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Home My WebLink About20192736.tiffUSE BY SPECIAL REVIEW (USR) APPLICATION DEPARTMENT OF PLANNING SERVICES * 1555 N. 17TH AVENUE * GREELEY, CO 80631 WWW.we1dgov.com * 9704100-6100 * FAX 97O-3O4i6498 FOR PLANNING DEPARTMENT USE: AMOUNT APPLICATION RECEIVED BY DATE RECEIVED: CASE # ASSIGNED: PLANNER ASSIGNED: Parcel Number: 0 0 4 3_ 3 3 i 0 _ 0 0_ 0 0 2 Address of site: TBD Legal Description: NW 1/4 NW 114 Zone District: AG Acreage: 12,811 FEESS OF THE PROPERTY: Name: John L. Peters Company: Peters 313 Ranch, Inc Phone #: (970) 895-2305 (A► 12 digit number on Tax ID. information, obtainable at www.ireIdgov.com). Section: 33 Township:1 N Range: 63 W Floodplain: '' J eological Hazard: yossi Q Airport Overlay: YON Street Address: 57851 County Road 81 City/State/Zip Code: Grover, CO 80726 Name: Email: NIA Company: Phone It: Street Address: City/State/Zip Code: Name: Company: Phone ##: Street Address: City/State/Zip Code: Email: Email: APPLICANT OR AUTHORIZED AGENT: (See below: Authorization must accompany all applications signed by Authorized Agents) Name: Tracey Jensen Company: Summit Midstream Niobrara, Phone It (970) 987'4538 Street Address: 707 Wapiti Ave., Ste. 202 City/State/Zip Code: Rifle, CO 81650 -- - Email: tiensen@summitmidstream.com PROPOSED USE: Proposing a compressor station to compress up to 30MM FD of rich, wet natural gas from a variety of producer well pads. The facility will operate 24/7. 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 cored 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 indicating that the signatory has to legal authority i sign for the ration. Si gL #'' re: Owner or Authorized Agent Print Name Date Signature: Owner or Authorized Agent Date Print Name Rev 4/2016 USE BY S.' ECIAL REVIEW (USR) QUESTIONNAIRE Planning Questions: Planner on Call 970-400-6100 1. Explain, in detail, the proposed use of the property. This compressor station will compress up to 301\AMCFD of rich, wet natural gas from a variety of producer well pads at pressures below 50psig. The station is designed to handle natural gas liquids that fall out in the pipeline or through the compressors and after the water is separated, the liquids will be pumped through a new pipeline to our Hereford Ranch Processing Plant east of this station. The gas stream will be dehydrated through a TEG system after compression and will discharge into a new gas pipeline up to 1200psig that feeds into our Hereford Ranch Processing Plant. The station will include all necessary inlet and discharge filters as well as new electrical infrastructure. 2. Explain how this proposal is consistent with the intent of the Weld County Code, Chapter 22 of the Comprehensive Plan. The Weld County Code, Chapter 22, Comprehensive Plan, has been reviewed and the proposed compressor station is consistent with the intent of the Comprehensive Plan, including Land Use, Environmental Resources and Natural Resources. Impacts to environmental resources such as air, water, waste, noise and public health would be minimal and only during construction. 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 parcel is located within Division 1— A (Agricultural) Zone District. Per the County Code, Oil and Gas Facilities may be developed within Division 1-A, with submittal and approval of a Weld County Oil and Gas Location Assessment (W0GLA.). Summit Midstream Niobrara, LLC has submitted a WOGLA for review. Describe what type of land uses surround the site. Explain how the proposed use is consistent and compatible with surrounding land uses. Currently there are 2 Oil & Gas Industry pads north of us and a 3rd in the permitting process. What are the hours and days of operation? 24 hours a day, 7 days a week. 6. List the number of full time and b'or part time employees proposed to work at this site. No fulltime me employees on site. Operators from our Hereford Facility will service this station. 7. If shift work is proposed, include the number of employees per shift. N/A , List the number of people who will use this site. Include contractors, truck drivers, customers, volunteers, etc. No fulltirne employees but approximately 80 during construction phase. 9. If this is a dairy, livestock confinement operation, kennel, etc., list the number and animals. N/A type of 10. Describe the type of lot surface and the square footage of each type: (e.g. asphalt, gravel, landscaping, dirt, grass buildings) Approximately 25% gravel and 75% dirt. 1.1. How many parking spaces are proposed? How many handicapped (ADA) parking spaces are proposed? N/A 12. Explain the existing and proposed landscaping for the site. No vegetation will be in our station for safety (fire hazard) reasons. 13. Describe the type of fence proposed for the site (e.g. 6 -foot chain link with earth tone slats) We will have 6 -foot tall fencing with 3 strand barbed wire on top. 14. Describe the proposed screening for all parking and outdoor storage areas. N/A 1. Explain any proposed reclamation procedures when termination of the Use by Special Review activity occurs. If the station is removed in the future, we will reclaim to original nature. 16. Who will provide fire protection to the site? Grover Volunteer Fire Department 17. List all proposed on -site and off -site improvements associated with the use (e.g. landscaping, fencing, buildings, drainage, turn lanes, etc.) and a timeline of when you will have each of the improvements completed. Fences, buildings and drainage will all be completed in approximately 5-6 months. Engineering Questions: 970-400-3750 1. Describe how many roundtrips per day are expected for each vehicle type: Passenger Cars/Pickups, Tandem Trucks, Semi-Truck/Trailer/RV (Roundtrip = 1 trip in and 1 trip out of site) 1-2 roundtrips in pickup trucks for operations staff, 3-4 round trips for Semi Trucks with water hauling trailers. 