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HomeMy WebLinkAbout20132317.tiffUse by Special Review Application Packet DCP Midstream, LP Lucerne ll Gas Plant Expansion Weld County, CO February 28, 2013 Introduction DCP Midstream, LP (DCP) is in the process of expanding operations in Weld County, CO. The expansion project will include expanding the existing Lucerne Gas Plant (4th Am USR 552) located at 31495 County Road 43, adding three to four new compressor stations and interconnecting pipelines. This Use by Special Review permit application addresses the new Lucerne II Gas Plant Expansion which will include vacating the 4th AM USR 552 and permitting the expanded Lucerne Gas Plant under a new Use by Special Review Permit. Additional USR permit applications will be submitted for the remaining compressor stations and pipelines separately. The Lucerne II Gas Plant Expansion site is located approximately 1.5 miles northeast of Greeley, CO, in Section 28, Township 6 North, Range 65 West. DCP intends to construct the gas plant between the summer of 2013 through the fall of 2014. The current Lucerne Gas Plant covers approximately 12 acres, and the new Lucerne ii Gas Plant Expansion will be constructed on an adjacent parcel. Although the expansion site is approximately 80 acres, only about 40 acres are expected to be disturbed by the construction and operation of the plant. After construction, the site will be fully fenced with a six -foot -high chain link fence topped with barbed wire. The area inside the fence will be graveled. The area outside the fence will be re -vegetated with native grasses. Four to six full-time employees are expected to be employed at the Lucerne II Gas Plant. The plant will function 24 hours a day, 7 days a week, year-round. A septic system will be installed to accommodate post -construction sewage. Water will be provided for all uses, including fire suppression, by the North Weld County Water District. DCP met with Mr. Alan Overton, District Engineer for the North Weld County Water District, regarding the District's ability to supply potable water for the proposed Lucerne II Gas Plant. The existing plant has a 3/4" water line currently providing water to the facility, and the North Weld County Water District will provide a 12" water line and add a fire hydrant for the Lucerne II expansion. DCP met with Chief Hugh Kane and Fire Marshall Matt Carey from the Eaton Fire Protection District. A Knox key override will be installed to allow emergency access to the front gate. Fire hydrants will be installed at the periphery of the site, and fire detection systems including flammable gas detectors and flame detectors will be installed in certain process facilities within the plant. The Weld County Code provides in Section 19-9-40 that noise levels for industrial or construction sites be below 80 dB(A) from 7:00 a.m. to 9:00 p.m. and below 75 dB(A) from 9:00 p.m. to 7:00 a.m. DCP does not foresee exceeding these limitations during the construction or operation of the Lucerne II Gas Plant. The Weld County Code also provides in Section 23-2-250 that light rays from outdoor lighting will not shine directly onto adjacent properties where such would cause a nuisance or interfere with the use on the adjacent property. Also stipulated in the code is: "Neither direct nor reflected light from any light source may create a traffic hazard to operators of motor vehicles on public or private streets and colored lights that may be confused with or construed as traffic control devices shall not be used." DCP does not intend to use excessive lighting and does not foresee exceeding Weld County Code limitations regarding lighting at the Lucerne II Gas Plant Expansion. SITE SPECIFIC DEVELOPMENT PLAN AND USE BY SPECIAL REVIEW (USR) APPLICATION FOR PLANNING DEPARTMENT USE DATE RECEIVED: RECEIPT # /AMOUNT # 1$ CASE # ASSIGNED: APPLICATION RECEIVED BY PLANNER ASSIGNED: Parcel Number 0 8 0 3 2 8 0. 0 0 0 3 7 See a �o .h €.d ) (12 digit number - found on Tax I.D. information, obtainable at the Weld County Assessor's Office or www.co.weld.co.us) Legal Description Southeast Quarter , Section 28 , Township 6 North, Range 65 West Zone District: AG , Total Acreage: 107.841 , Flood Plain: No , Geological Hazard: No Airport Overlay District: No FEE OWNER(S) OF THE PROPERTY: Name: DCP Midstream LP Work Phone # 970-356-9700 Home Phone # 970-378-6345 Email jkuchinski@dcpmidstream.com Address: 3026 4th Avenue Address: City/State/Zip Code Greeley, CO 80631 Name: Work Phone # Home Phone # Email Address: Address: City/State/Zip Code Name: - Work Phone # Home Phone # Email Address: Address: City/State/Zip Code APPLICANT OR AUTHORIZED AGENT (See Below: Authorization must accompany applications signed by Authorized Agent) Name: Joseph Kuchinski Work Phone # 970-356-9700 Home Phone # 970-378-6345 Email jkuchinski@dcpmidstream.com Address: 3026 4th Avenue Address: - City/State/Zip Code Greeley, CO 80631 PROPOSED USE: Expansion of existing DCP Midstream Lucerne Gas Plant, 4th AmUSR-552 I (We) hereby depose and state under penalties of perjury that all statements, proposals, and/or plans submitted with or contained within the application are true and correct to the best of my (our)knowledge. Signatures of all fee owners of property must sign this application. If an Authorized Agent signs, a letter of authorization from all fee owners must be included with the application. If a corporation is the fee owner, notarized evidence must be included indicat'ng that the si tatory4as to legal authority to sign for the corporation. QS • I CAS ature• wner or thorized Agent -2 LI0/3 Date Signature: Owner or Authorized Agent Date E �r 2 Exhibit H Deed and/or Ownership Information Three properties will comprise the Lucerne II Gas Plant Expansion. Their summary legal descriptions follow: 1. Parcel number: 080328400003 — 2.49 Acres - Existing Lucerne Gas Plant 2. Parcel number: 080328400004 — 5.85 Acres - L Shaped "add-on" to existing Lucerne Gas Plant 3. Parcel number: 080328000037 — 80.19 Acres - East half of SE quarter of Section 28 - Lucerne II Gas Plant Expansion 4. A portion of Parcel number: 080328000077, consisting of approximately .5 acres and located north of the existing Lucerne Gas Plant 5. Parcel number: 080328000076, consisting of approximately .6 acres. See attached documentation concerning deed and ownership information. 2 or 2 Exhibit D USR Questionnaire 1. Explain, in detail, the proposed use of the property. The site for the Lucerne 11 Gas Plant Expansion is 80 acres (the entire proposed USR will consist of 87 acres, including the existing plant). Only about 40 acres will be disturbed in the building or operation of the new gas plant. The plant will be used to collect raw natural gas from nearby gathering systems and process and compress the gas for delivery to sales pipelines. The gathering system expansion will enable DCP to service producers in the Niobrara Shale development to the north of DCP's existing facilities. 2. Explain how this proposal is consistent with the intent of the Weld County Code, Chapter 22 of the comprehensive plan. The proposed use is consistent with the comprehensive plan's intent to foster development of the natural resources of Weld County. 3. Explain how this proposal is consistent with the intent of the Weld County Code, Chapter 23 (zoning) and the zone district in which it is located. The proposed use is consistent with the intent of the agricultural zone district, as it will foster the development of oil and gas resources. Pursuant to Section 23.3.20 of the Weld County Code, oil and gas production facilities are allowed as a matter of right in the agricultural zone district. Further, the proposed use will not interfere with any existing agricultural operations, as the expansion site is currently maintained as a native grass field, and is not in agricultural production. 4. What type of uses surround the site (explain how the proposed use is consistent and compatible with surrounding land uses). The site is surrounded by cultivated agriculture parcels Section 23-3-20 of the Weld County Code provides that oil and gas production facilities are allowed as a matter of right in the agriculture zone district. The actual plant site is not used for agricultural production at present. By keeping the plant footprint small, it is intended that surrounding agricultural areas will not be affected by the plant's presence. 