discharge reporting to the basin has been provided. Stormwater will be managed in accordance with the Stormwater Management Plan (SWMP), North Weld Landfill (W MC 2016), issued and approved under the Colorado Discharge Permit System (CDPS) Permit No. COR-900412 by the CDPHE Water Quality Control Division. 611 Erosion Potential Evaluation An evaluation of the effects of erosion due to rainfall on the proposed water balance final cover system was performed. The analysis consisted of using the Revised Universal Soil Loss Equation, Version 2 (RUSLE2) erosion modeling software (USDA 2010) to estimate the amount of soil loss caused by sheet and rill erosion of the final cover after one year and five years of vegetative growth on the final cover. Annual soil loss due to erosion at one and five years was predicted to be 2.9 tons/acre/year and 1.4 tons/acre/year, respectively, and less than the maximum soil loss tolerance of 5 tons/acre/year. i:115\1538880104010404 edop fnl dec161appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 13 1538880 Table 2: Open Channel Summary Channel Designation Channel Lining Design Peak ".we (cfs) Channel Slope (f ift) Left Slope (H: Side 1V) Right Slope (H: Side IV) Bottom Width (ft) Minimum Channel Depth (ft) Maximum Velocity (ft/sec) Maximum Normal Flow Depth (ft) Run -On (R1) 93.4 0.013 3.0 3.0 5 5.9 :1.7 TRM Run-On (R2) 119.4 0.012 i:3.1 3.0 3.0 5 3.1 6.1 2.0 TRM Run -On (R3) TRM I 125.8 0.012 3.0 I 3.0 3.1 6.1 2.1 Run -On (R4) TRM 165.8 0.022 3.0 3.0 I 5 I 3.1 8.3 I 2.0 Bench (D1) TRM 126.6 0.020 4.0 3.0 8 3.0 7.0 1.5 Bench (D2) TRW 84.8 0.020 4.0 3.0 8 3.0 6.2 :1.2 Bench (D3) TRM 153.3 0.020 3.0 4.0 8 a 3.0 7.4 1.7 Bench (D4) TRM A I 208.7 0.020 3.0 I 4.0 I 8 # I 3.0 8.0 # 1 2.0 Bench (D5) TRM 108.7 0.020 3.0 4.0 8 3.0 6.7 1A Downchute (D6) 6 dumped riprap inches 1.5 0.250 3.0 3.0 20 3.0 2.6 0.03 Downchute (D7) 18 inches dumped riprap 236.5 0.262 3.0 3.0 I 20 I 3.0 19.1 I 0.6 Downchute (D8) w 24 inches grouted riprap 525.6 0.262 I 3.0 3.0 20 m 3.0 25.4 0.9 Perimeter (D9) Grass 60.8 0.012 I 3.0 3.0 12 3.0 4.5 1.0 Perimeter (D10) w Grass 99.6 0.012 3.0 3.0 1 12 1 3.0 5.3 1 1.3 Perimeter (D11) TRM 645.7 0.012 3.0 3.0 18 4.0 8.9 3.0 Perimeter (D12) Grass 40.2 0.017 a 3.0 3.0 I 12 I 3.1 4.4 I 0.7 Perimeter (D13) a TRM 645.7 � 0.012 3.0 3.0 20 4.0 8.7 2.9 Notes: 1. (Q denotes drainage basin location of the channel shown in Figures 2 and 3. i:\15\1538880\0400\0404 edop fni dec16\appendix d_drainage reportkapp d unit 2 drainage rot 2l dec16, docx Golder Ass o dates December 2016 14 1538880 7.0 CONCLUSIONS 7.1 Compliance with Weld County Code This Drainage Report has been prepared in compliance with Section 23, Article XII of the Weld County Code. This document is submitted as part of the Engineering Design and Operations Plan (EDOP) for the permitting of NWLF Unit 2 and in support of a Weld County Certificate of Designation (CD) and Use by Special Review (USR) permit application for the expanded NWLF facility. WMDSC is requesting a variance from Article XII, Section 23-12-30►, Part D of the Weld County Code to allow on -site retention rather than detention of site runoff. 7.2 Drainage Concept The general concept for management of stormwater for Unit 2 of NW LF is to manage the runoff completely separate from the existing Unit 1 structures and return flow to historic drainage patterns, to the extent practical. Additionally, the stormwater management system was designed to retain runoff from the developed footprint of the site on -site in order to comply with the requests of the neighboring properties, specifically the Pierce Lateral agricultural canal to the east and CDOT to the south of the NWLF site. Unit 2 as designed is not predicted to have negative impacts on adjacent properties or property owners located upstream or downstream. Emergency spillway discharge from the Unit 2 retention pond will be contained within the NWLF site by the existing landscaping berm along the southeastern and southern property boundaries. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates December 2016 15 1538880 8.0 REFERENCES Federal Emergency Management Agency (FEMA). 2016. FEMA National Flood Hazard Layer (NFHL). Available online: https://hazards.fema.govifemaportaliwpsiportaliNFHLWMS (accessed August 12, 2016). U ational Oceanic and Atmospheric Administration (NOAA). 2013. Precipitation -Frequency Atlas of the United States, NOAA Atlas 14, Volume 8, Version 2.0. S. Perica, D. Martin, S. Pavlovic, I. Roy, M. St. Laurent, C. Trypaluk, D. Unruh, M.Yekta, and G. Bonnin. NOAA, National Weather Service, Silver Spring, Maryland, 2013. Available online: http://hdsc.nws.noaa.govlhdsclpfds/pfds printpage.html?Iat=40.5918&Ion=-104.8250&dat (accessed August 25, 2016). U nited States Army Corps of Engineers (USAGE). 2013. HEC-HMS Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) [computer software]. Version 4.0. December 2013. U nited States Department of Agriculture (USDA). 2010. Revised Universal Soil Loss Equation 2 (RUSLE2), Version 2.0.4.0. U SDA Natural Resources Conservation Service (NRCS). 1986. Urban Hydrology for Small Watersheds Technical Release 55 (TR-55). June 1986. U SDA NRCS. 2016. Custom Soil Resource Report for Weld County, Colorado, Southern Part. Extracted from Web Soil Survey application August 25, 2016. U rban Drainage and Flood Control District (UDFCD). 2016. Urban Storm Drainage Criteria Manuals, Volumes 1, 2, and 3. January 2016. Waste Management of Colorado, Inc. (WMC). 2016. Stormwater Management Plan, Waste Management Disposal Services of Colorado, Inc., North Weld Landfill. PERMIT NO: CO900412. August. Weld County (WC). 2016. Weld County Charter and County Code. April 2016. i:115\1538880104010404 edop fnl decl6\appendix d_drainage reportlapp d unit 2 drainage rpt 21dec16.docx Golder Associates FIGURE a NORTH WELD LANDFILL, UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO _, V For Collins (1104.14141 .e YJt r 1 I: C' SITE LOCATION Br" -.: 4 NORTH WELD LANDFILL PROPOSED UNIT 2 BOUNDARY —,..,m,.,- -_ A 2016-12-21 ISSUED FOR WELD COUNTY USR ALE DVS JAR MEM REV s -444-0D DESCRIPTIwi, DESIGNED PREPAP,Z-D REVIEWED APPlOVECI Prepared for: Waste Management Disposal Services of Colorado, Inc. 40,000 Weld County Road 25 Ault, Colorado 80610 \stk / WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. NSULTAN- Golder Associates GOLDER ASSOCIATES INC. 4= UNION BLVD, SUITE 300 LAKEWOOD, CO USA +1(303}984 0540 wwn.v.golder.coom Prepared by: Golder Associates Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado 80228 DRAWING LIST SHEET NO. T.TI.F REVISION 1 TITLE SHEET A 2 HS i OR!C DRAINAGE BASIN HU f1N MAP A FIJI I Y DEVELOPED DRAINAGE BPASNN MA A 4 STORMWd.ATER CONTROLS PLAN A g DETAILS (1 Elf 2) A e DETAILS (2 OF r) A F T NORTH WELD LANDFILL, UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO TITLE SHEET uF N 1538880 c. .rJII UL FIUURE -H13 c'c.1a'i Lt'JI Jiit'3PJLUI Mit.HMIA I'391i+v,+. W. c1 I:a'3 Kit. &V Jn ILL+1It0 :1 P.'I_' L LJ tCl Ct a' -42 x f I 458 000 NI 1 I 1 I x 459 0QC .V • 71t }e +r, III 1 �/ 114:1 rxlipyr-r-4 I I I Hut •ow x hh hh hh h h S55; ~�J ff - VIE7 I' f ✓V 4}- I } a 524C 525o es- JJ/r� f Veete bkP Ir �YG N 8 m RIPRAP DISSIPATOR - 5880 5090 — 5130 5140- 5 situp 4.y50 sito 5180 - x180 119C - - - - � _ + �, S20C )I etio isito .' .' },i ' .\ tt.. s� .. +i \ \\ \ l \i +ii ++ N, \\\, .� \� \ i\ \ ,�\. \ \ N. . 'r ''+, `1 \ 4 ,'S+, \�i i ', \ 4 \\\ \\\ \ \ ? \ \ be° ' \\ \\:\\\\ \\ \ \ cri \\_ \ \ \\ \ _emir \ 1 i + \ \ \ )hc 41 \‘‘: \`, } � � '+ ` 111\\i ++. , 5 t1 _ 51,20 slot '�\ i\ �'� +4 iV '4 i.�i4\ ' V4\ \\\\\'\\'\\\\\ \ ect %Kit \\:\ 401 TAIL A 2016-12-21 ISSUED FOR WELD CCiUN uSR NIL JAR MEM 5090 5120 7 5130 NI rr • SECTION 2 SEE NOTE 6 lor 1-vdd ;1/4,— 5970 4. 5060 FEET 41510 MO NI 450 000 N 458 00;13 N WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC C 04.1 cbc, Golder Associates GOI DER ASSOCIATES INC 44 UNION BLVD, SUITE 30C LAKEWOOD. CO USA LEGEND EXISTING TOPOGRAPHY (SEE ImOTF 1) —5283— pRoposED 1-1NAL CLOSURE GRADES 2.636 USR 1527 BOUNDARY EXISTING FENCE PROPOSED FENCE UNIT 1 TERRACE CHANNEL UNIT PERIMETER CHANNEL UNIT 2 BENCH CHANNEL — UNIT 2 RUN-ON DIVERSION CHANNEL SLOPE INDICATOR RUN-ON DIVERSION EAS44 BOUNDARY 3ASIN ID AREA (IN ACRES) NOTES JANUARY 26, 23°2 Als:D MILLER CREEK AERIAL MAPPING PHOTOGRAPHY DATED FEBRUARY 21, 2016. EXISTING CONTOUR INTER1.0A1 IS 2 FEET BASED ON NAVD86 ELEVATIONS NORTH WELD :-ANDFILL PARCEL BOUNDARY PROPOSED N EVII USE BY SPECIAL REVIEW NSF.; BOUKDARY 5. SEE SHEET 9 FOR CHANNEL SECTION DIMENSIONS. 6. ALIGNMENT OF ACCESS ROAD IS APPROXIMATE AND MAY VARY THROUGH UNIT 2 OPERATIONS NORTH WELD LANDFILL. UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO HISTORIC DRAINAGE BASIN RUN.ON MAP 2 1 53888 CI , x , x 460 ODD N I_ I X _ X 458 000 N ti� 488 000 N1 x XK x x x 9 OM 90 L N at 7. r..�. 'Y �3'CP 1 . 1 \ *it -14Y4 I i 3G in RCP CULVERT \I I S1 x x Xr \,; —a-181n HOPE CULVERT tal m ao C C C ;m 5.0% t X NE'W ACCESS ROAD TIE-IN TO EXISTING ROAD J 7-. ti t/ r rr 1+ II )' 1 m 6120 - 5130 5140 - 51hr? =, 5160- 51 -ep — 3100 • 51p0 5400 .r" I RIPRAR DISSIPATOR 2.2% i -HOBO A 2018.12.21 ISSUED FOR WELD COUNTY USR SF'S NIL JAR MEM REV ?WY MA^ -OD DESCRIPT'ON DES.3N PREPARED REV lEJ':D APP ROVEC w 0 en 50a0- 5100 5110 5120 5130 �- 4',:s Tao N 0 2C0 460 000 N 400 1"= 00' F_ET [5A 000 N 458 COO N WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. CONSULTANT G0tDER ASSOCIATES INC 44 UNION BLVD. SUITE 30C LAKEWOOD, CO USA +11303)9600540 uw. w.galder.0011 LEGEND 52190 EXISTING TOPOGRAPHY ISEE NOTE 1) PROPOSED FINAL C'1OSURF c2RA.DES USR 1527 BOUNDARY --------- EXISTING LIMIT OF WAS1 E (LfNI T 1) — — — — — PROPOSED LIMIT OF WASTE (UNIT T,) X — EC,ST;NG FENCE PROPOSED FENCE UNIT 1 TERRACE CHANNEI. UNIT I (PERIMETER CHANNEL UNIT 2 BENCH CHANNEL UNIT '2 PERIMETER CI IAINNEL — UNIT 2 RUN-ON DIVERSION C -t NEL SLOPE INDICATOR RUNOFF BASIN BOUNDARY 2 0% SALIR II) AREA (IN ACMES) NOTES 1. EXISTING TOPOGRAPHY IS A COMPOSITE OFAEROME-RIC INC. PHOTOGRAPI+Y (DATED JANUARY 28.2012 AND MILLER CREEK AERIAL MAPPJNG PHOTen RAP1iY DATED FEBRUARY 21, 2C' 5. 2. EXISTING CONTOUR INTERVAL IS 2 F[ET EASED ON NAVD8R FI‘FVATIONS. 3. COORDINATE SYSTEM IS iN NAO27 STATE KANE COLORADO NORTH. 4. NORTH WELD LANDFILL PARO L ROUNI3ARY PROPOSED AS NEW USE BY SPECIAL REVIEW fUSR1 BOUNDARY. SEE SHEET 9;CR CHANNEL SECTION DIMENSIONS. 6 Al IGNMENT rCF ACCESS ROAD IS APPROXIMATE AND MAY VARY THROUGH UNIT 2 OPERATIONS. NORTH WELD LANDFILL, UNIT 2 DRAINAGE REPORT WELD COUNT', COLORADO FULLY DEVELOPED DRAINAGE BASIN MAP 1O. rest- c..=nti�A'9' �`rd r:� A r 0 ;6' JV iaLtIO lA1 15388&0 1.::_.•. GI LEGEND E 2 180 000 E 2189 500 E ? 189 000 Re' z F 2 188 600 rollo E 2 188 000 E2181b0D E, 2 187 00C E 2186500 F.. ? 186 004 2 185 500 2 r' I I z TWOS fi 2 N . • •PERIMETER CHANNIF I- SEE DETAIL 1 GPa31 WFL D COUNTY ROAD 84. 2 z z LOY/ WATER CROSSING I SEE DETAIL `•, 6 ft .\ ' LOWER DDWNG BITE CHANNEL j � SEE SEC -POP. L. '` 'r' - - ` ' 'iy ••'` TVIi-t0 A 'TW-09 l A, f ''/"- t R c - Spy Qs Bti -- MI LE '• .7 5 _../ SE EC ION ,c, 7e �` 1 - ) TE RAC STILLINGrBASI, SEC DETA`i GP -35 ' P1 ° /�D]SSIPA.TIONEIN SEE DETAIL,/ i �,P-N4 I t' 75 WIDE WESTERN `1 AREA POWER A RITY EASEMENT i � I �I) 9 GP -37 TV.1. 8 ' 7 1 T'': 13 4 GP -2 _ Gqp N 1.9 C II as C! I USR 1527 -711 x X X x wL.S11- -N FSEI 123 ° ar Crs- PPER'DOW Li OF -27 4 I !CHANNEL SEE SECTION ,� OP -2t:. 8.0% BENCH CHANIIEL SEE SECTION xtu • in F211 SEED r, 6., its � � ti ,. \'sue ' 4 N 4 . e a l+ke { _.3M{1[ y II. — L s o UNIT 2f`ei STORMWATtR $ RETENTION n POND et,-;A✓v A77 AC -FT) 'P-.'95 I TO *OT•CN C Jh1F If I -E'•- '--T'.-'" SE DET>+l1 I Lo c... \ \il * 'ZI . I ,V` II ,,\ \ 4,. Nita I ` -11 `t 1111 ` s 1 4 4 n vS 2 S v 7 • ` RETENTION POND ~ �+.s, 0 J EMERGENCY SPILLWAY- , SEE DETAIL- - -I',�- r _ ''4• - DUMPED RIP•RAP tv'F IBIN) APRON (20 FT ATCREST BY60 FT AT TOE. 20 FT RUN QUT I Pi5Nc FLOOR) salt t STOCKPILE AREA CHA • ACC' „NS ROADE Is —I NI U rAE17 — l r } B PERIMETER t' : ANN Fl SSIN SEE_)-E17lt - GP -25 4_ -49 - CO z 75 FT OFFSET 0 52(30 GP -2.2 e. II 7:J. 5.0% i rr 4 1 r rr Bf'ICit4 CHANNE_ II`% ` ' � JL` R CROSSING ( r -IEEE [TAIL --'21•:-- I 0 Ib 2 x x) EXISTING UNIT 1 STORIVAIATER 1.I RETENTION '1 POND H (142.2 AC -FT) xI - 510o X12., Xfrt _:�= re,.-; -3 GP -1'i — o AMY 11$-" z 9 U3 In a z a W lea a—i.a.—a f. ■ SP -1 x— x_ _. _-f� co ry I' �? R D 25 St1OP ENANCE SCALEHOUSE .`Q. ` Q i 7 j G1'-2 A 2018.12.21 ISSUED FOR WELD COUNTY USR ALB DVS JAR MEM REV YYYY-MM.DD DESCRIPTION DESIGNED rf '2ARED REVIEVWED APPROVED 7 I 1 196 FT r OFFSET J o1 -nor C -3 FACILITY ENTRANCE n .-I U, a lcd n n u N Ill a z V z —8280 PROPOSED FINAL CLOSURE GRADES UNIT 2 PIGGYBACK OVER EXISTING UNIT I --- PROPERTY DOI INDARY (SEE NOTE 4} USR 15€7 BOUNDARY EXISTING LIMIT OF WASTE (UNIT 1) - w - - PROPOSED _IMIT OF WASTE (UNIT 21 EXISTING FENCE E21900©0 E 2 189 500 1280- EXISTING TOPOGRAPHY (SEE NOTE I) E2189000 E 2 198 500 E2188000 2187 500 E 2181 000 E2188500 E 2 185 000 F? 185 504 ■I. C ... X — PROPOSED FENCE UNIT 1 TERRACE CHANNEL UNIT 1 PERIMETER CHANNEL UNIT 2 BENCH CHANNEL UNIT 2 PERIMETER CHANNEL UNIT 2 RUN-ON DIVERSION CHANNEL EMS ROADS PROPOSED ACCESS ROAD SLOPE INDICATOR EXISTING BUILDINGS EXISTING' MONITORING WELL LOCATION TEMPORARY WELL LOCATION (SEE NOTE 5) EXISTING CAS PROBE LOCATION PRO'PCSED GAS PROBE LOCATION ;APPRO)CMATE1 (INSTALLATION TO BE PHASED WITH LA!4DFILL DEVELOPMENT) - - t; IFlT WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC- C a `4S viL TA'4T ates GOLDER ASSOCIATES INC. 44 UNION BLVD, SUITE 300 LAKEWOOD, CO USA 41 (303)980 0540 rL•Llrw.golder Corn 20% NTIN-9 T'WN-06 joicGP-23 GP -35 NOTES 1. EXISTING TOPOGRAPHY IS A COMPOSITE OF AEROME'R C NC. PHOTOGRAPHY DATED JANUARY 28.2012 AND MILLER CREEK AERIAL MAPPING PHOTOGRAPHY DATED FEBRUARY 21. 2018, 2 EXISTING CONTOUR INTERVAL IS 2 FEET BASED ON NA1.0SS ELEVATIONS. 3. OOORDINATE SYSTEM IS IN NAD27 STATE PLANE COLORADO NORTH 4. NORTH WELD LANDFILL FARO=LAC1UNDARY PROPOSED AS NEW USE 13Y SPECIAL. REVIEW (USR) BOUNDARY TEMPORARY MONI T C'R"NG WELLS INSTALLED BY SWIFT RIVER ENVIRONMENTAL SERVICES. LLC AS PART C$ 2016 HYOROGEOLOGIC SITE INVESTIGATION. 6. RETENTION BASIN DESIGN INCLUDES ALLOWANCE FOR 1 -FT MINIMUM FREEBOARD. CAPACITIES REPORTED ON THIS SHEET DO NOT INC_IJCE VOLUME OF FREEBOARD. 7. ALIGNMENT or ACCESS ROAD IS APPROXIMATE AND MAY VARY THROUGHOUT UNIT 2 OPERATIONS AND AT CLOSURE 4 3D0 607 I 1"-330' F►FT rs:'.ID: T NORTH WELD LANDFILL. UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO r IEI STORMWATER CONTROLS PLAN Si W' " L.C�c 1 '� »-inn OVAL PROJECT 'C' 1538880 E., e' FIr9IIRF y ✓r Si n 33k '1 5 n = L7. li 1 3 EXISTING GRADE VARIES SCALE N.T,s, (MI RUN-ON CHANNEL SECTION DETAIL DO'.ThCl LUTE CHANNEL f SEC SECTION B h� tyei 15. IAPPRC'X 1 i rf Y 15' iAPPROX. PREPARED SUBGRACE 12 FT -F r SCALE Nts. r3-.\\ STILLING BASIN DETAIL ) 4 A' N. 5 EXISTING GRADE .--\\ PERIMETER CHANNEL SECTION 1 rTYP'.) SEE DETAIL PERIMETER CHANNEL ++ \j SECTION 2(TYP,) SEE DETAIL SCALE N.T.S. TERRACE CHANNEL TO DOWNCHUTE INTERSECTION DETAIL CONTINUE HI PHAP 10 FT ;MIN -1 UPSTREAM OF INTERSECTION I �ti�ti� a GFT 4 ++' +a ? 1YNR — GRADE TO DRAIN 3 � _ PERIMETER ROAD ir 6 IN ROAD BASE / MATERIAL • GRADE TO DRAIN 25 FT (MIN,' DEPTH VARIES SEE CHANNEL SCHEDULE ON THIS $I-IEET COMPACTED SSTRUCTURAI. FIL,_ WIDTH VARIES $EE CHANNEL SCHEDULE ON THIS SHEET SCALE N.T.S. re -2-N\ PERIMETER CHANNEL DETAIL 4 S .J FINAL COVER SYSTEM 1 PRE'AIRED SUSCRADE. �j PERIMETER CHANNEL SCHEDULE CHANNELSIDESLOPE (SS) (H:V} MINIMUM CHANNEL SLOPE (R4) MINIMUM CHANNEL BOTTOM WIDTH (B) iFT) MINIMUM CHANNEL DEPTH (D) (FT) CHANNEL LINING SECTION 1 3:1 1.2 -2 3 GRASS SECTION 2 3;1 1.2 'K 4 TF:M SECTION 3 3:1 1.2 20 4 TRM O'ROUTED RIP -RAP OR ENGINEER --I—LOWER DOWNCHUTE APPROVED E0U?VALENT 5 r— SNOWED Rip ,P /1/C (SEE NOTES 1. 2, ANDS) '_.2 CHANNEL SEE SECTION i OR ARTICULATED CONCRETE BLOCK 12 OZ!S GEOTOfriLE 1 !+ / PERIMETER CHANNEL 42 FT(MIN.) 4 = MN.) 1$ IN WIDE—._ CONCRETE XJTOFF WALL SCALE `4'S ' n a 16 FT 1 1 c1-``Ji GFT� STILLING BASIN SECTION NiN r FINAL COVER SYS-Elal ��r FT.4 r \I f -• ' rets ' NOTES 1. RIPRAP SHALL BE PLACED TO A THICKNESS OF 1 5 TIMES THE Ng DII41ENBIQN. 2. LOWER DOWNCHUTE AND STILLING BASIN RIPRAP SHALL HAVE Dso OF 24 IN. 3. RIPRAP SHALL BE GROUTED TO ONE HAI F OF LAYER THICKNESS (MINIMUM) A 2016-12-21 ISSUED. FOR WELD COUNTY USR ALB DVS ..AR MEV REV YYYv MM LID DESCRIPTION DESIGNED PREPA-RED RSVIEV:FD At - IP " FINAL' OVER:SYSTEM 3 ET L DUMPED OR CIROUTED RIPRAP ORARTICULATED CONCRETE BLOCK II OSEE NOTES 1.8, AND 3) f I III 3 rT INFkSYSI WASTE FINAL COVER SYSTEM -- 20 =I 12071SYOEOTEXTILE SCALE NI$ ,f'l, DOWNCHUTE CHANNEL SECTION NOTES 1. RIPRAP SHALL BE PLACED TO A THICKNESS OF 1.5 TIMES THE U.,Q DIMENSION, 2, UPPER DOWNCHUTE CHANNEL DUMPED RIPRAP SHALL HAVE I3/47 OF BIN, MIDDLE DOWNCHUTE CHANNEL DUMPED RIPRAP SHALL HAVE Du,QF 181N. LOWER DOWNCHUTE CHANNEL GROUTED RIPRAP SHALL HAVE DK OF 24 IN AND SHALL BE GROUTED TOC*JE HALF OF LAYER THICKNESS (MINIMUM). 3. ARTICULATED CONCRETE BLOCK (ACM) MAY BE SUBSTITUTED ran RIPRAP IN DOWNCHUTE CHANNEL ACS SHALL HE INSTALLED IN ACCORDANCE WITH MANUFACTURERS HECOMMMENDATIONS. rADO-ON BERM COMPACTED GENERAL FILL QR WATER BALANCE PINAL COVER MATERIAL SCAL€ N T,E, C BENCH CHANNEL SECTION 5 �{ ALL BENCH CHANNELS SHALL BE GRASS -LINED r FINAL COVER SYSTEM I WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO, INC. CONS uL'rANL Golder Associates GOLDER ASSOCIATES INC_ 44 UNION BLVD. SUITE 390 LAKEWOOD. CO USA .1 (393} 980 0540 www.gatcler.c+orte PROJECT NORTH WELD LANDFILL, UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO DETAILS (1 OF Sri ?FV Cd A FIGURE F.; 1538860 [:1 MODIFIED FROM ANSI C. J t� �,g_ i � L;�L � H.; P LW.3 "...'i WHA 1 �.N4TICLtATFI] CONCRETE ®LOCK ( EE NOTE 1 J Cs - WASTE —' GIN ROAD BASE MATERIAL FINAL COVER SYSTEM -- SCALE N S. (72. ACCESS ROAD DETAIL j+ COMPACTED-9i STRUCTURAL FILL / IFT (MIN) I2Vt EXISTING PERIIE 7 ER CHANNEL 9 IN (MIN.) —, ROADOASE 3 FT O 36 IN RCP PIPE 7 L 6 IN THICK LOOSE GRANULAR BEDDING UNIT 1 LINER — SYSTEM 4 II _'--k`iC 1 EST cps S WASTE SCALE N_T.S. ( 3 ``, EXISTING UNIT 1 PERIMETER CHANNEL CULVERT CROSSING DETAIL RUN-ON CI IANNEL r) I 51 'T `rs-er J t 1% 50 FT DUMPED RIPRAP SEE NOTES Z 3, AND 4 SCALE T.S. (5 ' DISSIPATION BASIN PLAN VIEW DETAIL 1 e./. PERIMETER CHANNEL SECTION SEE DETAI EL 6G5D UNIT 2 STORMWATER RETENTION BASIN •,t t�4�lE'I� ll I - PERIMETER ROAD �� J- GIN ROAD RASE MATERIAL � ,!4,:mai,‘.,...zitscier,,,fra1 �l rJ' r BIAXIAL CE(}G1UD r tmm 80 FT 4 r` r r PERIMETERROAD 6 IN ROAD BASE MATERIAR L 10 S IN THICK AGGREGATE PREPARED SURGRADE OR BEDDING LAYER COMPACTED STRUCTURAL. FILL RAf2<FILL WITH COMPACTED STRUCTURAL FILL GEOTEXTILE (WOVEN MOu4OFILAMENT) PERIMETER ROAD (TYP.) SCALE N_T.,S. N, LOW WATER CROSSING SECTION \,_eirld 1 ARTICULATED CONCRETE BLOCK SHALL OE INSTALLED IN ACCORDANCE WITH MANUFACTURER'S RECOMMENDATIONS. see SCALE KT :$ ny LOW WATER CROSSING DETAIL SECONDARY SPILLWAY �• (PROJECTED) GRASS•LINED TRANSITION FROM LOW-WATER CROSSING TO RETENTION POND CHANNEL PERIMETER Cf-IANNEI. 2 SECTION 3 SEE DETAIL 2C FT COMPACTED STRUCTURAL FILL 01$INHCPEPiPE ! — ,BTE AS 6 IN (MIN ROAUeASE \ 4 s�tie� a Elk F resM- SCALE N.T.s. I:\lEXISTING EXISTING UNIT 'I BENCH CHANNEL CULVERT CROSSING DETAIL JECTEO�IrJr !MIN ) r - E_. 507c SEE NOTES 2, 3, AUDI DUMPED RIP -RAP El. 606E .-dtLi L% IMIN) 3 POND 1! FT ',MN.) "I—. SEE NOTE 1 —-I I ICI I -Ii IE EntF,;�lKM r: ~��_ -III t: III VIII=1I1=1 1 I I' � ' [ 1-11 I I El I f� iii =i I —L-i 11-11 c -I II I I-1 i j Imo= I I I I( -I B I-1 I I--III--III, - leitTi rm I II [Sri= 1 II11> I I, III' I Cl I Iz 1 =c I ! I I—! 1 I III =' I Hi I LET T=rTi�1 I ITz I I 1 Illl I rat . (-�1 �H ( 0- I I'^a II —t I j-- , -III__.. j III t.l 1-1 iczt scALF r. T S ( 6 `�� RETENTION BASIN SPILLWAY DETAIL S r A 201$-12-21 ISSUED FOR WELD COUNTY U$H ALB DO`S JAR Mai REV. YY"Y-MM•DD DE5CRPTInN DESGNED PREPARED RFVIFW€D td-PH-ovEC WASTE MANAGEMENT DISPOSAL SERVICES OF COLORADO. INC. criN L! AN COLDER ASSOCIATES INC. 44 UNION BLVD. SUITE 300 LAKEWOOD. CO USA .1 (303) 980 0540 www.golder.com NOTES 1. EXISTING GRADE DOWNSTREAM OF EMERGENCY SPILLWAY VARIES. SPLLWAY DISCHARGE AREA wrLL BE REGRADED TO DRAIN DURING UNIT 2 OPERATIONS. 2. RIPRAP SHALL SE PLACED TO A TH CKNESS OF 1.5 TIMES THE D;, DIMENSION. 3. RIPRAP SHALL HAVE A C. , OF £ P4. 4. RIPRAP SHALL BE PLACED ON 12 OZ,ISY GEOTE,X ILt NORTH WELD LANDFILL, UNIT 2 DRAINAGE REPORT WELD COUNTY, COLORADO DETAILS (2 JF 2) FT - TECT NO 1 38880 REV A r.GIIF:f- '.lE'.91.RlMMTCCE'S 'JOT NAT1f'.N.1ffiTIF. cif -J. -rem INF£ rFTREF C APPENDIX A UNIT 2 SURFACE WATER RUN-ON AND RUNOFF CONTROLS CALCULATIONS Golder Associates CALCULATIONS Date: December 21, 2016 Made by: SPS cs'S Project No.: 1538880 Checked by: DIM 'V i a Site Name: North Weld Landfill, Unit 2 Reviewed by: JAR ift, Subject APPENDIX A: SURFACE WATER RUN-ON AND RUNOFF CONTROLS CALCULATIONS 1.0 OBJECTIVES Determine the locations and sizes of surface water run-on and runoff controls to manage the stormwater affecting the development of Unit 2 of the North Weld Landfill facility (Facility). 2.0 METHODOLOGY The Facility footprint area is approximately 155 acres and the contributing area of the upstream drainage basins impacting the Facility footprint is approximately 35 acres. Drainage basins (watershed areas) for the proposed surface water run-on and runoff control systems were delineated based on planned and existing two -foot contour interval topography. Times of concentration were calculated using the methodology described in TR-55 (NRCS 1986) for sheet flow, shallow concentrated flow, and channel flow, HEC-HMS modeling software (U ACE 2013) was used to combine and route the surface runoff from the delineated drainage basins in order to estimate peak discharges and total stormwater volumes. The peak flows are used to size the proposed channels, culverts, and energy dissipater. Excel spreadsheet calculations based on Manning's equation were used to size the proposed channels, assuming normal depths. Required riprap median diameters (D5o) for proposed channel linings were developed using Design of Rock Chutes (Robinson et al. 1998). The Federal Highway Administration's H1 -6 culvert analysis program (FHWA 2014) was used to evaluate proposed culvert designs. Bentley's FlowMaster software was used to determine the retention basin emergency spillway dimensions and the flow capacity of existing channels (Bentley 2009). Energy dissipaters were sized using Urban Drainage and Flood Control District (UDFCD) methodology (UDFCD 2016a and 2016b). 3.0 DESIGN CRITERIA The storm drainage criteria presented in the Weld County Charter and Code (Weld County 2016) was used as the design basis for the project, except in certain instances where it is superseded by UDFCD design criteria (UDFCD 2016). A summary of this project's design criteria follows: ■ Site precipitation from NOAA Atlas 14 (NOAA 2013) (see Appendix A-1): x:ltucson\prajects115proj\1538880 north weld Iandtlltil53888 Kappa run-on&runoff calcs_20161221.docx Golder Associates Inc. 4730 N. Oracle, Suite 210 Tucson, AZ 85705 Tel: (520) 888-8818 Fax: (520) 888-8817 w w.golder.com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation CALCULATIONS Page 2 of 8 Project No.: 1538880 Made by: SPS -_ Site Name: North Weld Landfill, Unit 2 Checked by: -c2.10-1A1 OMW Date: December 21, 2016 Reviewed by: JAR 7 alt i n Event Des(inches) Precipitation Depth 2 -year, 24 -hour 1.76 5 -year, 1 -hour 1.15 25 -year, 24 -hour 3.38 100 -year, 1 -hour 2.78 100 -year, 24 -hour 4.66 • Hydrologic soil group (HSG) B soils were determined to be the underlying soil conditions for all upgradient areas affecting the site based on the effective NRCS soil mapping (NRCS 2016), provided in Appendix A-1 , ■ Composite SCS curve numbers (CN) were developed for all basins based on the following: • CN = 84 for landfill surface (RUST 1997) • CN = 85 for agricultural lands, fallow, poor cover, HSG B soils (NRCS 1986) • CN = 98 for pond areas (NRCS 1986) • Hydrologic modeling: • SCS Type II synthetic rainfall distribution used based on site location • TR-55 time of concentration method (NRCS 1986) • Lag time is equal to 60 percent of the time of concentration. The minimum lag time is 3.6 minutes, based on a minimum time of concentration of 0.1 hour (NRCS 1986) • Maximum length of sheet flow is 300 feet (NRCS 1986) ■ Hydraulic structures (channels, culverts, energy dissipaters, etc.) designed for the 100 -year, 24 -hour peak discharge: • Bench, perimeter, and run-on channel design: Channels to be lined with grass or turf reinforcement matting (TRM) Manning's roughness coefficients of 0.035 (for design capacity) and 0.030 (for design velocity) were assumed for both grass and TRM linings Maximum design velocity for grass -lined channels = 5.5 feet per second Freeboard = one foot minimum All channels will be trapezoidal with the following cross section properties: Channel Type Yp Bottom (freet Width y Side Slope H�V p � � Bench 8 4:1 (bench side), 3:1 (berm side) Perimeter 12 or 18 3:1 a Run-on 5 3:1 x:ktucsonlprojects\l5proj\1538680 north weld landfill\1538880_appa run-on&runoff calcs_20161221.docx Golder Associates CALCULATIONS Page 3 of 8 Project No.: 1538880 Made by: SPS:1--K� `_- Site Name: ' North Weld Landfill, Unit 2 Checked by: DIM r ` / Date: December 21, 2016 Reviewed by: _ JARAi' • Downchute channel design: Channels to be lined with articulated concrete blocks (ACB) or riprap - Manning's roughness coefficient of 0.026 (for both design capacity and velocity) was assumed for ACB Manning's roughness coefficients of 0.040 (for design capacity) and 0.035 (for design velocity) were assumed for riprap Riprap will be specified for required D50 of 24 inches or less Freeboard = one foot minimum All channels will be trapezoidal with 3:1 side slopes and 20 -foot minimum bottom width • Culvert design: Minimum diameter = 18 inches (UDFCD 2016a) Culvert material to be either reinforced concrete pipe (RCP) or high -density polyethylene (HDPE) pipe, both with assumed Manning's n values of 0.012 Ratio of design headwater to diameter (HW/D) less than 1.5 (Weld County 2016) ■ Retention design (Weld County 2016): • Required storage volume = 1.5 x (100 -year, 24 -hour runoff volume) • 4(H):1(V) side slopes or flatter • Basin freeboard = one foot minimum • Emergency spillway designed to convey 100 -year, 1 -hour peak discharge at maximum depth of 6 inches 4.0 CALCULATIONS Four basins (Basin R1 — R4) have been delineated north of the expansion area to reflect the run-on from existing watersheds that will impact the Facility (see Figure 2 of the Drainage Report). The results from the hydrologic routing model developed for these basins will be used as the basis for sizing the run-on collection channels. Thirteen basins (Basins D1 —D13) have been delineated to determine the runoff from the proposed Facility expansion area (see Figure 3). The hydrologic modeling was developed to combine and route these basins per the proposed grading plan in order to properly size the required channels, downchutes, and retention basin. Runoff from all the delineated basins will report to the proposed retention basin in the southeast corner of the Facility. The HEC-HMS model inputs and outputs are included as Appendix A-1. Channel design calculations are also provided in Appendix A-1. A stilling basin will be placed directly at the toe of the downchute; supporting calculation and documentation for that design are included in Appendix A-2. x:\tucsan\projects115proj\153•588(7 north weld landfill\158888(} appa run-on&runDff calcs_20161221 docx Golder Associates CALCULATIONS Page 4 of 8 Project No.: 1538880 Made by: SPS 2 Site Name: North Weld Landfill, Unit 2 Checked by: DMW - r- Date: December 21, 2016 Reviewed by: JAR ,•, _ 5a0 RESULTS 5.1 Run-on Analysis One continuous run-on channel has been designed along the west and north perimeter of the Facility. Four channel sections were evaluated to account for the run-on from basins R1 through R4 each contributing to this channel. The channels are located within the drainage basins delineated in Figure 2 with alignments and the typical section shown in Figures 4 and 5, respectively. A summary of the 100 -year, 24 -hour design flows, flow depths and velocities for each section are provided in Table 1, Table 1: Run-on Channel Design Summary Basin Location 100 -year, Peak 24 -hour Discharge (cfs) Side Slope (H :'V) Bottom Width (feet) Total Depth (feet) Peak Velocity (fps)f Channel Lining R1 93.4 3:1 5 3.1 5.9 Grass R2 119.4 3:1 5 6.1 Grass 3.1 R3 125.8 3:1 5 3,1 6.1 Grass R4 165.8 3:1 5 3.1 8.3 Grass 5.2 Runoff Analysis 5.2.1 Channel Design Five bench channel sections, four perimeter channel sections, and three downchute channel sections have been provided to collect and convey runoff generated within the Facility. The channels are located within the drainage basins delineated in Figure 3 with alignments and typical sections shown in Figures 4 and 5, respectively. A summary of the 100 -year, 24 -hour design flows, flow depths, and velocities for these channels are provided in Tables 2 through 4. Table 2: Bench Channel Design Summary Basin Location 100 -year, Peak Discharge (cfs) 24 -hour Side (H:V) Slope Bottom Width (feet) Peak Velocity f (Rs) Channel Lining Total Depth (feet) D1126.6 4:1 (L), 3:1 (R) 8 3.0 I 7.0 Grass D2 84.8 4:1 (L), 3:1 (R) 8 3.0 6.2 Grass O3 153.3 3:1 (L), 4:1 (R) 8 3.0 7.4 Grass D4 208.7 3:1 (L), 4:1 (R) 8 1 3.0 8.0 Grass D5 108.7 3:1 (L), 4:1 (R) 8 3.0 6.7 Grass x:ktucson\projects\15projk153888d north weld landfilll1538880 apps run-on&runoff calcs_20161221.docx Golder Associates CALCULATIONS Page 6 of 8 Project No.: 1538880 Made by: SPS Site Name: North Weld Landfill, Unit 2 Checked by: DMW,-, Date: December 21, 2016 Reviewed by: JAR Table 3: Downchute Channel Design Summary Basin Location 100 -year, Peak 24 -hour Discharge (cfs) Side Slope (H:10 Bottom Width (feet) Peak Velocity (fps) Channel Lining Total Depth (feet) D6 1.5 3:1 3.0 _. 