2. Describe the expected travel routes for site traffic. Expected travel route is off WCR 136.5 onto an existing oil field road. 3. Describe the travel distribution along the routes (e.g. 50% of traffic will come from the north, 20% from the south, 30% from the east, etc.) 100% of Traffic comes from the east. 4. Describe the time of day that you expect the highest traffic volumes from above. Heaviest traffic times are between 7am and 4pm. S. Describe where the access to the site is planned. We have existing access off WCR 136.5 but will apply for additional access road Drainage Design: Detention pond summarized in a drainage report is required unless the project falls under an exception to stormwater detention requirements per code section 23-12-30 F.1. The proposed detention pond has enough capacity for a 100 -year storm, complying with. Section 23, Article VII of the Weld County, Colorado building code. The complete drainage report is provided in the appendix section of the USR application. Environmental Health questions: 970e304-6415 x2702 1. What is the drinking water source on the property? Bottled water 2. What is the type of sewage disposal system is on the property? Porta Johns 3. If storage or warehousing is proposed, what type of items will be stored? N/A 4. Describe where and how storage and/or stockpile of wastes, chemicals and/or petroleum will occur on this site? Engineered tanks with secondary containment systems. If there will be fuel storage on site indicate the gallons and the secondary containment. State the number of tanks and gallons per tank. N/A 6. If there will be washing of vehicles or equipment on site indicate how the wash water will be contained. N/A 7. If there will be floor drains indicate how the fluids will be contained. N/A 8. Indicate if there will be any air emissions. (e.g. painting, oil storage, etc.) The Brahma Compressor Station will have air emissions associated with the proposed equipment. Summit Midstream Niobrara, LLC submitted a construction permit application to the CDPHE on 02/11/2019 to seek authorization for the potential air emissions associated with this site. The construction permit application included all equipment with potential emissions above APEN (Air Pollutant Emission Notice) reporting thresholds found in Colorado Reg. 3 Part A. 9. Provide a design and operations plan if applicable. (e.g. composting, landfills, etc.) N/A 10. Provide a nuisance management plan if applicable. (e.g. dairies, feedlots, etc.) N/A 11. Additional information may be requested depending on type of land use requested. Building Questions: 970-400-6100 1. List the type, size (square footage), and number of existing and proposed structures. Show and label all existing and proposed structures on the USR drawing. Label the use of the building and the square footage. MCC Building —1,800 sq. ft. — Proposed House electric & control hardware and instrument air package— See USR drawing for further details Compressor Building— 11,050 sq. ft. — Proposed — House natural gas compressors and associated equipment — See USR drawing for further details. 2. Explain how the existing structures will be used for this USR? These structures are required for safe operations of the natural gas compressors and associated equipment. 3. List the proposed use(s) of each structure. MCC Building — This structure houses sensitive electrical components necessary for the operation of the site. Compressor Building — This structure houses the natural gas compressors. COLDER REPORT Drainage Report Brahma Compressor Station Weld County, Colorado Submitted to: CAM Integrated Solutions 385 Inverness Parkway, Suite 190 Englewood, CO 80112 Submitted by: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado, USA 80228 +1 303 980-0540 19117923-1-R-0 March 6, 2019 March 6, 2019 19117923-1-R-0 Table of Contents 1.0 CERTIFICATION OF COMPLIANCE 4 2.0 INTRODUCTION 5 3.0 SITE LOCATION AND DESCRIPTION 5 5 3.2 Site Description 5 4.0 HYDROLOGIC DESIGN CRITERIA 5 4.1 Regulations 5 4.2 Hydrological Criteria 6 5.0 DRAINAGE BASINS 6 5.1 Run-on Basins 6 5.2 On -site Runoff Basin ...6 5.2.1 Pre -development 6 5.2.2 Post development 6 6.0 DRAINAGE DESIGN 7 6.1 General Concept 7 6.2 Pre -development Runoff 8 6.3 Post -development Runoff 8 7.0 DETENTION POND 8 7.1 Pond Capacity 8 7.2 Outlet Structure 9 8.0 CONCLUSION 9 3.1 Site Location TABLES Table 1: NWLF Site Rainfall Event Data .............6 Table 2: Post -development Site Imperviousness 7 Table 3: Pre -development Peak Flow Runoff ...8 Table 4: Post -Development Peak Flow Runoff 8 GOLDER ii March 6, 2019 19117923-1-R-0 Table 5: Required Detention Basin Volumes 8 Table 6: Detention Basin Stage -storage Volumes 9 FIGURES AND DRAWINGS Figure 1: On -site Runoff Basin (Pre -development) Figure 2: On -site Runoff Basin (Post -development) Drawing BRA -SW -0002: Developed Drainage Plan Drawing BRA -SW -1015: Detention Pond Spillway and Overflow Plan, Sections, and Details APPENDICES APPENDIX A Custom Soil Resource Report for Weld County, Colorado, Northern Part, Brahma Compressor Station APPENDIX B NOAA Point Precipitation Data APPENDIX C Pre -development Runoff Calculations APPENDIX D Post -development Runoff Calculations APPENDIX E Detention Pond Capacity Demand Calculations APPENDIX F Outlet Structure Design Calculations APPENDIX G Overflow Weir Design Calculations 4, GOLDER iii March 612019 19117923-1-R-0 1.0 CERTIFICATION OF COMPLIANCE The Weld County Certification of Compliance is included on the following page. Ati> GOLDER 4 CERTIFICATION OF COMPLIANCE ENGINEERING DESIGNED TO WELD COUNTY CODE STANDARDS AND CRITERIA I Jeff Rusch Consultant Engineer for CAM Integrated Solutions, on behalf of Summit Midstream ("Applicant"), understand and acknowledge that Applicant is seeking land use approval of the proposed Brahma Compressor Station ("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 4461:4741:364:**Scte • is 00468E 1 = :f r a (ell dp. rA{{i. •A s J Lr i f 41 Eng41/er' Sgnature I ) Describe 2) Describe 