5. Describe, in detail, the following: a. Number of people who will working at this site. Construction crews will consist of up to 150 people. After construction is completed, approximately 4 to 6 people will be employed at the plant full time. This includes operations and maintenance staff that will service the combined operations of the existing and expanded plant facilities. b. Number of employees proposed to be employed at this site. 4-6 full-time employees c. Hours of operation. 24 hours a day, seven days a week, 365 days a year. d. Type and number of structures to be erected (built) on this site. One office building and one warehouse will be constructed. Process equipment associated with the gas plant includes: Inlet metering, filtering and condensate separation systems to receive incoming wellhead gas from nearby gathering systems; Compressors to increase the pressure of the gas prior to treatment; Chemical treatment of the gas to remove carbon dioxide and hydrogen sulfide using an amine process; Dehydration system to remove water vapor within the gas stream; Separation of natural gas liquids from the gas stream (which are sold separately via pipeline); Associated metering and utilities servicing the processes above. e. Type and number of animals, if any, to be on this site. None. f. Kind of vehicles (type, size, weight) that will access this site and how often. In addition to employees' vehicles, there will be pickup trucks and large delivery trucks will access the site daily. Pickup truck traffic is estimated at 5 - 7 pickup trips per day. Delivery truck traffic is estimated at 3 - 5 trips per day. Weight estimates for delivery trucks vary from 10,000 lbs to 60,000 lbs. g. Who will provide fire protection to the site? The gas plant is located within the Eaton Fire Protection District. Potable water and water for fire suppression will be purchased from the North Weld County Water District. h. Water source on the property. During construction, the contractor will be required to provide potable drinking water. Construction water will also be purchased from the North Weld County Water District. DCP met with Mr. Alan Overton, District Engineer for the North Weld County Water District, regarding the district's ability to supply potable water for the proposed Lucerne II Gas Plant Expansion. The existing plant is serviced by a 3/4" water line, and the North Weld County Water District will construct a 12" water line and hydrant that will service the Lucerne II Gas Plant Expansion. J• i. Sewage disposal system on the property. During construction, the contractor will be required to provide and maintain sanitary facilities. Post -construction, a septic system will be used. DCP will contract to professionally engineer the proposed septic system. If storage or warehousing is proposed, what type of items will be stored? DCP will not store or warehouse any materials. The following storage tanks will be used to contain the processed natural gas at the site until removal for delivery to market: • Amine Storage Tank: One tank at 1,000 BBLS • Condensate Storage Tank: Four tanks at 400 BBLS ea • Refrigerant Storage Tank: One tank at 156 BBLS • Hot Oil Storage Tank: One tank at 300 BBLS • Methanol Storage Tank: One tank at 12 BBLS • Waste Water Storage Tank: Two tanks at 300 BBLS • Produced Water Storage Tank: One tank at 210 BBLS • Lube Oil Storage for Residue Compressors: One tank at 150 BBLS • Lube Oil Storage for Refrigeration Screw Compressors: One tank at 150 BBLS • LP Condensate Storage Tanks: One tank at 714 BBLS • Used Oil Tanks: One tank at 100 BBLS 6. Explain the proposed landscaping for the site. DCP will landscape the disturbed area outside the perimeter fence with native grasses. The plant within the perimeter fence is graveled for fire protection reasons and dust suppression. 7. Explain any proposed reclamation procedures when termination of the USR activity occurs. At completion of construction, the site outside of the fenced boundary will be re -vegetated with native grasses. The area inside the fenced boundary will be graveled. If operations at the site were to cease. DCP will adhere to COGCC regulations concerning site abandonment and reclamation. 8. Explain how the storm water drainage will be handled on the site. The site will be graded so water flows into an on -site stormwater detention pond. The pond will be sized to contain 100% of the runoff predicted from a 25-year/24-hour duration storm. A manual valve will be installed on the detention pond to allow periodic drainage after inspection by a plant operator. If any contaminants are present in the pond upon inspection, the contamination will be removed prior to release of water from the pond. 9. Explain how long it will take to construct this site and when construction and landscaping is scheduled to begin. Construction will take approximately one year. DCP plans to start construction in the summer of 2013 with completion in 2014. 10. Explain where storage and/or stockpile of wastes will occur on this site. No storage of wastes will occur on the site. Wastes will be properly containerized prior to removal from the site in a timely manner. Liquid wastes are typically trucked to a refinery for reclamation of the hydrocarbons. Non -hazardous solid waste (such as cardboard, paper, wood pallets, etc.) are typically sent to a landfill. A screened trash enclosure will be designated on the plat for storage of wastes prior to removal. Information for the waste disposal companies DCP intends to use is included in Exhibit S. Exhibit E Weld County Road Access Information Traffic Control Plan As shown on the attached access permit application form, DCP intends to construct a new access road to the Lucerne II Gas Plant on Weld County Road 43 to accommodate large vehicles that are anticipated to access the site during construction and operation of the plant. DCP will contract to build the access road, and contractors will follow safety recommendations required by the Weld County Public Works Department. The existing access road off of Weld County Road 43 will remain in service during construction for non -construction traffic. DCP's guidelines require that contractors ensure the safety of other drivers using public roadways, and such guidelines include: • Construction on the access road will only occur during the day. • Appropriate signage will be placed 500 ft from the construction to warn drivers from both directions of upcoming construction. • As a general guideline, vehicles and equipment will not block County roads. If equipment is expected to temporarily obstruct traffic, cones will be used to direct traffic around the obstruction, and traffic control workers will direct traffic. • The access off of the County Road will be constructed according to Weld County Public Works standards, including provisions for 70 -foot turning radii off of the County Road, sufficient length to allow trucks to pull completely off the County Road prior to stopping, grading to prevent runoff from the access road to drain onto the County Road, and installation of double cattle guards to remove mud from trucks coming off of the plant site and onto the County Road. WELD COUNTY ACCESS PERMIT Weld County Public Works Dept. 1111 H Street P.O. Box 758 Greeley, CO 80632 Phone: (970) 304-6496 After Hours: (970) 356-4000 Emergency Services: (970) 304-6500 x 2700 Inspection: (970) 304-6480 Permit Number: AP12-00325 Issuance of this permit binds applicant and its contractors to all requirements, provisions, and ordinances of Weld County, Colorado. Project Name: Lucerne Plant Access Applicant Information: Name: Paul Park Company: DCP Midstream Phone: 970-539-1908 Email: pdpark@dcpmidstream.com Location: Access is on WCR: Nearest Intersection WCR: Distance From Intersection: Number of Existing Accesses: Planning Process: USR 43 43 1400 2 Road Surface Type & Construction Information: Road Surface: Asphalt Culvert Size & Type: 24" Steel Start Date: Finish Date: 03/14/2013 & WCR: 64 Materials to Construct Access: 3/4" Class 6 Road Base Required Attached Documents Submitted: Traffic Control Plan: Yes Certificate of Insurance: Yes Expiration date: 03/14/2013 Property Owner Information: Name: Company: Phone: Email: Proposed Use: Temporary: Single Residential: Industrial: Small Commercial: Oil & Gas: Large Commercial: Subdivision: Field (Agricultural Only)/Exempt: Access Pictures: II Yes A copy of this permit must be on site at all times during construction hours Daily work hours are Monday through Friday DAYLIGHT to 1/2 HOUR BEFORE DARK (applies to weekends if approved) Approved MUTCD traffic control/warning devices are required before work begins and must remain until completion of work Special Requirements or Comments Please utilize the existing access points. CR 43 is a collector roadway with a setback of 60 feet from the centerline of the existing roadway. Approved by:itaaj_ Janet Carter, Weld County Public Works Date: 10/17/2012 Print Date -Time: 10/17/2012 8:22:36PM Report ID: PW00008v002 Page 1 of 1 Applicant Name Weld County Public Works Dept. 1111 H Street P.O. Box 758 Greeley, CO 80632 Phone: (970)304-6496 Fax: (970)304-6497 Pay\ Parr 1( Company DC p/I kl c�. S�-�' L a. wl Address 30 2„.4 'I't. A0 ev,c7Lo t City l�'� °�- r.k.ei State CO Zip S 06 3) Phone Business Phone 9-10 - S3 g- 11. 0 v Fax it EXt51-1vt5 ACc(_Sse,S ACCESS PERMIT APPLICATION FORM Property Owner (If different than aApplicant) DC \P (Lew Fax E-mail F cl p a rk 0c crviA;asiteaN.t,Cool Parcel Location & Sketch J The access is on WCR 9 3 Nearest Intersection: WCR Lk 3 & WCR 6 9 Distance from Intersection ).b 90'4-1900' Parcel Number O 8 03 2.. O° 0 0 37 Section/Township/Range qE� T6A, R b 5 A) Is there an existing access to the property? ES NO N Number of Existing Accesses a. Road Surface Type & Construction Information ce Asphalt / Grave( Treated _ Other Culvert Size &Type 29 Sleek v+ Soc�� eik-k-TaKcr' 3 Materials used to construct Access e( roe, 4 t)'t r_ Construction Start Date Finish Date Proposed Use o Temporary (Tracking Pad Required)/ $75 o Small Commercial or Oil & Gas/$75 o Field (Agriculture Only)/Exempt Name Address City State Zip E-mail A = Existing Access 4= Proposed Access T T WCR 4 WCR o Single Residential/$75 o Large Commercial/$150 I e! Industrial/$150 o Subdivision/$150 Is this access associated with a Planning Process? o No i<d"USR o RE o PUD O Other Required Attached Documents - Traffic Control Plan -Certificate of Insurance - Access Pictures (From the Left, Right, & into the access) By accepting this permit, the undersigned Applicant, under penalty of perjury, verifies that they have received all pages of the permit application; they have read and understand all of the permit requirements and provisions set forth on all pages; that they have the authority to sign for and bind the Applicant, if the Applicant is a corporation or other entity; and that by virtue of their signature the Applicant is bound by and agrees to comply with all said permit requirements and provisions, all Weld County ordinances, and state laws regarding facilities construction. Signature Printed Name Pct.) D Park Date ! -13 `, Approval or Denial will be issued in minimum of 5 days. Approved by Revised Date 6/29/10 Typical Traffic Control Plan Diagram / ROAD WORK •' AHEAD no FT rd kAl 500 vi ROAD WORK AHEAD 1. The above diagram is typical for normal shoulder work applications. Additional signing may be required. 2. Vehicles or construction equipment shall not be parked in the travel way and should be moved to the shoulder. If vehicles or construction equipment are not able to be moved out of the way of traffic, channelizing devices are required for day use only. No night time obstructions are allowed. - AC 09 IPRODUCER MARSH USA INC. 1000 MAIN STREET SUITE 3000 HOUSTON, TX 77002 Attn: houston.certsemarsh.com; Fax: (212) 948-0509 1676269.01234--10-11 INSURED i DCP MIDSTREAM. LW 370 17TH STREET, SUITE 2500 DENVER, CO 80202 CERTIFICATE OF LIAE3ILITY INSURANCE I DATE WDD/YYYY) 104/30/ 04/3O/2010 THIS CERTIFICATION IS ISSUED AS A MATTER OF INFORMATION ONLY AND CONFERS NO RIGHTS UPON THE CERTIFICATE HOLDER. THIS CERTIFICATE DOES NOT AMEND, EXTEND OR ALTER THE COVERAGE AFFORDED BY THE POUCIES BELOW. INSURERS AFFORDING COVERAGE INSURER A: N/A INSURER B: N/A INSURER c: American Guarantee & Liability Ins Co INSURER 0: Zurich American Insurance Company i INSURER E COVERAGES 1V/A NAIC # 14/A 26247 0251 63 THE POLICIES OF INSURANCE LISTED BELOW HAVE BEEN ISSUED TO THE INSURED NAMED ABOVE FOR THE POLICY PERIOD INDICATED. NOTWITHSTANDING ANY REQUIREMENT, TERM OR CONDITION OF ANY CONTRACT OR OTHER DOCUMENT WITH RESPECT TO WHICH THIS CERTIFICATE MAY BE ISSUED OR MAY PERTAIN, THE INSURANCE AFFORDED BY THE POLICIES DESCRIBED HEREIN IS SUBJECT TO ALL THE TERMS, EXCLUSIONS AND CONDITIONS OF SUCH POLICIES. AGGREGATE LIMITS SHOWN MAY HAVE BEEN REDUCED BY PAID CLAIMS. • LTR INSRa TYPE OF INSURANCE POLICY NUMBER i POLICY EFFECTIVE I DATE IMLVDD/YYYY) POLICY EXPIRATION DATE(MMIOOIYYYY) •--- ` UNITS D GENERAL X _ LIABILITY I COMMERCIAL GENERAL LIABILITY JJ CLAIMS MADE CXJ OCCUR GLO 9264607-00 05/01/2010 I 05/0112011 €ACHOCCURRENCE $_ .1000,OQ0 DAMAGE TO REl TEO'� FREMISES(Eaoccur:once) S MED EXP (Any Dne person) $ PERSONAL & ACV INJURY $ 1,000,000 I GENERAL AGGREGATE $ 2,000,000 GENERAL X AGGREGATE LIMIT APPLIES PER POLICY� PRO I ` L JECT I i LOC PRODUCTS • COMP/OP AGC� 2,000,000 IS D AUTOMOBILE X ...- LIABILITY ANY AUTALL OWNED AUTOS IBAP9264608-00 05/01/2010 05/01/2011 COM(Ea BINEDINGLE LIMIT Is 1,000,000 I$ BODILY INJURY (Per person) - BODILY INJURY (Per accident) $ PROPERTY DAMAGE (Per accident) $ —1 — GARAGE 1 LIABILITY ANY AUTO ( AUTO ONLY • EA ACCIDENT'S OTHER EA ACC THAN $ AUTOONL qGG $ C EXCESS IT]DEDUCTIBLE / UMBRELLA UABIUTY OCCUR f X'] CLAIMS MADE RETENTION S UMB-9264615-00 I 05/01/2010 05/01/2011 EACH OCCURRENCE ,$ 5,000,000 AGGREGATE 1$ 5,000,000, 1$ $ IS D WORKERS COMPENSATION AND EMPLOYERS' LIABILITY ANY PROPRIETOR/PARTNER/EXECUTIVEY/N OFFICER/MEMBER EXCLUDED? "'1 (M.andafory Jn NH A es. descr be under L_. J SPECIAL PROVISIONS below WC 9264606.00 05/01/2010 05/01/2011 i YICSTATU_ X ._71)AY-UMIT.S0TH E.. EACH ACCIDENT a 1,000,000 E.L. DISEASE - EA EMPLO 1.000.000 EA_ DISEASE - POLICY LIMITT$ �$ $ 1,000,000 DESCRIPTION OTHER OF OPERATIONS/LOCATIONSNFHICI RciFYLL umnwc ennen Dv zR,„nDce.. ..,•,.....- ................._..- CERTIFICATE HOLDER EVIDENCE OF INSURANCE ACORD 25 (2009/01) HOU-001415035-10 CANCELLATION J SHOULD ANY OF THE ABOVE DESCRIBED POLICIES BE CANCELLED BEFORE THE EXPIRATION DATE THEREOF, THE ISSUING INSURER WILL ENDEAVOR 70 MAIL a�� DAYS WRITTEN NOTICE TO THE CERTIFICATE HOLDER NAMED TO THE LEFT, BUT FAILURE TO DO SO SHALL IMPOSE NO OBLIGATION OR LIABIUTY OF ANY KIND )}UCPpO¢N D�g¢ THE INSURER, ITS AGENTS OR REPRESENTATIVES. Al Mar5hEUSraSENTAAYE Jennie Clements CI 1998-2009 ACORD CORPORATION. All Rights Reserved The ACORD name and logo are registered marks of ACORD y• - 3 cZ Exhibit F Evidence of Adequate Water Supply During construction, the contractor will be required to provide drinking water. DCP met with Mr. Alan Overton, District Engineer for the North Weld County Water District, regarding the District's ability to supply potable water for the proposed Lucerne II Gas Plant. The existing Lucerne Gas Plant is serviced by a 3/4" water line, and the North Weld County Water District will provide a 12" water line and hydrant that will service the Lucerne II Gas Plant Expansion. North Weld County Water District 32825 CR 39 Lucerne, CO 80646 (970) 356-3020 water@nwcwd.org Exhibit G Evidence of Adequate Sewage Disposal During construction the contractor will be required to provide and maintain sanitary facilities. Post construction, a septic system will be used, and which DCP will have professionally engineered. The system will be installed by a licensed plumber in compliance with the engineered plans and ISDS (septic) permit. FOR COMMERCIAL SITES, PLEASE COMPLETE THE FOLLOWING INFORMATION BUSINESS EMERGENCY INFORMATION: Business Name: DCP Midstream, LP. Phone: 970-356-9700 Address: 3026 4th Ave. City, ST, Zip: Greeley, CO 80631 