2.6 6 inches dumped or AC B riprap D7 236.5 I 3:1 20 I 3.0 19.1 18 inches dumped or Ac 6 riprap D8 525.6 3:1 20 3.0 25.4 24 inches grouted or AC riprap B Table 4: Perimeter Channel Design Summary Basin Location 100 -year, Peak Discharge (cfs) 24 -hour g Side Slope (H:V) Bottom Width (feet) Peak Velocity'channel (fps) Lining Total Depth P (feet) D9 60.8 3:1 12 3.0 4.5 Grass D10 99.6 3:1 12 3.0 5.3 Grass D11 645.7 3:1 18 4.0 8.9 TRM D12 40,2 3:1 12 3.0 4,4 Grass D13 645.7 3:1 20 4.0 8.7 TRM A stilling basin has been designed at the toe of the downstream -most downchute located in Basin D8. This stilling basin will be boulder -lined to facilitate energy dissipation and will be a minimum of 33 -feet long, sufficient to contain the anticipated hydraulic jump that would form during the 100 -year, 24 -hour event. 5, 2.2 Low-water Crossing At the junction of perimeter channels for Basins D 11 and D12, the combined runoff will be directed into the on -site retention basin by an at -grade low-water roadway crossing of the perimeter road and a short perimeter channel section. This depressed roadway area will be ACB-lined for improved stability. This crossing has been designed to limit the flow depth to 1 foot or less during the 100 -year, 24 -hour event. Flow depth calculations for this crossing are provided with the channel calculations in Appendix A-1. The runoff entering the retention basin is expected to form a hydraulic jump upon reaching the basin floor. To minimize the potential for erosion, 18 -inch median diameter dumped riprap will be extended through the basin inlet and along the basin floor for approximately 20 feet, the estimated length of the hydraulic jump. -r x:\tucson\projectsll5proj\1538680 north weld landfill\1538880_appa run-on&runoff calcs 20161221.docx Golder Associates CALCULATIONS Page 6 of 8 Project No.: 1538880 Made by: SPS Weld Landfill, Unit 2 Checked by: DMW - Site Name:North Date: December 21, 2016 Reviewed by: JAR 5.2.3 Culvert Design Culverts have been designed where the proposed access road crosses two existing Unit 1 drainage facilities near the southwest corner of Unit 2: an existing bench channel and an existing perimeter channel. As there will be no modifications to these existing drainage structures, the design discharges have been referenced from previous designs. For the perimeter channel culvert crossing, the referenced design discharge is 30 cubic feet per second (cfs), which takes into account the design update for the Unit 1 haul road improvements recently submitted to Weld County (Golder 2016). The bench channel design was included as part of the original site development plan (RUST 1996), but no design discharge was available for reference. The culvert design flow used for this crossing is 5 cfs, which is based on the flow capacity using the existing channel dimensions and bed slope and assuming one foot of freeboard is provided. The channel capacity calculation is provided in Appendix A-3. The culvert design is summarized in Table 5. Table 5: Access Road Culvert Design Summary Location Pipe Diameter QDESIGN (cfs) Headwater Design Depth (feet) Available Headwater Depth (feet) HW/D and Type Perimeter Channel 36 -inch RCP 301 2.6 4.0 0.9 Bench Channel 18 -inch HDPE 52 1.4 3.0 0.9 Notes 1). Referenced from previous design (Golder 2016). 2). Developed from previous design (RUST 1996). 5.2.4 Retention Basin Design The 100 -year, 24 -hour runoff volume reporting to the proposed retention basin in the southeast corner of the Facility is 44.1 acre-feet. The design retention volume per Weld County design standards is 1.5 times the 100 -year, 24 -hour volume or 66.2 acre-feet. The design volume is met at elevation 5,066.2 feet and the basin crest elevation is 5,070 feet, exceeding the minimum 1 -foot basin freeboard criteria. In accordance with Weld County design standards, an emergency spillway is provided to convey the 100 -year, 1 -hour peak discharge of 296 cfs that reports to this basin. A 315 -foot -long spillway is required to convey the peak discharge at a maximum depth of 6 inches (0.5 feet). The spillway invert elevation is 5,069 feet and the flow depth at the peak discharge (296 cfs) is 0.5 feet. Another retention basin requirement is that the 100 -year, 24 -hour runoff volume discharges the basin within 72 hours. This requirement will be met by infiltration through the in situ underlying soil. Based on the in situ hydraulic conductivity of 3.6 x 10-3 centimeters per second (cm/sec) (5.1 inches/hour), it is estimated x:\tucsonkprojects115proj 153B88O north weld landfi llti153888Q_appa run-on&runaff calcs_20161221.docx Golder Associates CALCULATIONS Page 7 of 8 Project No.: 1538880 Made by: SIBS c;.) Site Name: North Weld Landfill, Unit 2 Checked by: DMW Ned, ivy &Ai Date: December 21, 2016 Reviewed by: JAR .47 that total runoff volume will discharge in approximately 25 hours. Drain time calculations are provided in Appendix A-4. 6.0 REFERENCES Bentley Systems Inc. (Bentley). 2009. FlowMaster [software package]. Version V8i. November 2009. Federal Highway Administration (FHWA). 2014. HY-8 Culvert Analysis Program [computer software]. Version 7.3. August 2014. Golder Associates Inc. (Golder). 2016. Supporting Hydrologic and Hydraulic Calculations; North Weld Landfill Paving Improvements (Letter). September 22, 2016. National Oceanic and Atmospheric Administration (NOAA). 2013. Precipitation -Frequency Atlas of the United States, NOAA Atlas 14, Volume 8, Version 2.0. S. Perica, D. Martin, S. Pavlovic, I. Roy, M. St. Laurent, C. Trypaluk, D. Unruh, M.Yekta, G. Bonnin. NOAA, National Weather Service. Silver Spring, Maryland. 2013. Available online: http://hdsc.nws.noaa.govlhdsclpfds/pfds_printpage.html?Iat=40.5913&ton=-104.8250&dat (accessed August 25, 2016). Robinson, KM., G.E. Rice, and I.C. Kadavy. 1998. Design of Rock Chutes. March 1998. Rust Environment and Infrastructure, Inc. (RUST). 1996. Site Development Plan for Waste Management Disposal Services of Colorado, Inc., North Weld Sanitary Landfill. Weld County, Colorado. January 1996. RUST. 1997. Updated Design and Operations Plan, North Weld Landfill, Ault, Colorado. November 1997. fa United States. Army Qorps of Engineers (USAGE). 2013, HEC-HMS Hydrologic Engineering Center — Hydrologic Modeling System (HEC-HMS) [computer software]. Version 4.0, December 2013. United States Department of Agriculture (USDA). Natural Resources Conservation Service (MRCS). 2016. Custom Soil Resource Report for Weld County, Colorado, Southern Part. Extracted from Web Soil Survey application August 25, 2016. Urban Drainage and Flood Control District (UDFCD). 2016a. Urban Storm Drainage Criteria Manual, Volume 1, Management, Hydrology and Hydraulics. January 2016. UDFCD. 2016b. Urban Storm Drainage Criteria Manual, Volume 2, Structures, Storage and Recreation. January 2016. Weld County. 2016. Weld County Charter and County Code. April 2016. x:ktucson\projects\l5proj\1538880 north weld Iandlill\1538880_appa run-on&runoff talcs 20101221.docx Golder Associates APPENDIX Ant APPENDIX A -'I -'I Precipitation Frequency Data Serer Page 1 of 4 NOAA Atlas 14, Volume 8, Version 2 Location name: Ault, Colorado, US's Latitude: 40.5918°, Longitude: -104.8250° Elevation: 5107 ft* * source: Google Maps POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Try paluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOM, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration 5 -min 10 -min 15 -min 30 -min 60 -min 2 -hr 3 -hr 6 -hr 12 -hr 24 -hr 2 -day 3 -day 4 -day 7 -day 10 -day 20 -day 30 -day 45 -day 60 -day Average recurrence interval (years) 1 0.241 (0.193-0.3QQ 0.353 (0.282-0.439 0.431 (0.344-0.536 0.585 (Q.468-0.728 0.719 (0.575-0.895 0.853 (0.685-1.05) 0.924 (0.745-1.14) 1.05 (0.855-1.28) 1.25 (1.02-1.51) 1.51 (1.24-1.81) 1.73 (1.43-2.05) 1.89 (1.57-2.23) 2.01 (1.67-2.37) 2.27 (1.90-2.66) 2.51 (2.10-2.93) 3.25 (2.74-3.75) 3.83 (3.24-4.41) 4.52 (3.84-5.17) 5.05 (4.30-5.76) 2 0.291 (0.232-0.362) 0.425 (0.339-0.530) 0.519 (0.414-0.646) 0.703 (0.561-0.875) 0.865 (0.690-1.08) 1.03 (0.824-1.27) 1.11 (0.895-1.37) 1.28 (1.04-1.56) 1.50 (1.22-1.82) 1.76 (1.44-2.11) 2.03 (1.68-2.41) 2.20 (1.82-2.60) 2.33 (1.94-2.75) 2.67 (2.23-3.13) 2.97 (2.49-3.46) 3.78 (3.18-4.37) 4.41 (3.73-5.08) 5.18 (4.39-5.93) 5.81 (4.94-6.63) 5 0.386 (0.307-0.482) 10 0.480 (0.379-0.602 0.566 0.703 (0.450-0.706) (0.555-0.881 0.690 (0.549-0.861) 0.932 (0.741-1.16) 1.15 (0.916-1.44) 1.37 (1.10-1.70) 1.49 (1.19-1.83) 1.72 (1.39-2.10) 1.97 (1.60-2.39) 2.23 (1.82-2.68) 2.57 (2.11-3.06) 2.75 (2.27-3.26) 2.90 (2.40-3.43) 3.35 (2.79-3.94) 3.73 (3.11-4.36) 4.64 (3.89-5.37) 5.34 (4.50-6.16) 6.24 (5.28-7.16) 7.01 (5.95-8.01) 0.858 (0.677-1.08) 1.16 (0.914-1.45) 1.44 (1.14-1.80) 1.72 (1.37-2.14) 1.87 (1.49-2.31) 2.15 (1.72-2.64) 2.41 (1.95-2.94) 2.68 (2.18-3.23) 3.06 (2.50-3.66) 3.25 (2.66-3.87) 3.41 (2.81-4.05) 3.94 (3.26-4.64) 4.36 (3.62-5.12) 5.34 (4.46-6.22) 6.10 (5.12-7.06) 7.09 (5.97-8.16) 7.96 (6.72-9.14) 25 0.631 (0.489-0.841) 0.923 (0.716-1.23) 1.13 (0.873-1.50) 1.52 (1.18-2.03) 1.90 (1.48-2.55) 2.29 (1.79-3.04) 2.49 (1.96-3.29) 2.83 (2.23-3.69) 3.11 (2.46-3.99) 3.38 (2.70-4.30) 3.80 (3.03-4.75) 4.00 (3.20-4.97) 4.18 (3.36-5.16) 4.77 (3.83-5.81) 5.25 (4.22-6.34) 6.30 (5.09-7.51) 7.13 (5.78-8.44) 8.22 (6.69-9.66) 9.22 (7.51-10.8) 50 0.763 (0.572-1.02) 1.12 1.33 1.57 1.93 (0.838-1.50) (0.960-1.82) (1.08-2.20) (1.26-2.75) 1.36 1.63 1.92 2.35 (1.02-1.82) (1.17-2.22) (1.32-2.68) (1.54-3.35) 100 0.910 (0.655-1.24) 200 1.07 (0.738-1.50) 500 1.31 (0.863-1.88 1.84 (1.38-2.47) 2.32 (1.74-3.11) 2.20 (1.58-3.01) 2.78 (2.00-3.80) 2.60 (1.79-3.63) 3.30 (2.27-4.61) 3.18 (2.09-4.55) 4.06 (2.67-5.80) 2.79 3.36 3.99 4.93 (2.11-3.72) (2.44-4.56) (2.77-5.54) (3.27-6.99) 3.04 3.66 4.36 5.40 (2.31-4.03) (2.68-4.95) (3.05-6.03) (3.60-7.62) 3.42 (2.62-4.48) 3.70 (2.85-4.79) 3.99 (3.09-5.11) 4.42 (3.44-5.57) 4.63 (3.61-5.80) 4.82 (3.77-6.01) 5.44 (4.27-6.70) 5.94 (4.67-7.26) 7.04 (5.57-8.49) 7.90 (6.28-9.47) 9.07 (7.23-10.8) 10.1 (8.11-12.0) 4.08 (3.00-5.45) 4.36 (a23-5.75) 4.66 (3.48-6.Q9) 5.09 (3.82-6.55) 5.30 (4.00-6.78) 5.50 (4.16-7.00) 6.13 (4.66-7.72) 6.64 (5.06-8.29) 7.76 (5.95-9.57) 8.66 (6.67-10.6) 9.89 (7.65-12.0) 11.0 (8.55-13.3) 4.82 (3.39-6.58) 5.08 (3.60-6.85) 5.40 (3.86-7.22) 5.81 (4.18-7.65 6.03 (4.36-7.89) 6.23 (4.52-8.12) 6.86 (5.0Q-8.83) 7.36 (5.39-9.40) 8.49 (6.27-10.7) 9.42 (6.99-11.8) 10.7 (7.97-13.3) 11.9 (8.88-14.7) 5.89 (3.97-8.22) 6.13 a (4.16-8.45) 6.47 (4.44-8.84) 6.83 (4.72-9.21) 7.06 (4.91-9.46) 7.26 (5.07-9.69) 7.85 (5.52-10.4) 8.32 (5.87-10.9) 9.45 (6.72-12.2) 10.4 (7.45-13.4) 11.7 (8.43-14.9) 12.9 (9.34-16.4) 1000 1.51 (0.958-2.16 2.22 (1.40-3.17) 2.70 (1.71-3.86) 3.67 (2.32-5.24) 4.69 (2.97-6.70) 5.71 (3.65-8.08) 6.26 (4.03-8.82) 6.78 (4.41-9.46) 6.99 (4.59-9.66) 7.35 (4.88-10.1) 7.65 (5.13-10.4) 7.89 (5.33-10.6) 8.09 (5.49-10.9) 8.63 (5.90-11.5) 9.06 (6.23-12.0) 10.2 (7.07-13.3) 11.1 (7.79-14.5) 12.5 (8.78-16.2) 13.7 (9.69-17.7) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid. PMP values. Please refer to NIOAA Atlas 14 document for more information. Back to Top PF graphical http://hdsc.n s.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=40.5918 lon=-104.8250&dat... 8/25/2016 Precipitation Frequency Data Server Page 2 of 4 Z • 1 5- 10 ao IVO 04 a . 6 • 4 4 4 • 4 .1 1 '4 4 4 4 :4 4 • 4 V 4 .q 4 .4 4 -4- • 4 4 4 4 • 4 4 1 f • Y 4 V . c c 1 M • • r Duration 2 NOAA Atlas Mr Volume 8., Version 2 • • • • • e •_ 1 1 I r • i • • / • 1 e to • 1 • • e 4 • 1 1 P 1 I • 1 t • • i • 1 4 ♦ 1 • 4 r e 1.. .•--J.•-_...1 • • • 4 4: i 4 • 1 M • M • 1 f • • 1 1 F • Y 1 • • • 1 re re re —0 —013 • Y • 10 25 50 100 200 Back to Top Average recurrence interval (years) RavelTh : 4i 1 I >i >4 rao AI re 73 73 —0 0 0 L(1 O rni it, gel 500 1000 Maps & aerials ,;.Thu Aug 2520:01:552016 Small scale terrain ��w�u Laramie lo- tirra! crest Cheyenne Q 10 w Fotrt -41 MS le INE jr; PaSY, ovelan "all all"� V Greer y T j M k .1. a 'Fir- e-, Gat: e _80under a Forge cegt'. Denver 4 Aurora ,came Scottsbktiff 0 Alliance 0 `;•iclrney Pownee National Qfiri1ng °MMSS1ind 50 km recurrence IIni a cal iyears.l 1 10 25 50 100 200 500 100E Duration 10-rn'in 15-m rr� 30 -min P FLArgnmund a14w•'"IA PIN I 2 -day 3 -clay 4 -day i A_,1.1 ga., I tir ut*F •__rl SF svvx 30 -day 45 -day 60 -day Ogallala Map Report a map error http://hdsc.n s.noaa.gov/hdsc/p d /p d firi.ntp . e.htrnl 'l .t=40.5918&tan=-104.8250&dat,.. 8/25/2016 Precipitation Frequency Data Serer Page 3 of 4 Large scale terrain 25 Go gie 7 Google 1 2 km' Large scale map 84 23 23 2 k 25 36 I 22 Large scale aerial 24 N Ell Map ,$eport a rrra ► error - 71 I 24 Map , Report a reap error !rna.,ery a Reportmap error IIMPI0S Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 http://hdsc.n s.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=40.5918 lon=-104.8250&dat... 8/25/2016 APPENDIX A-1-2 APPENDIX A-1-3 TABLE '1 SUBBASIN SUMMARY TABLE North Weld Landfill (Unit 2) Run -On and Runoff Hydrology Project Number: 1538880 Desi a n Storm 100 -Year Reccurence Interval Storm Duration (hours) 2 -Year Depth (inches) 100 -Year Depth (inches) Storm Distribution 24 1.76 4.66 II Date: 12/19/16 By: Chkd: _SIDS DMW Apprvd: JAR Subbasin ID Subbasin Area (ft2) Subbasin Area (acres) Subbasin Area (sq mile) CN=85 CN=84 CN=98 Composite SCS Curve No. S = 1000 - Unit Runoff Q (in) Runoff Volume (ac -ft) Runoff Volume (fta) Fallow Agricultural Lands, B Soils Landfill Surface Pond Area (acres) 10 CN D1 1,303, 704 29.9 0.0468 29.9 CN = 84 1.90 2.96 7.38 321,689 D2 944,543 21.7 0.0339 21.7 CN = 84 1.90 2.96 5.35 233,066 D3 1,496,125 34.3 0.0537 34.3 CN = 84 1.90 2.96 8.47 369,169 D4 635,291 14.6 0.0228 14.6 CN = 84 1.90 2.96 3.60 156,758 D5 1,128, 332 25.9 0.0405 25.9 CN = 84 1.90 2.96 6.39 278,416 D6 14,466 0.3 0.0005 0.3 CN = 84 1.90 2.96 0.08 3,569 D7 13,323 0.3 0.0005 0.3 CN = 84 1.90 2.96 0.08 3,287 D8 6,476 0.1 0.0002 0.1 CN = 84 1.90 2.96 0.04 1,598 D9 663,358 15.2 0.0238 15.2 CN = 84 1.90 2.96 3.76 163,684 D10 599,984 13.8 0.0215 13.8 CN = 84 1.90 2.96 3.40 148,046 D 11 196,832 4.5 0.0071 4.5 CN = 84 1.90 2.96 1.11 48,568 D12 381,441 8.8 0.0137 8.8 CN = 84 1.90 2.96 2.16 94,121 D13 315,058 7.2 0.0113 0.3 6.9 CN = 97 0.31 4.31 2.60 113,115 R1 836,160 19.2 0.0300 16.3 2.9 CN = 85 1.76 3.06 4.89 212,890 R2 360,374 8.3 0.0129 6.6 1.6 CN =85 1.76 3.06 2.11 91,753 R3 80,352 1.8 0.0029 0.9 0.9 CN =84 1.90 2.96 0.46 19,827 R4 779,252 17.9 0.0280 14.5 3.4 CN = 85 1.76 3.06 4.55 198,401 Total: 9,755,071 223.95 0.35 56.43 2,457, 955 X:kTucson4Projectst.15proj'15388-B0 North Weld Landfill.Attachments'NWLF_BasinH&H.xlsm CSS . tat le Colder Associates TABLE 2 BASIN TIME OF CONCENTRATION CALCULATIONS North Weld Landfill (Unit 2) Run -On and Runoff Hydrology Project Number: 1538880 Date: 12/19/16 By: SFS Chkd: DMW Apprvd: JAR Flow Segment 1 Flow Segment 2 Subbasin ID I Subbasin Area (sq mile) Composite Curve Number I otal Lag (0.61-c) (min) I otal Travel Time (min) Type of Flow Length (ft) Slope (ftfft) Roughness Condition'' I ypical Hydraulic Radius (Channel Only) (ft) Travel Time (min) Type of Flow Length (ft) Slope (tUft) Roughness Condition(ll I ypical Hydraulic Radius (Channel Only) (ft) Travel Time (min) D1 0.0468 84 6.5 10.8 Sheet 289.9 0.048 A Smooth 2.7 Shallow 434.2 0.044 U Unpaved 2.1 D2 0.0339 84 aA 14.0 Sheet 293.5 0.049 A Smooth 2.7 Shallow 845.3 0.070 U Unpaved 3.3 03 0.0537 84 5.1 8.5 Sheet 75.8 0.050 A Smooth 0.9 Channel 2957.2 0.020 G Grass -lined 1.12 7.6 04 0.0220 84 6.3 10.5 Sheet 298.2 0.184 A Smooth 1.6 Channel 2646.3 0.020 G Grass -lined 0.75 3.9 D5 0.0405 84 6.7 11.2 Sheet 281.3 0.048 A Smooth 2.6 Shallow 470.5 0.047 U Unpaved 2.2 D6 0.0005 64 1.8 3.0 Sheet 127.5 0.055 A Smooth 1.3 Channel 200.9 0.224 R Ripra.p 0.04 1.6 D7 0.0005 84 1.1 1.9 Sheet 26.0 0.058 A Smooth 0.4 Channel 260.2 0.264 A ACE 0.03 1.5 08 0.0002 84 0.8 1.4 Sheet 26.2 0.057 A Smooth 0.4 Channel 128.8 0.264 A ACE 0.02 1.0 D9 0.0238 84 7.9 13.2 Sheet 247.6 0.048 A Smooth 2.4 Shallow 213.1 0.231 U Unpaved 0.5 D10 0.0215 84 8.9 14.9 Sheet 233.5 0.210 A Smooth 1.3 Channel 3051.7 0.012 G Grass -lined 0.72 13.6 011 0.0071 84 4.2 7.0 Sheet 155.0 0.214 A Smooth 0.9 Channel 920.8 0.012 G Grass -lined 0.39 6.1 012 0.0137 84 4A 7.3 Sheet 129.0 0.068 A Smooth 1.2 Shallow 292.6 0.195 U Unpaved 0.7 D13 0.0113 97 4.4 7.4 Sheet 188.2 0.036 A Smooth 2.2 Shallow 101.4 0.1x8 U Unpaved 0.3 R1 0.0300 85 1.4 2.3 Sheet 69.3 0.075 A Smooth 0.7 Channel 1758.8 0.314 G Grass -lined 0.72 '1.5 R2 0.0129 85 10.1 16.9 Sheet 218.6 0.023 B Fallow 9.7 Shallow 650.1 0.019 U Unpaved 4.9 R3 0.0029 84 9.1 15.2 Sheet 190.3 0.011 D Fallow 11.9 Shallow 237.9 0.043 U Unpaved 1.2 R4 0.0280 85 17.5 29.2 Sheet 138.0 0.027 B Fallow 6.3 Shallow 2520.6 0.016 U Unpaved 20.3 Notes: (1) Refer to Attachment A for Roughness Condition descriptions and Tc Coeffiecients. i;'.TucsoiiTrojects\15proj'.1528880 NorthVJ_!Id LandflII\Attechmons:'.N'WLL_BasinH&:H.xlsini t i�a t:offir WAss&TTates TABLE 2 BASIN TIME OF CONCENTRATION CALCULATIONS North Weld Landfill (Unit 2) Run -On and Runoff Hydrology Project Number: 1538880 Date: 12119/16 By: SFS Chkd: DMW Apprvd: JAR Flow Segment 3 Flow Segment 4 Subbasin ID Subbasin Area (sq mile) Composite Curve Number Type of Flow Length (ft) Slope (ftift) Roughness Condition* I ypical Hydraulic Radius (Channel Only) (ft) Travel Time (min) Type of Flow Length (ft) Slope (ftlft) Roughness Condition* I ypical Hydraulic Radius (Channel Only) (ft) Travel Time (min) D1 0.0468 84 Channel 2182.6 0.020 G Grass -lined 1.02 6.0 02 0.0339 84 Channel 2577.8 0.020 G Grass -lined 0.85 8.0 D3 0.0537 84 D4 0.0228 84 D5 0.0405 84 Channel 2197.2 0.020 G Grass -lined 0.95 6.3 06 0.0005 84 D7 0.0005 84 D8 0.0002 84 D9 0.0238 84 Channel 2480.2 0.013 G Grass -lined 0.76 10.4 D10 0.0215 84 011 0.0071 84 D12 0.0137 84 Channel 1267.0 0.017 G Grass -lined 0.59 5.4 D13 0.0113 97 Shallow 518.5 0.012 lJ 50 R1 0.0300 85 R2 0.0129 85 Channel 500.0 0.012 G 0.68 2.3 R3 0.0029 84 Channel 300.6 0.012 G 0.35 2.2 R4 0.0280 85 Channel 788.0 0.022 G 0.75 2.5 Notes: (1) Refer to Attachment A for Roughness Condition descriptions and To Coeffiecients. i;',TucsoiiTrojects\15proj'.1538880 Ncorth''N_!Id LandflII\Attechmcnts:'.N'AIL_BasinH&:H.xlsini 'ArQ, WAss&TTates TABLE 3 FLOW RESULTS FROM HEC-HMS North Weld Landfill (Unit 2) Run -On and Runoff Hydrology Project Number: 1538880 HEC-HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Run -On and Runoff 100-yr, 24 -hr 24 hour, 1 min Hydrologic Element Drainage Area (sq mile) Peak Discharge (cfs) Time Peak of Total Volume (ac -ft) D1 0.047 126.6 02Jan2050, 00:00 7.3761 D10 0.022 52.7 02Jan2050, 00:02 3.3858 D11 0.007 21 01Jan2050, 23:57 1.1199 D12 0.014 40.2 01Jan2050, 23:58 2.1607 D13 0.011 42.9 01Jan2050, 23:57 2.594 D2 0.034 84.8 02Jan2050, 00:02 5.3395 D3 0.054 153.3 01Jan2050, 23:58 8.4675 D4 0.023 62.1 02Jan2050, 00:00 3.5937 D5 0.041 108.7 02Jan2050, 00:00 6.3827 D6 0.001 1.5 01Jan2050, 23:57 0.0789 D7 0.001 1.5 01Jan2050, 23:57 0.0789 D8 0.000 0.6 01Jan2050, 23:57 0.0316 D9 0.024 60.8 02Jan2050, 00:01 3.7493 Junction-Downchutel 0.088 236.5 02Jan2050, 00:00 13.8377 Junction-Downchute2 0.199 525.6 02Jan2050, 00:01 31.2589 Junction -D10 0.045 99.6 02Jan2050, 00:07 7.0791 Junction -D11 0.265 645.7 02Jan2050, 00:03 41.5751 Junction -D4 0.077 208.7 02Jan2050, 00:02 12.0052 Junction -R1 -R2 0.043 119.4 01Jan2050, 23:59 6.9688 Junction -R2 -R3 0.046 125.8 02Jan2050, 00:00 7.4192 Junction -R4 0.074 165.8 02Jan2050, 00:03 11.9373 Junction -Stilling Basin 0.244 604.1 02Jan2050, 00:02 38.3672 Reach -D10 Perimeter Channel 0.024 60 02Jan2050, 00:09 3.6933 Reach -011 Perimeter Channel 0.244 603.1 02Jan2050, 00:03 38.2945 Reach -D11 -D12 -to -Basin 0.265 645.7 02Jan2050, 00:03 41.5454 Reach -D4 Bench Channel 0.054 152 02Jan2050, 00:03 8.4115 Reach -D6 -D7 0.088 236.2 02Jan2050, 00:00 13.8353 Reach -D7 -D8 0.199 525 02Jan2050, 00:01 31.2566 Reach -R1 -R2 0.030 92.9 01Jan2050, 23:58 4.8733 Reach -R2 -R3 0.043 119.1 02Jan2050, 00:00 6.9625 Reach -R3 -R4 0.046 125.5 02Jan2050, 00:02 7.4004 R1 0.030 93.4 01Jan2050, 23:57 4.8836 R2 0.013 31 02Jan2050, 00:03 2.0954 R3 0.003 7 02Jan2050, 00:02 0.4567 R4 0.028 50.8 02Jan2050, 00:10 4.5369 Sink-RetBasin 0.276 674.5 02Jan2050, 00:03 44.1394 Sink-Runon 0.074 165.8 02Jan2050, 00:03 11.9373 X:ITucsonlPrcjects115proj\1538880 North Weld LandfillRAttachmentslNWLF BasinH&H.xlsm roes viv‘w r Golder Associates z O H 0 U J c g C� J W z 2 IC C) T r { DMW Cif} -, iD: ii ii co Crt r--4in N t 0 c C J z va c}W z e 0.. Channel Roughness Parameters 1 Mannings 'n' for Stability (Velocity Calcu lation} 0000 co C7 0 co C7 0 C o CD 0© co CD CDCDCDCOCD 0, CD O CA 0 O CV 0 0 CA CD O 01 C7 6 CD 0) CJ 0 CD C7 C7 6 CD00007 07 0 0 OD 0 0 C, 0 0 OD 0 6 CO C7 0 CD OD CD 6 41 01 O O co CA C7 0 Mannin€gs 'n' for Capacity (Depth Calculation) 0.035 CE0.° L3 Cf3 000000 0di66666 LJ ce) Lo Cf1 u7 RI C CM C) CV CCJ CD CD 0.035 in CD 0 666 la OD C7 0 cJ CD LC'} CD C3 6 Le) cO C]0 6666 Ll CD LO op CD C7 v C7 (D CV C7 O Design Channel Lining Turf Reinf. Turf Reinf. Turf Reinf. Turf Reinf. Turf Reinf_ ACB ACB ACB ca) c tin (13 0 C) c Turf Reinf. W a CO CA O Grass -lined Turf Reinf. Turf Reinf. Turf Reinf. Turf Rein!. a cu a ACB C GO 0 f— HI— HH <<<C70E-00HHII—I—Cr C Channel Design Geometry fl.c Ecg.E .C t 3.0 3.0 3.0 0 c._. cei 3.0 3.0 0 � 3.0 0 el 3.0 4.0 1. -c 4.0 v- ce5 v- v - cri 2.0 r- c Bottom Width (ft) 00 00 00 00 00 CA CV 03 T 12 'r t 20 UD it, ill Lil 50 CO 3.0 3.0 4.0 0 4.0 3.0 00 3.0 0000 3.0 00 3.0 3.0 m a r 4-2 ° _ J 4.0 0 '*.f' 3.0 0 € i 3.0 3.0 0 M 3.0 0 M 3.0 3.0 0 P'} 0 C40 3.0 3.0 3.0 3.0 3.0 0 cp 0 •.,.. 