3) Describe the the why Weld it proposed is County not possible alternative Code criteria to meet with VARIANCE a County rational variance REQUEST is Code. which being requested. supports the intent of the Weld County Code. of which the Weld engineering 1 properties specific Planning understand constraints. and Director and the agree public. Approval that I understand indicated the intention of the if this when signed Code variance by director is request to reduce impacts is approved or appointee: it of development is not precedent on neighboring downstream setting and is based on site Planning Director Name Signature Date of approval 1/13/15 March 0, 2019 19117923-1-R-0 2.0 INTRODUCTION This Drainage Report is prepared on behalf of the applicant, Summit Midstream, in support of a Weld County Use by Special Review (USR) permit application for the proposed Brahma Compressor Station (hereinafter referred to as the Compressor Station). The new Compressor Station will be used to compress rich, wet natural gas from a variety of product well pads and discharge through new pipelines to the Hereford plant. The purpose of this Drainage Report is to summarize stormwater management improvements proposed as part of the development of the Compressor Station. A site development plan is provided in Drawing BRA -SW -0002. The new Compressor Station will result in an increase in imperviousness of the site, which will result in additional peak stormwater runoff. This Drainage Report summarizes the increase in runoff and the design of stormwater management facilities required to mitigate downstream impacts. 3.0 SITE LOCATION AND DESCRIPTION 3.1 Site Location The proposed Compressor Station site is located in Weld County, Colorado, approximately 7.4 miles west of Hereford, Colorado, in the NW1/4 /4 of the NW1/4 /4 of Section 33, Township 12 North, Range 63 West of the 6th Principal Meridian. The site consists of approximately 12.8 acres located approximately 1.4 miles west of the western terminus of Weld County Road 136.5. The site is bounded to the west by the County Road 65 right-of-way. The Compressor Station site and surrounding land are zoned (A) Agricultural and are located in unincorporated Weld County. The site is in a non -urbanizing area of Weld County pursuant to the Weld County Code. There are no lakes, streams, or water resource facilities within the property. Existing access to the site is from a well pad service road extending west from the Weld County Road 136.5 terminus. 3.2 Site Description Natural, pre -development topographic elevations within the project area range from a high of approximately 5,494 feet above mean sea level (ft AMSL) along the western site boundary to a low of 5,481 ft AMSL in the northeast corner of the site. Natural topography generally slopes between 1% and 3% from west to east-northeast The United States Department of Agriculture (USDA) National Resources Conservation Service (NRCS) designates the surficial soil types at the site as Ascalon fine sandy loam (NRCS 2018) at slopes varying between 0 and 6%. Olney fine sandy loam soils are classified under Hydrologic Soil Group B, are well drained with low runoff potential, and have moderately high to high capacity to transmit water. The Custom Soil Resource Report for Weld County, Colorado, Southern Part is provided in Appendix A. 4.0 HYDROLOGIC DESIGN CRITERIA 4.1 Regulations The drainage calculations summarized in this Drainage Report were prepared in compliance with applicable design criteria set forth in Chapter 8, Article XI of the Weld County Code, the Urban Storm Drainage Criteria Manual (USDCM), and the Weld County Storm Drainage Criteria Addendum to the Urban Storm Drainage Criteria Manual. More specifically: Peak flow site runoff from pre- and post -development site conditions was calculated from the 10 -year and 100 -year, 1 -hour point precipitation data; > GOLDER 5 March 6, 2019 19117923-1-R-0 A detention pond was sized to provide storage of runoff from the 100 -year, 1 -hour storm event and the water quality capture volume (WQCV); The detention pond outlet was designed to release at a rate no greater than the pre -development runoff rate from the 10 -year, 1 -hour storm event; and iJ The detention pond emergency weir was designed to convey the 100 -year, 1 -hour post -development storm event at a depth less than 6 inches. The Rational Method (USDCM spreadsheet UD-Rational-2.0) was used for calculating peak runoff for the pre - and post -development conditions. The detention pond was then sized using the USDCM spreadsheet UD-Detention_v3.07. 4.2 Hydrological Criteria Point precipitation data was obtained from the National Oceanic and Atmospheric Administration's (NOAA) Precipitation Frequency Data Server website. The values, summarized in Table 1, were based on NOAA Atlas 14, Volume 8, Version 2.0 (NOAA 2013) and the latitude and longitude of the site. The NOAA Atlas data report is provided in Appendix B. Table 1: NWLF Site Rainfall Event Data Storm Event Rainfall Depth (inches) 10 -year, 1 -hour 100 -year, 1 -hour 1.43 2.47 5.0 DRAINAGE BASINS 5.1 Run-on Basins Run-on basins located upgradient (i.e., west) of the Compressor Station site are currently cut off from the site by the Weld County Road 65 right-of-way embankment. 5.2 5.2.1 On -site Runoff Basin Pre -development On -site drainage historically flows from west to east-northeast via sheet flow. The pre -development on -site drainage basins are approximately 12.8 acres in total size and have natural slopes ranging from 1 to 3%, as shown in Figure 1. The pre -development imperviousness of the site was estimated at 2%. 