Business Owner: DCP Midstream, LP Phone: 970-356-9700 Home Address: 3026 4th Ave. City, ST, Zip: Greeley, CO 80631 List three persons in the order to be called in the event of an emergency: NAME TITLE Greg Kardos Dave Stults ADDRESS PHONE Asset Director 3026 4th Ave., Greeley, CO 80631 970-373-7536 Facility Supervisor 3026 4th Ave., Greeley, CO 80631 970-301-6087 Paul Park Compliance Coordinator 3026 4th Ave., Greeley, CO 80631 970-539-1908 Business Hours: 24 hours/day Days: 7 days/week Type of Alarm: X None Burglar Holdup Fire Silent Audible Name and address of Alarm Company: N/A Location of Safe: N/A MISCELLANEOUS INFORMATION: Number of entry/exit doors in this building: 3 Location(s): North side, west side and south side Is alcohol stored in building? No Location(s): Are drugs stored in building? No Location(s): Are weapons stored in building? No Location(s): The following programs are offered as a public service of the Weld County Sheriff's Office. Please indicate the programs of interest. X Physical Security Check Crime Prevention Presentation UTILITY SHUT OFF LOCATIONS: Main Electrical: MCC Building Gas Shut Off: N/A Exterior Water Shutoff: Interior Water Shutoff: North side Restroom Exhibit M IGA Boundary Statement The Lucerne II Gas Plant site is not located within a defined IGA Boundary. According to the Weld County Property Information Portal, the closest IGA boundary surrounds the town of Eaton and is approximately four miles northwest of the plant location. The City of Greeley boundary is located about 1.4 miles west/southwest of the project site. o • iii .. �l w EATON IGA .J MEM r m%4,. ` , ‘�� .e-.:.-3. .11 ii:o -§ ir li r? NI 46'..., -7 47 : 4 :;- Exhibit O Preliminary Traffic Statement Construction of the Lucerne II Gas Plant Expansion is planned from the summer of 2013 through the fall of 2014. During construction, traffic will increase on county roads that access the site. Construction crews are estimated at up to 150 individuals daily and construction equipment will access the site on a regular basis. Once construction is complete in 2014, traffic to the Lucerne II Gas Plant will decrease. Four to six full- time employees who will access the site daily are anticipated during plant operation. Three to five large delivery trucks are also expected daily. Exhibit P Flood Hazards The Lucerne II Gas Plant site is located within FEMA floodplain panel 080266-0629, Weld County, Colorado. The site is not within a floodplain as defined by FEMA. The closest floodplain runs along Sand Creek about a mile to the east and is defined as a "Zone A" floodplain with a 100 -year recurrence probability. Exhibit R Dust Abatement Plan During construction, water trucks will be used to maintain dust suppression. Also, a stormwater management plan will be followed to mitigate soil erosion and sediment transport during the construction phase. After construction is complete, the site will be stabilized using native vegetation outside of the fenced area. Areas within the fenced boundary will be graveled, as will the access drive. If necessary, a water truck will be used to control dust after construction. Exhibit S Waste Management Plan Purpose This plan projects the quantities and types of waste that will be generated through operation of the Lucerne II Gas Plant Expansion and details waste management and disposal. The plan further outlines the operational chemicals to be stored on -site, which may require future disposal. Objective This plan will ensure wastes generated at the Lucerne II facility are managed according to all local, state and federal regulations. Further, this plan defines operational chemicals used or stored on -site which require specific disposal pathways. This plan is written to provide training and guidance to site workers to ensure all materials are properly handled and disposed. Chemicals Stored On -Site • Amine Storage Tank: One tank at 1,000 BBLS • Condensate Storage Tank: Four tanks at 800 BBLS ea • Refrigerant Storage Tank: One tank at 156 BBLS • Hot Oil Storage Tank: One tank at 300 BBLS • Methanol Storage Tank: One tank at 12 BBLS • Waste Water Storage Tank: Two tanks at 300 BBLS • Produced Water Storage Tank: One tank at 210 BBLS • Lube Oil Storage for Residue Compressors: One tank at 150 BBLS • Lube Oil Storage for Refrigeration Screw Compressors: One tank at 150 BBLS • LP Condensate Storage Tanks: One tank at 714 BBLS • Used Oil Tanks: One tank at 100 BBLS (Note that these are the same facilities described in Exhibit D of this application.) DCP containerizes all waste and contracts its disposal with a government -permitted facility(ies). Furthermore, a spill prevention, control, and counter measures (SPCC) plan will be developed to outline appropriate actions in the event of a spill. The plan will be specifically developed for the Lucerne II Gas Plant Expansion prior to initiation of start-up activities. It will cover secondary containment requirements, response actions, and waste disposition and disposal in the event of a spill or release. DCP has detailed policies and procedures in place that will be applied to the specifics of any spill or release resulting from the operations. DCP's SPCC plan will be written in accordance with requirements set forth by the Environmental Protection Agency. Trash removal and Septic Services will be provided by: Redi Services, LLC, 7601 Miller Dr. Unit G, Frederick, CO 80504 720-378-7873 April 26, 2013 Mr. Kim Ogle Weld County Department of Planning Services Planning Division 1555 N. 17`h Avenue Greeley, CO 80631 Project: Subject: Dear Mr. Ogle: WHITE Engineering, Inc. 362.0 W. loth Street Suite #4ro Greeley, CO 80634 mobile: (o3) 819-1222. email: christina@whiteengineeringinc.coin DCP Midstream Lucerne II Gas Plant Drainage Plan Attached is the Drainage Plan developed in accordance with Weld County Planning Division guidelines for the DCP Lucerne II Gas Plant. I hereby certify that this report for the drainage design of the DCP Midstream Lucerne II Gas Plant was prepared by me in accordance with the provisions of the Weld County storm drainage criteria for the owners thereof. Sincerely, Rodney D. Burrows, PE 971-533-6665 Permitting - Engineering - Construction Management DCP MIDSTREAM LUCERNEII GAS PLANT Page I of 7 DRAINAGE CALCULATIONS FOR DCP LUCERNE2 GAS PLANT Rodney D. Burrows, PE CALCULATE POND VOLUME REQUIREMENT FOR THE WATER QUALITY CAPTURE VOLUME (WQCV) per Urban Storm Drainage Manual Method WQCV = K [a (0.91 *13— 1.19 *12 + 0.78*I)] Where WQCV is in watershed inches a = adjustment for BMP drain time = 1.0 for 40 -hour drain time K = adjustment for location (= 1.0 for Greeley) I = imperviousness, as a decimal (= 0.80 estimated) WQCV = 1 [1 (0.91 * 0.83 —1.19 * 0.82 + 0.78 * 0.8)] = (0.4659 - 0.7616 + 0.624) watershed inches = 0.3283 watershed inches Required Storage = (WQCV) Area 12 — 0.3283 in * 41.46 acre 12 in/ft = 1.1343 acrefeet = 49,409 cubic feet REQUIRED STORAGE VOLUME PER DCP CRITERIA: (DCP voluntarily designs for a 24-hr/100-year storm) V DCP = Area * 3.8 "( I oo-yr/24.hr storm) = 41.46 acre * 3.8"*ft = 13.129 acre feet 12 in = 571,899 cubic ft DCP's internal practice exceeds USD WQCV method by a factor of 571.899 cft=11.5748 OK ✓ 49,409 cft DCP MIDSTREAM LUCERNEII GAS PLANT Page 2 of 7 Detention Pond Volume Calculations VOLUME REQUIRED TO MEET DCP CRITERIA OF 100-YR/24-HR STORM Area of sub -basin 41.46 acres Runoff coefficient 0.85 Rainfall depth 3.8 watershed inches Volume required 11.15965 acre feet VOLUME OF PROPOSED DETENTION POND Using the average end area method Pond spillway elevation is at: 4690.0 ft Pond bottom is at: 4686.0 ft Elevation Area ave. area depth volume sqft sqft ft cft 4686 80000 4687 129870 4688 136441 4689 143,500 4690 151580 Cumulative volume in cft Cumulative volume in acre -ft 104935 1 104935 133156 1 133155.5 139971 1 139970.5 147540 1 147540 525601 cft 12.06614 acre-feet Summary: Volume proposed is: 12.06614 / 1.0652 11.328 times the WQCV required Volume proposed is: 12.06614 / 11.16 1.0812 times the DCP criteria of a 100-yr/24 hr storm DCP MIDSTREAM LUCERNEII GAS PLANT Page 3 of 7 DRAINAGE CALCULATIONS VOLUME REDUCTION CONSIDERATIONS: The USD manual suggests that retention pond volume can be reduced by cascading runoff through multiple connected and unconnected basins. At this site, DCP feels that multiple pools within the site near the process area are undesirable for safety reasons. We do not want spills pooling near the process area.