4'l".. CO i V t tzu En O C1! on o O N 0 6 O Cl 0 0 G CV +0 o O N O 6 O Ct7 N 6 N CO {V 6 Cl 4+a N o N r O 6 N r- 0 6 N r- 0 6 I- N Cl. N N Cl N co 6 O v- O 6 C'7 (N C) o CD 6 o Q o o 6 0 6 HEC HMS Element ID for Q r O D2 CO Junction -D4 0 co 0 Junction-Downchutel Junction-Downchute2 cn O Junction -D10 Junction -D11 No Reach -D11 -D12 -to -Basin r c Junction -R1 -R2 Junction -R2 -R3 Junction -R4 Junction -R4 Junction -D11 Q100 from HEC-HMS (cfs) C4 T CO CO 153.3 208.7 f� T 1iJ ID CA 525.6 on (A co CD (0 N 645.7 CD r CO T OD r 00 T 645.7 Reach Designation Bench Channel (D1) Bench Channel (D2) Bench Channel (D3) Bench Channel (D4) Bench Channel (D5) Downchute (D6) Downchute (D7) Downchute (D8) Perimeter Channel (D9) Perimeter Channel (D10) Perimeter Channel (D11) Perimeter Channel (D12) Perimeter Channel (D13) Run -On Channel (R1) Run -On Channel (R2) Run -On Channel (R3) Run -On Channel (R4) Run -On Channel Dissipater Low Water Crossing K_kTucson\Projects\15proj11538880 North Weld LandfillAttachments\NWLF_BasinH&H.xlsrn TABLE 4 CHANNEL HYDRAULIC ALCULATIONS North Weld Landfill (Unit 2) Run -On and Runoff Hydrology PROJECT NO.: 1538880 Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Reach Designation Hydraulic Calculations Channel Evaluations O100 from HEC-HMS (cfs) Maximum Velocity (ftisec) Maximum Normal Flow Depth (ft) Froude Number Normal Depth Shear Stress (Iblf9} Stream Power (W1m2) Top Width of Flow (ft) Top Width of Channel (ft) Available Freeboard (ft) Bench Channel (Dl) 126.6 7.0 1.5 1.22 1.90 192.27 18.6 29.0 1.5 Bench Channel (D2) 84.8 6.2 1.2 1.19 1.54 139.08 16.6 29.0 1.8 Bench Channel (D3) 153.3 7.4 1.7 1.24 2.09 223.77 19.7 29.0 1.3 Bench Channel (D4) 208.7 8.0 2.0 1.26 2.44 284.67 21.7 29.0 1.0 Bench Channel (05) 108/ 6.7 1.4 1.21 1.75 170.16 17.8 29.0 1.6 Downchute (D6) 1.5 2.6 0.03 2.78 0.44 16.9 20.2 38.0 3.0 Downchute (D7) 236.5 19.1 0.6 4.62 9.33 2583.2 23.4 38.0 2.4 < 1/2 %/el. Head Downchute (D8) 525.6 25.4 0.9 4.96 14.90 5482.9 25.5 38.0 2.1 c 1/2 Val. Head Perimeter Channel (D9) 60.8 4.5 1.0 0.91 0.75 49.8 17.9 30.0 2.0 Perimeter Channel (D10) 99.6 5.3 1.3 0.95 1.00 77.6 19.8 30.0 1.7 Perimeter Channel (D11) 645.7 8.9 3.0 1.08 2.32 299.5 36.0 42.0 1.0 Perimeter Channel (D12) 40.2 4.4 0.7 1.03 0.76 48.7 16.3 30.6 2.4 Perimeter Channel (D13) 645.7 8.7 2.9 1.07 2.16 272.6 37.3 44.0 1.1 Run -On Channel (R1) 93.4 5.9 1.7 1.00 1.44 123.3 15.4 23.6 1.4 Run -On Channel (R2) 119.4 6.1 2.0 0.97 1.50 131.9 17.0 23.6 1.1 Run -On Channel (R3) 125.8 6.1 2.1 0.97 1.54 137.1 17.3 23.6 1.0 Run -On Channel (R4) 165.8 8.3 2.0 1.31 2.79 333.6 17.2 23.6 1.1 Run -On Channel Dissipator 165.8 3.7 0.9 0.72 0.58 30.9 55.5 68.6 2.2 Low Water Crossing 645.7 7.4 1.0 1.40 1.21 130.3 99.4 120.0 1.0 (1) Note: Comments and Warnings: < 1.0 ft indicates freeboard is less than 1 foot. c 1/2 Vel. Head indicates that the remaining freeboard is less than 1}2 the velocity head (V2/2g) suggesting water may splash out. Warning: VxD>9 indicates that the velocity times the depth is greater than 9 112/sec; which is undesirable and may be ur Unstable V indicates that calculated velocity exceeds the recommended maximum for the lining material. Unstable T indicates that calculated shear stress exceeds the recommended maximum for the lining material. K_kTucson\Projects115proj11538880 North Weld LandfilllAttachments1NWLF_BasinH&H.xlsrn December 2016 1538880 Attachment A Time of Concentration and Mannings Flow Coefficients TR-55 (1986) Sheet Flow Travel time (SCS Upland Method) b.K 0.007 (re L ) 0.5 0.4 (p2) S Where: Tt = travel time (hr); n' = roughness coefficient; L = flow length (ft);. P2 = 2-yr storm depth (inches); s = slope (ft/ft) flow velocity = L/(60Tt) Flow Type Surface Type roughness n Surface Description A B C D 0.011 0.05 0.06 0.17 E F 0.15 0.24 G H 0.41 0.13 I 0.40 J 0.80 Smooth surfaces (concrete, asphalt, gravel, bare soil) Fallow (no residue) Cultivated soils: Residue cover <= 20% Cultivated soils: Residue cover > 20% Grass: Short grass prairie Grass: Dense grasses Grass: Bermuda grass Range (natural) Woods: Light underbrush Woods: Heavy underbrush or Description Smooth Fallow Cover<20 % Cover"20% Short Grass Dense Grass Bermuda Grass Range Light woods Heavy Woods Shallow Concentrated Flow Velocity (SCS Upland Method) v = mSU 5 Where: v = velocity (fps); m = roughness coeffient; S = slope (ft/ft) Flow Type Surface Type Roughness m Surface Description Short Description o 2 P 20.3282 Paved Surfaces Paved co cu. U 16.1345 Unpaved Surfaces Unpaved 0 Channel Flow Velocity (Mannings Velocity) v = 1.49/n Rh/L3S1r2 Where: v = velocity (fps); n = roughness coeffient; Rh = Hydraulic Radius (ft), S = slope (ft/ft) Lining Type Mannings n for Depth Tannings n for Velocity Material Maximum Velocity Maximum Shear Stress A 0.026 0.026 ACB 25 C 0.024 0.022 CSP 50 E 0.025 0.022 Earth -lined 3 G 0.035 0.030 Grass -lined 5 I 0.017 0.013 Ductile Iron 50 P 0.012 0.009 Plastic 25 R 0.040 0.035 Riprap 16 T 0.035 0.030 Turf Reinf. 10 1.5 Z 0.060 0.005 Other 25 XATucson\Projects\15•proj\1588880 North Weld Landfill\Attachments\NWLF_BasinH&H.xlsm Golder Associates December 2016 HEC-HMS Basin Model Schematic ft& Basin Model [Run -On and Runoff] Current Run [Run -On & Runoff-100yr,2dhr] Attachment B HEC-HMS Screen Captures and Inputs I° IftP T 1538880 X;\Tucson\Projects\15proj\1538880 North Weld Landfill\Attachments\NWLFBasin H&H.xism .y!ti Ja r Guider Associates December 2016 Sub Basin Area Subbasin Area (m12) D1 0.046800 D10 0.021500 D 11 0.007100 D12 0.013700 D13 0.011300 D2 0.033900 D3 0.053700 D4 0.022800 D5 0.040500 D6 0.000500 D7 0.000500 D8 0.000200 D9 0.023800 R1 0.030000 R2 0.012900 13 0.002900 R4 0.028000 Attachment B HEC-HMS Screen Captures and Inputs Loss SCS Curve Number Subbasin Initial Abstraction (in) Curve Number Impervious (%) 01 84 0 D10 84 0 D11 84 0 012 84 0 D13 97 0 D2 84 0 D3 84 0 D4 84 0 D5 84 0 06 84 0 D7 84 0 D8 84 0 D9 84 0 R1 85 0 R2 85 0 R3 84 0 R4 85 0 Transform SCS Unit Hydrograph Subbasin Graph Type Lag Time (min) D1 Standard 7 010 Standard 9 D11 Standard 4 012 Standard 4 D13 Standard 4 D2 Standard 8 D3 Standard 5 04 Standard 6 D5 Standard 7 06 Standard 4 07 Standard 4 D8 Standard 4 09 Standard 8 R1 Standard 4 R2 Standard 10 R3 Standard 9 R4 Standard 18 Routing Kinematic Wave Channel Reach Length {ft} Slope (ft/ft) Manning's n Subreaches Invert Shape Diameter {ft} Width (ft) Side Slope (xH:1V) Reach -D10 Perimeter Channel 3065 0.012 0.03 2 Trapezoid 12 3 Reach -D11 Perimeter Channel 940 0.012 0.03 2 Trapezoid 18 3 Reach -D11 -D12 -to -Basin 740 0.023 0 03 2 Triangle 3 Reach -D4 Bench Channel 2680 0.020 0.03 2 Trapezoid 8 3.5 Reach -D6 -D7 270 0.250 0.026 2 Trapezoid 20 3 Reach -D7 -D3 150 0.252 0.026 2 Trapezoid 20 3 Reach -R1 -R2 755 0.013 0.03 2 Trapezoid 5 3 Reach -R2 -R3 375 0.012 0.03 2 Trapezoid 5 3 Reach -R3 -R4 1300 0.022 0 03 2 Trapezoid 5 3 1538880 X:\Tucson'.Projects\1sproj\538880 North Weld Landfill\Attachrnents\NWLF_BasinH&H.xlsrn As.soc1ittes December 2016 Attachment B HEC-HMS Screen Captures and Inputs Is 13lohal Summary Results for Run "Run -On Sc. Run off -100yrreethr" Project: NWLF Simulation Run: Run -On & Runoff-100yr,24hr Start of Run: 01Jan20.50,1 12:00 Basin Model: Ru1r1-On and Runoff End of Run: 02Jan2050, 12:01 Meteorologic Model: 100-yr, 24 -hr Compute Tiime:150ec201.6, 10:41:08 Control Specifications:24hr, 1rnin Show Elements: All Elements Volume Units; H IN cal.) i C -FT Sorting: :Alphabetic Hydrologic Element Drainage Area (P112) Peak Discharge (CFS) Time ofPeak Volume (AC -FT) D1. 0,0468 126.6 i 02Jan2005C, 00:00 7.3761 D10 0.0215 52.7 02Jan2050, 00:02 3.3858 D11 0.0071 21.0 01Jan2050, 23:57 1..1199 012 0..0137 40.2 01Jan2050f 23:58 2.1607 01.3 0,0113 42.9 01Ja1n2050, 23:57 2.5910 02 0,0339 84.8 02Jan20501 00:02 5.3395 03 0.0537 153.3 41]an2051Q, 2.3:58 8,4675 04 0,0223 511 42Jan2050, 00:00 3.5937 65 0.0405 108.7 021an2050,, 00:00 6.3827 D6 0.0005 1.5 i31Jan2d50, 23:57 0.0789 07 0,0005 1.5 01Jan2050, 23:57 0.0789 08 0,0002 0.6 011an2050, 23:57 0.0316 09 0,0238 60.8 02Jan2050, 00:01 3.7493 Junction-Downchute 1 0.0878 236.5 02'Jan205D, 00:00 13.,8377 Junction-O0wnchute2 0,1987 525.6 023an2050, 00:01 31.2589 Junction -D10 0.0453 99.6 02Jan2050, 00:07 7.0791 Junction -Oil 0:2650 645.7 02Jan2050, 00:03 41.5751 02Jan2050, 00:02 Junction -DI 0.0765 208.7 12.0052 Junction -R1 -R2 00429 119.4 01Jan2054, 23:59 6,9688 Junction -R2 -R3 0,0450 125.8 02Jan2050, 00:00 7.4192 Junction -R4 00/as 16 5.8 42Jan2454, 00:03 11.9373 02Jan2050,, 00:02 Junction -stilling Basin 0.2442 604.1 t 38.3672 Reach -D10 Perimeter Channel 0,0238 60.0 021an2050,, 00:0'9 3.6933 Reach-DI1 Perimeter Channel 0.2.142 603.1 02Jan2.050, 00:03 38.2.5145 021an2050, 00:03 Reach -D11 -D12 -to -Basin 0.2650 645.7 41.5.454 Reach -D4 Bench Channel 0.0537 152.0 02Jan2050, 00:03 8.4115 IReach-D6-D7 0,087'8 236.2 02Jan2050, 00:00 13,8353 Reath -D7 -D8 0,1987 525.0 02'Jan2050, 00:01 31.2566 013an2050, 2.3:58 Read, -R1 -R2 0.0300 92.9 4.8733 Reach -R2 -R3 0,0429 119.1 02Jan2050, 00:00 6.9625 Reads -R.3 -R4 0..0458 125.5 02Jan2050„ 00:02 7.004 R1 0.0300 93.4 01Jan2050, 23:57 4.8836 R2 0,0129 31.0 02Jan2050, 00:03 2.0954 RJ 0., 0029 7,0 02Jan2050, 00:02 0.4.567 R4 0, 0200 5Q.B 02Jan2050, 00:10 4,5369 Sink—ketBasin 0..2763 674.5 I 02Jan2050, 00:03 44.1.394 Si c-Runon 0.0.738 1165.8 021an2050,, D0:03 11.9373 :\Tucson\Projects\15proj\1538880 North Weld Landfill\Attachments\NWLF Basin H&H.xlsm i Global Summary Results for Run "Run -On & Runoff-100yr.lhr" a Project: MAILF Simulation Run: Run -On &Runoff-100yrr.ihr Start of Run: 01Jan2050, 12:00 End of Run: 02Jan2050, 12:01 Compute Time: 15Dec2016, 10:41:0 7 Show Elements: All Elements Basin Model: Run -.n and Runoff Meteorologic Model: 100-yr, 1 -hr Control Specifications:24hr, 1min Volume Units: IN to Sorting: Alphabetic Hydrologic Element Drainage Area (hF1I2) Peak Discharge ;LCFS) S;+ Time of Peak Volume (AC -FTC D1 0.0468 57.9 02Jan2050, 00:00 3,3301 D10 0.0215 23.9 02Jan2050, 00:03 1.5284 D11 0.0071 9.7 013an20,50, 23:.58 0.5057 017an 2:0 50, 23:58 D12 0.0137 18.5 0.9757 D13 0.0113 25.0 01Jan20.50, 23:57 1.693 D2 0.0339 38.7 02Jan2050, 00:02 2.4104 0.3 0.0537 70.4 OlJan2050, 2,3;59 18232 04 0..0228 23.4 02Jan2054, 00:00 1.6225 05 0.0405 49.6 02Jan2050, 00:00 2..88 16 D6 0.0005 0.7 0i1an205O, 23.:57 0.0356 D7 0.0005 0.7 Oi1an2050, 23:57 0.0356 D8 0.0002 0.3 01Jan2050, 23:57 0.0142 DO 0.0238 27.7 02Jan2050, 00;02 1.6926 Junction-Downthute1 0.0878 108.1 02Jan205O, 00:00 6.2471 Junction-Downchute2 0.1987 2.35..5 02Jan2050, 00:02 14.0952 Junction -DID 0.0453 41.3 02Jan2050, 00:10 3.1836 Junction -D11 0.2650 282.1 02Jan2050, 00:04 18.7245 Junction -D4 0.0765 93.9 02Jan205O, 00:03 5.1037 Junction -R.1 -R2 0.0429 56.2 02Jan2050, 00;00 3.2027 Junction -R2 -R3 0,0458 59.1 02Jan2050, 00:01 3.1050 Junction -R4 0.0738 78,1 02Jan2050, 00:04 5.4756 02Jan2050, 00:02 Junction -Sang basin 0.2142 254.9 17.29 14 Reath -D10 Perimeter Channel 0.0238 27.6 02_Jan2050, 00:12 1.6.552 Reach-Dii Perimeter Channel 0.2442 264.6 021an2050, 00:04 17.2431 Readi-D11-012-to-Basin 0.2650 281.1 023an2050,, 00:04 18.7068 Reath -04 Bench Channel 0.0537 69.9 02Jan2050, 00:05 3.7812 Reath -D6-07 0.0878 107.7 02Jan2050, 00:01 6.2455 Reath -D7 -D8 0..1987 236.2 02Jan2050, 00:02 14.0936 0Uan2050, 23:59 Reach -R1 -R2 0.0300 43.8 2.2394 Reach -R2 -R.3 0.0429 56.0 02Jan21050, 00.:01 1989 Reach -R3 -R.4 0.0458 58.7 022an2:050, 00:04 3.3908 R1 0.0300 43.9 01Jan20 50. 23:57 12459 R2 0.0129 14.4 02Jan2:050, Oil04 0.9633 R3 0.0029 3.2 02Jan2050„ 00:03 0.201E 1 R4 0.02$0 23.3 02Jan24,50, 00:10 2.0848 Sink-RewBasin 0.2763 295.9 02Jan20.50, 00:04 20.1761 Sink-Runon 0.0738 78.1 021an2050,, 00:04 5.4756 1538880 r Colder Associates APPENDIX A-2 Table +1 Channel Geometry and Flow Input Riprap Channel Evaluation North Weld Landfill, Unit 2 PROJECT NO.: 1538880 Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Reach Designation Design Q HEC HMS Element ID for Q Channel Design Geometry Riprap Calculation Methodology Channel Hydraulic Calculations Approximate Channel Length (ft) Bed Slope (ftift) Left Side Slope (H:1V) Right Side Slope (H:IV) Bottom Width (ft) Minimum Channel Depth (ft) Channel Curve Radius (ft) Mannings 'n' Normal Flow Depth ft ( l Flow Area (sq ft) Flow at Median Depth (ft) Width I Average Channel Velocity (ftlsec) Downchute (D6) 1.5 D6 200 0.250 3.0 3.0 ' _ 20 3.0 0.0 0.035 Robinson 0.03 0.7 20.10 2.21 Downchute (D7) 236.5 Junction-Downchutel 275 0.262 3.0 3.0 20 3.0 0.0 0.035 Robinson 0.68 15.0 22.04 15.79 Downchute (D8) 525.6 Junction-Downchute2 150 0.262 3.0 3.0 20 3.0 0.0 0.035 Robinson 1.08 25.2 23.25 20.88 Retention Basin Inlet 645,7 Reach -D11 -D12 -to -Basin 50 0.250 3.0 3.0 60 3,0 I 0.0 0.035 Robinson 0.66 40.9 61.98 15.77 Run -On Dissipator 1 165.8 Junction -R4 180 0.010 I 3.0 3.0 50 3.0 0.0 0.0350 USAGE Mild ! 0.85 44.8 52.56 3.70 X:\Tutson'iProjects\15proj\1538880 North Weld Landfl111Attu:hmerits\NWLF_BasinRiprap.xlsm Golder Associates Table 2 Robinson Method Riprap Size Calculation Riprap Channel Evaluation North Weld Landfill, Unit 2 PROJECT NO.: 1538880 Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Riprap Calculations Robinson for Steep Design of Rock Chutes Riprap (Bed Slopes >2% but <40%) Unit Flow (1) (cfsift) q Design Flow Q (cms) Unit Flow (cms/m) Width q Flow Concentration Factor Calculated Particle (mm) Size D50 (2) Factor Safety of Riprap (inches) D50 Size Reach Designation Downchute (D6) 0.07 0.042 0.007 1.25 26 1.20 1.2 10.73 6.697 0.997 1.25 369 1.20 17.4 Downchute (D7) Downchute (D8) 22.61 14.883 2.100 1.25 547 1.20 25.8 Retention Basin Inlet 10.42 18.284 0.968 1.25 358 1.20 16.9 Design of Rock Chutes (ASAE Paper No. 982136 7/98) Determine unit flow at incipient motion for rock particle size (1) Unit flow rate is 01 median width, adjusted by a flow concentration factor Is 1.25 'Flow Concentration Factor (1.25 from USAGE steep riprap method) (2) Bed Slope < 10%, q = 9.76e-7 Q01.89 S-1.50 10%<= Bed Slope <= 40%, q = 8.07e-6 Q01.89 S458 Factor of Safety over incipient motion 1.2 X:1Tucson\Projects\15proj\1538880 North Weld Landfilltlachments\NWLF_BasinRiprap.xism *Golder Associates Table 3 U.S. Army Corps of Engineers (Mild) Method Riprap Size Calculation Riprap Channel Evaluation North Weld Landfill, Unit 2 PROJECT NO.: 1538880 Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Riprap Calculations USAGE for Mild Method Riprap (Bed Slopes <2%) Reach Designation Design Flow 0 (cfs) Normal Flow Depth d (ft) Averaged Velocity Depth V (ftls) Velocity Distribution Coefficient ev Channel Side Correction Slopes Kai Calculated Particle Size D30 (ft) y Riprap Size D50 (in) I Run -On Dissipator 165.8 0.85 3.70 1.00 0.97 0.06 0.9 I i USACE E Paper EM 1110-2-1601, 6/30/94 D;0 -9CS C; C.d ! "r 1 Y V Inputs below as determined in EM 1110-2-1601, 6/30/94 I 1.1 0.3 165 2.2 2.0 0.910 1.5 : Minimum safety factor of 1.1 for moderate debris impact C5: Value of 0.30 for angular rock ys: Density of solids (pcf) Cg: Gradation Coefficient (D85/D15) T: Riprap Thickness (x 050) CT: Correction for thickness > 1.5 * D50 Note: A Cv of 1.25 should be used downstream of concrete channels due to the difference in velocity profiles Riprap DSO determined as recommended in EM 1110-2-1601, 6/30/94 Q X:\Tucson\Prc4ectsV1Spro M1538880 North Weld Lardfif(1AttathnerAsk.WJLF BasinRiprap.xism css Golder Associates HYDRAULIC JUMP CALCULATIONS North Welid Landfill (Unit 2) Hydraulic Jump Calculation PROJECT NO.: 1538880 Date: 12/19/16 By: SPS Chkd: DMW Apprvd: JAR Reach Designation Channel Configuration ' Hydraulic Calculations Design Flow (cfs) Bed Slope Left Side Slope (H:1V) Right Side Slope (H:1V) Bottom Width (ft) Maximum Channel Depth (ft) Mannings'n' for Capacity (Depth Calculation) Mannings 'n' for Stability (Velocity Calculation) Maximum Velocity (ft/sec) maximum Normal Flow Depth (ft) Normal Depth with Velocity 'n' (ft) Froude Number Conjugate Depth (ft) Lld2 Ratio Minimum Length of Jump (ft) Dcwnchute Toe (Basi 525.6 25.0% 3.0 3.0 20 3.0 0.026 0.026 I 25.0 0.92 0.92 4.85 5.54 6.01 33.31 iRetention Basin Inlet 645.7 25.0% 3.0 3.0 50 4.0 0.035 0.035 16.8 0.74 0.74 3.53 3.25 5.57 18.07 7.00 Length of Jump as a Function of Froude Number and Ratio to Conjugate Depth (d2) 6.00 - 4.00 - d, di + I2V,2d1 + di 2 8 4 Where: 3.00 r 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 Froude Number X!.Tucson'd'rajeds'.l5prro1533330 Mcr h W?rd landnllkAltehrnen&,,NWIJ'_Hydraulic J' nip Calc.xla dl = Depth before the jump V1 Velocity before the jump d2 a Depth after the jump: g = Acceleration of gravity 4- *IGolder Associates Chapter 9 Hydraulic Structures In non -cohesive soil channels and channels where future degradation is expected, especially where there is no drop structure immediately downstream, it is generally recommended that the stilling basin be eliminated and the sloping face extended five feet below the downstream future channel invert elevation (after accounting for future streambed degradation). A scour hole will form naturally downstream of a structure in non -cohesive soils and construction of a hard basin is an unnecessary cost. Additionally, a hard basin would be at risk for undermining. This configuration is shown in the profiles for GSB (Figure 9-12) and SC (Figure 9-17) drop structures. In some cases, the structure may have a net drop height of zero immediately after construction, but is designed with a long term net height of 3 to -feet to accommodate future lower' i g of the channel invert. 30 25 • 5 0 SC Drop T, — 4.9x + 0.47 s era's . sere GSB Drop y = 1.82x + 0.69 B18 Boulders Required for Entire GSB Drop B24 Boulders Required for Entire GSB Drop 10 15 >I< B30 Boulders Required for Entire GSB Drop 20 25 Unit Discharge (cis/ 30 35 20.7 = 529.4 cfs/25.6 ft flow width Figure 9-1. Stilling basin length based on unit discharge (for simplified design procedure) 2.2.6 Seepage Analysis and Cutoff Wall Design The simplified drop structure design only applies to drops with cutoffs located in cohesive soils. Therefore, it is necessary to determine surface and subsurface soilconditions in the vicinity of a proposed drop structure prior to being able to use the simplified approach for cutoff design. For a drop structure constructed in cohesive soils meeting all requirements of a simplified design, the cutoff wall must be a minimum of six feet deep for concrete and ten feet deep for sheet pile. If a proposed drop structure meets the requirements of the simplified approach, but is located in non - cohesive soils, guidance on determining the required cutoff wall depth is described in Section 2.4. January 2016 Urban Drainage and Flood Control District 9-7 Urban Storm Drainage Criteria Manual Volume 2 APPENDIX A-3 HY-8 Culvert Analysis Report Crossing Discharge Data Discharge Selection Method: Specify Minimum, Design, and Maximum Flow Minimum Flow: 0 cfs Design Flow: 30 cfs Maximum Flow: 55 cfs Table I - Summary of Culvert Flows at Crossing: Access Rd - Perimeter Channel Headwater (ft) Elevation Total Discharge (cfs) 36" RCP Discharge (cfs) Roadway Discharge (cfs) Iterations 100.00 0.00 0.00 0.00 1 100.98 5.50 5.50 0.00 1 101.42 11.00 11.00 0.00 1 101.81 16.50 16.50 0.00 1 102.14 22.00 22.00 0.00 1 102.43 27.50 27.50 0.00 1 102.56 30.00 30.00 0.00 1 102.99 38.50 38.50 0.00 . 1 103.28 44.00 44.00 0.00 1 103.61 49.50 49.50 0.00 1 103.96 55.00 55.00 0.00 1 104.00 55.53 55.53 0.00 Overtopping 1 C Rating Curve Plot for Crossing: Access Rd - Perimeter Channel Crossing Total Rating Curve Crossing: Access Rd - Perimeter Channel Crossing 105 100 10 0 30 ` 0 Total Discharge cts Table 2 - Culvert Summary Table: 36" RCP Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (ft/s) Tailwater Velocity (Ws) 0.00 0.00 100.00 0.000 0.000 0-N F 0.000 0.000 0.000 0.000 0.000 0.000 5.50 5.50 100.98 0.983 0.146 1-S2n 0.495 0.732 0.527 0.501 6.544 2.742 11.00 11.00 101.42 1.423 0.503 1-S2n 0.702 1.049 0.767 0.732 7.679 3.366 16.50 16.50 101.81 1.807 0.818 1-S2n 0.872 1.296 0.962 0.907 8.404 3.776 22.00 22.00 102.14 2.137 1.125 1-S2n 1.013 1.508 p 1.134 1.053 9.005 4.090 27.50 27.50 102.43 2.430 1.432 1-S2n 1.144 1.692 1.291 1.180 9.447 4.347 30.00 30.00 102.56 2.556 1.574 1-S2n 1.198 1.769 1.360 1.233 9.632 4.450 38.50 38.50 102.99 2.986 2.080 1-S2n 1.382 2.014 1.576 1.397 10.236 4.758 44.00 44.00 103.28 3.283 2.428 5-S2n 1.492 2.158 1.706 1.492 I 10.608 4.929 49.50 49.50 103.61 3.606 3.144 5-S2n 1.602 2.287 1.832 1.580 10.952 5.085 55.00 55.00 103.96 3.963 3.461 5-S2n 1.711 2.404 1.953 1.663 11.283 5.228 Straight Culvert Inlet Elevation (invert): 100.00 ft, Outlet Elevation (invert): 99.40 ft Culvert Length: 40.00! if, Culvert Slope: O.0150 Culvert Performance Curve Plot: 36" RCP P rfo mance Curve 'ulvert: 3 6" RCP ,104.0 c, 103.0 0 1025 1--1-1 102_0 ro 101_5 U ma, i c, _ Z 1005 • Inlet Control E1e Outlet Control E1ev 0 20 30 40 Total Discharge (cis) Water Surface Profile Plot for Culvert: 36" RCP Crossing - Access Rd - Perimeter Channel Crossing _ D e sia Discharge - 30_0 cfs Culvert 36" C?.. Culvert Discharge - - T ofs 104_0 1I_5 103.0 102 c 1 IVY 2 101 r _r 1I_)1.C-' 100 100.0 I9_5 -I- • • d IN :station (ft i Culvert Data Summary - 36" RCP Barrel Shape: Circular Barrel Diameter: 3.00 ft Barrel Material: Concrete Embedment: 0.00 in Barrel Manning's n: 0.0120 Culvert Type: Straight Inlet Configuration: Grooved End Projecting Inlet Depression: NONE I 40 50 Roadway Data for Crossing: Access Rd in Perimeter Channel Crossing Roadway Profile Shape: Constant Roadway Elevation Crest Length: 15.00 ft Crest Elevation: 104.00 ft Roadway Surface: Gravel Roadway Top Width: 36.00 ft HY-8 Culvert Analysis Report Crossing Discharge Data Discharge Selection Method: Specify Minimum, Design, and Maximum Flow Minimum Flow: 0 cfs Design Flow: 5 cfs Maximum Flow: 11 cfs Table 'I - Summary of Culvert Flows at Crossing: Access Rd - Bench Channel Headwater (ft) Elevation Total Discharge (cfs) 18" HDPE Discharge (cfs) Roadway Discharge (cfs) Iterations 100.00 0.00 0.00 0.00 1 100.56 1.10 1.10 0.00 1 100.82 2.20 2.20 0.00 1 101.05 3.30 3.30 0.00 1 101.26 4.40 4.40 0.00 1 101.38 5.00 5.00 0.00 1 101.71 6.60 6.60 0.00 1 101.98 7.70 7.70 0.00 . 1 102.28 8.80 8.80 0.00 1 102.62 9.90 9.90 0.00 1 103.00 11.00 10.97 0.00 36 103.00 10.97 10.97 0.00 Overtopping Rating Curve Plot for Crossing: Access Rd - Bench Channel Crossing 1033 102_5 II I C 03 102.0 CD �--'--� 101 _5 4-1 a -5 101.0 03 CD T 100_5 100.0 �. otal Crossing: Access ating Curve Rd - Bench Channel Crossing 6 10 12 Total Discharge(cis.) Table 2 - Culvert Summary Table: 18" HDPE Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (ft/s) Tailwater Velocity (Ws) 0.00 0.00 100.00 0.000 0.000 0-N F 0.000 0.000 0.000 0.000 0.000 0.000 1.10 1.10 100.56 0.564 0.0* 1-S2n 0.232 0.388 0.232 0.282 6.188 1.978 2.20 2.20 100.82 0.821 0.0* 1-S2n 0.332 0.555 0.347 0.366 7.045 2.352 3.30 3.30 101.05 1.046 0.0* 1-S2n 0.414 0.692 0.431 0.426 7.887 2.603 4.40 4.40 101.26 1.260 0.0* 1-S2n 0.478 0.803 0.507 0.474 8.358 2.797 5.00 5.00 101.38 1.378 0.0* 1-S2n 0.512 0.856 0.544 0.497 8.643 2.888 6.60 6.60 101.71 1.713 0.337 5-S2n 0.595 0.991 0.641 0.552 9.145 3.096 7.70 7.70 101.98 1.976 0.614 5-S2n 0.649 1.071 0.703 0.585 9.475 3.218 8.80 8.80 102.28 2.276 1.091 5-S2n 0.701 1.144 0.763 0.615 9.745 3.327 9.90 9.90 102.62 2.618 1.383 5-S2n 0.750 1.212 0.821 0.642 10.000 3.426 11.00 10.97 103.00 2.996 1.690 5-S2n 0.798 1.268 0.876 0.668 10.245 3.518 * Full Flow Headwater elevation is below inlet invert. Straight Culvert Inlet Elevation (invert): 100.00 ft, Outlet Elevation (invert): 98.80 it Culvert Length: 40.02 if, Culvert Slope: 0.0300 Culvert Performance Curve Plot: 18" HDPE Performance Curve Culvert: 1 " HDPE • Inlet Control E1e •-. 102_5 I 102.0 CD I--1-1 101_5 4(71 101_0 03 100_, Outlet Control E1ev 0 10 12 6 Total Discharge cis) Water Surface Profile Plot for Culvert: 18" HDPE Crossing - Access Rd - Bench Channel Crossing , Design Discharge - 5.0 cfs Culvert - 18" HD?E.. Culvert Discharge - 5_0 cfs 103 0 102 5 — 102_0 101_5 0 101_0 03 100.5 w 100.0 99_5 99.0 _1n 10 30 40 50 20 Station (ft) Culvert Data Summary - 18" HDPE Barrel Shape: Circular Barrel Diameter: 1.50 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning's n: 0.0120 Culvert Type: Straight Inlet Configuration: Thin Edge Projecting Inlet Depression: NONE Roadway Data for Crossing: Access Rd - Bench Channel Crossing Roadway Profile Shape: Constant Roadway Elevation Crest Length: 21.00 ft Crest Elevation: 103.00 ft Roadway Surface: Gravel Roadway Top Width: 36.00 ft Worksheet for Unit 'I Diversion Berm Project Description Friction Method Solve For Input Data Roughness Coefficient Channel Slope Normal Depth Left Side Slope Right Side Slope Results Discharge Flow Area Wetted Perimeter Hydraulic Radius Top Width Critical Depth Critical Slope Velocity Velocity Head Specific Energy Froude Number Flow Type GVF Input Data Downstream Depth Length Number Of Steps GVF Output Data Upstream Depth Profile Description Profile Headloss Downstream Velocity Upstream Velocity Normal Depth Critical Depth Channel Slope Critical Slope Manning Formula Discharge Supercritical 0.035 0.03000 1.50 4.00 10.00 94.82 15.75 21.26 0.74 21.00 1.63 0.01944 6.02 0.56 2.06 1.23 ftfft ft ftfft (H:V) ft/ft (H:V) ft3Is ft2 ft ft ft ft ft/ft ft/s ft ft 0.00 ft 0.00 ft 0 0.00 ft 0.00 Infinity Infinity 1.50 1.63 0.03000 0.01944 ft ftls ft/s ft ft ft/ft ft/ft 1211212016 3:44:40 PM Bentley Systems, Inc. Haestad Methods ScibehirilejCBIEWMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Rating Table for Unit 11 Diversion Berm Project Description Friction Method Solve For Input Data Roughness Coefficient Channel Slope Normal Depth Left Side Slope Right Side Slope Normal Depth (ft) 0.50 1.00 1.50 Manning Formula Discharge Discharge (ft3/s) Velocity (ft/s) 5.07 32.16 94.82 2.89 4.59 6.02 0.035 0.03000 1.50 10.00 4.00 ftlft ft ftlft (H:V) ftlft (H:V) Flow Area (ft2) Wetted Perimeter (ft) Top Width (ft) 1.75 7.00 15.75 7.09 14.17 21.26 7.00 14.00 21.00 Bentley Systems, Inc. Haestad Methods Sc itie Ei iMaster V8i (SELECTseries 1) [08.11.01.03] 12112/2016 3:42:43 PM 27 S►iemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Cross Section for Unit 'I Diversion Berm Project Description Friction Method Solve For Manning Formula Discharge Input Data Roughness Coefficient Channel Slope Normal Depth Left Side Slope Right Side Slope Discharge 0.035 0.03000 1.50 4.00 10.00 94.82 ft/ft ft ft/ft (H:V) ft/ft (H:V) ft3/s Cross Section Image H: 1 Bentley Systems, Inc. Haestad Methods ScibehirilejCBIEWMaster V8i (SELECTseries 1) [08.11.01.03] 12/1212016 3:45:21 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 i'164uI1C' E i Ib'NuiT E L _ •t4thtT E11 7R NYl4X - 2Ifr %tL 1L1$ tarn 3NC'AFI FC R CI Ma ;IT bfru` 1 +I•I T'.• CHSKE Yd 3')FE, INIIEQ- "•I.14I, La.__ MAN1EMI&.c FAE41'Yr W� OK N l{APE 'IIetRT • 511q.'Dr L'tlfiait u 1 f�;MJWE.Is stool f NYtMI.._ 7R{:99 P S: 61.LLYEPY-•. I. FE5iwL.'fat litANa>CE - th N- EL,5o75.3 crl+Yi>,1: OM III LWai NCI I ' r TTI FT 11 WM q ;iOKN VOR $ in j SEE 1Fr•1. SFI. hr �T`• L- i 2i59Ci114 E T 'fl C& DR.UNI+CE CtIVER540,4 CRY SEE •.DETo.I 4, SHEET 1-. 1 I' 1 p ONvAN 1 FR9tat y ERIN PF.CTECTICS / ftliCHREO ifSETEFTCN PCI'Q f tWit Lt.. Web 91 tt1-CPC TO RAN twe au°tFT :SOLID E I 219004 E I, • PiKr'fPir attut tiScr. .M,... f ' e 1' 1 ,ti_�1 f I ��" I" — "t,v�TEleTI4f1 OH'.? 4VTL=1 CVL CRT `— i 11 ''Y� - IN'aET iD6 Gu,Tle f-1 �E6 r' 'I ti+L.a1EI,0ia 51ME Ka -m 41' - [..:r• -.Y 4-. I -o 5.2 DOLCIRstO rxrc 100 TNT' ik 4aah1 Df MAY d�R3C�l�la IAI Kr V*. IOIM INTTSstnlsww 9•C,7RBr11.IR Dr<clzristLN Mesa MO VOWED HUI\I LPACIVED C#1 P0,0 ',Ave; IIc71D will' %Kla Cl1 tO•1Lt t1/4_.0 LEtt N.TET'IaTTLM1 7JI4r. ' PROF'E4'v B0U'Oylt fNAI IRR# CCH4etHR R. rt4Q'. ION Pram -Ivan IR LtdIT Or Kr= rtGjit Or "Vole MILLDAM,71 SiAlE a_, SPOT ELEf.lttly CONTROL P0191 LoCANLD ;Mite - 3E4 Z 1REL ?ECET OWN °WINE @AMID*ATEF 1Mhta'DRKs w!L_ PHOTO GENII? GAS PRCeil r owtn Par PPQFCRTY •„AP.tCR sit iC IL1ER NMI a. 109 as a- GG&t m. s *- WIOTE8 1r ��iit wcunT 5. 903 2A�M,yLW9 c&nPMJb. . 5 5IEuAI!TR E ualt 6_ST.t IMILAGW SIN( K. Mt CUCTIA0IAI: fiVFN [CNC TERM 4IT1 ^MINT LS'I Are4'F (PPTRA1If1JM rM.Tlf1'ic, ttivatN cc' ItIr Clubs AND rNl .^.R.afwp S4UWN APS IIRWQ3XIULTE, Kt DATE OVI CRJ •I I ON acS ""RCSS SEE-W9t LAC✓.TTRY 4,1404.4 inse UR'ADZ EXdT4 INEKASIMIA lUii1. (AaD FILE: R4xb.V&4 Onto Ftit eRP �y� 26190 }l* r�4 A ITIACT TO 141:1 OAT I.INII/RI 1i9F. SITE CEVEI.^c17[NT FLANS Nt$TiI 'WM'_fYITLFY 11MCF'iea *CO touter/, CCV.