5.2.2 Post -development The development of the Compressor Station will increase on -site runoff due to the increase in imperviousness of the site. Post -development drainage basins were delineated, as shown in Figure 2 and summarized below: Basin 1 (7.5 acres), which will drain to the detention pond in the northeast corner of the site, will have an increase in site runoff due to the increase in site imperviousness. The developed site will be graded from the southwest to northeast at an approximately 1% slope. The site will consist of gravel driving surfaces, gravel 4 GOLDER 6 March 6, 2019 19117923-1-R-0 working surfaces, and equipment pads. The developed imperviousness for Basin 1 will be increased to 45.5% versus the pre -development imperviousness condition estimated at 2%. Basins 2 through 5 drainage (4.9 acres total) will be routed around proposed site development via diversion berms and returned to sheet flow downstream along historic flow paths. Table 2: Post -development Site Imperviousness Drainage Basin Type Post -development Area (ac) Imperviousness (%) Basin I Green Space 0 2 Gravel Roads 1.2 40 Gravel Site 5.6 40 Equipment 0.6 90 Detention Basin 0.2 100 Basins 2-5 Green Space 4.9 2 6.0 DRAINAGE DESIGN 6.1 General Concept The proposed stormwater management design for the Compressor Station site will generally maintain historic flow paths and location of discharge from the site. Runoff from the developed Compressor Station footprint sheet flows directly to the detention pond located in the northeastern (i.e., downgradient) corner of the site. Runoff from undeveloped portions of the site will be directed around the compressor site to the historical downgradient flow paths. The detention pond will have one outlet structure sized to discharge no more than the historic (pre -development) discharge rate from the 10 -year, 1 -hour storm event, and an overflow weir sized to pass the flow from the 100 -year, 1 -hour post -development storm event. Design calculations for stormwater controls are provided in Appendices C through G of this Drainage Report. > GOLDER 7 March 672019 19117923-1-R-0 6.2 Pre -development Runoff The historic, pre -development, peak flows for Basin 1 (discharging at the northeast corner of the site) for the 10 - and 100 -year, 1 -hour storm events are summarized in Table 3. Table 3: Pre -development Peak Flow Runoff Storm Event Peak Flow (cfs) 10 -year, 1 -hour 0.40 100 -year, 1 -hour 4.11 6.3 Post -development Runoff The post -development peak flows from Basin 1 for the 10- and 100 -year, 1 -hour storm events are summarized in Table 4. Table 4: Post -Development Peak Flow Runoff The post -development discharge is increased from the historic, pre -development peak flow due to the increase in site imperviousness. The increased flow will be routed to a detention pond and released from the pond at a rate no greater than the pre -development discharge rate. 7.0 DETENTION POND 7.1 Pond Capacity The runoff storage capacity demands from the 10 -year and 100 -year, 1 -hour storm event are summarized in Table 5. Table 5: Required Detention Basin Volumes Storm Event, Required Required Volume (ct) Volume (ac -ft) 10 -year, 1 -hour 16,423 0.38 100 -year, 1 -hour 43,822 1.01 The required detention pond volumes were used to size the detention pond to ensure that sufficient storage volume is provided. Table 6 provides a stage -storage capacity analysis of the proposed detention pond. 4 GOLDER 8 March 6, 2019 19117923-1-R-0 Table 6: Detention Basin Stage -storage Volumes Basin 00 Depth P_ ond (c Volume , Pond Volume (ac -ft) 5482.5 0 0 0 5483 0.5 4,468 0.10 5484 1.5 18, 015 0.41 5485 2.5 38,960 0.90 5485.2 2.7 44,137 1.02 5485.3 2.8 46,852 1.08 5485.5 3.0 52,534 1.21 7.2 Outlet Structure The detention pond was designed to release detained water from up to the 100 -year, 1 -hour storm event at a rate approximately equal to the historic flow rate from the 10 -year, 1 -hour storm event. The outlet structure will consist of a 30 -inch -diameter vertical riser pipe with perforated holes to allow water to drain via an 18 -inch -diameter smooth -walled discharge pipe. The outlet structure and discharge pipe were sized using the UD-Detention, v3.07 USDCM spreadsheet. The results show that the discharge structure will allow a maximum flow of 0.4 cubic feet per second (cfs) to discharge the pond during the 100 -year, 1 -hour storm event, which is equal to the pre -development peak discharge rate from the 10 -year, 1 -hour storm event. Outlet structure details are provided in Drawing No. BRA -SW -1015. An overflow structure from the detention pond is also provided to pass the 100 year, 1 -hour post -development peak flow rate at a depth of no more than 6 inches. The overflow weir structure was sized using Hydraflow Express. Overflow structure details are provided in Drawing No. BRA -SW -1015. 8.0 CONCLUSION 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 Use by Special Review (USR) permit application for the proposed Brahma Compressor Station. Off -site runoff will be routed around the proposed Compressor Station footprint via perimeter diversion berms and discharged along historic flow paths. The increased runoff from the developed site will be detained on site via a detention pond and released downstream from the site at a rate no more than the historic (i.e., pre -development) peak flow rate from the 10 -year, 1 -hour storm event. Any impacts that would be observed from the increased runoff due to development will be mitigated with the construction of the proposed detention pond and associated outlet structures. Golder and the G logo are trademarks of Golder Associates Corporation https:11golderassociates.sharepoint.comisites1104781/project filesl6 deliverables!reports/1-r-drainage_reportll-r-0_06mar19119111923-1-r-0- brahma_compressor_station_drainage_report_05mar19.docx 4 GOLDER 9 Figures and Drawings .eI18•h]AS Thin 1217hiPM I PrlomiEy:JFt h Ca A.?ttE4?