* No credit for reducing required storage due to cascading pools was used in these calculations. We assume 100% of stormwater will drain to retention basin. *Two minor exceptions are the two spill containment areas proposed around liquid storage tanks within the plant. DCP MIDSTREAM LUCERNEII GAS PLANT Page 4 of 7 POND INFLOW AND OUTFLOW CALCULATIONS MAXIMUM INFLOW RATE INTO DETENTION POND Based on 100-yr, 24 -hr storm For total rainfall, d = 3.8 watershed inches in 24 hrs Average rainfall = 3.8 in = 0.1583 in 24 hrs hr Maximum peak rainfall 2 inches/hr based on duration For peak inflow, use: Q = C • I • A y 41.46 acres 2 inches/hr 80% imperviousness = 66.336 CFS For average inflow, Q = C • I • A 41.46 acres .146 inch/hr 80% imperviousness = 4.84253 CFS POND OUTFLOW CALCULATIONS After pond fills up to spillway elevation, water will spill over the spillway based on flows exceeding the 100-yr total rainfall. Since pond will drain continuously after that, set maximun flow beyond that arbitrarily to 0.5 inches/hr. This is about 3 times the average rainfall in the 100-yr/24-hr storm. Qouttlow = C • I • A 41.46 acres 0.5 inch/hr 80% imperviousness = 16.584 CFS Spillway wier and outflow channel capacity must exceed: 16.584 CFS. DCP MIDSTREAM LUCERNEII GAS PLANT Page 5 of 7 WEIR (SHARP CRESTED) FLOW CALCULATIONS This concrete weir serves as the spillway for the detention pond. Q = Ce • Le • He 3/2 L ----- effective ht (depth) of flow above crest elevation in feet (try 12") effective length of crest in feet Coefficient discharge from Handbook of Hydraulics, King & Brati Drainage in CFS Q = Ce • 5' • 1.03/2 Q = 3.2756*5'* 1.0' = 16.378 CFS for 5' effective depth and 6' wide weir For Q equ;rei = 16.6 CFS, then depth of flow = slightly above 12" above weir This is equivalent to a rainfall intensity of about 0.5 in/hr after the pond fills up with a 24-hr/100-year storm. So weir outflow design is OK Design pond wall height with 1.5 ft freeboard minimum above spillway. DCP MIDSTREAM LUCERNEII GAS PLANT Page 6 of 7 OUTLET FLOW IN A 10' -LONG, 8" PVC PIPE: Pressure head = 2' = 24 inches water = 1.765 inches Hg (based on average depth as pond drains) Per Toricelli Equation: Q=CdA2�l2gh 2' 32.2 ft/sec2 0.3491 sgft > Cd = Coefficient of discharge - 0.61 for sharp -edged pipe = 0.61 •0.349 ft2 1 128.8 ft2/sect = 0.61 •0.349ft2 • 11 = 2.34 CFS For a volume of 525,601 cubic feet, pond will drain in about or 3744 minutes or 62.4 hours Less than 3 days, so OK 224,616 seconds DCP MIDSTREAM LUCERNE2 GAS PLANT Page 7 of 7 Rainfall maximum flow calculations For peak flows into detention pond Sheet flow at northeast part of pond north swale middle swale south swale C I A Q runoff Intensity Area max flow coef ft/hr acre cfs 0.85 0.291667 12.2 3.024583 0.85 0.291667 8.8 2.181667 0.85 0.291667 8.4 2.0825 0.85 0.291667 12.1 2.999792 cumulative area 41.5 10.28854 Depth of flow in typical swale feeding in to pond Width - ft depth - ft slope flow - cfs 10 0.5 0.005 12.2 Mannings roughness - 0.011 Hydraulic radius = A/F =2.5/10 = 0.25 for 6" deep flow Per the Chezy-Manning equation: v=( 1.49 * (rH 2!3)* s° .5)/n v=(1.49 *0.397*0.0707)/0.011 v= 3.801925 feet/sec for 6" deep flow Q=v*A 19.00962 cfs for 6" deep flow Q=v*A 15.84135 cfs for 5" deep flow Q=v*A 3.960338 cfs for 2" deep flow Q=v*A 1.584135 cfs for 1" deep flow Swales will flow at 1.5" deep or below for design rainfall, at swale with highest flow Note: This might cause hydroplaning if the swale were on a public road, but these swales are inside the plant fence and are not accessible to public drivers, and plant vehicles are not allowed to drive fast enough to hydroplane. Exhibit N Preliminary Drainage Report The existing Lucerne Gas Plant site and the Lucerne II Gas Plant Expansion are located on a relatively flat site draining generally south and southeast towards the South Platte River. The plant site falls within the drainage watershed of Sand Creek, which drains generally south towards the South Platte River. The Sand Creek watershed is approximately 1 to 2 miles wide (measured east -west) and is about 5 miles long (measure north -south). The plant site is located on the west side of the watershed (about a half -mile west of Sand Creek) and is in the approximate center of the watershed measured north -south. Most of the watershed is generally flat, with square -mile sections within the watershed generally draining towards borrow ditches running parallel to County Roads along section lines. Runoff from the site currently drains towards County Road 43 immediately east of the site, and towards County Road 64 running along the south property line. 1. Current Off -site to On -site Drainage: Because an abandoned railroad embankment runs along the north boundary of the project site, stormwater from off -site, coming from the north, is routed around the site to the County Road 43 borrow ditch. No significant runoff enters the site from off -site. Such conditions currently exist and will not change as a result of this project. 2. Current On -site Drainage: Within the existing Lucerne Gas Plant, stormwater runoff is generally directed south and southeast via surface flow to collector ditches along the southern and eastern edges of the site. Water is then conveyed via these ditches to an existing shallow detention pond located a few hundred feet east of the plant. Although the detention pond will be relocated in the proposed construction of the expansion project, no other changes to the existing on -site drainage will be required. On -site drainage for the proposed expansion flows via surface drainage to the south and southwest across undeveloped fields on the north side of the parcel and an irrigated cornfield on the south side of the parcel. The general drainage of the expansion site will remain flowing to the south, with minor modifications as discussed below. 3. Current On -site to Off -site Drainage: Runoff from the location of the proposed expansion plant flows off -site into an existing irrigation ditch in the approximate middle of the parcel, and via surface flow to the borrow ditches running along County Roads 43 and 64. From there, stormwater flows into Sand Creek and eventually into the South Platte River. The general drainage patterns will remain unchanged in this project. 4. Proposed On -site Drainage: In the proposed site development, the existing stormwater detention pond will be relocated several hundred feet southeast so that it can collect all the stormwater runoff from the new and existing plant sites. The site will be graded generally flat, with a slight ridge running north - south along the center of the new process area. Water surface flows both east and west away from this ridge so that runoff and winter snowmelt does not collect around the main process area. Runoff will be collected in shallow swales on the east and west sides of the process area, and those swales will drain to the new detention pond. The swales will be located around the periphery of the expanded plant in such a way as to collect runoff from all process areas associated with both the existing plant and the new expansion plant. The design of the new detention pond will be based on collecting 100% of the runoff predicted from a 25 - year, 24 -hour duration storm. After the rain from a large storm subsides, a plant operator will check the water in the pond for any sheens indicative of hydrocarbon contamination, If any contamination is found, the contaminated water will be removed by DCP and hauled to a refinery. Non -contaminated water can then be released via a normally -closed manual valve to flow off -site in a controlled manner. Miscellaneous culverts will be installed around the proposed expansion site where needed for pedestrian and vehicular traffic during rainstorms. Erosion control best practices will be employed prior to construction in compliance with engineered drawings and a County Public Works