&IUDC sser EC% n1.4111 Ma aV Sec BY —P 9 Y1 9.14AL GRADE AND SURFACE WATER MMIAOEMfMt PLAN Waste Munugernent Disposal Services of Colorado, Inc. Sri v II MUMS% pin V PI I jP]y i9p',7 1 I &P1 3iY14 V i 1 L €WI CI INC WOKE . RUT $0 Jinn 4. 1 , ;' • z W ez- C J U 3- T ita cc co SEPARATION CAL MODULE H L_ T 6 J L 0 HAIL L ROAD 1 J •. ON BERM r•pat cum Mill <nii K 5 n W CO J C M a zx 4 g M1 cc .72 U 0 U CL ›- (In T T 1s 1: Q;4 7-1 .. a 4 C . E ,3; e, O.L; — i ci•0 CS CC to _a V n O m ao (7 of rt Lur t.c.1 1 �. APPENDIX A-4 Worksheet for Emergency Spillway Project Description Solve For Input Data Discharge Crest Elevation Tailwater Elevation Crest Surface Type Crest Breadth Crest Length Results Headwater Elevation Headwater Height Above Crest Tailwater Height Above Crest Weir Coefficient Submergence Factor Adjusted Weir Coefficient Flow Area Velocity Wetted Perimeter Top Width Headwater Elevation Gravel 296.00 ft3rs 5069.00 ft 5068.00 ft 5.00 ft 315.00 ft 5069.50 0.50 -1.00 2.69 1.00 2.69 156.17 1.90 315.99 315.00 ft ft ft US US ft2 ftls ft ft Bentley Systems, Inc. Haestad Methods SditehitilejEadwiMaster V8i (SELECTseries 1) [08.11.01.03] 12119/2016 12:38:56 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Golder Associates CALCULATIONS Date: Project No.: Subject: Project Short Title: 12/19/2006 1538880 Retention Basin - Drain Time Calculation North Weld Landfill, Unit 2 Made by: Checked by: Reviewed by: SPS DIM JAR coe s vistAi Goal: Estimate Drain Time for 100 -Year, 24 -Hour Runoff Volume Reporting to Retention Basin Reference: New Jersey Department of Environmental Protection, Divison of Watershed Management, New Jersey Stormwater Best Management Practices Manual , Chapter 9.5 Infiltration Basins, February 2016 Given: 100 -Year, 24 -Hour Runoff Volume reporting to basin: In -Situ Hydraulic Conductivity: Retention Basin Stage -Storage -Surface Area 3.6 x 10"3 cm/sec or Elevation Surface Area (acres) Cumulative (acre-feet) Volume 5050 0.05 0.0 5:51 0.47 0.3 5052 1.23 1.1 5053 2.21 2.8 5054 3.46 I 5.6 5055.18 9.4 5056 4.33 13.7 5057 4.48 -1-8-1 5058 4.64 22.6 5059 4.80 ' 27.4 5060 4.96 32.2 - -- 5061 5.12 37.3 5062 5.28 4.5 5063 5.45 47.8 - 5064 5.62 53.4 5065 5.79 591 5066 5.96 64.9 ' 506/ 6.14 71.0 5068 6.31 77.2 5069 6.49 83.6 5010 6.68 8/.O Drain Time Calculation Drain Time = Infiltation Area x Design Permeability Rate 100 — Year, 24 - Hour Runoff Volume 44.1 acre — ft x (12 inches/Pt) Drain T'ime - - (4.18 acres) x (5.1 inches/hour) 44.1 acre-feet 5.1 inches/hour Basin Floor (Infiltration Area) X:\Tucson\Projects115projk1538880 North Weld Landfil9'MttachmentskNWLP_BasinLrainTime.xlsx APPENDIX B UNIT 1 SURFACE WATER CALCULATIONS APPENDIX B -'I cflarlieCaSalson nannaleaCt====znialfliartritaragialheilitil.9klate.kanagipaltarenvarprramormsoc MectZAWMUlaisailediaa _ UPDATED DESIGN AND OPERATIONS PLAN NORTH WELD SANITARY LANDFILL AULT, COLORADO Prepared By: Rust Environment & Infrastructure, Inc. 5575 LTC Parkway, Suite 200 Englewood, Colorado 80111 January 1996 sie 9' t 0 to. 6 t b V Revised y Waste Management Disposal im: f; Collorefido, Inc.. November; 1927 NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN FIGURES 1 - t Prr• p'• - • . r•;, fir - C`i-- '•+`- .t.. •• • • - C r • • 't t . • S • - C 3 1 + .1 • .\ — rill As, '-{ ' Ns.- ... =2- i ( . .......:‘ '41 • 'I.'S. •-•••-ile7"1.:"1.4"-::::11•4•.1.7•-• ' . "%is .. % ">. t.4. ..:;419i ‘.:\ .... \ ."Y.\ t ▪ '•-'w--r••- J -N.�_ ..,.+. I-. 'v"L. N. -••••••••N \ . .�\'aS •�(__'�t lL •`•.,L' - •y ' I. gariseasseiwer .ht4 .. S i _�Iw.es - i I �iad�--;4-4 %^+�1f,en.,;>41 --P :-�-•'`_ _ } f y 1 + L L • •t. r - r -•"" I t r r� r 1 ..,p '*" • `•.L 4• t't L t ` 1 1 - -_ t f C 1t i i ` 1 = i S • x,°� t •ry a,'. titc4;,': .r•Y. --:. '-.Jt.�:'- ., `tip •_C"k a 7\.. • 7' •-.....,. . •' - —.r— ..-- ...• 4 .S i • b-Th ,v f L I r t • t \ ' :; l , • , l'i, -{ 1 \ - � ` ; ` '' } ` . • i i `i t 1 1 \ ! +� tit r =i' I I i/ • ="\- 41/41 i • • • a , ten 4. r• 9 I. 1 S i .� 1 { )r i lt ��t1 �.; -y. ° 1y1/4,1•`tt `vim.\,. -1,-,,,..1/4.:11t , ;' !t ' ✓. y 1iii ti-•�'• } 5• 'h�a �•�• ixi ) a 014 sear aregallgrOPINIIPI 110. SFr leia0 42 at erride Naltaalk ale Ma DM Ilia MIS wal Sal lee MOSISSIIIne gam len Mt ant gisma MIPS Ma St le St NIS Illef AV al OW or IMIL ISM irinifiar ▪ • a Oa sap i If 4 Mr WS a ear IIIE lets NS SS Ma HIM Ma Melt got ler Milt it rar an Mr SNP Ma Ma itairranWOINkillispor. ( C HAN 146 L, La chin e pas 4 NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN APPENDIX B LANDFILL PERIMETER CHANNELS DESIGN Rust Environment as Infrastructure CALCULATION SHEET PAGE OF 41 PROJECT O. i224921,/fro TENT --- L dt.. (cep; SUBJECT t - Prepared By ens. Date 12e15 PROJECT ! , .'"'. ,, .r ----- . � Reviewed By /41e1pOs Date tt, A l Approved By Date Parente te ; esiek:fitmeit-e eskitela peel aortal 3'4 A peak t i s .1 'fie at 100 t t t ) +2 ' - kalif/ norm e vies + t Croon1Hoot. I capoesost ii 1 +a +"kc et". r m tutee .. ID" d 4444 Wort FDA' AD $,sJMeI,friv fiek &hoot t +a- saI s fegtoltc v ori ikeer y Ofinhoshilirr a +0 3 son► 4 -rat Ame4 tot. pa INA ; Hots s 1a r .' f t s #- tiirc. son!1 ,pt. rs } lleta (4 FebtivicLAr art keit lock woo, ewireikala Sea - .t -r ,` ► 411:"Pri 1'1► raer ► tte '- 4 kre ''$ k Cb t tt ' g. i i thrwai rir 1 i Vt k, Gi ; �r' . 4446a.* Alt 1 +' e. + j MCP 41$ + + ' i rs i fitz bests 4frievtvor.... is f. cerficomean at -4•1 a in 40L,A0L- Pieta) • - 07 C 4 +.)# rz..#0` rsto w V; o 4ti How 11A%,c,.1 &DAIS flow assatinelpt s4 a on First data Vei *to' 'o ft $ vs c drS. a r' ; - leo Imo. C. l,9 ter‘ acrilfti Row 4 -In c.. c.. rte. f'*o asks► on t 1Qgusted o s sec. vuh. fie (A.) tatiorta. Ira tires ire rarikA fat eisi'orievit,tot+rci, sea is 5 t;red. ass m' j 1 ' .. c,, Ceps/+V t. pea 1 1..� d i reel 'Ss'arid. ra 0ot/stir Co vivtiAri eta : cadAr 52) % cosier X11 t TA acct* A O5 s o s 'M kat. 4- , oii) i O• ( 3 r scoot r kdavive I ciao rat O. 0 3•C ricktiaj risa, t` p .- rap a + DO ' r+r %se r+C. i Precc Oltrinserv1/4.. 1100 a ?rake hie%) re az in I to "' rat& 'Pi home"" Z. re) 11 rev 1 1 r94 sca'e: 4 sq inch cr,5 is i Rust Environment & infrastructure CALCULATION SHEET • PAGE OF ,ieitr PRO;.; ECT NO 12 4,5- I _ CL ENS 4J en 40rft,_ SUBJECT Per i% #- c-_....-- --- Pfeoared By 64145 Date _12_ `, sore COL on Ceirt n Kier I Reviewed By M 4 Date Ase'7"_ Approved By _....-... Date it; gr i reasol*r-s ^ea ths t artioc.ineci F Ore. nee* e.. ;tit° ° ItiA miel mein +5 ,t-, ;,,,. /oleo c n he fer��., ,.,, , t& ("HA litikLT 43 t- h e_, $ 1.4 lea CIPt 441 c. COI 9 4.444 usAtitdisterkil, res Q Isar s is tit -ca. -pis cs AFB SeC Cas all 0 C avid, F 4200 00O TSB glsre> II too Coro .3020 Fie I 7-10 1 1 co c 64(0 Sty t', dale lt Sao i,olo 4LO ArtirecktteA. . 0 12 to 12.x! LZ 60 catO og Dl 10 ,0 .24 %Lc,I & & *to aio Ole' O oas 0,02 O30o4 0 004, 0103 0ztI 646001 00(, 00,04 • OLI O .04 C CI, en CIP r off+'' of 008 0.0`2 - £1° 3 c4 c cas Coct cr 9-5 UDC+ ci445 1 33 C. ,5 orr ars 233 c9 -j cs es• ko-INA see \ „rare 40 etei ea sm. 44.4.4., cLAN\-ttcAt1/4.44h L v.) IseCitess ketr+S b L 15 lat,e,r ,,,ifr1/4 S i to 1 1. r42-461.67; to v"sh's' Cr g— 41n, g.. -14s list fine tot le r Se e -e. \ 5 . 413, scale: 4 sq./inch • .. r 1 Rust Environment & Infrastructure Denver Division - Solid Waste Design Surface Water Run -Of - Open Channel Sizing FILE NAME: Cpench an.wk3 DISK NAME: North Weld USES CHANNEL DIMENSIONS AND SLOPE TO CALCULATE V AND Q FROM MANNING'S EQUATION FOR OPEN -CHANNEL FLOW: Project: North Weld Sanitary Landfill By: ES CHANNEL NAME Channel A -> B SIDESLOPEI z 1.0 Channel Channel E -> F Channel F ->O Channel G -> H Channel Ft -> I Channel I -> J Channel 2 -> 3 Channel 6 -> 7 1.0 Channel 7 -> 8 Channel 9 -> 10 Channel 10 -> 11 Channel 11 -> 12 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 SIDESLOPE 2 z 1.0 1.0 1.0 1,0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.486 213 1/2 �_-- r s n Prof. No.: 82488.100 Date: 02 -Oct -95 Checked Sy: MRH WIDTH (b) (1 12.0 12.0 12.0 12.0 12,0 2.0 .0 2.0 2.0 2.0 2.0 DEPTH (d) (ft) 1.000 2.400 2.500 1.800 1.600 2.100 1.400 0.028 0.025 0.004 0.004 0.009 0.006 0.006 0.006 0.045 0.026 Rust Environment & Infrastructure Denver Division - Solid Waste Design Surface Water Run -Off - Open Channel Sizing FILE NAME: Openchan.wk3 DISK NAME: North Weld USES CHANNEL DIMENSIONS AND SLOPE TO CALCULATE V AND 0 FROM MANNING'S EQUATION FOR OPEN -CHANNEL FLOW: Project: North Weld Sanitary Landfill By: EGS 1.486 213 1/2 n Prole No.: 82488.100 Date 02 -Oct -95 Checked By: MRH MANNINGS AREA (A) F DRL.C RAD. VELOCITY I jV)(fps) IMAX. O1( FLOW ) REG. FLOW (cis) CHANNEL NO. 01 (sq ft (rMft) NAME - Channel A -a B 0.035 13.000 0.877 2.75 35.8 35.0 36.1 35.0 0.035 7.560 0.552 4.78 Channel B -> C Channel C -> D 0.035 8.890 0.588 4.71 41.9 35.0 Channel 0 -> E 0.035 14.410 0.954 4.87 ' 70.1 69.0 Channel E -> F 0.040 20.250 1.247 5.09 103,1 100,0 Channel F ->G 0.035 34.580 1.839 4.03 13943 133,0 Channel C -> H 0.035 40.553 2.051 4,33 175.8 175.0 Channel H -> I - 0.040 25_410 1.520 6.95 183,4 175.0 Channel I -> J 0,040 36.250 1.901 5,50 235.6 233.0 J Channel 1 -> 2 4.78_ 27.6 24.0 0.035 5.760 0.883 Channel 2 -> 3 0.035 6.840 0.965 3.93 26.9 24.0 0.035 7.410 1.005 3.30 24.4 24.0 Channel 3 -> 5 Channel 5 -> 6 0.035 8.610 1.084 3.47 29.9 28.0 Channel 6 -> 7 0.040 5,760 0.883 4.95 28.5 28.0 Channel 7 -> 8 0.035 8.610 1.084 3.47 29.9 28.0 Channel 8 -> 9 H 0.040 4.760 0.799 6,78_ 32.3 _ 32.0 Channel 9 -> 10 0.040 8.840 0.965 5.85 40.0 36.0 Channel 10 -> 11 0.035 9.240 1.124 4.10 37.9 36.0 Channel 11 -> 12 0.035 10.560 1.202 4.29 45..3___ 44.0 North Weld Sanitary Landfill Perimeter Channel Schedule Channel Designation Landfill Terraces Channel A -> B Channel B -> C Channel C -> D Channel O -> E Channel E -> F Channel F -> Channel G -> H Channel H -> I Channel I -> J Channel 1 -> 2 Channel 2 -> 3 Channel 3 -> 5 Channel 5 -> 6 Channel 6 -> 7 Channel 7 -> 3 Channel 8 -> 9 Channel 9 -> 10 Channel 18 -> 11 Channel 11-> 12 Slope (1V 0.040 8.005 0.028 0.025 0.014 0.014 0.004 0.004 0.020 0,013 0.015 0.009 0.006 0.006 0.021 0.006 0.045 0.026 0.008 04 008 Flow Rate (cis) 66.0 3.0 35.0 35.0 89.0 100.0 133.0 175.0 175.0 233.0 24.0 24,0 28.0 28.0 28.0 32.0 38,0 36.0 44,0 Velocity (ftis) 6.16 2.75 4.78 4.71 4.87 5.09 4.03 4.33 6.95 6.50 4.78 3.93 3.30 3.47 4,95 3.47 6.78 5.85 4.10 4.29 Bottom Width b. (ft} 12 12 12 12 12 12 12 }12 12 24.0 2 2 Water Depth de (ft) 1.3 1.0 0.6 0.7 1.1 1.4 2.4 2,8 1.8 2.3 1.6 1.8 1.9 2.1 1.6 2.1 1.4 1.6 2.2 2.4 Channel Depth De (ft) 1.5 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3+0 3,0 3+0 3,0 3;0 3.0 3.0 3;0 3.{ 3.0 3.0 Channel Lining Grass (Rip Rap Ends) Grass Grass Grass Grass Grass Grass Grass Rip Rap Rip Rap Grass Grass Grass Grass Rip Rap Grass Rip Rap Rip Rap Grass Grass NORTH WELD SANITARY LANDFILL UPDATED DESIGN AND OPERATIONS PLAN APPENDIX C SEDIMENTATION POND OUTLET DESIGN Rust Environment i infrastructure Z e COI :c es Motrig &deco setP . _._ ilia WW1 a...a ._--••• •••••••IM• CALCULATiON SHEET sJeJ,_cr _DEurr tens eiF -o Vent y 014 at • . • .F ' • w .;• 4 d • sor .7- goo ,?,;2•'i • 00 m4 s- ° 6MAE' M..• _(,• _ _ _p'_ _ _ : r o z. e t c rR M eks-''i"' sit r a + P 3 ' A t T*e Jo T' H co tr. ° S Am i Tout '' 1�farhJ b ;ate i$ 2tEN D es litittePro aro lacer an L0 ca f''tr h.i tOO Pte c. 5 Q P 4 Aar sat'Jr Sarnia D as to. At e- Des Leib pia c ht.(' i } r� +- t. W Idid Coop\- ' k a r' ' s Dap -- +per ' ; 'Note s it Cr; krater taw 'I' ; t, 13 , toil 3 All Skive re" t thee.r Cats; ‘ ; itritss % l' t. atwes ;et Kew. +a ateAwici ris +"kt ' -c ne usha., irer- ra • crrOM °Kit Snt4. GLeAttet 0 pea N.S-cfr k6 Ps of.. IOC depia.r irciriok treisceaSe irmkdoer.,. i-c ri. , .r r to cose e.•,r- 4:::t/tar a ,.,vet. yvr--i 4h43 a► -Act rct +les Pit o tee . 4..,1 4 .,t. ► tokatieVH. rowte. e Se 5e tear S+br {; : o trkeiss •. c lP ' gel- p esti t ' ;ter r. . let 14eic"StCOLS S or 9rtatasc iAln4 ryeS + + .se 44141. ‘a eel/cot-Ai •9-ro Ns% nuts gocrere v rk ea\ c ft OctseIS Ca FY% p kat 4-ed„, Pr rA Pro creessok Ore, 4rii+"'` Pita I ‘o iv\ co Irciatacte ) so; I Cuo -c-frikar go,.) 14-0; -0 i ... .. ttca.,.nrot. ' oil G ra +l ? D 8a.*eotas +-kat. Moat-it:Yeti4- .-+ - e. t4 lroyson fro test t k -+ 4 serk O p : ,,, 5; 4-.e. ...• p fa sx, i ark t `r a <set_ fiAtteka finoac-t; iolmaakeks • scare: 4 sq rich Rust Environment & Infrastructure CALCULATION SHEET SUBJECT STE MIAJ4-r1 Wop rr Sere,v14tris * . ASkrok Wrt SDP - ! E + '2 •r nut... -t '►Ir 4-v t11 r a ,r'ti r M map •.y 1.►X' '� _r ''1 • 0 ,• -� :,•' - • �• 4 1 4 WIM i see ctql Leo yL i 1�ti•M-rr s1 J ion 'c- 5ed it lista ht. fri c et ponot -, prey ro As i 40 ist1P pi -„ 14-A2 i",s Jim 'mot cx, 3 eat emp gherfritervir.T , .flak, citrocsaale '-t-ea. a ;- Li o 7' otr b , i. " -f.k, r `0 ft 1 +.• n.is S • 7' l 1/4; r +r,s paesit. ... Iaum.) ote heA INA rink. cot 4,O kocf. aerts 0 ;Om-. of How co Oa b•e. Cst fetaditer44 from :resitrg, frotkic At 0 ek at • Pea- igiq3/4 O4.C CietJGOJ'i*.OS•le- 'Ss I) fes 'Peva Aro irlit wesSes? Peak O4o:se-kiwi st. crows. Q r: e tok. ss .0 r;en e , a k 0 u `- Siam kc L'cr s. leo east.. 1 4 40 'Ur 6, h i ; Peo-14% ;kik% F =a a., 3 3 • 0 as p., t h 4 10 + • o cei-s Pea aegeterio 0. z siD 9-4.- "ThrtD z iv / , g Ctrdfr n Awe otej I ` -t& Item ta.." sr + . s. ar")1 '~, `a. ofroo( c tc it 1,`c' letAsioLices o'er. ski -me" - - Letieelet scale: 4 se inch Quick TR-55 Version: 5.46 /N: 1315430243 Page 1 TR-55 TABULAR HYDROCRAPH METHOD Type II Distribution (24 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5YR. SD Hydrograph file: --> NORTH .HYD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Feinstein October 2, 1995 ››» Input Parameters Used to Compute Hydrograph <ccc Subarea Description AREA (acres) CN Tc (hrs) * Tt (hrs) Pre o ip . (in) Runoff Ia/p (in) input/used subarea subarea subarea subarea subarea subarea subarea g f e d C b a Travel 6.80 5.50 11.00 8.60 17.50 18.30 54600 80.0 80.0 80.0 80.0 60.0 80.0 80.0 0.20 0.10 0.20 0.10 0.10 0.20 0.40 0.20 0.20 0.10 0.00 0,00 0.00 0.00 2.20 2.20 2.20 2.20 2120 2.20 2.20 0.69 0.69 0.69 0.69 0.69 0.69 0.69 . 23 . 23 . 23 . 23 . 3 . 23 . 23 . 30 . 30 .30 . 30 . 30 . 30 . 30 time from subarea outfall to composite watershed outfall point. Total area = 121.70 acres or 0.1902 sq.mi Peak discharge = 59 cfs WARNING: Drainage areas of two or more subareas differ by a factor of 5 or greater. Computer Modifications of Input Parameters <<ccc Subarea Description Input Values Tc * Tt (hr) (hr) Rounded Values Ia/p Tc * Tt Interpolated (hr) (hr) (Yes/No) Ia/p Messages subarea ;ubarea subarea subarea subarea subarea subarea g f e d c b a 0.20 0.10 0.20 0.10 0.10 020 0.40 0.20 0420 0,10 0a00 0.00 0.00 0.00 No No No No No No No * Travel time e from subarea outfall to composite watershed ershed outfall point, * Tc & Tt are available in the hydrograph tables. Quick TR-55 Version: 5.46 S/N: 1315430243 Page 2 TR-55 5 TABULAR HYDROGRAPH METHOD Type II Distribution (24 hr. Duration Storm) Watershed file: Hydrograph file: Executed: 10-02-1995 12:36:06 --> NORTH5YR . WSD - - NORTH 2= North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2, 1995 >>>> Subarea Summary of Subarea Times to Peak ‹‹c‹ subarea subarea subarea subarea subarea subarea subarea g f 0 d C b a Composite Watershed Peak Discharge at Composite Outfall (cfs) 4 4 7 9 18 14 29 Time to Peak at Composite Outfall (hrs) 12.3 12*3 12.3 12,1 1261 12,2 12.4 59 12.3 Quick TR-55 Version: 5.46 N: 1315430243 Page 3 TR-55 5 5 TABULAR HYDRO .PH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5 R. WSD Hydrograph file: - _ > NORTH . MYD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike �F a ins 'M.. e i n October 2; 1995 Composite Hydrograph Summary (cfs) Subarea Description 11.0 11.3 11.6 11.9 1240 12.1 12.2 12.3 1244 hr hr hr hr hr hr hr hr hr ;u}barea g 0 0 0 0 0 1 2 4 4 subarea f 0 0 0 0 0 0 2 4 4 subarea e 0 0 0 0 0 2 5 7 6 atharea d 0 0 0 1 5 9 5 2 2 subarea, c 0 0 0 3 11 18 10 4 3 nubare a b 0 0 0 1 4 11 14 10 5 learea a 0 0 0 0 2 7 17 28 29 Total (cfs) 0 0 0 5 22 48 55 59 53 Subarea Description 12.5 12.6 12.7 12.8 13.0 13.2 13.4 13.6 13.6 hr hr hr hr hr hr hr hr hr Subarea. g 3 2 2 1 1 1 1 1 0 ;ubare a, f 3 2 1 1 1 1 0 0 0 subarea e 4 3 2 2 1 1 1 1 1 subarea d 1 1 1 1 1 1 1 1 1 subarea c 3 2 2 2 2 1 1 1 1 .subarea b 4 3 3 2 2 2 1 1 1 subarea a 24 18 14 11 7 6 5 4 4 Cotal (cfs) 42 31 25 20 15 13 10 9 8 Quick TR-55 Version: 5.46 SiN: 1315430243 TR-55 5 5 TABULAR HYDRO PH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: --> NORTH5Y . SD Hydrograph file: -- - > NORTH . HYD North Weld. Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike He iriste in October 2, 1995 Composite Hydrograph Summary (cfs) Page 4 Subarea Description 1400 hr 14.3 14.6 hr hr 15.0 15.5 hr hr 16.0 16.5 hr hr 17.0 17.5 hr hr subarea g subarea f subarea e subarea d subarea c Subarea b subarea a 0 0 1 0 1 1 4 0 0 1 0 1 1 3 0 0 1 0 1 1 3 0 0 1 0 1 1 3 0 0 0 0 1 I 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 0 0 0 0 1 1 2 .sotal (cfs) 7 6 6 6 4 4 4 4 4 Subarea Description 18.0 hr 190 20.0 hr hr 22.0 26,0 hr hr subarea subarea f subarea e subarea d subarea c ;ubarea b iubarea a 0 0 0 0 1 1 2 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 Total (cfs) 4 1 1 1 0 Quick TR-55 Version: 5.46 B/N: 13154 3 0243 Page 5 TR-55 TABULAR HYDROGRAPH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:35:05 Watershed file: --> NORTH5 YR . WSD Hydrograph raph file: - - > NORTH .HAD North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2/ 1995 Time (hrs) Flow (cfs) 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13.0 13.1. 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 1460 14.1 14.2 14.3 14.4 14.5 14.6 0 0 0 0 0 0 0 2 3 5 22 48 55 59 53 42 31 25 20 18 15 14 13 12 10 10 9 8 8 8 7 7 6 5 6 6 6 Time (hrs) 14.8 14.9 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16.0 16.1 16.2 16.3 16.4 16.5 16,6 16.7 16.8 16.9 17.0 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 18.0 18.1 18.2 18.3 18.4 Flow (cfs) 6 6 6 6 5 5 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 Quick TR-55 Version: 5.46 S/N: 1315430243 Page 6 TR-55 5 5 TABULAR HYDROGRAPH RAPH METHOD Type II Distribution ( 4 hr. Duration Storm) Executed: 10-02-1995 12:36:06 Watershed file: - - > NORTH5YR . W D Hydrograph graph file: --> NORTH .HYD D North Weld Sanitary Landfill 5 -Year, 24 -Hour Storm Event Run-off By: Mike Heinstein October 2, 1995 Time (hrs) Flow (cfs) 18.6 18.7 18.8 18.9 19.0 19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 19.9 20.0 20.1 20.2 20.3 20.4 20,5 20.6 20.7 20.8 20.9 21.0 21.1 21.2 21.3 2144 21.5 21.6 21.7 21.8 21.9 22.0 22.1 22.2 22.3 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1. I I 1 1 1 1 1 1 1 1 1 Time (hrs) Flow (cfs) 22.4 22,5 22.6 22.7 22.8 22.9 23.0 23.1 23,2 23.3 23.4 23.5 23.6 23.7 23.8 23.9 24.0 24.1 24.2 24.3 224.5 4 . 4 24.6 24.7 24.8 24.9 25.0 25.1 25,2 25.3 25.4 25.5 25.6 25,7 25.8 25,9 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 APPENDIX B-2 Golder Associates Inc. 44 Union Boulevards Suite 3W Lakewood, CO USA 80228 Telephone (303) 9804)540 Fax (303) 985-2080 October 14, 2002 Mr. Doug J enberr'ry Colorado Department of Public Health and Environment FIMW MD-SWI -82 4300 Cherry Creek Drive South Denver, Colorado 80246.1530 Ms. Cindi Etcheverry Weld County, Department of Public Health and Environment 1555 N. 17th Avenue Greeley, Colorado 80631 Our Ref.: 023-2387 RE: NORTH WELD SANITARY LANDFILL (NWSL), RETENTION POND CONSTRUCTION QUALITY ASSURANCE Dear Mr. Ikenberry and Ms. Etcheverry: On behalf of Waste Management Disposal Services, Inc. (WMDS), Golder Associates Inc. (Golder) is providing this letter to outline a Construction Quality Assurance (CQA) Plan for modification of the existing detention pond at NWSL and request approval of the CQA Plan and the design modification. As previously discussed with ADS, the current pond design includes a stormwater outlet structure. Because of the concern by the Colorado Department of Transportation (CDOT) regarding discharge of stormwater onto the State Right of Way, CDPHE had requested NWSL consider converting the stormwater detention pond to a retention pond. Accordingly, WMDS is proposing the detention pond at NWSL be modified to a retention pond in accordance with the enclosed modified design calculations provided by Earth Tech, Inc. on February 19, 2002. These calculations provide the required dimensions for a retention pond that will store the 100 -year, 24 -hour storm event from the 119 acre completed landfill. The results of this analysis are being incorporated into construction drawings by WMDS. These construction drawings will provide survey points that establish the slope and bottom elevations of the retention pond. Golder will review survey data provided by a licensed surveyor during construction and certify that it is within design tolerances established by the specifications. Upon certification of the survey data, Golder will provide a certification letter sealed by a Professional Engineer in Colorado along with as -built drawings and survey tables that demonstrate that retention pond has been built in accordance with the design. Since NWSL would like to incorporate this work in with the Phase 2 Module I constriction project an expeditious review of this design modification and CQA Plan is appreciated. Colorado Department of Public Health and Environment Doug Ikenberry Weld County, Department of Public Health and Environment Cindi Etchever 7 7 w2 - October 14, 2002 023-2387 If you have any questions feel free to contact the undersigned at 303-980-0540. Sincerely, ti OLDS SSOFIA, INC. f Mark M Clain, P.E. Senior rojcct Manager Attachment: Design Calculations cc: Kin Ogle, WCDPS w/attachment Alan Scheere, WMDS wiattachment Bill Hedberg, WMDS &attachment MEM/ljd t'\O C2\OtO 232387.01OQ 05252.00c Golder Associates • ATTACHMENT HMENT - .:. „ -. . - . - . • - •• :_;-: October 2002 is wrolow 2323$7.OI iia.05 zsg Doc Golder Associates 023-2387. 5575 DTC PArk way, Suite 200, Englewood, Colorado 80111-343;6 February 19, 2002 Mr. Alan Scheere Waste Management of Colorado at CSI 2090 E. 104th Avenue, Suite 300 Denver, Colorado 80233 Re: Re -Evaluation of North Weld Sanitary Landfill Retention Pond and Ground Water Discharge Permit Requirement Dear Mr. Scheere: Earth Tech, Inc. has completed a re-evaluation of the North Weld Sanitary Landfill' s (NWSL) proposed retention pond to store the runoff resulting from a 100 -year, 24 - hour storm event from the fully developed landfill. The re-evaluation of the pond to contain the 100 -year, 24 -hour storm runoff is required due the Colorado Department of Transportation' s concern regarding NWSL's discharge of collected storm water to the Colorado State HIghway 14 right-of-way south of the site. The calculations completed to evaluate the pond are attached. The loo -year, 24 -hour storm event volume is approximately 22.6 acre-feet Using a 1.5 factor of safety((approximately 34 acre-feet) for available storage, the pond's dimensions, as previously designed, can remain at a length of approximately 600 feet and a width of 400 feet with 4KIV side lopes. The depth should be increased by 1.5 feet to 8 feet (elevation 5066.0 feet) in order to limit the top of water elevation to approximately 5073.5 feet, This depth assumes that sediment storage of 2 feet (elevation 5066,0 to 5068,0) is incorporated into the pond's design. Earth Tech contacted the Colorado Department of Public Health and Environment Water Quality Control Department to determine if the surface water storage pond would require a ground water discharge permit. Mr, Liuzzi of the Water Quality Control Department indicated that under the Colorado Discharge Permit System Regulations [SCR 1002-61, f 4 l)(b)(iii), attached], any storm water retention or detention impoundment is exempt from the ground water discharge permit requirement. If you have any questions concerning this re -sizing of the NWSL retention pond, please contact me at (505) 350-1306 or Randy Thompson at (303) 694--6660. Very truly yours, Earth Tech, Inc. Michael R. Heinstein, F.E. Civil Engineer cc: Randy Thompson, }I.E. r \44645‘rawsi\portii-analysis.doc EARTHSTECH Telephone 303-694-6660 Facsimile 303.694.4410 Attica INTERNATIONAL LTD. COMPANY ATTACIIMENT1 CALCULATIONS "'- NWSL RETENTION POND RE-EVALUATION CALCULATION SHEET PROJECT: Waste Management — North Weld Sanitary Landfill — Weld County, Colorado ado CALCULATION TITLE: North Weld Sanita Landfill Retention Revaluation PROJECT NUMBER: 39973.0702 PREPARED BY: MRH PROBLEM STATEMENT REVIEWED/CHECKED BY: DATE: December 16, 2001 PA EgOF a The purpose of this evaluation is to determine the size of the North Weld Sanitary Landfill NW retention pond to store the runoff from a 100 -year, 24 -hour (NWSL) storm event from the fully developed 119 -acre site. DESIGN CRITERIA The flow into the NWSL retention pond was determined during the completion of the January 1995 i h will be used to estimate to Development Plans. The storm hydrograph the total volume of water that must be stored by the pond. SITE LOCATION AND LAYOUT Noah €�Id Say f ��fill NWSL is located approximately six miles west of Colorado State Highway 85 on Colorado State Highway 14. The facility's address is 40000 Weld County Road 25, Ault, Colorado 80610, Final grades for the NWSL were designed to promote positive drainage of precipitation runoff (Site Development Plans [January 1996]). Runoff from the landfill dull slopes will collect in channels and will be conveyed to the proposed retention pond that will be located in the southeast corner of the site. The proposed retention pond was initially designed with 2H:IV sideslopes but, to facilitate easier access to collected sediments, the sideslopes will be flattened to 4 : 1pond was V. The retentionsized to control the runoff volume as a result of a 100 -year, 24 -hour storm event from the 119 acre completed landfill. ANALYSIS RESULTS AND DISCUSSION NWSL Retention Pond_ Capacitv,a5nalysis .............. 1. Design factors developed during the completion of the January 1996 Site Development Mans which were used in this analysis include: p h ch a. 100 -year, 24 -hour storm event flow into the pond from the landfill 214 cis; b. Inlet channel invert elevation to pond ; approximately 5070.0 feet; c. Inlet channel top of water surface elevation due to 100 -year storm = 5072.3 feet; and d. Inlet channel top of sideslope elevation = 5074.0. e. Factor of safety = 1,5 (10O -year, 24 -hour runoff volume) [to account for existing water that may be in the pond at the time of the storm event, etc. CALCULATION SHEET PROJECT: Waste Management— North Weld Sanitary Landfill — Weld County, Colorado CALCULATION TITLE: North Weld Sanitary Landfill Retention Revaluation PROJECT NUMBER: PREPARED BY: REVIEWED/CHECKED BY: 39973.0702 MRH Sediment Stara Working Stormwater Volume aramonemom— _ DATE: December 16, 2001 NWSL Retention Pond Volume Capacity Estimate Elevation Area - (acres) 5068.0 8007.0 5068.0 Toyof Pond Notes: - 5068.0 5060.0 5070.0 5071,0 6072.0 5073.0 5074.0 Cumulative Volume of Storage cre-fl) 0 5A1 5.41 5.53 10.82 ._.