•]S Time .21?:1fl PM CLIENT CAM INTEGRATED SOLUTIONS 385 INVERNESS PARKWAY, SUITE 150 ENGLEWOOD, Co 80112 CONSULTANT TITLE FIGURE 1 PRE —DEVELOPMENT DRAINAGE GOM,Q/PQN LEGEND S A • 0 50 100 150 FEET BASIN I.D AREA (AC) BASIN DELINEATION FLOW PATH LENGTH FN I PRDJEC`r CAM INTEGRATED SOLUTIONS BRAHMA COMPRESSOR STATION 385 INVERNESS PARKWAY. SUITE 150 WELD COUNTY, COLORADO ENGLEWOOD, CO 80112 ODNEULTANT GOLDER T,T,E FIGURE 2 POST -DEVELOPMENT DRAINAGE CONL7iiTION 0 2019-04-05 ISSUED FOR DRAINAGE REPORT REV, Y`dYY-MM-DD DESCRPT:ON MBR MBR SPS JAR DESIGNED PREPARED- ^ EViEWED APPROVED www.4oider.com PROJECT NO. 19117923 A C D E F C H J K L FA C P d1 6j 39 J6 37 36 35 34 33 32 3C 29 7? 23 22 20 19 18 17 15 15 14 13 11 9 • 6 5 4 .3 .? 1 A NOTES: SO' R.Q.R. FOR. COUFITY RDb 65 (BOOK 858/PAGE 273) (RECEP110F1 No.. 416872) DWG NO. i 1 •y -..I -Eve vim EAST. MAW YIOSTREMI GAS PIPEUNC (RECEPTION Ho. 4371843) srm PERIIETER SEPIA (3H:iv) (top 5411 NOD SEED. AS NECESSNR1') • 6' -or HIGH (MN.) CdiNN-LINK FENCE (NP. AROUND SITE PERIMETER) Man mow. 549, ' RAT, L 24' -Os WOE (INN.) INTERIOR SITE ACC'ES ORkE (GRAVEL SE1RFAC`_o) �T 5.112 \N I TRAFFIC Rfl ARROW (IYP,J 0 a 0 0 0 0 r I 1 37 It 0 I -- •1 8RWa COMP12tSMJTTFON (APPROX. O MICEFENCED AREA) SITE SURFACE WOUND STATOR EEquIPMENT MC TO FENCE UNE) (GRAVEL SURFACE) I 9 4 - 1, 5171 _ 491 • 51� _ l:a REFERENCE DRAWINGS DESCRIPTION NO. r • DEVELOPED DRAINAGE PLAN REVISION INFORMATION REVISION BY CHKD APP'D DATE BRA -SW -0001 mown- AND LDCA71RH W PIPS. PLOT PLNN. AND NOTES A ISSUED FOR STERNAL RENEW Sn (YIP CIF 02/Iv/19 BRA -W-1015 RETENTION POND SPILLWAY WI OVERFLOW PUN, SECTIONS, AND DETAILS I C ISSUED FOR C LINT REVEW tssto FOR CLENT REVIEW SPB SAI CMR MIR CIF CMF DUN/19 02/72/19 D RUED FOR ORANACE REPORT APPOIOIit SPI SYR CAE 03/06/19 24'-U' WIN SITE ENTRANCE ACCESS 'DIVE (G1TAV17: SURFACE) PROPERTY LINE nip.) a ,DOUBLE CATTLE CLARET (16 rT. IWYEL 11MO1H) 3D' r iMOE STATION ENTRANCE SLOE GATE NEW IC SO. FT. SELF -SUPPORTED CDMPRESSDR STATION 501 (6 FT, HIGH MAC) a a c CAM at t 6'—p' HIGH (YIN.) CHAIN-INIC FENCE (TIP. AROUND SITE PERIMETER) ME REMOTER EON (31-1:14) ITOP SOIL AHD SEED, AS PIECESSNRI' 4'—O• WIDE (MIN.) NM GATE (TYP. FOR 61 r .471 DRAWN: SPB r • i 02f 15/19 CHECKED: CZAR 02/19/19 APP°D: COIF 02/19/19 AFE j: i i i i i DETENTION POND — ND TIMID/SRAt4L E AREA (10 —YEAR STORM EVENT 1,930,IME = 0.35 ACTS —FT; t00 —"DEAR STORM EVENT VOLUME = ITO CAT —FT; AVAILABLE VOLUME 0 EL 5485.58 = 1.20 ACRE -FT) LEGEND Ei85TING CONTOUR PROPOSED CONTOUR PROPOSED ACCESS/FACILTTY GRAVEL DRIVE ORthC FLOW ARROW PROPOSED SILT FENCE GRAPHIC SCALE SUMMIT MIDSTREAM BRAHMA COMPRESSOR STATION DEVELOPED DRAINAGE PLAN WELD COUNTY COLORADO c276 _ 20 0 ID 20 17 so SCALE: { FRET inch = 40 it. AS NOTED 41 -1D 39 3.9 36 35 34 33 32 31 30 29 28 27 25 25 24 23 22 PROJECT Na 19-046 DRAWING NO: BRA -SW -0002 Net 21 20 1H 17 1C 1i 13 12 H 6 5 4 2 1 PLOT °ATE ; 3/6/2019 PLOTTED BY : SEIME'T FILE NO E : BRA -SW -0002 NEW 5'—O` NCH (MIN'.) CHAIN —LINE{ _ . . .fw. 45-6- t FAWN , BASIN i'-01 FENCE (SEE U k No. EPA —SW -1012 FOR AO01T10NAL INFORMATION) : It '.4 .ii y f 'n-. i I r 1 a a T.0. DRAIN BASIN `,`- I EL 5485.33' o 1� 1 ... ;,f DRAINAGE PIPE INIERT _... 1n II -i EL 5482.67 I' 1h Il1 IFS II !1' I,p *MN d'P ,lalilk/ o - a____ , , .,,,;L FWD END SECTICA MENTION FOND 1 DISCHARGE EL 5462.00'@-O --• I■ I I a 5482.54' • L I,■' •�- •,ate ELD. DRAIN BASIN Ii +,. :�. L I,-.4ii.V.,V4 �,. "xl ._s. ;-`.��y- EL 548133' b t c. -..„..,•,-....„Y -`` ;�Y NEW W VA. BRIO BASIN 14/ DOMED SMOOTH W"} Iu CREATE BENCH NDN-SHR NEW 98' OW. CORRUGATE() HOPE GRATE {6Y Nri T DR A PR D � WIMP DRAINAGE PPE cSEE 'DRAINAGE PIPE I'1SFN.IATIDN DETAIL ON THIS DWG. MIN. (SEE `DIM BASIN PERFORATION ON THIS CM) GROUT WHIN BASIN TO LwIT THE NADUNI OF STRONG -- PROVIDE in RIP -RAP 12': F'--0' {A,) CDOI TYPE AI, FOR ADD111ONAL IFWORIMTIEN) ring DETAIL WATER IN 0.0. BASH _.• 1 O% = PROLE' NEW INTE I& COUPLER SPIGOT .. I h PROVIDE WOAEN GEOTEKIIE BET'W'. nom (TO IXYNNECT ORNNAGE PIPE TO GONG FLANS ENO SECiOH) LKs23 OR APPROVED EQUAL)FABRIC'S la PRECAST CONC. FLARED ENO SECTION T : T'' ' Wit REMOVABLE GU. AIL. TRASH G1ARD r r . f I Jr •`o + no r SPILLWAY LOCATION EC SALE: A i I .. E. 5+2.0i +7O -7 • -a Tie=N 1'-D' B m �. I B m : WS I • - HIGH ,, NI I , NEW 6I-0" FENCE I i .I 1012 ti AMOK ORAL I NERLIATDO - ` 6'-O' ace? 9'-055 I 3'-2' 22'-5` 2'-10" 7'-2' C W -B r I I 3 DETEHOOH POND CONTROL IE WATER SURFACE I 1 T.O. SPILLWAY MET F� L Et. 548526t T.O. SPILLWAY DISCHARGE EL 548530' v I EL 5485.00' - - -- -� 3 o I T.C. CONC. EL 548340' EW.r RI r y S`7 Jl4012° ITitImo_t� °-'I •' CUBES 10'-r (Ku.) FENCE FASTS r.., } ?1 s• a 111 n , 4s 5 �3* l � /li` % ' (' E.W. ¢• ABOUT CENTERLINE OF SPILLWAY. EXTEND FENCE MESH TO 4" *CAE FIN. COW EL ti'-° AIP-RAP COOT TYPE IA, 44.1r (MAIL.) dr PROVIDE NEW DETENTION POND SPILLWAY �__� On = 12": 2'-0` (MIL WK.) PROLE WOVEN GEOTEKITLE ETV. AND OVERFLOW PLAN 30' pA DRAIN BASIN SCALE: 1/F4. = 1'-0' U PAIR AND 5WBGRADE (LFABRICS U522 DR 50 APPKO'IED [DUAL) SECTION SCALE: 1/4• a I.-0. ATTACH NON -WOVEN FILTER FABRIC (200 GPM FLOW THRU) TO EXTERIOR FACE OF BASIN TO COW? HOLES) {{ 10 BERM EL 5489.00' ��---._ 5'-a' B' -B' S' -D' 120 RADIAL AREA POR • DNARYIGE PIPE PLACEMENT OF HOLES 4' 8' D" 4"I SECT10N D --CI I �r ► SPILLWAY RADIAL AND DEMI4G MATERW. SHALL BE CLASS I '! OR CUSS II MATERIAL CONFORMIKI TD MIA 02321 T.O. BASIN 30 DIAL SOLID GRATE TA SPILLWAY )) AIM BE PLACED UNIFORMLY II 8y (WAX.) LHTS AVID EL. 5+85.33' Ps COMPACTED TO 1510 OF STANDARD PROCTOR (ASTM �- WEEP WALL Ft 54E13.25' B, i}} D688 UAXMIUTA DRY DENSITY AT (±)2x OF OPRITLMA EL *iii••i MDISfURE COWER 4 J •i + A. 1 .rL - - {3 1/4" Elk HOLES a j * �.' y —ICN. EL $481 -DO' 1 7:11 . _ 4 . �7+v i FIT C (4) 11/s7 UAL HOLES r°r' y-5 ,z • 4 •(4 2 TRENCH WEN El 5483.67' / i 1 a" DM- HOLES as / e A ; •y► (PPE O.D. + I II EL 483.33' --F►y�,ff i:itw;i:A:..: ... _ _ � T "�, d -R r/�Jll. rTi -• IA! • iv4 Y c. DIX HOLES � "r T. 1'-4' MIN.) (8) 1/"2" • * i EL. 544 4$3 B.O. DETENTION POND 'I/ 1C.'1 EL. 5482.51'N /4et2E.W.Ew. (LL4I•) N, r DRAINAGE PIPE INSTALLATION DETAIL B.O. SPILLWAY .t',• 1/2" = 1"-0` WEEP WALL + Sete � f EL 5482 'A' f �rt Y L ^1-[r'G"6'Z1'.1"&.34 +�•7;,r .•.��a. 'T.'!�'R'A: ITEE � ? 2SF Z4 :Y ?Y#+7 aftr3 67t r j• f ' DRAINAGE PIPE SHALL BE INSTALLED IN .AGCORAIWCE WITH "STANDARD .