Permit for grading of the site. Post -construction, permanent erosion control measures will be finalized, and the areas outside of the perimeter fence will be reseeded with native seed mixes. PRELIMINARY DRAINAGE REPORT 4-25-13 For: DCP Lucerne II Gas Plant 31495 Weld County Road 43 Lucerne, CO 80634 Owner: DCP Midstream 3026 4`h Avenue Greeley, CO 80631 970-378-6372 Paul D. Park, Manager of Compliance pdpark@dcpmidstream.com Stormwater Manager and SWPPP Contact(s): Christina White White Engineering, Inc. c/o DCP Midstream 3026 4`r' Avenue Greeley, CO 80631 503-819-1222 cwhite@dcpmidstream.com Preliminary Drainage Report Preparation Date: April 25, 2013 Estimated Project Dates: Start of Construction: 10/ 01 / 2013 Completion of Construction: 10/ 01/ 2014 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 Table of Contents I. GENERAL LOCATION AND DESCRIPTION 1 II. DRAINAGE BASINS AND SUB -BASINS 2 III. DRAINAGE DESIGN CRITERIA 3 IV. DRAINAGE FACILITY DESIGN 7 V. WETLAND PRESERVATION AND MITIGATION 9 VI. CONCLUSIONS 9 VII. APPENDICES 10 ii Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 I. GENERAL LOCATION AND DESCRIPTION 1. Location a. Property description: A part of Section 28, Township 6 N, Range 65 W of the 6th P.M., County of Weld, State of Colorado. (SE 1/4 of Section 28) b. Local streets within and adjacent to the subdivision: There are no public roads within the parcel. Access to the site will be via an existing access point on WCR 43, about a'/ mile east of the site. c. Major drainage ways, facilities, and easements within and adjacent to the site: There are no such existing features within the project site. d. Locations of other utilities: Electrical utility lines currently serve the project site and are shown on the site plan. e. Names of surrounding developments: There are none. The parcel is surrounded by irrigated cropland. 2. Description of Property a. Area in acres: The property encompasses 92.79 acres overall, including 33 acres in the area that will be disturbed in this project. There are 41.5 acres in the total developed project area at the conclusion of the project. b. Ground cover: A portion of the site is the existing Lucerne Gas Plant, which is graveled. The remainder of the site is irrigated cropland. c. Major drainage ways: There are none on the parcel. Excess stormwater typically runs downhill and generally towards the southeast into Sand Creek about a'''A mile east of the site, where it is eventually conveyed to the Cache la Poudre River about a mile and a half south of the site. 1 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 d. General project description: A 41.5 -acre portion of the subject parcel will be developed into a new, expanded natural gas compressor station with associated equipment, buildings, and a 70 -foot communications tower. The remainder of the site will remain as irrigated cropland. e. Irrigation facilities: The undeveloped portion of the site is serviced by an existing irrigation network fed by the Greeley No. 2 canal to the north and an existing irrigation ditch network. There is an existing concreted irrigation canal running east -west along the north edge of the subject property, parallel to the entrance road to the existing site. This canal will be left unchanged in this project. f. Proposed land use: An expansion to an existing natural gas compressor station (industrial). g. Groundwater characteristics: The groundwater at the site will be unaffected and left unchanged as a result of this project. II. DRAINAGE BASINS AND SUB -BASINS 1. Major Basin Description a. Reference to major drainage way planning studies, etc.: The FEMA FIRM map shows the project site located well above the 100 -year floodplain. b. Major basin drainage characteristics, existing and planned uses: The Sand Creek watershed extends about 10 miles north of the project site and drains generally southward before feeding into the Cache la Poudre River. In the reach of the creek nearest the site, the creek is exceptionally flat and meandering. The areas around the project in all directions are agricultural and consist primarily of flat, irrigated cropland. The adjacent properties are all currently agricultural in use. 2 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 c. Identification of all irrigation facilities within the basin, which will influence or be influenced by the local drainage: The basin has an extensive irrigation network fed by irrigation canals and distribution ditches. However, this project will have no effect on the irrigation system. Runoff from the project site will not increase due to this project. In fact, because 100% of the runoff from a 100 -year storm will be temporarily detained within the site, the surge of runoff that typically affects downslope property with excess water from storms will be slightly reduced by this project. Excess stormwater will be released after a day or two, when it can more easily be accommodated by existing drainage ways, creeks and rivers. There is no particular effect of any irrigation network on the design of this project, neither upslope nor downslope of the site. 2. Sub -basin Description a. Discussion of historic drainage patterns of the property: Historically, most stormwater soaked into existing land in this area because the area is flat with sandy and sandy -loam soils. Excess stormwater runs generally southeast to Sand Creek and then south into the Cache la Poudre River. No significant change to that pattern has occurred recently because the area around the site is largely undeveloped cropland. No change to that pattern is proposed in this project. Because the existing access road and abandoned railway grade run along the north edge of the property, excess stormwater coming from north of the property is diverted to the east and around the property. There are no offsite-to-onsite stormwater flows on the property (neither currently, nor proposed in this project.) b. Discussion of off -site drainage flow patterns and impact on development under existing and fully developed basin conditions as defined by the Planning Department: DCP's intent in constructing this gas plant site is to have no significant impact on development upstream or downstream of the site. No changes to the drainage patterns around the site are proposed. Because DCP intends to temporarily detain all of the runoff from a 100 -year storm within the plant site (for a day or two), the project will not add to any downstream runoff during extreme storms. The water will be released more slowly, after the peak of the flood flows subside. 3 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 III. DRAINAGE DESIGN CRITERIA 1. Development Criteria Reference and Constraints a. Discussion of previous drainage studies and/or pertinent master plans for the site: There are no such studies for the site. b. Discussion of the effects of adjacent drainage studies: DCP is not aware of any such studies. The surrounding land is all agricultural cropland in use, and our project will have no significant off -site effects, c. Discussion of the drainage impact of site constraints such as streets and transportation facilities, utilities, existing structures, and the development or site plan: There are no drainage impacts from any of these features. The nearest roads are'/ mile away from the project site. The only structure on the parcel, other than existing gas plant buildings and equipment, is an existing farmstead on the eastern edge of the parcel. 2. Hydrological Criteria a. Identify design rainfall: The temporary detention pond was designed to retain 100% of the runoff from a 24- hour/100-year storm, or 4 watershed inches. For design of culverts and swales, DCP used a 2 -year peak rainfall of 3.8 inches/hr. b. Identify runoff calculation method: DCP used the rational method (Q= C*I*A) for peak stormwater flows. c. Identify detention discharge and storage calculation method: DCP assumed 100% of the stormwater runoff will be temporarily detained in the pond. This is about eight times as much stormwater runoff storage as would normally be required using the WQCV method. d. Identify design storm recurrence interval: DCP designed and sized the detention pond for a 100-year/24-hour storm. 