--....__..... 5.53 0 0.0 5.70 5.7'0 1.0 5.87 11.74 2.0 6.01 18.03 3.0 6.14 24.56 4.0 628 31.40 S. 6.4 38.52 1 6.0 Depth of Water 0 0 0 1_ Storage volumes and primary structure outflow rates based on a 595 ft x 400 ft retention pond with 4H:1 V sideslopes and located as shown on the January 1996 Site Development Plans. 2. Using the pond volume capacity estimates, the 100 -year, 24 -hour storm hydrograph, developed during the January 1996 completion of the Site Development Plans, can be easily stored in the pond. Pond dimensions: 600 feet in length, 400 feet in width and a total of 8 feet in depth. WOW _ PONDe2 Version: 5.17 S/N: 1295130221 EXECUTED: O7 10e2OOO 11:10:12 Page 1 **, ***** -************ **** *************, ********************* ******* * North Weld Sanitary Landfill * Revised Retention Pond Characteristics Widened Pond to 600x400 * Mike Eeinsteln July 10,2000 * * ***** *** * ** * **** ******* * ** ******* * * ** *** * * **-********** **** *** ** * ** *** * Inflow Hydrograph: NWELDHYD.HYD Rating Table file: NPD D . PND rah -INI AL CONDITIONS ---- Elevation = 5069.80 ft Outflow = 0.00 cfs Storage = 0.00 ac -ft GIVEN EN POND DATA I ELEVATION I (ft) I 15069.80 5070,00 5071.00 1 5072.00 J 5073.00 1 5074.00 I. OUTFLOW I STORAGE 1 (cfs) I (ace ft) I 0.0 0.5 3.5 6.7 10.2 13.0 0.0001 1.1701 7.1101 1361901 19.4001 11. 25.7501 } Met •- Faint ,1.fi4 _ blen S r .4"telt e t SIN eflo INTERMEDIATE ROUTING COMPUTATIONS 23/t (cfs) 0.0 283.1 1720.6 3192.0 4694.8 6231.5 Time increment (t) = 0.100 hrs. • ,• .+ e ► wr .,o, a r an a Imatect,i PS1dr-L C 2S1't + 0 {cfs} 0.0 283.6 1724.1 3198.1 4705.0 6244.5 etc trona a4t 445 61 ,2 ;la 4,1;44% s ;Tweet. kb siirtaven arc,. POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11:10:12 Pond File: Inflow Hydrograph: Out flow Hydrograph: INFLOW HYDROGRAPH I TIME I (hrs ) 11.000 11.100 11.300 11.200 Ja. 1 . 3 0 0 11.400 11.500 11.600 11.700 11.800 11.900 12.000 12.100 1f�� 12 . 2Y Y 12.300 12.400 12.500 12.600 12.700 12.800 12.900 13.000 13.100 13.200 13.300 13.400 13.500 13.600 13.700 13,800 13.900 14.000 14.100 14.200 14.300 14.400 14.500 14.600 14.700 14.600 14.900 15,000 15.100 15.200 15.300 15.400 INFLOW (cfs) 1 I 7.001 8.001 9.001 10.001 12.001 14.001 16. 001 30.001 44.00) 58.001 112.001 192.001 214,001 197.001 172.001 128.001 89.001 66.001 50.001 42.001 35.001 31.001 27.001 24.001 22.001 21.001 20.001 19.001 18.001 18.001 17.001 16.0{0 1 16.00 15.001 15.001 14.001 14.001 { 14.001 4 _ oo l 13.001 13.001 13.001 12.001 12.001 11.001 NWPOND . PND UWELDEYD . HY D @WFLO . YD I I I I I I 1 11+12 (cfs) 15.0 17.0 19.0 22.0 26.0 30.0 46.0 74.0 102.0 170.0 304.0 406.0 411.0 369.0 /300.0 2 1 7.0 155_0 116.0 92.0 77.0 66.0 58.0 51.0 46.0 43.0 41.0 39.0 37.0 36.0 35.0 33.0 32.0 31.0 30.0 29.0 28.0 28.0 28.0 27.0 26.0 26.0 25.0 24.0 23.0 0,1 kr% 1. ROUTING COMPUTATIONS 2S/t -- O (cfs) 0.0 14.9 31.8 50.7 72.4 98.1 127.6 173.0 246.1 346.8 5149 815.6 1216.7 1621.1 1982.0 2272.6 2479.2 2623.3 2727.9 2808.1 2'813.1 2926.8 2972.3 3010.7 3043.9 3074.0 3102.0 3127.8 3151.6 3174.2 3195.8 3215-2 3233.6 3250.9 3267.1 / 3282.3 3296.3 3310.4 3324.3 3337.2 3349.0 3360.8 3371.5 3381.2 3389.9 2511 + 0 1 OUTFLOW (cfs) I (cfs) 0.01 15.01 31.91 50.61, 72.71 98.41 128.11 173.61 247.01 348.11 516.81 818.91 1221.61 1627.71 1990.11 2282.01 2489.61 2634.2 2739.3 2819.9 2885.1 2939.1 2964.8 3023.3 3056.7 3086.9 3115.0 3141.0 3164.8 3187.6 3209.2 3228.8 3247.2 3264.6 3280.9 3296.1 3310.3 3324.3 3338.4 3351.3 3363.2 3375.0 3385.8 3395.5 3404.2 0.00 0.03 0.06 0.13 0.17 0.23 0.31 0.44 0.63 0.99 1.61 2.45 3.30 4.08 4.71 5.16 5.48 5.70 5.88 6.02 6.14 6.24 6.32 6.39 6.46 6.52 6.57 6.63 6.68 6.72 6.77 6,81 6.85 6.89 6.93 6.96 6.99 7.02 7.05 7.08 7.11 7.13 7.16 7.18 Page 2 1 ELEVATION (ft) I 1 5069.80 5069.81 5069.82 '.r•;5069.84 5069.85 5069.87 I 5069.89 1 5069.92 5069.97 5070.04 5070.16 5070.37 5070,65 5070.93 5071.18 5071.38 5071.52 5071.62 5071.69 5€ 71-74 5071.79 5071.82 5071.85 5071.88 5071.90 5071.92 5071.94 I 5071.96 5071.98 5071.99 5072.01 1 5072.02 5072.03 1 5072.04 5072.05 5072.06 1 5072.07 5072.08 5072.09 1 507210 5072.11 50.2,12 5072.12 15072.13 ! 5072.14 •*i a. ► 4.3 -1S-.5 oc' c tQ coca 3 4 w c4 3,140 c+ 4i4130c 6. Cott et p 1.510. E 3a cS3 VII. 3Set c4 3o,tactcc- 5q fig 0 a- GI. cc - 000 cac- aCti *L O 11-ilos cc ItC 51,0 c5 s 3j 140 c4 in° CS 10 44.0 C*' line c4 24 LSO ci 140 to a- il d 2-0 C $- Col WO roc' it* 44 GiSootcr- ; le o 14-6Q Cc' 5100 re. ry T cac. 46 M- t c1 p e'4 tom, cc - 4, tpxo cot ,iioc flb c M1 ito lima di. F. POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: O7-1O-2OOO 11:10:12 Pond File: NWPOND .PND Inflow Rydrograph: NWELDfYD. HYD Outflow }Iydrograph ; NWFLOW .HYD INFLOW YDROGRAPH ROUTING TIME (hrs) 195OO 15.600 15.300 15.8DO 15.900 16.000 16.100 16.200 16.300 16. 4OO 16.500 16.600 16.700 16.800 16.900 17.000 17.100 17.200 17,300 17,400 17.500 17.600 17,700 17.800 17. 9OO 18.000 18.100 18.200 18.300 18.400 18.500 18.600 � 18,1j00 18.800 18.900 19.000 19.100 19.200 19.300 19.400 19.500 19.600 19.700 19.800 19.900 20.000 INFLOW I (cfs) I 11.001 11.001 10.001 10.001 9.001 9.001 9.001 9.001 8.001 8.001 8.001 8.001 8.001 8.001 8.001 8.OOj 8.001 8.001 7.001 7.001 7.001 7.001 7.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 6.001 5.001 5.001 5.001 5.001 5.001 4.001 4.001 4.001 I 11+12 1 (cfs) 22.0 22.0 21.0 20.0 19.0 18.0 18.0 18.0 17.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 15.0 14.0 14.0 14.0 / 14 .0 13.0 12.0 12.0 12.0 12.0 12,0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 11.0 10.0 10.0 10.0 10.0 9.0 8.0 8.0 1 2S/t ` O 1 (cfs) 3397.5 3405,1 3411.6 3417.1 3421.6 3425.1 3428.6 3432.0 3434.4 3435.9 3437.3 3438.7 3440,1 34415 3442.9 3444.3 3445.7 3447.1 3447.5 3446.8 3446.2 3445.6 3445.0 3443.4 3440.8 3438.2 3435.6 3433.1 3430.5 j 342�J 8.0 3425.5 3423.0 3420.5 3418.0 3415.5 3413.1 3410.6 3408.2 3404.7 3400.3 3395.9 3391.6 3387.2 3381.9 3375.6 3369.4 I 1 1 COMPUTATIONS 2S.lt + O (cfs) 3411.9 3419,5 3426.1. 3431.6 3436.1 3439.6 3443.1 3446.6 3449.0 3450.4 3451,9 3453.3 3454.7 3456.1 3457.5 3458.9 3460.3 3461.7 3462.1 3461.5 3460.8 3460.2 3459.6 3458.0 3455.4 3452.8 3450.2 3447.6 3445.1 3442.5 3440.0 3437.5 3435.0 /'� 3432.5 3430.0 3427.5 3425.1 3422.6 3419.2 3414.7 3410.3 3405.9 3401.6 3396%2 3389.9 3383.6 OUTFLOW (cfs) 7.20 7.21 7.23 7.24 7.25 7.26 7,27 +.28 7.28 7.28 7.29 7.29 ( 7 • . 2 1 7.29 7.30 7.30 7.30 7.31 7.31 7.31 7.31 7.31 7.31 7.31 7.30 7.30 7.29 7.28 7.28 7.27 7.27 7.26 7.25 7.25 7.24 7.24 7.23 7.23 7.22 7.21 7.20 7.19 7.18 7.17 7.16 7.14 7.13 Page 3 IELE TYONI (ft) 5072.14 5072.15 5072.15 5072.15 5072.16 5072416 50.72.16 5072.16 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072,17 5072.17 5072.17 5072.17 5072.17 5072.17 5072.17 5072417 5072.17 5072.17 5072.16 5072.16 5072.16 5072.16 5072.16 5072.16 5072415 5072.15 5072.15 5072.15 5072•115 5072.14 577^ �f d2, 14 5072.14 5072.13 5072413 5072,13 5072.12 fl0 cc $ is c 1 110 4 iac-4 :1442.00 I, .,eta cc. c4 1aa cif 30,E a J#o4..aC. j oft 3 bid, '4 ac -c - 3.)m c 3-00 c4 Z13'0 c$ t ' 3 }�J 2.1 rip t+ II 310 .1'540'4 lag o cif 3* C5 Lai i g tl 4 €o cif arlit, if} 1,`+tp c4 14100 Cji I$oo c4- 1% Sad c.4 1.17a6 C9~ tr cox II IN D a- LC sl© Lie 1 I J POND -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11.10.12 Pond File: NWPOt0 . PND Inflow Hycirograph: NWELDHYD . HYD Outflow Hy ograph : NWFLOW . HYD INFLOW HYDROGRAPH ROOTING COMPUTATIONS TIME (hrs) 20.100 20.200 20.300 20.4Q0 20.500 20.600 20.700 20.800 20.900 21.000 21.100 21.200 2.1300 21.400 21.500 21. 600 21.700 21.800 21.900 22.000 22.100 122.200 2 2 . 3 0 0 22.400 22.500 22.600 22.700 22.800 22.900 23.000 23.100 23,200 23.300 23.400 23.500 23.600 23.700 23.800 23.900 24.000 24.100 24.200 24.300 24.400 24.500 24.600 [ INFLOW I (cfs) 1 4.001 4.001 4*Q01 4.001 4.001 4.001 4..00) 4.001 4.001 4.001 4.001 4.00 4.00 4.00 4.00 4.00 4400 4400 4.00 4.00 4,03 4.00 4.00 4.00 4.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 1.00 11+12 (cfs) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 /8 .0 8 ♦ 0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 7.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 5.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.0 2S/t - 0 (cfs) 3363.1 3356.9 3350.8 3344.6 3338.5 } 3332.4 3320.3 3314.3 3308.4 3302.4 3296.5 3290.6 3284.7 3278.9 3273.1 3267.3 3261.6 3255.8 3250.1 3244.4 3238.8 { 3233.2 3227.6 3222.0 3215.5 3208.0 3200.5 3193.0 3185.6 3178.3 317049 3163.6 3156.4 �j +� 3148..E 3138.9 } 3129.8 3120.6 3111.6 3102.5 3093.5 3084.6 3075,6 3066.8 3057.9 3048,1 Page 4 2 S/ t + 0 I OUTFLOW I tLEVATI ON (cfs) I lcfs) I (ft) I 3377.41 3371.11 3364.91 3358.81 3352.61 3346.51 3340,41 3334.4 3328.31 3322.3 3316.41 3310.41 3304.5 3298.6 3292.7 3286.9 3281.1 3275.3 3269.6 3263.8 3258.1 32}52'. 4 3246.8 3241.2 3235.6 3229.0 3221.5 3214.0 3206.5 3199.0 3191.6 3184.3 3176.9 3168.6 3161.4 3152.1 3142.9 3133.8 3124.61 3115,61 3106.51 3097.51 3088.6, 30794G I 3070.81 3060.9 7.12 7.10 7.09 7.07 7.06 7.04 7.03 7.02 7.00 6.99 6.97 6.96 6.95 6.33 6.92 6.90 6.89 6.88 6.86 6.85 6.84 6.82 6.81 6.60 6.79 6.77 6.75 6.74 6.72 6.70 6.68 6.67 6.65 6.64 6.62 6.60 6.58 6.56 6.54 6.52 6.50 6.48 6.46 6.44 6.42 6.40 I I I I I I 5072.12 5072.11 5072.11 5072.11 5072.10 5012.10 072.09 5072.09 5072.09 5072.08 5072,08 5072.07 5072.07 5072.07 5072.06 5072,06 5072.05 5072.05 5072.05 5072.04 5072.04 5072.04 5072.03 5072.03 5072.02 5072.02 5072.02 5072.01 5072.01 5072.00 5072.00 5071.99 5071.99 5071.98 5071.97 5071.97 5071.96 5071.96 5071.95 5071.94 5071.94 5071.93 5071.93 5071.92 5071.91 5071.91 %1%No c- &- 1S % tl�+� c.J 44° c5- isMaoc4 11otc c LAS° 4.V t4*to a- �; 080 c4 II ck II no 44- ago tio4 gin 44 ho is 4-Zo c* nta tc FAO a / ere Ito ig-P coce 3-24, .44 S'io POD -2 Version: 5.17 S/N: 1295130221 EXECUTED: 07-10-2000 11:10:12 Pond File: NWWOND .FND Inflow Hydrograph: NWELD YD t HYD Outflow Hydrograph: NWFLOW -HID INFLOW HYDROGRAPH ROUTING COMPUTATIONS 1 TIME airs) 24.700 24.800 24.900 /25.000 25 s 100 25.200 25.300 25.400 25*500 25. 600 25.700 25«800 25. 900 INFLOW 1 (cfs) I 1.00i LOU! 1.001 1.001 1.001 1.001 1.001 0.001 0.001 0.001 0.001 0.001 11+12 (cfs 2.0 2.0 2.0 2.0 2.0 2.0 2.0 1.0 0.0 0.0 0.0 0.0 1 2S/t - 0 (cfs) 3037.4 302647 3016.0 3005.4 2994.8 2984.3 2973.8 2963,4 2952.0 2939,7 2927.4 2915.2 2903.0 2S/ft + 0 1 (cfs) f I 3050.11 3039.41 3028.71 3018.01 3007.41 2996.81 29+86.31 2975.81 2964.41 2952.01 2939.71 2927,41 2915.21 Page 5 OUTFLOW (cfs) 6.38 6.35 6.33 6.31 6.28 6.26 6.24 6.22 6.19 5.15 6.14 6.11 6.08 c �- ELEVATION (ft) 5071.90 5071«89 5071.98 5071.88 5071.87 5071.86 5071.86 5071.85 5071.84 5071.83 5071.82 5071.82 5071.81 rt„ raft. a 514 F I cir 360 4.+ 3 O 4-;- 34azic 34.0 3ito c iitter.c' 1%bar D cc. $4 141O c 1$O c.f X92.1 34TO c f. T -t•.- Id 3i a. . e AITACIMENT COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT WATER QUALITY CONTROL DEPARTMENT COLORADO DISCHARGE PERMIT SYSTEM REGULATIONS 5CC12 1002-61.14(fl)(BXM) COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT WATER QUALITY CONTROL COMMISSION REGULATION NO, 61 cOtORADODISCHARGE PERMIT synpvi ADOPTED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY EFFECTIVE: AMENDED; EFFECTIVE: AMENDED: EFFECTIVE; AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: November 171 1981 December 20,1981 March 291 1982 April 29,1983 September 13, 1983 Dr 31, 1983 May 15, 1984 June 30, 1984 April 14, 1986 May 30, 1986 June 2, 1987 July 31, 1988 May 2, 1988 July 1, 1989 November 2 1988 December 30, 1988 July 10, 1989 August 31 "1989 December 4, 1990 July 1, 1991 January 8,1991 March 21991 June 4,1991 July 1, 1992 November 4, 1991 December 30, 1991 AMENDED: January 6,1992 January -6, 1902 April 7, 1992 July 1, 1993 June 2, 1992 June 30,1992 February 2, 1993 March 30, 1993 August 2,1993 September 30, 1993 July 11, 1934 August 30, 1994 AMENDED: November 14, 1994 November14, 1994 December 12, 1994 January 30,1995 January 9, 1995 March 2; 1995 November 13, 1995 December 30, 1996 May 13, 1996 Juno 38, 1996 I AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: EMERGENCY ENCY AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: AMENDED: EFFECTIVE: July 14, 1997 August 30, 1997 March 10, 998 April 30, 1998 February 9, 1999 March 30, 1999 March 9, 1999 March 30, 1999 March 9, 1999 April 30, 1999 January 8, 2001 March 2, 2001 November 13, 2001 Decorator 30, 2001 TABLE OF CONTENTS Ent 110 Colorado D iscis q1 Q F ermi ,Sypte -�_,_'. inula ion ■,a.ara+#ai4 f!!a• tat• 1 6141 Genet* Pt VisicIn lirra+i/rT.T.• v41T.TMT.t4+IRrrr rar }a. si (1) Scope and Purpose r r aaa►ae■• ! a•rs/ae+: T.Ikf1R+Nlta4+; fa4 1 (2) Incorporation by Reference if4ra}r+f•s+a 4ta�• +t 1*44 .iY ►at+a{.+i* isiira }i ■aaa r/r• I (3)SeveLabilit ►a it f! w}+fiiia} aY•ar r.+.R+}ia /ii pets I 612 Definitions sea i.sraf lrhlra lf.i} t!■t t4iF i+a ages •}iar r+ir!• 1 61.3 Applicablittv 13 (1) Applicability Generally 13 (2) Applicability a Stormate/ i /i.TTaahs*i st4 sat a;a r, ■!1R►tRsr rte+♦ 13 a�ai,aa_ft■,■■slrarhfht i (3) Applicability - Concentrated Aquatic Animal Production Facilities 24 (4) Applicability a Aquaculture Projects cast...l..., a r++ 25 (5) Applicability r Silviculture Activities ■.!!! ar •*I...r*rrTt/►RRR*• r ease. 25 61.4 a lic tior for. a Permit, i*.a1e,■r4at t!*lT.h_.rart t!*Y■yR■■ti■+Mal44T+ia}I...a1.f♦ 25 � . _... ... Generally �y �'`� emu+ (1) Application Requirements- Genetalll /r.r►T•l It itf l+/zrae ■, ITs sr Mi _aYrrar++• alts 25 (2) Application Requirements e Existing •Manufacturing* Com ercial* Mining, and Silvaculture Discharges . R T r,i ,. i. • t .... a 30 (3) Application Requirements ents a Storrnwaterl..i ai.wise.,....f.!►t.aii i.i.44*•. T._R,.. 34 (4) Application Requirements w Manufacturing, ng, of mercial, Mining and BiMMicultur l Facilities which Discharge Only Non -Process Water r{ }/ ■ itr to as re rar. ► r.■a r!!• }a ai a 50 (5) Application Requirements - New and Existing Aquatic Animal Production Facilities ..■■! 51 (6) Application Requirements a New and Existing POTWs a...■.}hr .■.i •.T,t t 52 (7) Application Requirements - New Sources and New Discharges P, ii •f f Y 1+., a a. }i .. i 53 (8) Application Requirements For Housed Commercial Swine Feeding Operations 55 61.5 Review, Determination, otice and �i.i a i 'M+! # 55 (1) Review of an Application ...,t .a h •. }} ii• .i • • r, t.. of R 55 (2) Public Notice and Comment a Draft Permits l,rh•.,ra.S *St+h}..i+ ,..,. 56 (3) Public Meetings on Draft Permits 4 1 •h ar rr .rraa 58 (4) Public Access I to Information if lr.riti :,..Rrl.. ►a fr,{rt a.. i. 59 61.6 Issued Permits #tiiti fa.air }.. !•itttht4+It titan, t•TIR.q►...dirt it TR rsal.R 60 61.7 Pemiit Adrudicatory Hearin€ /il/TTtTT!/fin t■Rf►.tt 60 (1) Administrative Stays a Renewal Permits ...}ttf4t}traa1.; , If 61 61.8 Terms and Conditions of Permits }+r}r, iitr..,.,.162 (1) Prohibitions •.ee•#r.i 7TT►.TTRf1•TT••77••rr jLr•i i.• (2) Definition of Effluent Limitations * f a• • s 63 (3) Conditions of Permits nitV i/ra rlia t!!!*•aTa a.srtt t,.raa;r} rt• 41r•/+a•raa 82 i I PAGE 61.9 (1) (2) 61.10 61.11 61.12 61613 (1) (2) (3) (4) (5) (6) 61.14 (1) (2) (3) (a) (5) (6) (7) (8) (9) (10) 61.15 61 .16 fkAcnitoringt Recording and Reporting i i+►ri+A M44 rit,t r4„t, ra- r■:,ar•yt•a rr sr 8 Notification Requirements • a •a r•rs: as♦rraraa.ta* 89 Transfer of Permits r ++ ► r t 4 t 91 Terms and Conditions Applicable to Domestic Wastewater Works tit*..4a.+.r,+4 91 Permit Modificationr Suspensions Revocation and Reissuance and Termination .. 93 Effect of Permit Issuance r aa a 96 Discharges to Ditches and Other MantMade Conveyance Structures, Conditions for Phase II Municipal Stormwater Permits .. *t4.41r•. t ■ .+..�t.. r. t Qualifying Local Programs s . ....4F.a,r•.r r►a,.,l.4r«.a««4ar►+4:+ 1-•••••111.• 9 ,,....#,.101 Other Types ofPermits 3►ct**rt.r a.aaa ra +.rfr+ a •a •ra ♦ra4i 102 Temporary and Extended Permitstrts4 f„ ■,.a.eas* rs*tr4 r• •rrr.+rra.a►4■,•rrr*ta 102 General Permits •- i,aawrYaa►aa aarraas ti rrr 102 ivi,od cat _nd renewal f_ ermits !Antibacrklrsllcjirm•••ii►►4riMYFft*►itfl►k•ti „ann. a►at•yai►rar,r+ 105 War.Qvalitt8taftdarcis Barspd, Permits ir Determination of Economici_Environmental Public ltlll...j Energy Impact Variances I. 107 105 Ho eJi$SMmtuerciaISwineFeJaQpecflQnMf! wrafarr■■r•a 110 Scope and Purpose :r ai.PV • i aaau a F-■waa.,rraaaa aa.a 1410 Specific Applicability 110 Applications and Required Plans i as _ , ....... r r... 110 Requirements for Housed Commercial Swine Feeding Operations+r e a t ,.i116 Permit Fees „r,r a F .... 126 Enforcement 126 Vrar.u-n i •at r.. 127 a Applicability 127 Regulation by Implementing Agencies s. r+ i/ t+ t r R** t t 4 4 r, 4► I t t i l r s M i a t a i •. i a t. s r r r t l R a a r 125 Impacts from Surface Waters4f■FtrFpa■rtaaf as ■raa 125 Point of Compliance 128 Verification cation Monitoring 129 Control Plan a r 129 Land Disposal .rer•aiaa ■ a a ■wrrtr 129 Land Treatment i 130 Impoundments •.fa., r.. -■.+..a.. 130 Application and Operation Requirements 131 Permit Fees so General Provisions 4apa,_..,.•_r_. -.r.., .aa.t..a. ■. 131 d,l in7station by the Division„F •s• • t-3Mr++i►# tiF., e.i as .• •...is 132 (b) The Division shall take immediate enforcement action against any housed commercial swine feeding operation that has exceeded the agronomic rate limit of subsection 61.13(4)(e). 61.14 GROUND WATER 00) APPLICABILITY (a) Pursuant to this section a permit shall be required for ail land application discharges and for all discharges from impoundments unless: (I) The discharge is exempted under section 61.14(1)(b); (ii) The discharge is subject to regulation by one of the implementing agencies described in 61.14(2); (iii) The impoundment has received a waiver from the Division pursuant to section 61.14(9)(a); or (iv) The owner of a land application system can demonstrate that <A) The design and operation of the system will result in complete evapotranspiration of the effluent; (B) There is adequate storage provided for the effluent during periods of inclement weather or where the ground has been frozen unless the provisions of (A) above, can be met during the entire year; and; (C) Any augmentation plan or substitute supply plan for the land application site does not provide a credit for return of the effluent to ground water. (b) The following facilities are specifically exempted from coverage under the ground water discharge provisions of this regulation: (I) Any impoundment subject to regulation under the Uranium Mill Tailings Radiation Control Act, 42 U.S.C., Section 7901, et seq. as amended. (ii) Any impoundment used in the treatment, storage or recharge of raw or potable water; (iii) Any stormwater retention or detention impoundment. (iv) Any impoundment or land application system for which a currently valid certificate of designation has been obtained pursuant to the Solid Waste Disposal Sites and Facilities Act, C.R.S. 1973, 30-20-1011 et seq. as amended, and other impoundments or land application systems subject to regulation under that Act which are not part of a wastewater treatment system for which a Colorado Discharge Permit System (CDPS) permit for a discharge to surface waters is required. (v) Any tank which does not result in a discharge to ground water. 127 APPENDIX B-3 Golder Assiciates CALCULATIONS Date: 08 -November 2010 Made by: Project No.: 103-81825 Checked by: Subject: Supplemental Runon H&H Calculations Reviewed by: Project NWLF Drainage Improvements Short Title: 1.0 OBJECTIVES MBR Ve3 v Size a culvert to collect and divert stormwater runoff contributing to the maintenance shop area from the western portions of the landfill property to the landfill perimeter channels. Peak 100 -year, 24 -hour stormwater flowrates for the landfill were calculated in a previous calculation (RUST, 1995). This report will determine the 100 -year, 24 -hour peak flow contributing to a point upgradient of the maintenance shop area. This peakflow will then be added directly (no routing) to the flowrates provided in the RUST calculation to determine if the as -designed perimeter channels will be adequate to accommodate the additional runoff. .0 METHODS • The contributing basin was delineated based on site topography, see Figure 1. SCS Curve Number (ON) methodology is used to model the basin to the north of the existing berm and shop area; TR-55 methodology was used to model the basin in HEC-HMS (USAGE, 2009). Parameters including subbasin area, CN, lag time, and slope are entered into HEC-HMS to develop a peak flow. Attachment A presents the manning's n and overland flow coefficients. A routing diagram displaying the routing logic is included in the attached HEC-HMS output (Attachment B). Channel dimensions provided by Waste Management were analyzed using a spreadsheet that solves for normal depth using manning's equation to verify that the additional stormwater flows determined in this calculation would not cause overtopping. Culvert sizing was performed using HY8 culvert sizing software (FHWA, 2009). 3.0 DATA AND ASSUMPTIONS NOAA Technical Atlas 2 precipitation depths (NOAA, 1973): Return Period (years) Precipitation (inches) Depth 2 1.7 --- 100 4.0 [IA The rainfall hyetograph assumed an SCS Type II storm distribution. Minimum lag time is 3 minutes. Ea SCS Curve Number was assumed to be 84 for consistency with the RUST calculations Manning's roughness coefficients: Channel Lining/Material Manning's n for Stability Manning's n for Capacity Grass 0.030 0.033 Riprap 0.035 0.040 HDPE (culvert) 0.012 0.012 JA10JOBS\103-81825 NW'LF Drainage Improvements\Surface water\Runyon H&H Calculaiion_docx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 vwww.golder.com Golder Associates: Operations in Africa, Asia, Australasia. Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Waste Management of Colorado 11 -October 2010 North Weld Landfill 2 103-81825 Runoff contributing to the site was assumed to be bounded by the fence line to the west, as there is a ditch on the westernside of the fence to intercept stormwater from the county road. Culvert sizing assumed smooth -wall corrugated HDPE culvert with a conventional entrance. CALCULATIONS Figure 1 presents the subbasin delineation and approximate locations of the affected perimeter channel reaches. Table 1 presents the area -weighted curve number calculations. Table 2 shows the time of concentration calculations but due to uncertainties in determining a defined flow path a conservative, minimum lag time of 3 -minutes was used. Table 3 includes a summary of the HEC-HMS model output. Table 4 provides channel geometry provided by Waste Management and flow information for the perimeter channels. The peak flow from the western runon area as determined from the HE -HIS model was conservatively added directly to the peak flows in the perimeter channels as reported in the RUST report. HY8 output for the culvert sizing calculations are presented as C. li,..)SIONS/RFSOLTS The HEC-HMS results indicate that the estimated 100 -year, 24 -hour peak flow from the western run-on area is 7 cubic feet per second. The HY8 results indicate that an 18 -inch diameter smooth wall HDPE culvert is adequate to pass the 7 cubic feet per second design flow. Based on the channel dimensions provided by Waste Management the additional peak flow will not adversely impact the as -designed perimeter channels. However, in order to provide adequate cover for the proposed culvert under the access road perimeter channel Reach 5-6 was steepened and Reach 6-7 was flattened to allow for a lower pipe invert elevation at the outlet, this change is reflected in Table 4. 04- TACHMENTS NT Attachment A - Travel Time, Manning's n, and Overland Flow Coefficients Attachment B - HEC-HMS Model Parameters Attachment C - HY8 Model Output HE -HMS Hydrologic Modeling System [computer software] August, 2009. US Army Corps of Engineers Version 8.4 U.S. National Oceanic and Atmospheric Administration (NOAA). 1973. Precipitation Frequency Atlas of the Western US, Atlas No. 2, volume ill - Colorado.. Silver Spring MD : US Department of Corn m erce. I.S. Federal Highway Administration (FHVVA). 200'x_ HY8 Version 7.2 FHWA Culvert Analysis. Washington, DC.: FHA Office of Technology Applications. U. S. Soil Conservation Service (USSCS). 1986. Urban Hydrology for Small Watersheds, 2nd edition (USSCS Technical Release Number 55). Washington D.O.: United States Department of Agriculture. J:11DJOBS'\1U3-B1875 NWLF Drainage Improvements\Surface waler\Runon H&H Calcula(ion.docx Golder Associates. IA10 C8:57 NUrhry I flaIICd: 1 I/ dJ10 t5tium MHialhey A1nrn4 rn3 4 411 DRAFT .7l 5120 r x 8 O N CNI z O IX In Us' U5 • I- z w ILI a z H J WO w V o -o J (75 < J C° LU Z zinc O O1 at ?P,..ECT Nv. 103-8162' No. NM f= C,iiv Basin REV. A SCALE AS SHOWN' DESICN' MBR ',0/35/10 CAC}n MBR 10/05/10 C-IECK REVIEW FIGURE 1 TABLE 't SUBBASIN SUMMARY TABLE Waste Management North Weld Landfill Project Number: 103-81825 Desion Storm 100 -Year Reccurence Interval Storm Duration (hours) 2 -Year Depth (inches) 100 -Year Depth I (inches) Storm Distribution 24 2.2 4.0 II Date: 1 11811 0 By:: MBR Chkd: Y le( Apprvd: Subbasin ID Subbasin Area (fk2} Subbasin Area (acres) Subbasin Area (sq mile) CN = 84 Composite SCS Curve No. S = 1000 - Unit Runoff Q (in) Runoff Volume (ac -ft) Runoff Volume (ft) Landfill Slopes (acres) 10 ON A 87,265 2.00 0.0081 2.00 CN = 84 1.90 2.37 0.40 17,243 Total: 87,265 2.00 0.00 0.40 17,243 J:11 DJOBS1103-81825 NWLF Drainage Improvements\Surface water\Runon H&H.xlsm Page 1 of 1 Golder Associates 11/8/2010 TABLE 2 BASIN TIME OF CONCENTRATION CALCULATIONS Waste Management North Weld Landfill Project Number: 103-81625 Date: `1:B.r1ti By: it R Chlttl: Alpi Lail) A pprvd: Flow Segment 1 Floe/ Segment 2 Flow Segment 3 / Subbasin IC l Subbasir Area I {sq mile) Composite Curve plumber Totat Lag (0.6`Te) (min) Total Travel Time (min) eype of Flow Length (t) I Slope Mitt) Roughness Conditicr(l) Tyrplcal Hydraulic ' Radius (Channel Only) (ft) Travel Time (min) I Type of Flow Length (ft) Slope , ift"ti Roughness 2endition{': Typical Hydraulic ' Radius (' hanr,el Only) ;ft) Travel Time (ruin) Type 04 How F Length (ft) Slope (Mt) Roughness Condition'" Tyaical Hydraulic Radius (Channel Only) (ft) Travel Time {min) A I 0.0031 84 15.4 253 Sheet 100.0 0.010 E Short Grass 15 6 Shallow 590_0 0.010 Li Unpaved 6,1 Channel 630 0.008 E Earth -lined 0.34 4.1 Notes: 1) Refer to A,tta;flrnen: A for Roughness Condition descriptions and To Cceffieciel,ts. J.t1JJOS I,111'1,-BS825 NVI/LF C'ra:najc Imrrnrr..wrrrFe rf v tenIct'.Rarnn HH.xis m Fags 1 of 1 Golder Associates 11/6;2010 TABLE 3 FLOW RESULTS FROM HE -HMS Waste Management North Weld Landfill Project Number: 103-81825 HEC-HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 1118110 By: MBR Chkd: 4 ' 7 vi MALe Apprvd: Western Runon 100 -year 24 -hour 48 -hr 5 -min Hydrologic Element Drainage Peak Area Discharge (sq mile) (cfs) Time of Peak Total Volume (ac -ft) A 0.0081 7.0 05Jun2020, 00:55 0.4 Page 1 of 1 Golder Associates J:11DJOBS\103-81825 NVVLF Drainage Impravements\Surface water\Runon H&H.xlsm 11/8/2010 ., Channel Hydraulic Calculations Waste Management North Weld Landfill PROJECT 103-81825 Date: 1118110 By: MDR _ Chkd: +lo "fie Apprvd: °� Reach Designation Estimated 10Q- year Flow Rate Ids) Channel Design Geometry Channel Roughness Parameters Hydraulic Calculations Channel Evaluations Bed Slope (ftlft) cleft Side Slope (H:1'V) Right Side Slope (H:1V) Bottom Width (ft) Minimum Channel Depth (ft) Design Channel Lining Mannings 'n" Mannings 'n' for Capacity for Stability (Depth I (Velocity Calculation} I Calculation) Nlaximunn Velocity (fusee) Maximum Normal Flow Depth (fl) I Fraud° Number Normal Depth Shear i Stress (Ib1Fts) Stream Top Width of Power Flow Mini} {ft) Top Width of Channel (ft) Available Freeboard {ft) S m C4 Reach 1 - 2. 