� sK�. d , 4- 1 ?. 14 . - ' P9(C0IIE 8' COOT CUSS 1J 'De 3 •••• to •Q • • AMU D2321, PRACTICE FOR LINEE1tiGR4LrtID SOUTH ELEVATION DAN) ' �► 'v INSTPLLATIOH OF THERMOPLASTIC PPE FOR SEATERS AIRO 6 (COMPACTED) BaCIN CONC. / ,a out mei FLOW APPLICATIONS". LATEST WON. f y At SECTION Li k DRAIN BASIN PERFORATION DETAIL •scar: 1/'2` = 1'-D'�`'Mr1r'\ SCALE: 1/2" = T' -O' NOTES: REFERENCE DRAWINGS REVISION INFORMATION 0 CAM SPB 02/25/19 MIDSTREAM SCALEDRAWN. AS NOTED DWG NO. DESCRIPTION NO, REVISION BY CHKD APP'D DATE © `SUMMIT ISSUED FOR INREVIEW $P6 CWR CRT OS/05/I4 r -ii J41 iv�'r_ CHECKED: CIF! 93/05/19 _ BRAHMA COMPRESSOR STATION PROJECT N 19-046 D ISSUED FOR ORAR4ACf FiEPOKI APPENDIX SPB GNP CMF 03/06/IQ APP'D: OW 03/05/19 DETENTION POND SPILLWAY AND OVERFLOW PLAN, SECTIONS, AND DETAILS ORAIFANO NO: REV: AFE f: WELD COUNT( COLORADO BRA -SW -1 01 S B 41 4] 39 38 36 35 34 33 32 3I 34 29 -.7 26 25 '24 23 22 B 21 2a 19 17 1E 15 14 13 12 9 B 7 5 4 2 1 PLOT ELATE - 3/6/2OI9 PLOTTED B : SOAKER FILE RIME : BRA -SW -1015 APPENDIX A Custom Soil Resource Report for Weld County, Colorado, Northern Part, Brahma Compressor Station USDA United States =�"-- Department of — Agriculture ARCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Weld County, Colorado, Northern Part Brahma Compressor Station February 27, 2019 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nres.usda.gavlwpsl portal/n reslm ain /so i l sf health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.govllacatorlapp?agency=arcs) or your N RCS State Soil Scientist (http://www. nres.0 sda.gov/wps/portal/nresfd etail/soils/contactu sl? cid=nres142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the N RCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface 2 How Soil Surveys A►re Made 5 Soil Map 8 Soil Map (Brahma Compressor Station) 9 Legend 10 Map Unit Legend (Brahma Compressor Station) 11 Map Unit Descriptions (Brahma Compressor Station) 11 Weld County, Colorado, Northern Part 13 4 —Ascalon fine sandy loam, 0 to 6 percent slopes 13 5 —Ascalon sandy loam, 5 to 9 percent slopes 14 References 16 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil -vegetation -landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 Custom Soil Resource Report scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil -landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil -landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field -observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and 6 Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 40° 58' 18" N 0 T 0 0 40° 5.8'7"N 104° 26' 53" W r 1040 26' 53" W 546460 546510 546560 Soil Map may not be valid at this sea 544440 N A 514510 5.z 65 eD 546610 5415610 Custom Soil Resource Report Soil Map (Brahma Compressor Station) 546660 544060 Map Scale: 1 :2 280 if printed on A landscape (11" x 8.5") sheet. Meters 0 30 60 120 180 Feet 100 200 400 600 Map projection: Web Mercator Corner coordinates: WG584 Edge tics: UTM Zone 13N WGS84 9 546710 546710 546760 546780 544810 546810 546860 ��I 5`6860 546910 5461}10 104° 26' 31" W 104° 26' 31" W 0 40° 58'18"N 40° 50 N Custom Soil Resource Report MAP LEGEND Area of Interest (AOI) Area of Interest (AOl) Soils O Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features tv Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot .74 4:4 74 0 O V a i • 90 0 324 Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale.. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Weld County, Colorado, Northern Part Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date (s) aerial images were photographed: Oct 22, 2014 Oct 2, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 10 Custom Soil Resource Report Map Unit Legend (Brahma Compressor Station) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 4 Ascalon fine sandy percent slopes loam, 0 to 6 26.4 100.0% 5 Ascalon sandy loam, 5 to 9 percent slopes 0.0 0.0% Totals for Area of Interest 26.4 100.0% Map Unit Descriptions (Brahma Compressor Station) The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate 11 Custom Soil Resource Report pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 12 Custom Soil Resource Report Weld County, Colorado, Northern Part 4 —Ascalon fine sandy loam, 0 to 6 percent slopes Map Unit Setting National map unit symbol: 2tI p5 Elevation: 4,550 to 6,050 feet Mean annual precipitation: 12 to 17 inches Mean annual air temperature: 46 to 54 degrees F Frost -free period: 135 to 160 days Farmland classification: Farmland of statewide importance Map Unit Composition Ascalon and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit Description of Ascalon Setting Landform: I nterfl u ryes Landform position (two-dimensional): Backslope, summit Landform position (three-dimensional): I nterfluve Down -slope shape: Linear Across -slope shape: Linear Parent material: Wind -reworked alluvium and/or calcareous sandy eolian deposits Typical profile Ap - g to 7 inches: fine sandy loam Btl - 7 to 13 inches: sandy clay loam Bt2 - 13 to 18 inches: sandy clay loam Bk - 18 to 48 inches: sandy loam C - 48 to 80 inches: sandy loam Properties and qualities Slope: 0 to 6 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (sat): Moderately high to high (0.60 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline (0.1 to 1.9 mmhos/cm) Sodium adsorption ratio, maximum in profile: 1.0 Available water storage in profile: Moderate (about 6.8 inches) Interpretive groups Land capability classification (irrigated): Se Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No 13 Custom Soil Resource Report Minor Components Olnest Percent of map unit: 8 percent Landform: Interfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down -slope shape: Linear Across -slope shape: Linear Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Otero Percent of map unit: 7 percent Landform: Interfluves Landform position (two-dimensional): Footslope