4 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 e. Discussion and justification of other criteria: Rather than design for a WQCV pond and allow the excess water to go through the spillway, DCP has voluntarily increased the size of the pond to allow 100% of the volume to be detained. The reason for that is that we want to double check the runoff after the storm is over to ensure there is no hydrocarbon sheen that would indicate that there has been an inadvertent spill or discharge within the site. In the event of such contamination, DCP would use a vacuum truck to remove the contaminants before allowing the runoff to proceed off site. This method is much more conservative than that required in the Urban Storm Drainage Criteria Manual. f. Discuss if off -site flows will be routed around the proposed site or over the spillway for the 100 -year developed condition. Off -site flows from land upslope (north) of the site are currently routed east around the site by the existing access road and abandoned railway grade located along the north edge of the property. This routing is unchanged in this proposed project. Off -site stormwater will continue to flow around the east side of the property as before. 3. Hydraulic Criteria a. Identify various conveyance capacity references: The only storage facility involved is the stormwater detention pond DCP proposes at the downslope (south) end of the project site. The only conveyances within the site will be earthen ditches used to collect onsite stormwater runoff and convey that runoff to the proposed stormwater detention pond. None of these ditches will be on public property, and all are inside the perimeter fence of the project. There is one culvert proposed at the proposed new access point off of the County road. b. Discussion of other drainage facility design criteria used: None 5 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 c. Identify detention outlet type, including 100 -year water surface elevation, and spillway/overflow facility. The detention facility is a shallow graveled pond with earthen banks that provide about 1.5 feet of freeboard above a concrete spillway. The pond is sized to detain 100% of a 24- hr/100-year storm (about 8 times the capacity of the WQCV requirement). The concrete spillway is a concrete weir with a concrete outflow, and is sized to safely convey a 100 -year flow, even after the pond is filled by a separate 24-hour/100-year storm volume. The outlet will have an 8" diameter outlet pipe with a normally closed gate valve accessible at the spillway. After large rainfalls, a DCP operator will examine the pond for evidence of any inadvertent spills or contamination, and if no contamination is evident, will open the valve to drain the pond. By draining the pond slowly a day or so after a big rain, downstream flooding and sediment contamination will be reduced as compared to letting much of the excess stormwater flow downstream during the actual storm. Calculations and details are attached in the Appendices. d. Identify water quality outlet configuration DCP does not propose a traditional water quality outlet configuration, where excess stormwater flow above the WQCV flows through the pond during the design storm. Rather, we propose to capture 100% of a 24-hr/100-year storm within the pond. Any flows above that will flow over the spillway. After the design storm subsides, a DCP operator will examine the detained water for evidence of inadvertent contamination. If no contamination is evident, the operator will release the water via an 8" diameter manual valve. This will provide superior water quality control, and will provide an additional measure of safety against possible accidental leaks and spills within the plant. Calculations for the outlet are included in the Appendices. e. Identify culverts, including diameter, type and slope. DCP proposes no new culverts other than a single 24" diameter reinforced concrete culvert at the east property line for a new access road. The culvert will be about 150 feet long to accommodate 70 -foot -turn radii into and out of the plant. The culvert inlet and outlet will be protected with 10 -foot square pads of 6" to 8" rip rap in accordance with County standards. Calculations and details are included in the Appendices. The slope of the culvert will match the existing grade of the road borrow ditch — approximately 1%. In all other areas within the plant, vehicles will cross ditches using concrete drivable swales rather than culverts. This will limit the depths of the ditches required to drain the main portions of the plant and will allow maintenance vehicles to drive over and through the shallow ditches when necessary. 6 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 f. Identify sewer inlets, manholes, etc. DCP proposes no underground storm sewer features. Instead, we propose shallow stormwater runoff ditches that are crossed, where necessary, by drivable concrete swales. None of the features are installed in public rights -of -way or in areas accessible by the public. g. Discuss permanent erosion control features. The stormwater detention pond and the spillway/outlet are the only permanent erosion control features. h. Discuss and justify criteria and/or calculation methods for water quality, check dams, drop structures, rundowns, etc., that are not presented in the Weld County Code. Not applicable. We believe the criteria and design methods presented meet or exceed the Weld County Code. 4. Waiver/Variance from Criteria a. Identify provisions by section number for which a waiver or variance is requested: No waivers of County regulations are requested or required. 5. Stormwater Quality Considerations a. DCP has proposed a temporary detention pond that is over 8 times the size of that required by the WQCV calculations. This will have the added benefit of improving the water quality of the stormwater released from the pond. b. Grading, Sediments and Erosion Control plans and details are included in the plan set submitted with this application. IV. DRAINAGE FACILITY DESIGN a. Facility design concept and drainage patterns: DCP proposes a stormwater detention pond at the downhill (south) side of the project site to capture 100% of the runoff from a 100-year/24-hour storm. The project site drains south towards the pond (both before and after development). Water from the pond outlet is released after major storms and continues to flow south across irrigated cropland in the same patterns as pre -development. 7 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 b. Compliance with off -site runoff considerations: This concept basically reduces stormwater runoff during the initial storm to nearly zero. Excess stormwater will be released after it is inspected by a technician a day or so after the storm. c. Discuss the contents of all tables, charts, figures, or drawings in the report. The only attachments are the calculations and the drawings. They are self-explanatory. d. Discuss anticipated hydraulic structures (channels, pipes, rundowns, etc.). The only hydraulic structures are small, shallow ditches within the plant fence designed to convey stormwater to the pond, and the pond itself (including concrete spillway and 8" diameter pipe outlet with a normally closed valve.) One culvert is proposed at the new County road access point. e. Anticipated and proposed drainage patterns: The existing gas plant drains southeast towards an existing detention pond. Since that pond is located in the area where DCP proposes to build the new plant expansion, the existing detention pond will be filled and a new pond constructed at the south end of the project site. 100% of the overall new proposed site drains south towards the new proposed storage detention pond. During construction, a channel will be dug to capture runoff from the contractor laydown staging yard as well. Runoff after leaving the pond will be allowed to flow onto the existing field downslope from the plant (where it currently drains). f. Water quality considerations: By temporarily detaining 100% of the runoff for a couple of days, the water will be allowed to settle and downstream sedimentation will be reduced. g. Discuss maintenance access and aspects of design, including maintenance plan. The only maintenance envisioned is that if sediment starts to fill in the pond, DCP will have a backhoe operator dig out the sediment and relocate it elsewhere on site, and reuse the sediment for spreading on the roads following winter ice and snow storms. DCP will have the backhoe dig out the sediment when it gets about 6" deep or deeper. Because we propose no culverts within the plant itself, no particular maintenance will be required to keep the driveways within the plant clean. If the culvert at the County Road entrance becomes clogged, DCP will clean it out using a water jet. 8 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 h. Provide copies of CDPHE, CAFO, DRMS, or State Engineer's permit applications where applicable. Not applicable at this time. Note that the pond depth, volume and storage durations are below the thresholds at which the State Engineer requires a permit. 