24.0 0,015 2.0 2.0 3 3.0 G Grass -lined 0,035 0 030 4.7 1.10 0.97 1.03 701 7 4 15.0 1,9 Reach 2 - 3 24.0 0 009 2.0 2.0 3 3.0 G Grass -lined 0.035 I 0.030 3S 1.25 0.77 0.70 39.8 8 D 15.0 1.7 Reach :3 - b 24.0 0.006 2.0 2.0 3 3.0 G Grass lined 0.+335 3.4 1.38 D.63 0.52 25.3 •0.03D 87.0 8.5 15.0 1.6 Reach 5 0 Reach 6 - 7 35.0 0.014 2.0 2,0 3 3 0 G Grass -lined 0.035 0.030 5.1 1.35 0.95 1.18 8:4 1 8.3 15.0 1.8 35.0 0.015 2.0 2.0 3 3.0 G G Grass -lined 0.035 0.030 5.2 I 1.33 1.00 1.25 94.0 15.0 1.7 Reach 7-8 35.0 0.000+ 2.0 2.0 3 3.0 Grass -lined 0.035 0.030 3.7 1.67 I 0.65 0.62 33.0 9.7 15.0 1.3 Reach 8 - 9 39.0 0.045 2.0 2 0 3 3 0 R Riprap 0.040 0.035 7.1 1.14 1.45 3.20 331.6 7.6 _ 15.0 15.0 1.9 Roach 9 -10 _ 43.0 0.026 .2.0 2 0 3 3.0 3.0 R G Riprap 0.040 0.035 6.0 1.37 1.13 2.23 194.2 8.5 1.6 Reach 10 - 11 43.0 0.008 2.0 0.008 2.0 2.0 2.0 3 Grass -lined 0.035 11030 4.4 4.6 1.72 0.75 0.86 - 54.2 9.9 15.0 11.3 Reach 11 - 12 51.0 3 3.0 G Grass -lined 9.035 0.030 1.96 D.78 8 0.93 61.5 10.5 15.0 1.1 J:w1:LjfLlS11rri s1R75 NWL= 1}+amain Inrr+avernt3n24Slrn`I1G:ewnterlL2unnn I I.&?c 24 ism (1) Note: Comments and Warnings: < 1.0 Ft indicates freeboard is less than 1 foot. <1/2 Vel. Head indicates that the remaining freel:ward is less than 1/2 the velocity head 0/212g) suggesting water may splash our Warning: Vx.D>9 indicates that the velocity limns the depth is greater than 9 ft`Jsec, which is undesirable and may be u1 Unstable V indicates that calculated velocity exceeds the recommended maximum far the lining material. Unstable T indicates that calculated shear stress exceeds the reeomrnended maximum; for the lining material. P.rz"e 1 of 1 Colder Associates 11+'Sa'2010 Attachment A Travel Time, Manning's n, and Overland Flow Coefficients Attachment A Time of Concentration and Mannings Flow Coefficients TR-55 (1986) Sheet Flow Travel time (SCS Upland Method) Tt = 0.8 0,007 (n' L `F �0.5 S 0.4 � 2 Where: T1= travel time (hr); n' = roughness coefficient; L = flow length (ft); F2 = 2-yr storm depth (inches); s = slope (ft/ft) flow velocity = Lf(60TJ Flow Type Surface Type roughness n Surface Description Short Description sa r. 0 0 U) A B C 0 E F G H I J 0.011 Smooth surfaces (concrete, asphalt, gravel, bare soil) 0.05 Fallow (no residue) 0.06 0.17 0.15 0.24 0.41 0.13 0.40 0.80 Cultivated soils: Residue cover c= 20% Cultivated soils: Residue cover > 20% Grass: Short grass prairie Grass: Dense grasses Grass: Bermuda grass Range (natural) Woods: Light underbrush Woods: Heavy underbrush Smooth Fallow Coverc20% Cover>20% Short Grass Dense Grass Bermuda Grass Range Light woods Heavy Woods Shallow Concentrated Flow Velocity (SCS Upland Method) v = mS°.5 Where: v = veloci ty (fps); rn = roughness coeffient ; S = slope (ft/ft Flow Type Surface Type Roughness m Surface Description Short Description ° c - P 20.3282 Paved Surfaces Paved o U 16.1345 Unpaved Surfaces Unpaved .c L1 in� Channel Flow Veloci Mannings Velocity) v = 1.49/n Rh"Sz11 Where: v = veloci Mannings n Mannings n Lining Type for Depth for Velocity 0.026 0.026 C E G 1 P R 0.024 0.025 0.022 0.022 0.035 0.017 0.030 0.013 0.012 0.009 0.040 0.035 T z 0.035 0.030 0.060 0.005 (f is) Il=rou hness coeffient; Rh = Hydraulic Radius (ft), S = slo e (fttft) Material Maximum Velocity Maximum Shear Stress ACB CSP Earth -lined Grass -lined Ductile Iron Plastic Riprap Turf Reinf. Other 25 50 3 5 50 25 16 10 7 1.5 25 1 of Golder Associates Inc J:t10JOBS\103-81825 NV'VLE Drainage Improvements\Surface water\Runon H&H.xlsm 11/8/2010 Attachment B HEC-HMS Model Parameters Attachment B HEC-HMS Screen Captures and Inputs HEC-HMS Basin Model Schematic Basin Model [Western.Runanj Current. Run [100-yrearj asa ' AP ink. 1 tWi Sub Basin Area Subbasin Area (mil) A 1 0 003100 Loss SCS Curve Number Subbasin Initial Abstraction (in) Curve Impervious Number (%) A I 84 0 Transform SCS Unit Hydrograph Subbasin Lag Time (min) A 3 Pagel oft Golder Associates, Inc. J:U0JOSS1103-81625 MAILF Drainage lmprovements\Surface warerRunon HBH.xfsm 11/8/2010 Attachment C HY8 Model Output HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert I Cltcissilizz- =1rossi1Y2 1 -Smooth HDPE., Deshzu Dischaisze - A cfs (_illl tel t ( :1111 el t 1. Cub -ells Disc:hai ge - 7.1) c' c 5132.0 5131.5 5131.0 0 5130.5 5130.0 W 5129.5 5129.0 5128.5 r 50 100 1 r I 1 I i 1 1 1 I I r 1 1 I 1 1 1 1 1 I 1 I I 250 15,,.+ 1200 150 200 Station (ft) 1 1 1 1 I r� 1 I I I 1 1 I 1 1 1 1 1 1 I 1 1 1 1 1 I . I I I I I I 1 I I I 1 I. I 1 I I Table I - Culvert Summary Table: Culvert I Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (Ws) Tailwater Velocity (ft/s) 0.00 0.00 5129.80 0.000 0.0* 0 -NF 0.000 , 0.000 0.000 1.300 0.000 0.000 0.70 0.70 5130.24 0.440 0.0* 1 -stn 0.248 0.309 0.249 1.300 3.551 0.000 1.40 1,40 5130.43 0.631 0.0* 1-S2n 0.358 0.442 0.361 1.300 4.231 0.000 210 210 5130.59 0.786 0.0* 1-S2n n 0.447 0.542 0.448 1.300 4.741 0.000 2.80 2.80 5130.73 0.926 0.0* 1-S2n 0.516 0.632 ' 0.522 1.300 5.097 0.000 3.50 3.50 5130.85 1.050 r 0.0* 1-S2n 0.585 0.711 0.586 1.300 5.468 0.000 4.20 4.20 _ 5130,97 1.168 0.0* 1-S2n 0.647 0.783 0.647 1.300 5.777 0.000 4.90 4.90 5131.09 1,288 0.0* 1-S2n 0106 0.848 0.707 1.300 5.975 0.000 5.60 5.60 5131.21 1.414 0.0" 1-S2n 0.765 0.912 0.765 1.300 6.185 a. 0.000 6.30 6.30 5131.35 1.551 0.0* 5-S2n 0.821 0.967 0.826 1.300 6.320 0.000 7.00 7.00 5131.50 1.702 - 0.0} 5-S2n 0.877 1.022 0.878 1.300 6.513 0.000 theoretical depth is impractical. Depth reported is corrected. Inlet Elevation (invert): 5129.80 ft, Outlet Elevation (invert): 5128.40 ft Culvert Length: 155.01 ft, Culvert Slope: 0.0090 Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter 1.50 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning's n: 0.0120 Inlet Type: Conventional inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: None Table 2 - Downstream Channel Rating Curve (Crossing: Crossing 1 -Smooth HDPE) Flow (cfs) Water Surface Elev (ft) Depth (ft) 0.00 5129.70 1.30 0.70 5129.70 1.30 1.40 5129.70 1.30 2.10 5129.70 1.30 2.80 5129.70 1.30 3.50 5129.70 1.30 4.20 5129.70 1.30 4,90 5129.70 1.30 5.60 5129.70 1.30 6.30 5129.70 130 7.00 5129.70 1.30 Tailwater Channel Data a Crossing 1 -Smooth HDPE Tailwater Channel Option: Enter Constant Tailwater Elevation Constant Tailwater Elevation: 5129.70 ft Roadway Data for Crossing: Crossing 1 -Smooth HDPE Roadway Profile Shape: Constant Roadway Elevation Crest Length: 72.00 ft Crest Elevation: 5132.20 ft Roadway Surface: Paved Roadway Top Width: 100.00 ft APPENDIX B-4 Golder Associates CALCULATIONS Date: Project No.: Subject: Project Short Title: 14 -January -2013 123-82269 Supplemental H&H Calculations Revision 1 NWLF Drainage Improvements Made by: MBR Checked by: et",, Reviewed by: 1.0 OBJECTIVES This calculation serves as a supplement to the Engineering Design and Operations Plan (EDOP) prepared by RUST (RUST, 1995) to document changes to the hydrology and hydraulics calculations. In this revision the calculations originally prepared by Golder in 2010 are updated to reflect changes to the landfill perimeter channel as a result of the proposed liner grading associated with the construction of Phase 3a Module 3. Additionally, a culvert has been sized for an access road crossing over the perimeter channel, and the perimeter channel riprap revetment has been re -analyzed. Peak 100 -year, 24 -hour stormwater flowrates for the landfill were calculated in a previous calculation (RUST, 1995). This memorandum estimates a 100 -year, 24 -hour peak flow contributing to a point upgradient of the maintenance shop area which is subsequently added directly (no routing) to the flowrates provided in the RUST calculation to determine if the as -designed perimeter channels will be adequate to accommodate the additional runoff. ao METHODS The contributing basin for the maintenance shop area was delineated based on site topography, see Figure 1. SCS Curve Number (CN) methodology was used to estimate runoff from this area. Parameters including subbasin area, CN, lag time, and slope were entered into HEC-HMS to develop a peak flow. Attachment A presents the manning's n and overland flow coefficients. A routing diagram displaying the routing logic is included in the attached HEC-HMS output (Attachment B). Revised channel dimensions provided by Waste Management (Figure 2) were analyzed using a spreadsheet that solves for normal depth using manning's equation to verify that the additional stormwater flows determined in this calculation would not cause overtopping. Culvert sizing was performed using HY8 culvert sizing software (FHWA, 2009). .0 DATA AND ASSUMPTIONS ® NOAA Technical Atlas 2 precipitation depths (NOAA, 1973): TN- Ita. Aril Return (years) Period Precipitation (inches) Depth 2 17 100 4.0 The rainfall hyetograph assumed an SCS Type II storm distribution. Basin A lag time assumed to be 3 minutes (for consistency with previous calculations). SCS Curve Number was assumed to be 84 for consistency with the RUST calculations J:l12JOBS1123-82269 NWLF Perimeter ChannefkRurion H&H Calculationtlocx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 www.goldercom Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Waste Management of Colorado North Weld Landfill 14 -January -2013 123-82269 Manning's roughness coefficients: Channel Lining/Material Manning's n for Capacity Manning's n for Stability Grass 0.030 0.033 TRM 0.030 0.035 HDPE (culvert) 0.012 0.012 • Runoff contributing to the site was assumed to be bounded by the fence line to the west, as there is a ditch on the western side of the fence to intercept stormwater from the county road. • Culvert sizing assumed smooth -wall corrugated HOPE culvert with an entrance mitered to match the fill slope. i Maximum allowable peak flow velocity in the perimeter channel with grass lining is assumed to be 5.5 ftis. Channel reaches with peak velocities in excess of 5.5 Ws will be lined with TRM. 4.0 CALCULATIONS Figure 1 presents the subbasin delineation and approximate locations of the affected perimeter channel reaches. Table 1 presents the area -weighted curve number calculations. Table 3 includes a summary of the HEC-HMS model output. Table 4 provides channel geometry provided by Waste Management and flow information for the perimeter channels. The peak flow from the western runon area as determined from the HEC-HMS model was conservatively added directly to the peak flows in the perimeter channels as reported in the RUST report. 5.0 CONCLUSIONS/RESULTS The HEC-HMS results indicate that the estimated 100 -year, 24 -hour peak flow from the western run-on area is 7 cubic feet per second (cfs). The HY8 results indicate that an 18 -inch diameter smooth wall HDPE culvert is adequate to pass the 7 cfs design flow for the main haul road culvert with a headwater of 1.7 ft above the culvert invert and a 36 -inch diameter smooth wail HDPE culvert is adequate to pass the 24 cfs design flow for the access road crossing of the perimeter channel with a headwater of 2.4 ft above the culvert invert. Based on the channel dimensions provided by Waste Management, the additional peak flow will not adversely impact the as -designed perimeter channels. A summary of the estimated design flows and subsequent flow velocities is presented in the following table: Reach I.D sidslope Width Bottom (ft) Depth (ft) Lining 100 Peak (cfs) -year Flow 100 -year Velocity (fps) Peak 2H:1V 3 Grass 24 4.3 2H:1V 3 35 6.0 TRM 77±81 3 10 2H:1V 3 3 Grass 35 4.9 — 10 12 2H:1V 3 TRM 35 3.4 — 12-15 2 H: 1 V 3 3 Grass 43 5,4 15•-16 2H:1V 3 3 TRM 5.6 5P1 asts Management of CSarado North V1/2 I r_ Landfill �ican',, A le -:2 013 123-82269 6.0 LIST OF ATTACHMENTS Attarthririsra A Tr a n?.l Time. Mannin 's n, and Overland Flow Coefficients Attachment B - H EC -HMS Model Parame ers Attachment C - H'YF Mndel Output TO REFERENCES HEC-HMS Hydnologic Modeling Sy si [computer sc'fi'i arej August, 2009. US Army Corps of Er-gireers version 3,4 ,.i atir ri t Ottariic :and Altrimiptielic Administration (NO ..�Q. 1073. Preci ita'tt'r' Frequency Atlas of the 151em U4 ., Mas I'M. 2, volume. Ill - Cal:_Drat t. S 'Pier tpr: n!-_-1 MD : Department of Can it site. U.S,rmy Corps of Eni m'leers (LISAGE). 1994, fvdr3Lt',1t of Mrs .1.1 j Corirrol lil'a ,ric) . Engineer Manu i `1.t .1 C'-2-1 f„= r 1. Department ent {a= the Army. 'rx'i a5hi'.n ton Lin:fed 1a e ` over'ri % 'it Printing 'Office. U.S. Faders' Highway Administration (FHWA). 2109. HAT Ver5von `. 2 FifilW A CIL. err Aralysis. 4 itshin .ton, DC. FHA Office of Technolog Applications. LI. S. Sail :-n 1s ervata n Se n i ce ( US S ). 1D86. ..Urban Hyd4i gv :r -,.r `. , a i.i f ?ersh a rim (USSCS I oche K:al I '.base Number 55). Vi.i shiriglorn D.C.: United is as Departrueni of Agriculture. -a.- - EL-im 0 ... I J•9. -t- - -2-- J-- r�- it ti 4f y lV r" ,l t_ `1 6 r 1 i 11 I I I I — 5180 c: I 5 1'I ( , O \ . r .l`! iF ' '•�. ) ,, ` J7 it 3 i+ •`� 1� \ f / 1 Va 1 / 5 VI 111 5' / rr I1lII t ,i I r' / r r I,° f+ r +rj I tr _ 4 .�s 1.rt - 1 1 11 ti 1 1 II+ tom+ .. N.,... 41 � 1 t I ~1 s 4 I I 5 x r 1 T ` �' it+ 5s 1 r 4ti ` I /' I v 1 `� l F +1` v v �� r %' 1. ti —.'•-•,..........z......� t r �,. I .� — --ter-51701 -- — MOO — 5150 LEGEND • 12 • 9t ter 1 - EXISTING TOPOGRAPHY PERIMETER CHANNEL ALIGNMENT PERIMETER CHANNEL REACH I.D. fll \ r . r • on r_ — 0805 — O0L9 ORS arts- • BASIN DESIGNATOR BASIN AREA (at.) BASIN DELINEATION 4 f r' r' I In - —t„ f — .r , 01rN i rr rr •4 MI tit / 1 I4 i,• /t O sap - • sit _ _J_ le I 11 wirc r • fr i de 'I it's-- .1 ba V II III V Jr cc OCCESS ROAD pitman I 0 O U - a LIJ eal LIJ Z al 7) 8 rej DES GN NOR 10/n5170 CADD CFECK REVIEW FIGURE 1 1 a i 4 i i i i i i 15 LEGEND 16 12 250 1 _ 250' PROPOSED LINER GRADE TOPOGRAPHY PERIMETER CHANNEL ALIGNMENT PERIMETER CHANNEL REACH I• D. 250 WASTE MANAGEMENT NORTH WELD LANDFILL 500 Feet REVISED CHANNEL ALIGNMENT AND LANDFILL LINER GRADES Golder _Associates PROXCT Nu. m23-82268 CrFSGr ?ERR 12/14/12 ADO MDR 12/14/12 CHECK 12/14/12 9EME1! 12/14/12 plc #la. u..r.rori MN SCALE N/A 1 REV. FIG2 TABLE 't SUBBASIN BASIN U MMARY TABLE Waste Management North Weld Landfill Project Number: 103-81825 Design Storm 100 -Year Reccurence Interval Storm Duran (hours)24 2 -Year Depth (inches) 2.2 100 -Year Depth (Inches) 4,0 Storm Distribution I I Subbasin ID A Total: Subbasin Area (ft2) 87,265 87,265 J:ti10JOBS\1o3-81825 NWLF Drainage improver enteSurfaco waterdiunon H$W.xksm Subbasin Area (acres) 2.00 2.00 Subbasin Area (sq mile) 0.0031 0.00 CN = 84 Landfill Slopes. Date: 11/8110 By: _ MBR Chkd: Apprvd: iet Composite SCS Curve No. S = 1000 - Unit Runoff 10 n (in) Runoff Volume (ac -ft) Runoff Volume (& Page Ioft Golder Associates CN=84 0.40 17.243 0.40 17.243 11/8/2010 TABLE 3 FLOW RESULTS FROM HEC-HMS Waste Management North Weld Landfill Project Number: 103-81825 HE -HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 1118110 By: MBR Chkd: Vi7 Appryd; - Western Runon 100 -year 24 -hour 48 -hr 5 -min Hydrologic Element ' Drainage Peak Area Discharge (sq mile) Ws) Time of Peak Total Volume (ac -ft) 0.0031 7.0 05Jun2020, 00:55 0.4 Page .1 of 1 Golder Associates J:110JOBS\10'3-81825 NWLF Drainage Improvements\Surfaca water\Runon Heel xlsm 1118/2010 Table 4 Channel Hydraulic Calculations Waste Management North Weld Landfill PROJECT 123-82289 Date: 1/14113 By:: MGR V Chkd: c/"" Appnrd i /'S ChannelDeal Geometry Channel Roughness Parameters a rauftc Calculations Channel Evaluations Reach Desi atlon f2. Estimated 100 -year Flow Rate (cfs) ' Bed Slope (tt/k) Left Side Slops ; (H:1V) Right Side Slope (H:WV) Bottom Width (ft) i Minimum Channel Depth (It) Design Channel Lining Meanings in' F for Capacity pa ty (Depth Calculation) Mannings In for Stability (Velocity • Calculation) Maximum Velocity (ftisoc) Maximum m Normal Flow Depth (ft) Fraude Number Normal Depth Shear Stress (Ibfft?) Stream I Power j (MO i Top Width of Flow (ft) Top Width of Channel (ft) Available Freeboard (ft) 24.0 0:016 -2.11----,....% 3.4 G Grass -lined 0035 0_ t30 4.7 1.10 I 0.97 1.03 70.1 74 15.0 1.9 `Bch Reach 2 -3 24.0 0O09 2.0 2.0 3 3.0 -1---d-1 Grass -!rued _0.035 _ j 0,030 3.5 1.25 0.77 ) 0.70 398 6.0 15.0 1.7 ) g Reach 3 - 5 24.0 0.006 _ 2.0 2.0 3 3.0 G Grass -fined 0.035 0.030 3.4 1.38 0.83 0.52 25.3 8.5 15.0 1.6 I. Roach 5 - la /4.0 0.012 2.0 -7 10 3 3.0 G Grass -lined 0.035 0.030 4.4 1.15 0-89 0,89 55.8 7.6 15,0 1.8 = Reach 8 - 7 24.0 0.016 2.0 2.0 3 3,0 G Grass -lined 0,035 0.030 4.8 1,09 1.00 1.07 74.2 7.3 - - 16.0 1.9 d ,Reach 7 - 8 35.0 0.022 2.0 2.0 3 3.0 T Turf Reinf. D.035 11030 B_0 1.21 - 1,19 1.68 144.0 1.8 " 15.0 1.8 cm Reach 8 - 9 35.0 0.013 2.0 2.0 3 3.0 G Grass -lined i 0.035 0.03D 4.9 1.39 0.92 1.09 77.3 8.6 i 15.0 1.6 a Reach 9 -10 35.0 0.007 2.0 J 2.0 3 3.0 G Grass lined 0.035 0-034 3.9 1.60 0.70 0.70 40.0 9.4 15.0 1.4 ,4 Reach 10 - 11 35.0 0.037 2,0 2:0 3 3.0 T j Turf Reid. 0.035 0.030 7.2 1.06 1.52 2.45 256.9 7.2 15.0 1.9 : Reach 11 - 12 35.0 _ 0056 2.0 2.0 3 3.0 T ' Turf Rainf. 0.035 0.430 8.4 0.95 1.85 3.32 404.4 6.8 15.0 2.0 } Reach 12 - 13 1 39.0 j 0.013 2.0 2.0 3 3.0 G Grass-Ilned 4.035 0.030 6.1 1.45 0,94 1.18 87.0 8.8 15.0 1.5 & Reach 13 -14 43,0 0.013 2.0 2.0 3 3.0 + G Grass -lined 0.035 0.030 5.2 1.53 0.94 1.24 93.6 _ _ 9.1 16.0 1.5 Reach 14-15 43.0 0.014 2.0 ' 2.0 3 3.0 C Grass -lined 0.035 0.030 5.4 1.50 0.98 1.31 101.8 9.0 1 15.0 1,5 Reach 15 - 16 51.0 I 0.014 2.0 2.0 3 3.0 T Turf Reid. 0.035 ` 0.030 5.6 1.63 0.99 1.42 1 115.7 9.5 l 15.0 - I.4 J:112.J0B 1123-822e9 NWLF PercneterChanneP.Runon H&H.glam Page 1 of i Golder Associates 1) Note; Comments and Warnings: c 1.0 ft indicates freeboard is less than 1 foot. { 1/2 Vol. Head indicates that the remaining freeboard is less than 112 the velocity head (V212g) suggesting water may splash out. Warning: VxD>9 indicates that the velocity times the depth is greater than 912/sec, which is undesirable and may be u Unstable V indicates that calculated velocity exceeds the recommended maximum (or the lining material. Unstable T indicates that calculated shear stress exceeds the recommended maximum for the lining material. 1/14/2013 Attachment A Travel Time, Manning's n, and Overland Flow Coefficients Attachment A Time of Concentration and Mannings Flow Coefficients TR-554(1986) Sheet Flow Travel time (SCS Upland Method) 0.007 (a' L )(18 �a5 S. l(P2 Where: Tt = travel time (hr); n' = roughness coefficient; L = flow length (ft); P2 _ 2-yr storm depth (inches); s = slope (ft/fl) flow velocity = U(60T1) Flow Type r Surface Type roughness n Surface Description short Description ShootlOverland Flow A B C O F G H i J 0.011 Smooth surfaces (concrete, asphalt, gravel, bare soil) 0,05 Fallow (no residue) 0.06 Cultivated soils: Residue cover a 20% 0.17 Cultivated soils: Residue cover > 20% 0.15 'Grass: Short grass prairie 0.24 Grass: Dense grasses 0.41 Grass: Bermuda grass 0.13 Range (natural) 0.40 Woods: Light underbrush 0.80 Woods: Heavy underbrush • Smooth Fallow Cover<20% Cover>20 % Short Grass Dense Grass Bermuda Grass Range Light woods Heavy Woods Shallow Concentrated Flow Velocity (SCS Upland Method) v = mSn Where: v = velocity (fps); in = roughness coeffient; S = slope (Mt) Flow T e Surface Type Rou hness m : Surface Description Description i 'Lining Type , for Depth for Velocity A 0.026 , 0.026 0.024 ` 0.022 0.025 - - ` 0022 ©.035 0.030 0017 0.013 G T Z 0.012 0.009 0.040 0.035 0.035 1_ 0.030 0.060 0.005 U 20.3282 Paved Surfaces 16.1346 Unpaved Surfaces Paved Unpaved Channel Flow Velo Mannings Velocity) v = 1.49/n Rhi S„' - - Where: v = velocity (fps); n = roughness coeffrentr Rh = Hydraulic Radius in. S ! slope (ft1ft ' Meanings n Mannings n _ rMaximum t -Maximum Material Velocity Shear Stress ACS CSP Earth -lined Grass -lined Ductile iron Plastic Riprap Turf Reinf. Other 1 of 1 Golder Associates Inc J:1I0JOBS1103-81825 NWIF Drainage ImprovementslSurface water%Runan Ff&H.xrsm 25 50 3 5 5b 25 16 10 25 1.5 11/8/2010 Attachment B HEC-HMS Model Parameters Attachment B HEC-HMS Screen Captures and Inputs HECIHMS Basin Model Schematic Sub Basin Area Subbasin Nir A 0,003100 • Area I (mi'f Loss SCS Curve Number I Initial , A,bstra ct€on Curve impe r vi o us I, (nit Number (%) 8d 0 Subbasin A Transform SCSUnitWdrorah Subbasin A Lag Time (min) 3 Page 1of1 Golder Associates, inc. J11DJOBS1103-91825 MWLF Drainage Improvcmenlw%Surface water\Runon HAH,)dsm 11/8/2010 Attachment C HY8 Modes Output HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert a1 Crossing - Crossi _ . 1 -mooch HDPE, Des Disehaite - 7.0 cTh Culvert - Culvert 1, Culvert Discharge - 7.0 efts 5132.0 5131.5 C 5131 0 151305 0> 5130.0-7_ AMIEW Wag dad I e I 4 r I I I I I ...01S -ra -_-- a ...ma,.�ai 1aa tam mar 5129.5-7 r 5129.0 j 4.. 5128.5 rz S 50 I I 1 1 I I I L I 1 1 1 1 1 1 1 1 I 1 r 1 I I I 4 I 1 1 I r L I 1 I 1 1 I 1 1 I I I I I 1 I 1 I 1 1 1 I 1 e 1 I 1 $ I I 1 1 1 : r e e r r 1 a i I I I I I I I I I `I i p a a a a_ a I 1 I 1 I I I 1 I -I-_-------raa a _ _Ora -.tars---------E 1 1 1 1 I -1. _ 100 150 200 Station (ft) 250 ti I I I I I I I I I I 1 300 1 Table I Culvert Summary Table: Culvert I Total Discharge cfs) Culvert rt Discharge afs Headwater Elevation (ft) Inlet antral Depth eft) Depth �tl t Corttr�al (ft) Flaw Type Normal Depth (ft) critical Depth (ft) Cutlet Depth (ft) Taitwater Depth (ft) Outlet Velocity (ft/5) Taliwator Velocity 0.00 0 00 5129.80 0.000 0.0* 0 -NF 0.000 0.000 0.000 1300 0.000 0.000 070 5130.24 0.440 0.0' 1-52n 0.248 0.309 0.249 1.300 3.551 0.050 0.70 1.40 1.40 5130,43 0.631 D.0* 1-S2n 0.358 0.442 0..351 1300 4.231 0,000 2.10 210 5130.59 0.786 0.0' 0.447 0.542 0.445 1.300 4.141 0.000 2.80 2.80 5130.73 0.926 0.0' 0.516 0.632 _ _ 0.522 1.300 5.097 0.000 + 3.50 513085 1.050 0.0` 0.585 0.711 0.586 1.300 5.468 0.000 4.20 420 1168 0.0* 0 647 0.783 1.300 0.000 5130.97 5.777' 4.90 4.90 5131.09 1.288 0.0` 12n 0.706 0.848 0.707 1.300 5.975 0.000 5.60 5.60 5131.21 1.414 O.Ot 1 -S 2n 0.7650.912 0.765 1.300 0.000 6185 6.30 6.30 5131.35 1.551 0.0* 5-S2n 0.821 0.967 0.826 1.300 6.320 0.000 7.00 7.00 5131.50 1.702 0.0* 5-52n 1.022 0.878 1.300 6.513 0.000 0.877 * theoretical depth is impractical. Depth reported is corrected. Inlet Elevation (invert): 5129.80 ft, Outlet Elevation (invert): 5128.40 ft Culvert Length: 155.01 ft, Culvert Slope: 0.0090 AbA****rtt&-* Rtt **f *******tit!twt#nertt*4i-kiti-tip*t*i&ar****flt*grt*-*flti* Culvert Data Summary - Culvert I Barrel Shape: Circular Barrel Diameter 1.50 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning?s n: 0.0120 Inlet Type: Conventional Inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: None Table 2 - Downstream Channel Rating Curve (Crossing: Crossing 1 -Smooth HDPE) Flow (cfs) Water Surface Elev (ft) Depth (ft) 0.00 5129.70 1.30 0.70 5129.70 1.30 1.40 5129.70 1.30 2.10 5129.70 1.30 2.80 5129.70 1.30 3.50 5129.70 1.30 4.20 5129.70 1.30 4.90 5129.70 1.30 5.60 5129.70 1.30 6.30 5129.70 1.30 7.00 5129.70 1.30 Tailwater Channel Data - Crossing 1 -Smooth HDPE Tailwater Channel Option: Enter Constant Tailwater Elevation Constant Tailwater Elevation: 5129.70 ft Roadway Data for Crossing: Crossing 1 -Smooth HDPE Roadway Profile Shape: Constant Roadway Elevation Crest Length: 72.00 ft Crest Elevation: 5132.20 ft Roadway Surface: Paved Roadway Top Width: 100100 ft HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert 131 Crossing a Access Crossing, Design Dischargea 31.0 els Culvert - Culvert 1.,: Culvert Discharge - 31.0 -cg`s 5136 5135 5134 5133 5130 5129 1 I J � I uf, i -20 20 40 60 80 Station (if) 100 120 Table I - Culvert Summary Table: Culvert PI Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Nutlet Velocity (ft/s) Tailwater Velocity (ft/s) 0.00 0.00 5132.50 0.000 0.0* 0 -NF 0.000 0.000 0.000 0.000 0.000 0.000 3.10 3.10 5133.27 0.768 0.0* 1-S2n 0.311 0.535 0.325 0.381 8.485 2.159 6.20 6.20 5133.61 1.106 0.0* 1-S2n 0.415 0.769 I 0.429 0.562 9.665 2.675 9.30 9.30 5133.87 1.374 0.0* 1-S2n 0.519 0.957 0.527 0.701 10.928 3.014 12.40 12.40 5134.11 1.611 0.0* 1-S2n 0.615 1.111 0.620 0.817 I 11.827 3.273 15.50 15.50 5134.33 1.829 0.0* 1-S2n 0.679 1.252 0.682 0.919 12.130 3.485 18.60 18.60 5134.53 2.027 0.0* 1-52n 0.743 1.374 0.764 1.010 12.986 3.667 21.70 21.70 5134.71 2.214 0.0* 1-S2n 0.808 1.497 0.819 1.094 13.796 3.825 24.80 24.80 5134.90 2.399 0.0* 1-S2n 0.872 I. 1.600 0.924 1.171 13.432 3.966 27.90 27.90 5135.09 1 2.587 0.0* 1-52n 0.928 1.703 0.935 1.242 14.884 4.095 31.00 31.00 5135.28 I 2.783 0.0* 1-S2n 0.977 1.804 1.047 1.310 14.062 4.212 *******'h'J4******7k7 ***9k*****51tYY***** ***************Mfr**1FdFdkai********de*i ***ak*****drab*** Inlet Elevation (invert): 5132.50 ft, Outlet Elevation (invert): 5129.10 ft Culvert Length: 100.06 ft, Culvert Slope: 0.0340 ***********.