Landform position (three-dimensional1) Base slope Down -slope shape: Linear Across -slope shape: Linear Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No 5 —Ascalon sandy loam, 5 to 9 percent slopes Map Unit Setting National map unit symbol: 2tl mac Elevation: 3,870 to 6,070 feet Mean annual precipitation: 13 to 16 inches Mean annual air temperature: 46 to 57 degrees F Frost -free period: 135 to 160 days Farmland classification: Not prime farmland Map Unit Composition Ascalon and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Ascalon Setting Landform: Interfluves Down -slope shape: Linear Across -slope shape: Linear Parent material: Wind -reworked alluvium and/or calcareous sandy eolian deposits Typical profile Ap - o to 6 inches: sandy loam Bt1 - 6 to 12 inches: sandy clay loam Bt2 - 12 to 19 inches: sandy clay loam Bk - 19 to 35 inches: sandy clay► loam 14 Custom Soil Resource Report C - 35 to 80 inches: sandy loam Properties and qualities Slope: 5 to 9 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water ('}sat,J: Moderately high to high (0.60 to 2.00 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0 mmhostcm) Sodium adsorption ratio, maximum in profile: 1.0 Available water storage in profile: Moderate (about 6.8 inches) Interpretive groups Land capability classification ('irrigated): 4e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: B Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Minor Components Stoneham Percent of map unit: 10 percent Landform: I nterfl uves Down -slope shape: Linear Across -slope shape: Linear Ecological site: Loamy Plains (R007BY002CO) Hydric soil rating: No Manter Percent of map unit: 5 percent Landform: lnterfluves Down -slope shape: Linear Across -slope shape: Linear Ecological site: Sandy Plains (R067BY024 O) Hydric soil rating: No References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal! nres/detail/national/soils/?cid=nres142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www. nres. usd a.gov/wps/portal/nres/detail/national/soils/?cid=nres 142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www. nres. usd a.gov/wps/portal/nres/detail/national/soils/?cid=n res 142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/ home/?cid=nres 142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/ detail/national/land use/rang ep astu re/?cid = stel p rd b 10430 84 16 Custom Soil Resource Report UnitedStates Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430 -VI. http://www.nrcs.usda.goviwpsiportali arcs/d etai llsoils/scientists/?cid = nres l 42 p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nres.usda.goviwpslportal/nres/detailinationallsoils/? cid=nrcs142p2_053624 res 142 p2_6 63624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/InternetiFSE DOCU M ENTS/n res 142p2_662290. pd f 17 APPENDIX B NOAA Point Precipitation Data 311/2019 Precipitation Frequency Data Server NOAA Atlas 14, Volume 8, Version 2 Location name: Grover, Colorado, USA* Latitude: 40.9708°, Longitude: -104.44590 Elevation: 5482.42 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOAA, National Weather Service, Silver Spring, Maryland PF tabular PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Average recurrence interval (years) Duration 1 2 I 5 ll 10 I 25 J 50 100 200 500 J 1000 5 -min 0.256 (0.198-0.333) 0.307 (0.237-0.399) 0.398 (0.306-0.519) 0.482 (0.369-0.631) 0.608 (0.455-0.835) 0.714 (0.521-0.989) 0.828 (0.584-1.17) 0.952 (0.645-1.38) 1.13 (0.736-1.68) 1.27 (0.804-1.90) 10 -min 0.375 (0.290-0.487) 0.583 (0.449-0.760) 0.705 0.540-0.923) 0.890 (0.667-1.22) 1.05 (0.763-1.45) 1.21 (0.855-1.72) 1.39 (0.945-2.02) 1.65 (1.08-2.46) 1.86 (1.18-2.79) 15 -rain I 0.457 (0.353-0.594) 0.548 (0.423-0.713) 0.860 (O.658-1.13) 1.09 (4.1313 1.49) ! 1.27 (0.930-1.77) 1.48 (1.04-2.10) 1.70 (1.15-2.47) 2.27 (1.44-3.40) 30 -min 0.605 (0468-0.786) 0.727 (0.561-0.946) 0.945 (0.727-1.23) 1.14 (0.873-1.49) 1.44 (1.08-1.97) 1.68 l (1.23-2.33) 1.95 (1.37-2.76) 2.23 (1.51-3.24) 2.63 (1.72-3.92) 2.96 (1.87-4.43) 60 -min 0.731 F(0.565-0.950) 0.892 (0.688-1.16) 1.18 (0.905-1.53) 1.43 (1.10-1.88) 1.81 (1.36-2.49) 2.13 (1.55-2.95) 2.47 (1.74-3.49) 2.83 (1.92-4.11) 3.35 (2.18-4.97) 3.76 (2.38-5.63) 2 -hr 1.06 0}.825-1.36) 1.41 (1.1O-1.81) 2.19 (1.66-2.97) 2.58 (1.90-3.52) 2.99 (2.13-4.18) 4.06 (2.68-5.95) 4.56 (2.92-6.74) 3 -hr 0.925 (0.728-1.18) 1.15 (0.902-1.46) 1.54 (1.21-1.97) 1.89 (1.47--2.42) 2.41 (1.83-3.24) 2.84 (2.11-3.85)J 3.34 (2.37-4.58) 3.80 (2.62-5.39) 4.49 (2.98-6.54) 11 5.05 (3.26-7.40) 6 -hr j 1.08 (0.859-1.36) 1.32 (1.05-1.66) I 1.74E-1 (1.38-2.20) 2.70 (2.09-3.59) 3.19 (2.40-4.27) 3.70 (2.69-5.07) 4.26 (2.97-5.97) 5.05 (3.39-7.25) 5.69 (3.71-8.22) 12 -hr 1.28 0.03-1.59) I 1.52 (1.23-1.89) 2.33 (1.87-2.92) 2.91 (2.28-3.81) 3.40 (2.59-4.49) 3.92 (2.88-5.29) 4.48 (3.16-6.19) 5.27 (3.58-7.46) 5.91 (3.90-8.42) 24 -hr 1.51 (1.23-1.85) 1.75 (1.43-2.15) 2.18 (1.77-2.68) 2.57 (2.08-3.17) 3.65 I (2.81-4.76) 4.18 (3.11-5.56) 4.75 (3.40-6.48) 5.56 (3.83-7.76) 6.22 (4.15-8.74) 2 -day l 1.71 (1.41-2.07) 2.01 (1.66-2.43) 2.51 (2.07-3.06) 2.96 (2.42-3.61) 3.59 (2.86-4.55) 4.11 (3.20-5.26) 4.65 (349-6.07) 5.22 (3.76-6.98) 6.00 (4.17-8.22)1 6.62 (4.47-9.16) i 3 -day 1.89 (1.58-2.27) I 2.20 (1.83-2.65) 2.73 (2.26-3.29) 3.18 il (2.63-3.85) 3.83 (3.07-4.80) 1 4.36 I (3.41-5.52) 4.90 (3.71-6.34) 5.47 (3.97-7.24) 6.25 (4.37-8.48) 6.86 (4.67-9.41) 4e 2.04 (171-2.45) 2.36 (1.98-2.83) 2.80 V (2.41-3.47) 3.35 (2.78-4.04) 4.01 (3.23-4.99) l 4.53 (3.57-5.71) 5.08 (3.86-6.53) 5.64 (4.12-7.43) 6.42 (4.51-8.66) 7.03 (4.81-9.60) 7 -day 2.39 (2.03-2.83) 2.73 (2.31-3.24) 3.30 (2.78-3.92) 3.78 (3.17-4.51) 4.46 (3.63-5.48) 5.00 (3.97-6.21) 5.55 (4.26-7.04) 6.11 (4.50-7.94) 6.88 (4.88-9.15) 7.47 (5.16-10.1) 10 -day 2.68 (2.29-3.15) 3.05 (2.60-3.59) 3.67 I (3.11-4.33) 4.18 (3.53-4.95) I 4.89 (4.00-5.95) 5.45 (4.35-6.71) 6.01 (4.64-7.56) 6.58 (4.88-8.48) 7.35 (5.24-9.69) 7.93 (5.51-10.6) [20-day3.51 (3.03-4.07) 3.99 (3.44-4.63) _ 5.38 (4.60-6.28) 6.22 (5.13-7.43) 6.85 (5.54-8.29) 7.48 (5.84-9.24) i 9.48 (6.67-12.5) 30 -day I 4.21 (3.674.85) 4.78 (4.16-5.51) 5.68 (4.93-6.56) L6.41 (5.53-7.42) 7.36 (6.11-8.69) 8.06 (6.55-9.64) 8.73 (6.86-10.r) 9.38 (7.07-11.7) 10.2 (7.40-13.1) 10.8 (7.65.