2. Specific Details a. Detail drainage problems encountered and solutions at specific design points: There were no particular problems associated with the drainage at this site, other than the fact that it is very flat, and arranging the drainage to get to the pond was challenging. Rather than install numerous culverts within the site, DCP proposes concrete drive -over swales in locations where stormwater must cross the road. This allows for flatter drainage ditches without elevating the process area of the site excessively. b. Detention storage and outlet design: The pond was designed to hold all the runoff from a 100-year/24-hour storm. To prevent infiltration in the event of an inadvertent spill or leak, DCP will line the pond with a 12" clay liner. The outlet includes a spillway set at the 100 -year elevation. The spillway is wide enough to accommodate a 100 -year flow that might occur at the conclusion of a 100 -year storm. An 8" diameter steel irrigation gate valve will be installed to allow a technician to drain the pond after the pond water has been inspected for contamination. c. Provision of stormwater quality facilities: The detention pond will serve as the stormwater quality facility. d. Maintenance access and aspects of facility design: Maintenance equipment can enter the pond along the north side of the pond. Because there should be no activities within the pond, erosion of gravel into the pond should be minimal, but if there is any erosion, DCP will clean it out as required. e. Provision of easements and tracts for drainage purposes, including conditions and limitations for use: Since the property encompassing the plant and the surrounding parcel is 100% owned by DCP, there is no need for access or easements. DCP assumes that the County will not want DCP to use the pond for material storage or buildings. 9 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 V. WETLAND PRESERVATION AND MITIGATION (NOT APPLICABLE) VI. CONCLUSIONS 1. Compliance with Standards DCP believes that the proposed design complies with the Urban Storm Drainage Criteria Manual as adopted by Weld County. 2. Drainage Concept Effectiveness of drainage design to control damage from storm runoff flooding: Since DCP reduces stormwater runoff to zero during and immediately after the storm, we believe this shows an effective design. 3. Intent to inform neighbors of affects to irrigation systems DCP believes there will be no effects of any kind to any irrigation system outside the property. 4. Reference all criteria and technical resources used. No particular resources were used beyond the Weld County Code and the USDCM. 10 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 VII. APPENDICES 1. Hydrologic Computations a. Vicinity Map Attached on USR title sheet. b. FIRMette Map Attached. c. Soil Survey Map Attached on USR title sheet. d. Rainfall Map Attached. e. Land use assumptions regarding adjacent properties: Since none of these properties drain onto the project site, DCP made no assumptions regarding their future land use. Since DCP proposes no effects on stormwater runoff that would affect downslope sites, we also made no assumptions regarding the future land use of those properties. f. Initial and major storm runoff at specific design points: The only design point of consequence in this project is the outlet of the detention pond dam. DCP assumes the outlet is closed throughout a 100-year/24-hour storm. After inspecting the water for evidence of contamination, a DCP technician will release the water by opening a valve within 48 hours of major storms. g. Historic and fully developed runoff computations at specific design points: The fully developed runoff will be zero during the storm. DCP will open a valve to release the water within 48 hours at a low rate set to drain in about 24 to 40 hours. There isn't much runoff from this area now because it is in the middle of flat, irrigated cropland, and most of the water (98% during most storms) is soaked into the ground rather than running off. h. Hydrographs at critical design points: DCP did not do a hydrograph at the pond outlet because it would be a flat line on the zero axis during and immediately after the storm. 11 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 i. Time of concentration and runoff coefficient for each basin: The time of concentration will be on the order of 30 to 40 minutes. The reason it is relatively short is because the gravel doesn't soak in as much water as native grassland does. DCP has found published runoff coefficients ranging from 50% to 98% for graveled surfaces. Since most of the site gravel is uncompacted, washed gravel, DCP used 85% for the runoff coefficient (i.e., 85% of the stormwater will run off, 15% will soak into the ground). j. Computer model input and output. No computer model was necessary for this design. We capture 100% of the runoff from a 24- hr/100-year storm, and then slowly release the water after the storm subsides and after we have checked the water for any inadvertent contamination. 2. Hydraulic Computations a. Culvert sizing: No culverts are proposed, other than the single 24" diameter RCP culvert proposed at the County Road access point. b. Storm inlet sizing: There are no existing storm inlets, and none are proposed. c. Open channel design. Check structure and/or channel drop design: Other than the spillway outlet, there are no structures proposed. Since no channels are in publicly accessible areas, there are no particular life -safety issues involved. All the channels are shallow enough to drive through during storms. A swale calculation is attached. d. Riprap design. We will have a detail for 6" to 8" riprap with Mirafi 600X geotextile fabric and gravel bedding on the construction drawings. From experience, this is adequate for rundowns that only extend down about 4 feet to the base of the pond. e. Detention pond area/volume calculations, including 100 -year surface elevation and overflow facility (spillway): Attached. 12 Preliminary Drainage Report DCP Lucerne II Gas Plant 4-25-13 f. Downstream spillway/outfall capacity: Downstream flows will be limited to slow releases a day or two after major storms via an 8" diameter pipe into the cornfield below the site. No other effects on downstream properties are anticipated. Calculations are attached. g. Gutter and street capacity: There are no gutters or streets within the project or affected by the project. h. Computer models: No computer models were required for this design. 3. 24"x36" drawings and maps a. Historic Drainage Basin Map: b. Fully Developed Drainage Basin Map: c. Construction drawings, including sections at swales and channels: d. Construction drawings and details of detention pond: e. Grading Plan, including TOC for buildings: f. GESC plans including all BMPs: g. Details for pond outlet features: h. Show all culverts w/design info on construction dwgs: i. Show locations of all existing utilities: j. Show manhole and inlet inverts: k. Miscellaneous hydraulic structures/features: End of drainage report. 13 Attached Attached Attached Attached Attached Attached Attached Attached Attached Not applicable Not applicable Hello