*************,***************************************************** Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 5132.50 ft Outlet Station: 100.00 ft Outlet Elevation: 5129.10 ft Number of Barrels: 1 Culvert Data Summary - Culvert I Barrel Shape: Circular Barrel Diameter: 3.00 ft Barrel Material: Smooth HDPE Embedment: 0.00 in Barrel Manning's n: 0.0120 Inlet Type: Conventional Inlet Edge Condition: Mitered to Conform to Slope Inlet Depression: NONE Table 2 - Summary of Culvert Flows at Crossing: Access Crossing Headwater (ft) Elevation , Total Discharge (cfs) Culvert 1 (cfs) Discharge Roadway (cfs) Discharge Iterations 5132.50 0.00 0.00 0.00 1 5133.27 3.10 3.10 0.00 1 5133.61 6.20 6.20 0.00 1 5133.87 9.30 9.30 0.00 1 5134.11 1 12.40 I 12.40 0.00 1 5134.33 15.50 15.50 0.00 1 5134.53 18.60 18.60 0.00 1 5134.71 21.70 21.70 0.00 1 5134.90 24.80 24.80 0.00 1 5135.09 27.90 27.90 0.00 1 5135.28 31.00 31.00 0.00 1 5136.40 45.35 45.35 _ 0.00 Overtopping Table 3 - Downstream Channel Rating Curve (Crossing: Access Crossing) Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number 0.00 5129.10 0.00 0.00 _ 0.00 1 0.00 3.10 I 5129.48 0.38 2.16 0.30 0.68 6.20 5129.66 0.56 2.68 0.44 i 0.71 9.30 5129.80 0.70 3.01 0.55 0.73 12.40 5129.92 0.82 3.27 0.64 0.74 15.50 5130.02 0.92 I 3.49 0.72 0.75 18.60 A 5130.11 1.01 3.67 0.79 0.76 21.70 5130.19 1.09 3.82 0.86 0.77 24.80 5130.27 1.17 3.97 0.92 0/7 27.90 5130.34 1.24 4.09 0.98 0.78 31.00 5130.41 1.31 4.21 1.03 0.79 Tailwater Channel Data - Access Crossing Tailwater Channel Option: Trapezoidal Channel Bottom Width: 3.00 ft Side Slope (H:V): 2.00 (_:1) Channel Slope: 0.0120 Channel Manning's n: 0.0350 Channel Invert Elevation: 5129.10 ft Roadway Data for Crossing: Access Crossing Roadway Profile Shape: Constant Roadway Elevation Crest Length: 80.00 ft Crest Elevation: 5136.40 ft Roadway Surface: Gravel Roadway Top Width: 20.00 ft APPENDIX B-5 Golder Associates September 22, 2016 Ms. Hayley Brown Weld County Engineering 1555 N. 17th Avenue Greeley, CO 80631 Project No. 1538880 RE: SUPPORTING HYDROLOGIC AND HYDRAULIC CALCULATIONS; NORTH WELD LANDFILL PAVING IMPROVEMENTS Dear Ms. Brown: On behalf of Waste Management Disposal Services of Colorado, Inc. (WMDSC), Golder Associates Inc. (Golder) is pleased to provide Weld County Engineering (the County) with this letter summarizing the hydrologic and hydraulic calculations performed in support of the proposed paving improvements at the North Weld Landfill. As previously discussed between the County and WMDSC, WMDSC plans to pave approximately 1,000 feet of the main haul road along the west side of the landfill. Golder understands that the County requested additional information on potential drainage impacts on site drainage structures related to the increase in impervious area. On September 6, 2016, Senior Engineer Tom Schweitzer with WMDSC provided the County with a letter providing historical information on the design (storage capacity) and construction of the existing stormwater retention pond that ultimately receives stormwater runoff from the haul road to be paved. In response, the County requested additional hydrologic calculations supporting the proposed paving improvements. This purpose of this letter is summarize the scope and results of the hydrologic and hydraulic calculations performed to support the paving improvements. 1.0 STORMWATER MANAGEMENT SYSTEM DESIGN The stormwater management system for the North Weld Landfill was designed as part of the development of the Updated Design and Operations (D&O) Plan for the North Weld Sanitary Landfill originally prepared by Rust Environment & Infrastructure, Inc. in January 1996, and revised by WMDSC in November 1097. Runoff from closed landfill slopes and surrounding run-on areas is collected by permanent perimeter channels and conveyed to a retention pond located in the southeastern corner of the property. The highpoint of the property is in the northwest corner. Runoff from the primary haul road is initially collected in the western perimeter channel, as shown in the attached Figure 1. In 2010, Golder modified the facility hydrologic and hydraulic calculations to capture stormwater runoff from west of the primary haul road and convey it to the landfill perimeter channel via an 18 -inch culvert crossing beneath the primary haul road (Golder 2010). Golder subsequently modified the calculations again in 2013 to replace approximately 100 feet of perimeter channel with a 36 -inch -diameter culvert to allow for the development of a landfill access road across the channel alignment and to incorporate several changes to the perimeter channel alignment as a result of as -built liner grading plans (Golder 2013). The locations of these culverts are shown in the attached Figure 1. i:11511538880101001011U1haul rd imp. 22sep16\1538880 Itr fni nwlf haul rd improvements 22sep16.docx Colder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 www.golder.com Colder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Colder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Ms. Hayley Brown September 22, 2016 Weld County Engineering 2 1538880 2.0 HYDROLOGIC AND HYDRAULIC CALCULATIONS 2.1 Scope As the new paved section of the haul road will report to the culverts and perimeter channels, the affected channel sections and culvert crossings were re-evaluated to demonstrate that the structures will have sufficient conveyance capacity. As the perimeter channel discharges into the existing retention basin in the southeast corner of the property, the increased runoff volume was also estimated in order to verify that the basin will have sufficient storage capacity. 2.2 Methodology Drainage basins along the main haul road, which include the proposed pavement area, were delineated using site topography provided by WMDSC. The paved roadway was assumed to be crowned perpendicular to the centerline, with runoff from one basin (Al) draining west off the pavement, then south through a drainage ditch and ultimately reporting to the existing 18 -inch high -density polyethylene (HDPE) culvert under the haul road and the other basin (A2) draining east off the pavement into the landfill perimeter channel and continuing south to the existing 36 -inch HDPE culvert under the landfill access road. Consistent with the original hydrologic calculations, the Soils Conservation Service (SCS) methodology was used as the basis of the hydrologic modeling. SCS curve numbers and rainfall data were referenced from the previous Colder calculations (Colder 2010 and 2013). HEC-HMS (USAGE 2013) software was used to calculate peak discharges. For hydraulic analysis of the perimeter channel, Manning's equation flow calculation spreadsheets previously used for the channel design were updated for the purposes of this modification. The Federal Highway Administration's HY-8 culvert analysis program (FHWA 2014) was used to evaluate capacity of the previously -deigned culvert crossings. 2.3 Results The results of the HEC-HMS hydrologic analysis are presented in Table 1 below. Table 1: Peak Discharge Summary Basin . Drainage Area (acres) Basin Imperviousness (%) . 100-Yr, 24 -Hr Peak Discharge (cfs) Al (West) 2.2 14 7 m m A2 (East) 2.2 21 6 Due to a lack of detail provided in the original design calculations and supporting figures presented in the D&O Plan, it is unclear whether runoff from the main haul road and surrounding area west of the road was included in the original channel design. Therefore, it was conservatively assumed that these basin areas along the haul road and corresponding peak flows were not previously included in the areas and runoff volumes presented in the 1997 D&O Plan. As such, the calculated peak flows presented in Table 1 were added directly (no routing) to the perimeter channel flowrates provided in the 1997 calculations to determine if the as -designed perimeter channels and culvert crossings are adequate to accommodate the additional runoff from the pavement improvements. All channel reaches and culvert inlets as currently sized and constructed have adequate capacity to accommodate the additional discharge from the paved haul road and surrounding runoff areas shown in Figure 1 while maintaining a minimum of one foot of available freeboard. The additional discharge will result in an increase in total runoff volume of approximately 1.0 acre-feet requiring storage in the retention basin. As outlined in the retention basin documentation previously provided to the County by WMDSC, the design runoff volume reporting to the basin is 22.6 acre-feet prior i:115\153888th010010110\haul rd imp. 22sep16\1538880 Itr fnl nwlf haul rd improvements 22sep16.docx Gown AssocIates Ms. Hayley Brown September 22, 2016 Weld County Engineering 3 1538880 to the pavement improvements work. Conservatively assuming that the runoff from the main haul road and surrounding area west of the road was not previously included in the basin design, the total estimated runoff volume requiring storage will be 23.6 acre-feet. As constructed, the available volume for stormwater retention in the basin is 42.2 acre-feet (10.8 acre-feet set aside for sediment storage in the design calculations and 31.4 acre-feet of stormwater storage). This available storage volume does not include the storage volume set aside for maintaining one foot of freeboard (7.1 acre-feet) per Weld County Code requirements. Complete versions of the supporting hydrologic and hydraulic calculations are not attached to this letter. Complete copies of the calculations can be submitted to the county if required upon request. Please let me know if you have any questions regarding these calculations. Best Regards, GOLDER ASSOCIATES INC. Jeff Rusch, FE Senior Engineer cc: Tom Schweitzer, Waste Management Disposal Services of Colorado, Inc. Bill Hedberg, North Weld Landfill Kim Ogle, Weld County Planning Enclosures: Figure 1 J.Ia p i.\18',153888010100\01101baul rd imp. 22sep16\1538880 1588880 Itr-fnl nwff haul rd improvements 22sep16.docx Golder Associates FIGURE 1 LI\ ti! _ xNil 'gawp - t N I PlAIN HAUL ROAD CULVERT CS in I-DPEi.- r ACCESS ROfi.D CLLVERT (36 in HDPE) N — r - LEGEND —a- goo EXISTING GROUND CONTOUR ;ft -IV84 FXI5TING R0Af1S PEHI ME —ER CI IAN N EL ALIGNMENT 2 PERIME—ER CHANNEL REACH LOCATIC:4., AND ID RA IN FIFI INFATI0N PROPOSED IIAJL ROAD PAVED AREA CONCENTRATION 'DINT BASIN ID 4 WATERS! !ED AREA (ACRES) I"= .iiOC' FEET CLILN I lotif aim INANTE RIANDISEEMINT PROJECT NORTH WELD LANDFILL WELD COUNTY COLORADO MAIN HAUL ROAD IMPROVEMENTS f TITLE Airci RUNON BASIN DELINEATION AND SELECT PERIMETER CHANNEL LOCATIONS CONSUL IANI YYYY-MM-DD 201C -D9.21 DESIGNED SPS PRFPARFD J-IR RFVIFWFFJ APPROVED JAR PROP CT NO. CON T R{OI 1538880 0002 RFV. A FIt;LJRF 1 W T 4 1 ; z no Y 2 r T 1 APPENDIX F TRANSPORTATION IMPACT STUDY From: Hayley Ba Izano Sent: Tuesday, November 6, 2018 1:21 PM To: Bill Hedberg <bhedberg@wm.com> Cc: Kim Ogle <kogle@weldgov.com> Subject: North Weld Landfill USR Unit 2 Hello Bill, After reviewing the USR application for USR18-0065, Public Works has some concerns about the access to the site, the submitted Traffic Impact Study and the intersection of County Road 25 and Hwy 14. We would like to meet prior to the hearings for the case so that we can discuss these concerns. Would you be able to do this? If so, what is your availability to meet? Thank you Hayley Balzano Engineer Weld County Public Works 1111 H Street P.O. Box 758 Greeley, CO 80632-0758 (970) 400-3738 hbalzano@weldgov.com Confidentiality Notice: This electronic transmission and any attached documents or other writings are intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. If you have received this communication in error, please immediately notify sender by return e-mail and destroy the communication. Any disclosure, copying, distribution or the taking of any action concerning the contents of this communication or any attachments by anyone other than the named recipient is strictly prohibited. NORTH WELD LANDFILL, UNIT TRANSPORTATION IMPACT STUDY WELD COUNTY, COLORADO NOVEMBER 2016 Prepared for: Waste Management Disposal Services of Colorado, Inc_ 40000 WCR25 Ault, CO 80610 Prepared by: DELICH ASSOCIATES 2272 Glen Haven Drive Loveland, CO 80538 Phone: 970-669-2061 FAX: 970-669-5034 Project #1684 TABLE OF CONTENTS I. INTRODUCTION II. EXISTING CONDITIONS Land Use Roads Existing Traffic Existing Operation 2 III. PROPOSED DEVELOPMENT 7 Trip Generation 7 Total Traffic Projections 7 Geometry 7 Operation Analysis 11 IV. CONCLUSIONS 13 LIST OF TABLES 1. Current Peak Hour Operation 2. Short Range (2021) Total Peak Hour Operation 12 3. Long Range (2035) Total Peak Hour Operation 12 LIST OF FIGURES 1. Site Location 2. Existing Intersection Geometry 3. Recent Peak Hour Traffic 4. Site Plan 3 4 5 8 0 10 5. Short Range (2021) Total Peak Hour Traffic .. 6. Long Range (2035) Total Peak Hour Traffic APPENDICES A. Peak Hour Traffic Counts B. Current Peak Hour Operation/Level of Service Descriptions C. Short Range (2021) Total Peak Hour Operation D. Long Range (2035) Total Peak Hour Operation 1 —.DELI' H North Weld Landfill, Unit 2 TI , November 2016 ASSOC LATE I. INTRODUCTION This Transportation Impact Study (TIS) addresses the capacity, geometric, and control requirements for the proposed North Weld Landfill, Unit 2. The proposed North Weld Landfill, Unit 2 is located in the northeast quadrant of the State Highway 14 (5H14)IWeld County Road 25 (WCR2S) intersection in Weld County, Colorado. During the course of the analysis, numerous contacts were made with the project developer (Waste Management Disposal Services of Colorado, Inc.), Weld County, and CDOT. This study generally conforms to the format set forth in the Weld County TIS Guidelines. The study involved the following steps: Collect physical, traffic, and development data; Perform trip generation, trip distribution, and trip assignment; Determine peak hour traffic volumes; Conduct capacity and operational level of service analyses on key intersections; Analyze signal warrants and geometric requirements. The SH14IW+ R25 and WCR25/Landfill Access intersections were addressed in this traffic study. DEL ICH North Weld Landfill, Unit 2 TIS, November 2016 cASSOCIATES Page 1 II. EXISTING CONDITIONS The location of North Weld Landfill, Unit 2 is shown in Figure 1. It is important that a thorough understanding of the existing conditions be presented. Land Use Land uses in the area are primarily agricultural or vacant. There are residential uses to the southwest of the site. There are agricultural or vacant uses surrounding the site. Roads A schematic of the existing geometry at the SH 141W CR25 and WCR25/Landfill Access intersections is shown in Figure 2. The primary roads near the North Weld Landfill, Unit 2 are SH14 and WCR25. State Highway 14 is categorized as an R -A highway according to the State Highway Access Code (SHAG). Currently, SH14 has a two-lane cross section adjacent to the North Weld Landfill site. At the SH14/WR25 intersection, SH14 has an eastbound left -turn lane, one through lane in each direction, a westbound right -turn lane, a westbound right -turn acceleration lane, and an eastbound left -turn acceleration lane. The SH14/WCR25 intersection has stop sign control on WCR25. The posted speed on SH14 is 65 mph. Weld County Road 25 is a paved rural road with a two-lane cross section. At the SH 14IWCR25 intersection, WCR25 has the southbound approach in a single lane. Existing Traffic Figure 3 shows the recent daily and peak hour traffic counts at the SH 14IW R25 and WCR25/Landfill Access intersections. Raw peak hour traffic count data is provided in Appendix A. The peak hour counts were obtained in October 2016. Existing Operation Using the volumes shown in Figure 3, the current morning and afternoon peak hour operation at the SH14/WCR25 and WCR25/Landfill Access intersections is shown in Table 1. Calculation forms for these analyses are provided in Appendix B. The key intersections were analyzed using the unsignalized intersection techniques from the 2010 Highway Capacity Manual (2010 HCM). A description of level of service for DELI H North Weld Landfill, Unit 2 TIS, November 2016 rSSOClATE5 Page 2 SCALE: 1"=3000' SITE LOCATION Figure 1 �f L--DELICH ay, rASSOCIATES North Weld Landfill, Unit 2 TIS, November 2016 Page 3 N I CC i Landfill Access fee Ns* --■ - Denotes Lane SH14 - Acceleration Lane EXISTING INTERSECTION GEOMETRY Figure 2 -/I L-DELICH ASSOCIATES North Weld Landfill, Unit 2 TIS, November 2016 Page 4 7100 (2015) C" r N - 0 r a E U, a) (N I L41/41/4 23/21 316/377 —own-- RECENT DAILY AND PEAK HOUR TRAFFIC LU 0 2/19 50/13 rore Landfill Access 2318 -+— 392/291 T AM/PM Daily (year) SHI4 Afis N Figure 3 __JI 1— DELI H rASSOC1ATES North Weld Landfill, Unit 2 TIS, November 2016 Page 5 unsignalized lined intersections from the 2010 Highway Capacity Manual is provided in Appendix S. According to CDOT, the heavy vehicle factor on SH14, west of WCR25, is 11.3 percent. Since the North Weld Landfill generates a significant amount of truck traffic, it was assumed that 80 percent of the North Weld Landfill traffic is heavy vehicles. North of the Landfill Access, the heavy vehicle factor on WCR25 is 38 percent. The combination of the North Weld Landfill traffic and the traffic on WCR25, north of the Landfill Access, resulted in a heavy vehicle factor of approximately 75 percent for turning vehicles at the SH14NVCR25 intersection. The heavy vehicle factor for the through vehicles on SH14 was determined to be approximately 8 percent. Acceptable operation is generally defined as level of service (LOS) D or better, overall, during the peak hours. As can be seen in Table 1, the key intersections are currently operating acceptably with existing control and geometry. TABLE 1 Current Peak Hour Operation Intersection Movement Level of Service AM PM SH14JWCR25 (stopsign) SB LT/RT B B A A EB LT WCR25/Landfill (stopsign) Access WB LT/RT A A SB LT/T A A ainfliDELICH North Weld Landfill, Unit 2 TIS, November 2016 if c —ASSOCIATES Page 6 III. PROPOSED DEVELOPMENT The North Weld Landfill is an existing landfill facility, located in the northeast quadrant of the SH14/WCR25 intersection in Weld County. Figure 4 shows the site plan for the North Weld Landfill, both Unit 1 (existing) and Unit 2. Trip Generation Trip generation is important in considering the impact of a development such as this upon the existing and proposed road system. A compilation of trip generation information contained in Trip Generation, 9th Edition, ITE is customarily used to estimate the trips that would be generated by a proposed development. However, since the North Weld Landfill, Unit I is an existing operation and the proposal is to open another section of the site, few new site generated trips will occur. Therefore, it was assumed that the traffic generated by the North Weld Landfill, Unit 2 would cause an increase in site generated traffic at a rate of one percent per year. The short range (2021) and long range (2035) futures include the general growth of the North Weld Landfill, Unit 2 site generated traffic and an appropriate increase in background traffic due to normal growth. Access to the site will be via the existing Landfill Access to/from WCR25, which is approximately 200 feet north of SH14. Total Traffic Projections According to CDOT, the 20 -year growth factor on SH14 is 1.71. Using the CDOT 20 -year growth factor, short range (2021) and long range (2035) future through traffic on SH14 was determined. The traffic on WCR25, north of the Landfill Access, was assumed to increase at the same rate as the North Weld Landfill, Unit 2 (one percent per year). North of the existing Landfill Access, WCR25 primarily serves an existing Waste Management maintenance and truck storage facility, which is not part of the landfill operation. The one percent per year growth of this operation is considered to be conservatively high. Figures 5 and 6 show the respective short range (2021) and the long range (2035) total peak hour traffic at the key intersections. Geometry The short range (2021) and long range (2035) geometry at the SH14/WCR25 and WCR25/Landfill Access intersections can remain as it exists today. State Highway 14 is categorized as an R -A highway according to the SHAC. At the SH141' WCR25 intersection, SH14 has an eastbound left -turn lane, one through lane in each direction, a westbound right -turn lane, a westbound right -turn acceleration lane, and an eastbound left -turn acceleration lane. The SH 14AN R25 intersection has stop sign control on WCR25. The posted speed on SH14 is 65 mph. .0171iDEL ICH North Weld Landfill, Unit 2 TIS, November 2016 Pr- AT rSSOClATES Page 7 N SCALE: 1" 1000' SITE PLAN Figure 4 -a LDELICH reASSOCIATES North Weld Landfill, Unit 2 TIS, November 2016 Page 8 0 CO 0, CNI r CA C) 8600 cO r U) CN L41441/4 2/20 tc 52/14 Landfill Access \- 24/8 --.- 462/343 SH14 24/22 372/444 -•� AM/PM Daily °M SHORT RANGE (2021) TOTAL PEAK HOUR TRAFFIC Afis N Figure 5 __JI 1- DELI H rASSOC1ATES North Weld Landfill, Unit 2 TIS, November 2016 Page 9 Afis 7 (N O OO r LOCO it CO 12,100 i 30/30 ill 530/630 -Dm- 0 5/25 tir 60/15 Landfill Access 30/10 -+- 655/490 AM/PM Rounded to Nearest 5 Vehicles Daily maw- SHI 4 N LONG RANGE (2035) TOTAL PEAK HOUR TRAFFIC Figure 6 —011 LDELICH v' ASSOCIATES North Weld Landfill, Unit 2 TIS, November 2016 Page 10 Operation Analysis Operation analyses were performed at the SH14/WCR25 and WCR25/Landfill Access intersections. The operations analyses were conducted for the short range future, reflecting a year 2021 condition, and for the long range future, reflecting a year 2035 condition. Using the short range (2021) total peak hour traffic volumes (Figure 5), the SH14/WCR25 and WCR25/Landfill Access intersections operate as indicated in Table 2, Calculation forms for these analyses are provided in Appendix C. The key intersections operate acceptably with existing control and geometry. Table 3 shows the long range (2035) total peak hour operation at the SH14/WCR25 and WCR25/Landfill Access intersections (Figure 6). Calculation forms are provided in Appendix D. The key intersections will operate acceptably during the peak hours with existing geometry and control, 1--DELICH North Weld Landfill, Unit 2 TI , November 2016 s ASS OCIATES Page 11 TABLE 2 Short Range (2Q21) Total Peak Hour Operation Intersection Movement_ Level of Service AM PM SH14/WCR25 (stop sign) SB LT/RT C B EB LT B A WCR25/Landfill (stop sign) Access WB LT/RT A A SB LT/T A A Long Range (2035) TABLE Total 3 Peak Hour Operation Intersection Movement � Iip Level of Service DPI AM PM SH14/WCR25 (stop sign) C C SB LT/RT EB LT B A WCR25/Landfill (stop Access sign) WB LT/RT B A SB LT/T A A 1 LDELI H North Weld Landfill, Unit 2 TI , November 2016 Ay 1 cASSOCIATES Page 12 Ill. CONCLUSIONS This study assessed the impacts of the North Weld Landfill, Unit 2 on the road system in the vicinity of the proposed development in the short range (2021) and long range (2035) futures. As a result of this analysis, the following is concluded: The development of the North Weld Landfill, Unit 2 is feasible from a traffic engineering standpoint. It was assumed that the traffic generated by the North Weld Landfill, Unit 2 would cause an increase in site generated traffic at a rate of one percent per year. - The short range (2021) and long range (2035) geometry at the SH141WCR25 and WCR25/Landfill Access intersections can remain as they exist today. In the short range (2021) and long range (2035) futures, given an increase of the North Weld Landfill, Unit 2 traffic and an increase in background traffic, the SH 14/WCR25 and W R25/Landfill Access intersections will operate acceptably with the existing geometry and control. 1 DEL ICH North Weld Landfill, Unit 2 TIS, November 2016 v' "—ASSOCIATES Page 13 APPENDIX A DELICH ASSOCIATES 2272 GLEN HAVEN DRIVE LOVELAND, CO 80538 Phone: 19701669-2061 TABULAR SUMMARY OF VEHICLE COUNTS Date: 10/1212016 Observer: Vickie Day: Wednesday Jurisdiction: WeldCounty R = right turn S = straight L = left turn Intersection: SH14/WC1 25 Time Begins Northbound: Southbound: WCR25 Total north/south Eastbound: SH14 Westbound: SH14 Total east/west Total All L S R Total L S R i Total L S R Total L S R Total 7:15 0 4 9 13 13 8 72 80 128 2 130 210 223 7:30 0 4 14 18 18 3 101 104 107 2 109 213 231 7:45 0 9 i 2 11 11 8 85 93 77 4 81 174 185 8:00 0 8 112 20 20 4 58I 62 80 15 95 157 177 8:15 0 14 • 2 16 16 4 48 52 74 7 81 133 149 8:30 0 7 4 11 11 3 45 48 64 4 68 116 127 7. 15-8:j$ I 0 I 25 0 I 37 62 62 23 316 I 0 339 I 0 392 1 23 I 415 734 816 PHF n0I nla la nib Ia 0.69 n1a 0.66 0.78 I I I I I 0 72 0 78 Na I 0.81 I a I 0.77 0.38 0.8 I I 0.88 I 4:15 0 6 5 11 11 10 79 89 81 7 88 177 188 4:30 0 3 2 5 5 3 91 94 75 1 76 170 175 4:45 0 5 5 i 10 10 = 5 78 83 76 3 79 162 172 5:00 0 9 2 11 11 8 99 105 65 2 67 172 183 5:15 0 7 2 9 9 7 109 116 75 2 77 193 20.E 5:30 0 6 2 8 8 _ 6 93 99 62 2 64 163 171 4. 35 697 PHF3� I n0la I n!a I a , Na I 0.67 I nla 0.55 I 0.8 I 10.75 10.86 In1a 0.86 I Na I 0.96, 0.67 1 0.95 I l 0.91 I DELICH ASSOCIATES 2272 GLEN HAVEN DRIVE LOVELAND, CO 80538 Phone: 19701669-2061 TABULAR SUMMARY OF VEHICLE COUNTS Date: 10/12/2016 Observer: Matt Day: Wednesday Jurisdiction: WeldCounty R = right turn S = straight L = left turn Intersection: WCR25ANM Access Time Northbound: WCR25 Southbound: WCR25 Total Eastbound: Westbound: WM Access Total east/west Total All Begins L S R Total L S R Total northfsouth L S R Total L S R Total 7:15 17:30 1 9 10 0 5 5 15 0 8 0 8 8 23 0 5 5 0 5 5 10 0 13 0 13 13 23 7:45 3 9 12 1 0 1 I 13 0 11 1 12 x 12 x 25 8:00 i 2 17 i 19 1 2 3 22 0 18 1 19 I 19 I41 8:15 0 11 11 0 1 1 12 0 15 1 16 16 28 8:30 2 5 7 0 2 2 9 0 9 1 10 10 19 7:15-8:15 1 , 40 I 46 I 12 I + 14 60 I 0 50 52 I1 52 112 noa i0.5 0.59 0.61 n0 I0.5 0.6 1a 0 7 I I iliaI n!a n1aI a 4.69, nla 0.5 I D 68 1 I O.bB I 4:15 4 13 17 0 8 8 25 0 3 2 5 5 30 4:30 2 2 4 1 3 4 8 0 2 4 6 6 14 4:45 5 3 8 0 5 5 13 0 5 7 12 12 25 5:00 7 1 8 1 8 9 17 0 3 2 5 5 22 5:15 5 4 9 0 6 6 15 0 3 6 •9 9 24 5:30 5 3 8 0 6 6 14 0 2 3 5 5 19 4:30-5:30 53 32 I naa, 068, 1 0.63 0.81 I0.5 10.89 n0 1a I 0.67 I I n0la In!a I nla a I 0.65 , n1a, �j68 1 D b7 II 0.86 APPENDIX B HCM 2010 TWSC Recent AM 3: S H 14 & WC R25 Intersection Int Delay, s/veh Movement 1A EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow Major/Minor t 23 316 23 316 0 0 Free Free - None 400 - 0 - 0 85 85 74 7 27 372 Majorl 392 392 0 Free 0 0 85 5 461 Major2 23 23 0 Free None 250 85 74 27 tif 25 25 0 Stop 0 2 0 85 73 29 Minor2 37 37 0 Stop None 85 73 44 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 Approach 461 0 4.84 2.866 807 807 EB WB 0 887 461 461 426 7.13 6.93 6.13 6.13 4.157 3.957 239 477 509 531 231 477 396 509 513 SB HCM Control Delay, s HCM LOS 0.7 Minor Lane/Major Mvmt EBL EBT WBT WBR SBLn1 0 14.8 B Capacity (veh/h) 807 HCM Lane WC Ratio 0.034 HCM Control Delay (s) 9.6 HCM Lane LOS A HCM 95th %tile Q(veh) 0.1 - 441 - 0.165 - 14.8 - B - 0.6 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates recent am.syn HCM 2010 TWSC Recent PM 3: S H 14 & WC R25 Intersection I nt Delay, s/veh 0.9 Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow Major/Minor 'Pi t 21 377 21 377 0 0 Free Free - None 400 - - 0 - 0 85 86 76 8 25 438 Majorl 291 291 0 Free 0 0 96 9 303 Major2 8 8 0 Free None 250 85 76 9 24 24 0 Stop 0 2 0 85 54 28 Minor2 11 11 0 Stop None 85 54 13 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 Approach 303 0 4.86 2.884 934 934 EB WB 0 791 303 303 488 6.94 6.74 5.94 5.94 3.986 3.786 295 630 645 523 287 630 443 645 509 SB HCM Control Delay, s HCM LOS Minor Lane/Major Mvmt 0.5 EBL EBT WBT WBR SBLnI 0 13 B Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) 934 0.026 9 A 0.1 - 489 - 0.084 - 13 - B - 0.3 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates recent pm.syn HCM 2010 TWSC Recent AM 5: WC R25 & Landfill Access Intersection I nt Delay, s/veh 4.7 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow 50 50 0 Stop 0 0 0 85 80 59 Major/Minor Minorl or+ 4 2 6 40 2 12 2 6 40 2 12 0 0 0 0 0 Stop Free Free Free Free None - None - None 85 80 2 0 0 0 - 0 85 85 85 85 38 80 80 38 7 47 2 14 Majorl Major2 Conflicting Flow All 50 31 0 0 54 0 Stage 1 31 - Stage 2 19 - Critical Hdwy 7.2 7 - 4.9 Critical Hdwy Stg 1 6.2 - - - Critical Hdwy Stg 2 6.2 - Follow-up Hdwy 4.22 4.02 - - 2.92 Pot Cap -1 Maneuver 795 858 - - 1171 Stage 1 824 - - - Stage 2 835 - Platoon blocked, % - Mov Cap -1 Maneuver 793 858 - - 1171 Mov Cap -2 Maneuver 793 - - Stage 1 824 - - Stage 2 833 - - Approach WB NB SB HCM Control Delay, s 9.9 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 1.2 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 795 1171 - 0.077 0.002 - 9.9 8.1 0 - AAA - 0.2 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates recent am.syn HCM 2010 TWSC Recent PM 5: WC R25 & Landfill Access Intersection I nt Delay, s/veh 3.8 Movement WBL WBR NBT NBR SBL SBT Lane Configurations 4 Traffic Vol, veh/h 13 19 19 10 2 22 Future Vol, ve hlh 13 19 19 10 2 22 Conflicting Peds, #1hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - Veh in Median Storage, # 0 - 0 0 Grade, % 0 - 0 - 0 Peak Hour Factor 85 85 85 85 85 85 Heavy Vehicles, % 80 80 38 80 80 38 Mvmt Flow 15 22 22 12 2 26 Major/Minor Minorl Majorl Major2 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 59 28 0 0 34 0 28 - - - - 31 - - - - - 7.2 7 - 4.9 6.2 - - - - 6.2 - 4.22 4.02 - - 2.92 - 785 861 - - 1193 - 826 - - - - - 824 - - - 783 861 - - 1193 - 783 - 826 - - - - 822 - Approach WB NB SB HCM Control Delay, s 9.6 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 0.7 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 828 1193 - 0.045 0.002 - 9.6 8 0 - AAA - 0.1 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates recent pm.syn UNSIGNALIZED INTERSECTIONS Level -of -Service Average Total Delay seclveh A <10 B >10and c15 C >15andc25 D > 25 and c 35 E >35and <50 F > 50 APPENDIX C HCM 2010 TWSC Short Total AM 3: S H 14 & WC R25 Intersection Int Delay, s/veh Movement 1.4 EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow t 24 372 24 372 0 0 Free Free - None 400 - 0 - 0 85 85 74 7 28 438 Major/Minor Majorl 462 462 0 Free 0 0 85 5 544 Major2 24 24 0 Free None 250 85 74 28 26 26 0 Stop 0 2 0 85 73 31 Minor2 39 39 0 Stop None 85 73 46 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy 4.84 Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy 2.866 Pot Cap -1 Maneuver 745 Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 Approach 544 0 745 EB WB 0 1038 544 544 494 7.13 6.93 6.13 6.13 4.157 3.957 190 424 462 490 183 424 353 462 472 SB HCM Control Delay, s HCM LOS Minor Lane/Major Mvmt 0.6 EBL EBT WBT WBRSBLn1 0 16A C Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) 745 0.038 10 B 0.1 - 392 - 0.195 - 16A - C - 0.7 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates st am.syn HCM 2010 TWSC Short Total PM 3: S H 14 & WC R25 Intersection Int Delay, s/veh 0.9 Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow Major/Minor t 22 444 22 444 0 0 Free Free - None 400 - - 0 - 0 85 86 76 8 26 516 Majorl 343 343 0 Free 0 0 96 9 357 Major2 8 8 0 Free None 250 85 76 9 tif 25 25 0 Stop 0 2 0 85 54 29 Minor2 12 12 0 Stop None 85 54 14 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 Approach 357 0 4.86 2.884 886 886 EB WB 0 925 357 357 568 6.94 6.74 5.94 5.94 3.986 3.786 243 585 607 477 236 585 399 607 463 SB HCM Control Delay, s HCM LOS Minor Lane/Major Mvmt 0.4 EBL EBT WBT WBR SBLn1 0 14 B Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) 886 0.029 9.2 A 0.1 - 445 - 0.098 - 14 - B - 0.3 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates st pm.syn HCM 2010 TWSC Short Total AM 5: WC R25 & Landfill Access Intersection I nt Delay, s/veh 4.7 Movement WBL WBR NBT NBR SBL SBT Lane Configurations 4 Traffic Vol, veh/h 52 2 6 42 2 13 Future Vol, veh/h 52 2 6 42 2 13 Conflicting Peds, #1hr 0 0 0 0 0 0 Sign Control Stop Stop Free Free Free Free RT Channelized - None - None - None Storage Length 0 - - Veh in Median Storage, # 0 - 0 0 Grade, % 0 - 0 - 0 Peak Hour Factor 85 85 85 85 85 85 Heavy Vehicles, % 80 80 38 80 80 38 Mvmt Flow 61 2 7 49 2 15 Major/Minor Minorl Majorl Major2 Conflicting Flow All 52 32 0 0 56 0 Stage 1 32 - Stage 2 20 - Critical Hdwy 7.2 7 - 4.9 Critical Hdwy Stg 1 6.2 - - - Critical Hdwy Stg 2 6.2 - Follow-up Hdwy 4.22 4.02 - - 2.92 Pot Cap -1 Maneuver 792 857 - - 1169 Stage 1 823 - - - Stage 2 834 - Platoon blocked, % - Mov Cap -1 Maneuver 790 857 - - 1169 Mov Cap -2 Maneuver 790 - - Stage 1 823 - - Stage 2 832 - Approach WB NB SB HCM Control Delay, s 9.9 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 1.1 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 792 1169 - 0.08 0.002 - 9.9 8.1 0 - AAA - 0.3 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates st am.syn HCM 2010 TWSC Short Total PM 5: WC R25 & Landfill Access Intersection I nt Delay, s/veh 3.8 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow 14 14 0 Stop 0 0 0 85 80 16 Major/Minor Minorl or+ 4 20 20 10 2 23 20 20 10 2 23 0 0 0 0 0 Stop Free Free Free Free None - None - None 85 80 24 0 0 0 - 0 85 85 85 85 38 80 80 38 24 12 2 27 Majorl Major2 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 61 29 0 0 35 0 29 - - - - 32 - - - - - 7.2 7 - 4.9 6.2 - - - - 6.2 - 4.22 4.02 - - 2.92 - 782 860 - - 1192 - 825 - - - - - 823 - - - 780 860 - - 1192 - 780 - 825 - - - - 821 - Approach WB NB SB HCM Control Delay, s 9.6 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 0.6 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 825 1192 - 0.048 0.002 - 9.6 8 0 - AAA - 0.2 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates st pm.syn APPENDIX D HCM 2010 TWSC Long Total AM 3: S H 14 & WC R25 Intersection Int Delay, s/veh Movement 1.4 EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow t 30 530 30 530 0 0 Free Free - None 400 - 0 - 0 95 95 74 7 32 558 Major/Minor Majorl 655 655 0 Free 0 0 95 5 689 Major2 30 30 0 Free None 250 95 74 32 ter 30 30 0 Stop 0 2 0 95 73 32 Minor2 45 45 0 Stop None 95 73 47 Conflicting Flow All 689 Stage 1 Stage 2 Critical Hdwy 4.84 Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy 2.866 Pot Cap -1 Maneuver 646 Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver 646 Mov Cap -2 Maneuver Stage 1 Stage 2 Approach EB 0 WB 0 1310 689 689 621 7.13 6.93 6.13 6.13 4.157 3.957 125 344 388 421 119 344 287 388 400 SB HCM Control Delay, s HCM LOS 0.6 Minor Lane/Major Mvmt EBL EBT WBT WBR SBLn1 0 20 C Capacity (veh/h) 646 HCM Lane WC Ratio 0.049 HCM Control Delay (s) 10.9 HCM Lane LOS B HCM 95th %tile Q(veh) 0.2 - 319 - 0.247 - 20 - C 1 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates It am.syn HCM 2010 TWSC Long Total PM 3: S H 14 & WC R25 Intersection I nt Delay, s/veh 0.9 Movement EBL EBT WBT WBR SBL SBR Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow Major/Minor t 30 630 30 630 0 0 Free Free - None 400 - 0 - 0 95 95 76 8 32 663 Majorl 490 490 0 Free 0 0 95 9 516 Major2 10 10 0 Free None 250 95 76 11 ter 30 30 0 Stop 0 2 0 95 54 32 Minor2 15 15 0 Stop None 95 54 16 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 Approach 516 0 4.86 2.884 759 759 EB WB 0 1242 516 516 726 6.94 6.74 5.94 5.94 3.986 3.786 152 469 506 397 146 469 315 506 380 SB HCM Control Delay, s HCM LOS Minor Lane/Major Mvmt 0.5 EBL EBT WBT WBRSBLn1 0 16.7 C Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) 759 0.042 9.9 A 0.1 - 354 - 0.134 - 16.7 - C - 0.5 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates It pm.syn HCM 2010 TWSC Long Total AM 5: WC R25 & Landfill Access Intersection Int Delay, s/veh 4.8 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow 60 60 0 Stop 0 0 0 95 80 63 Major/Minor Minorl or+ 4 5 10 50 5 15 5 10 50 5 15 0 0 0 0 0 Stop Free Free Free Free None - None - None 95 80 5 0 0 0 - 0 95 95 95 95 38 80 80 38 11 53 5 16 Majorl Major2 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 63 37 0 0 63 0 37 - - - - 26 - - - - - 7.2 7 - 4.9 - 6.2 - - - - 6.2 - - 4.22 4.02 - - 2.92 - 780 851 - - 1161 - 818 - - - - - 828 - - - 777 851 - - 1161 - 777 - - 818 - - - - 825 - - Approach WB NB SB HCM Control Delay, s 10 HCM LOS B Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 2 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 782 1161 - 0.087 0.005 - 10 8.1 0 - B A A - 0.3 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates It am.syn HCM 2010 TWSC Long Total PM 5: WC R25 & Landfill Access Intersection I nt Delay, s/veh 3.7 Movement WBL WBR NBT NBR SBL SBT Lane Configurations Traffic Vol, veh/h Future Vol, veh/h Conflicting Peds, #!hr Sign Control RT Channelized Storage Length Veh in Median Storage, # Grade, % Peak Hour Factor Heavy Vehicles, % Mvmt Flow 15 15 0 Stop 0 0 0 95 80 16 Major/Minor Minorl or+ 4 25 25 15 5 30 25 25 15 5 30 0 0 0 0 0 Stop Free Free Free Free None - None - None 95 80 26 0 0 0 - 0 95 95 95 95 38 80 80 38 26 16 5 32 Majorl Major2 Conflicting Flow All Stage 1 Stage 2 Critical Hdwy Critical Hdwy Stg 1 Critical Hdwy Stg 2 Follow-up Hdwy Pot Cap -1 Maneuver Stage 1 Stage 2 Platoon blocked, % Mov Cap -1 Maneuver Mov Cap -2 Maneuver Stage 1 Stage 2 76 34 0 0 42 0 34 - - - - 42 - - - - - 7.2 7 - 4.9 - 6.2 - - - - 6.2 - 4.22 4.02 - - 2.92 - 766 854 - - 1184 - 821 - - - - - 813 - 763 854 - - 1184 - 763 - - 821 - - - - 810 - Approach WB NB SB HCM Control Delay, s 9.6 HCM LOS A Minor Lane/Major Mvmt NBT NBRWBLn1 SBL SBT 0 1.2 Capacity (veh/h) HCM Lane WC Ratio HCM Control Delay (s) HCM Lane LOS HCM 95th %tile Q(veh) - 817 1184 - - 0.052 0.004 - - 9.6 8.1 0 - AAA - 0.2 0 North Weld County Landfill 11/08/2016 Synchro 9 Light Report Delich Associates It pm.syn APPENDIX G DUST ABATEMENT ENT PLAN North Weld Landfill Dust Abatement Plan (Excerpted from NWLF Unit 2 Engineering Design and Operations Plan [EDOPJ) Dust generation (particulate emissions) at NWLF can occur from soil excavation, soil transport and placement, refuse compaction, and vehicular and equipment travel along site access roads. Dust raised from vehicular movement is controlled by wetting roads with water and/or applying commercially available dust suppressant compounds. Additional procedures used for controlling particulate emissions at NWLF consist of the following: • Paving and sweeping certain primary on -site access roads; • Monitoring visible dust emissions from unpaved site access roads by facility personnel to determine the need for and frequency of dust suppression watering; • Minimizing the size of the active working disposal area, to the extent practical; • Minimizing the size of borrow areas and areas disturbed from soil stockpiles, to the extent practical; • Applying leachate within the constructed waste disposal limits (i.e., within lined areas of the landfill); • Revegetation n of inactive areas; and • Posting and enforcing speed limit signs on site access and haul roads. APPENDIX H WASTE HANDLING PLAN North Weld Landfill Waste Handling Plan (Excerpted from NWLF Unit 2 Engineering Design and Operations Plan [EDOPJ) 1. NWLF is a non -hazardous, municipal solid waste (MSW) facility that accepts household, municipal, commercial, and industrial solid wastes, as approved. No regulated hazardous wastes, regulated radioactive wastes, or regulated polychlorinated biphenyls (PCB) are accepted by the facility. Although it is the generator's responsibility to accurately characterize its waste, WMDSC has implemented procedures to identify and screen wastes, specifically those that may► require special handling, to ensure that no regulated hazardous wastes, regulated radioactive wastes, or regulated PCB wastes are accepted at the NWLF facility. 2. Waste identification may be made by physically reviewing commercial and industrial processes, laboratory analysis, written survey, phone questionnaires, and/or waste load inspection, which will identify prohibited wastes or wastes requiring special handling. Prohibited wastes are rejected by the facility and are referred to a permitted hazardous waste transfer, storage, or disposal facility or other appropriate facility. Additional questions and/or observations of incoming wastes are completed at the gatehouse and a minimum of two random load inspections per week are completed at the disposal area. All approved solid waste that is generated on -site by office activities is disposed of in the landfill in accordance with the facility EDOP. 4. Leachate generated at NWLF is removed from leachate collection sumps (both temporary and permanent) on an as needed basis with the typical leachate management strategy to apply the leachate within the constructed waste disposal limits (i.e., within lined areas of the landfill) to manage fugitive dust. 5. All chemicals on -site are properly stored in labeled containers in the maintenance shop. A Spill Prevention, Control, and Countermeasure (SPCC) Plan has been prepared and implemented for the management of chemical and petroleum products. 6. All operations are performed and managed in accordance with the approved EDOP and Weld County development standards adhered to. 7. WMDSC will notify the CDPHE and the WCDPE of substantial revisions to approved operating plans. COLORADO Department of Public Health 6- Environment Dedicated to protecting and improving the health and environment of the people of Colorado June 26, 2018 Board of County Commissioners Weld County 1150 0 Street PO Box 758 Greeley, CO 80632 Re: Recommendation of Approval with Conditions Application for certificate of Designation North Weld Landfill/ Unit 2 SW/WLD/NWC 2.1 Members of the Board, On January 13, 2017, the Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division (Division), received from Weld County, Colorado, a referral notification requesting the Division's review of an engineering design and operations plan (EDOP) for a certificate of Designation (Application) for operation of the North Weld Landfill, Unit 2 (Facility) near Ault, Colorado. The applicant, Waste Management Disposal Services of Colorado, Inc,, is to be the owner and operator of the proposed Facility. The EDOP was received at the Division on January 13, 2017. The Division conducted a completeness review and provided a letter dated February 9, 2017 with a finding that the EDOP was complete in addressing the requirements. The Division reviewed the EDOP to determine its compliance with the requirements set forth in the Solid Waste Disposal Sites and Facilities Act, Title 30, Article 20, parts I and 10 (Solid Waste Act) of the Colorado Revised Statues (CRS), as amended, and with the regulations promulgated there under: the Regulations Pertaining to Solid Waste Sites and Facilities, 6 CCR 1007-2, Part 1 (Solid Waste Regulations). In accordance with the Solid Waste Statute, CRS 30-20-103, the Division conducted comprehensive technical evaluation of the EDOP. Division comments were developed in coordination with the Weld County Department of Public Health and Environment (WCDPHE). These comments were submitted to the applicant on May 4, 2017. On November 22, 2017, the applicant delivered a complete revision of the EDOP, identified as Revision 1, dated November 17, 2016. On May 16, 2018, the Division issued follow-on technical comments that were minor corrections or clarifications. The applicant 4300 Cherry Creek Drive S., Denver, co 80246-1530 p 303-692-2000 www. Colorado. gov/cdphe John W. flickenlooper, Governor I Larry Wolk, MD, MSPR, Executive Director and Chief Medical Officer Board of County Commissioners Recommendation for Approval with Conditions Application for certificate of Designation North Weld Landfill, unit 2 June 25, 2018 Page 2 issued replacement pages for the Revision 1 EDOP on May 18, 2018 that addressed all remaining corrections and clarifications. On May 24, 2018, the Division published a notice in the North Weld Herald requesting written public comments on the proposed North Weld Landfill, Unit 2. The public comment period ended on June 24, 2018, and the Division received no comments. It is the determination of the Division that the North Weld Landfill, unit 2 can comply with technical, environmental, and public health standards of the Solid Waste Act and the Solid Waste Regulations if the Facility is monitored and operated as stated in the CD Application and associated EDOP, Rev. 1 and with the Division's conditions of recommendation as stated below in this letter. Based on our review and determination, the Division recommends, with conditions, that the Facility may be approved by Weld County based on these and any local criteria. The final revised North Weld Landfill, Unit facility Application including the final revised EDOP and final resolution containing the CD must be placed in the Fadlityfs operating record. Our recommendation for approval of the Application including the final revised EDOP (Rev. 1) has the following conditions that must be incorporated into the CD if issued by Weld County: .. Compliance with this CD requires the owner /operator comply with the attached EDOP and any future Department -approved EDOP conditions, including both Department - approved amendments to the EDOP and Department -approved stand-alone plans necessary to comply with the Solid Waste Act and Regulations. Violation of the EDOP as so amended constitutes a violation of this CD. This CD need not be amended upon EDOP amendment unless required by Weld County. 2. CDPHE reserves the right to make unilateral modifications to the EDOP language and conditions at any time during the life of the facility, including during the post closure care period. CDPHE will consult with the county prior to doing so. 3. The Financial Assurance Plan, including independent third party or referenced cost estimate, shall be submitted to the Division for review and approval. In addition, the financial assurance mechanism must be in -place and approved by the Division prior to acceptance of waste material at the site. Please note that pursuant to the requirements of Section 1.8.3 of the Solid Waste Regulations, the closure and post - closure cost estimate must be adjusted annually to account for inflation or deflation by using the implicit price deflator for the gross domestic product. Additionally, the Facility must replace the original cost estimate every five (5) years unless otherwise required by the Division. Both the annual adjustment and the 5 --year update cost estimates must be submitted to the Division for review and approval. 4. Pursuant to C.R.S. 25-15-321 Waste Management shall grant to the Division an Environmental Covenant placing environmental use restrictions on the site to ensure protection of human health and the environment following closure of the solid waste disposal site and facility. 4300 Cherry Creek Drive S., Denver, Co 80246-1530 P 303-692-2000 www.colorado,govicdphe John W. Hicken Cooper, Governor I Larry Wolk, MD, fps P H, Executive Director and Chief Medical Officer Board of County Commissioners Recommendation for Approval with Conditions Application for Certificate of Designation North Weld Landfill, Unit 2 June 25, 2018 Page 3 5. The Facility must comply with the public health and environmental laws, standards, and regulations of the Department and all other applicable state, federal, and local rules, and ordinances, including requirements of the Air Pollution Control Division and Water Quality Control Division, which were outside the scope of the review conducted by the Solid Waste Program. As required by 30--20-104(3)(a) and (3)(b), Weld County is obligated to notify its citizens and conduct a public hearing regarding the proposed solid waste facility. Please forward a copy of the Weld County final resolution concerning the CD issuance or denial to the Division. Should you have any questions addressing the determinations herein please contact Andy Todd at (303) 691-4049 or by email at Andrew.Todd@state.co.us. Sincerely, ,- Andy Todd Solid Waste Permitting Unit Solid Waste and Materials Mgmt Program Hazardous Materials Waste Mgmt Division ec: Kim Ogle Ben Frissell Tom Schweitzer Bill Hedberg Jeff Rusch Jerry V`l enderson Solid Waste Permitting Unit Leader_ Solid Waste and Materials Mgmt Program Hazardous Materials Waste Mgmt Division Weld County Planning Department Weld County Department of Health and Environment Waste Management Waste Management Golder Associates 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colvrado.govlcdphe John W. H ckenlooper, Governor I Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer 0&' < F`rtAt %A) is ct 1;151 17 COLORADO Department of Public Health Et Environment Dedicated to protecting and improving the health and environment of the people of Colorado January 9, 2017 Mr. Bill Hedberg Sr. District Manager North Weld Landfill 40000 Weld County Road 25 Ault CO, 80610 RE: Completeness Review Determination: Complete Application for certificate of Designation (CD) North Weld Landfill, unit 2 Weld County, Colorado SW/ WLD / NWC 2.1 Dear Mr. Hedberg: The Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division (Division), received from Weld County, Colorado, a referral dated January 6, 2017 requesting the Division's review of an engineering design and operations plan (EDOP) for a new certificate of Designation (Application) for operation of the North veld Landfill facility in Weld County, Colorado. The referral and EDOP were received at the Division on January 13, 2017. The Division has reviewed the Application to determine its compliance with the requirements set forth in the Solid Waste Disposal Sites and Facilities Act, Title 30, Article 20, Parts I and 10 (Solid Waste Act) of the Colorado Revised Statutes (CRS), as amended, and with the regulations promulgated there under: the Solid Waste Regulations. In accordance with the Solid Waste Statute, CRS 30-20-103 (2), a "completeness review" of the Application is required within thirty (30) days of the Application referral from the local governing authority (Weld County). The Division has conducted the completeness review and has determined the Application to be substantiatly complete. The EDOP does not yet include a groundwater monitoring plan modified to account for new welts in the expansion area. The EDOP contains a placeholder for this plan and the applicant has committed to providing this plan within 30 days of the date of this letter, which the Division finds satisfactory. This completeness determination is contingent upon the applicant submitting the a groundwater monitoring plan within the 30 day timeframe or by March 13, 2017. Please note that it is not the intent or purpose of a "completeness review" to imply anything concerning the final approval (or disapproval) of the Application. In accordance with the Solid Waste Statute, CRS 30-20-103 (2), a comprehensive technical evaluation of the Application is required after the completeness review has been conducted, and the Division 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.govicciphe John W. H ickenlooper, Governor Larry Wolk, MD, .ASP H, Executive Director and Chief Medical Officer .IC 1; S r rt tc X 53. • • 1• I 3 ar i S rft • , R I4 C 1S • •3 f. r., :-r 4 } Mr. Bill Hedberg February 9, 2017 Page 2 has initiated the technical evaluation process. The Division may request additional information in order to clarify aspects of the Application before completing the technical evaluation. A formal recommendation of approval (or disapproval) of the Application per the Solid Waste Regulations will be made after the Division has completed its technical review. The Division is authorized to bill for its review of technical submittals at $125 per hour, pursuant to Section 1.7 of the Solid Waste Regulations. The fee ceiling is $35,000 for the review of your Application, and the review can include time for the completeness review, the technical evaluation, associated meetings, other communications, and any other related items. An invoice for the Division's review of the subject document will be sent under separate cover. Enclosed is a 30 -Hour Billable Time Notification Waiver/Cease-Work Notice. Please check the appropriate box on this notice and sign and date the waiver. This notice should be returned to Andy Todd at HMWMD B2 4300 Cherry Creek Drive South Denver, Colorado 80246-1530 Please note that the Department is authorized to bill for its review of technical submittals pursuant to Section 1.7 of the Regulations. An invoice for the Division's review of the above referenced documents wilt be transmitted under separate cover. Our fees and billing ceilings may be viewed online at https://www.cotorado.govipacificicdpheisolid-waste-regulations. Should you have any questions addressing the determinations herein please contact Andy Todd at (303) 691-4049 or by email at Andrew.Todd@staterco.us. Sincerely, Andy Todd Solid Waste Permitting Unit Solid Waste and Materials Management Program Hazardous Materials and Waste Management Division ec: Tom Schweitzer Kim Ogle Ben Erissell Jeffrey Rusch - - Waste Management -Weld CountyPlanning Department - Weld County Department of Health and Environment Golder Associates 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.govfcdphe John W. Hickenlooper, Governor I Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer DEPARTMENT OF PLANNING SERVICES 1555 North 17th Avenue Greeley, CO 80631 Website: 'ww.co.weId.co.us Phone: (970) 353-6100 Ext. 3540 Fax: (970) 304-6498 PLANNING INVOICE and RECEIPT SUMMARY January 05, 2017 Permit Number: Owner Name: Address: Application Type: Applicant: USR16-0047 WASTE MANAGEMENT CORP Planning\'Use By Special Review\NA ,NA WASTE MANAGEMENT C0RP C/O WASTE MANAGEMENT CHICAGO, IL 606901450 INVOICES: Invoice # 89182 Solid Waste Disposal Total Fee: Amount 20,000.00 20,000.00 PAYMENTS: Payment I pit # Method 95209 Check Total Paid: Ref # Payor 00128650' DEVIMA RANKIN Payment Date Amount Cashier 12/30/2016 $20,000.00 KOGLE $20,000.00 Report ID: PL00001 v003 Print Date -Time: 1/5/2017 3:32:00PM Page 1of1 Hello