-14.1) 45 -day 5.12 (4.49-5.84) 5.81 (5.09-6.64) 6.88 (6.02-7.89) 7.73 (6.72-8.88) 8.81 (7.36-10.3) 9.59 (7.84-11.4) i 10.3 (8.15-12.5) 11.0 (8.34-13.6) 11.8 (8.62-15.0) i 12.4 (8.84-16.0) 60 -day 5.901 (5.21-6.70) ll 6.69 (5.91-7.61) 7.92 (6.96-9.02) ll ll 8.86 (7.75-10.1) 10.1 (8.43-11.6) 10.9 (8.95-12.8) 11.6 (9.25-14.0) 12.3 (9.40-15.1) 13.1 (9.63-16.5) 13.7 (9.81-17.6) - 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% (for a given duration and average recurrence interval) will be greater than the upper are not checked against probable maximum precipitation (PMP) estimates and Please refer to NOAA Atlas 14 document for more information. of partial duration series (PDS). confidence interval. The probability that precipitation frequency estimates bound (or less than the lower bound) is 5%. Estimates at upper bounds may be higher than currently valid PMP values. Back to Top PF graphical https://hdscsnws.noaa.gov/hdsclpfds/pfds_printpage.html?Iat=40.970$&Ian=-104.4459&data=depth&units=english&series=pds 1/4 3/1/2019 Precipitation Frequency Data Server PDS-based depth -duration -frequency (DDF) curves Latitude: 403108°, Longitude: -104.4459c cZ 1i L.Y 0 4J ra Co �l7� 0 I C O 4J CLI CL 14 12 Cl 14 10 5 10 25 50 100 200 NOAA Atlas 14, Volume 6, Version 2 • IN kip Duration esti I rti riJ ' NL th H Average reLurrertce interval (years) , fa pfa f �r i 0 0Ln +I T set L c 500 1000 Created (GMT): Fn Mar 1 15:47:02 2019 Back to Top Maps & aerials Small scale terrain Average recurrence interval (years) 1 2 5� 10 25 50 100 200 500 1000 Duration 5 -min 10 -min 30 --rain 60 -min 2-mr 3 -hr 6-11r 12 -hr 24 -hr -day. 3 -ay 4 -day 7 -day 10 -day. 20 -day 30 -day 45 -day 60 -day, https://hdsasnws.noaa.govlhdsclpfds/pfds_printpage.html?Iat=40.9708&Ian=-104.4459&data=depth&units=english&series=pds 2/4 3/1/2019 Precipitation Frequency Data Server i i Large scale terrain Long:, F`euk_ 134516 • Lgrni:Iit 100km Denver 3 Large scale map Fort oilli s r, 'rune, e.nn.e ■ _ Greeley Longmont I 100km J 6.0 m i,� 3� �iP r Amami Large scale aerial N r L _ 1 https://hdsc.nws,noaa.gov/hdsc/pfdsfpfds printpage.html?lat=40.9708&Ion=-104.4459+ data=depth&units=english&series=pds 3/4 3/1/2019 Precipitation Frequency Data Server 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 Questions?: HDSC.Questionsnoaa.gov Disclaimer https://hdsc.nws..noaa.gov/hdsc/pfds/pfds_printpage.html?Iat=40.9708&lanr-104.4459&data-depth&units-english&series=pds 4/4 APPENDIX Pre -development Runoff Calculations Supplementary Design Information for UD-Rational Workbook Urban Storm Drainage Criteria Manual (USDCM) Volume 1, Chapter 6 - Runoff (March 2017) Version 2.00 released May 2017 Table d-1< Appliraltility of h} t9r°Io 1c methods Watershed Size (acres) Is the Rational Method Applicable? Is CUEIP Applicable? 0 tee 90 Yes Yes 90 to 160 No Yes 160& to 31000 No Yes' eater than, .Q � Yes (subdividing into smaller catchments regniied)1 Subdividuw into smart wirttetdrrrtents and mutt* 19tr rendtanl hydrogrephs use MOAN nay be neede450 accurately tua fei a catc'hueeut writ, sires of different wit afar- or percentage of imperviousness_ The general procedtie for Rational :lethod calculations for a'single catchment is as follows. I. Delineate the catchment bounden, and (toenail= its area.. 2. meat the tlkw path fcctit the trapper -angst alike catchment to the iiniga.point. Divide the flow path into reaches of similar flow lyre (e.g . overland Flow, shallow swale flow.. gutter flow_ crc.). Determine the lentil' and dote of eachreach- 3. Determine the rime of concentration, ft. for the selected. waterway. 4. Find the :ra nfall intensity..f. for the design storm using the calculated re and the rainfall itttensity- clu tic)n frequenc : curve (see Raiit t to diaper). 5, Determine tin rungif f#kient, C- 6. Calculate the peak flow rate. Q. from the catchment using Equation 6'l. The basic assumptions for the application of the Rational Method include: 1, The compiled maximum rate of ninon? $e ilvt dcig_ a poll is a f:ma,ction of the avers 4e rainfall rate '�'t g the Fiats oftcQncentrallOti RI? ih ui poi's. 2. The hydrologic losses in the catchment are Marisa nevus and uniform_ The runoff coefficienta , atiy' with respect to type of soils, impen'iorr: ness percentage. and rainfall frequencies. These coefficients repir.ekiesns the a"rrafte shire irfff sail tl° i ttditi . 3. The depth of rainfall aced it one that ttecurt Altai filet Mint M the istanii 16 the rime Of concentration. The design rainfall depth during that period is converted to the average rainfall intensity far that pei'POd? 4. The maximum runoff Atilt nra‘tua when die entity area is oiitiibnting Sew. This . SMilli Finn is Et t valid whet a`t mare intensely developed ponion r3fthe catchment &hone time of caneei:ttrattian produces a hileher rate ofninon' than the entire catchment with a longer time of concentration,. Table 6-4. Runoff coefficient equations based on NRCS soil group and storm return period NRCS Storm Return Period Soil ? Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year Group A CA= CA= C'.= CA _ ( = CA = CA = 0inillin 0. Mil- 76 0_ ;,,- _=2 0.&411124 i.S5i-4!_025 0.781+0.110 0.651+0251 B Ca= Ca = C' = CB = Ca= CB = CB = 0.8411.169 0.8611m BS 0.811-0.057 0.631+0.249 0.561+0.328 0.471+0426 0.371+0.536 CO COD= COD= COD = Cc'n = COD = COD = COD = 0.831'' ' 0.82110.1 35 0.74110.132 0.561 0_219 0A9110.393 0.41i 10_.484 0.32110.588 Where: i = % imperviousness (expressed as a decimal) CA = Runoff coefficient for Natural Resources Conservation Service (T'CRCS) HSG A soils CB = Runoff coefficient for NRCS HSG B soils Cap = Runoff coefficient for NRCS HSU C and 1U soils_ Table 4 ?. NRCS COUv*yrroc>p ! izeile r*, K Type of Land Surface Conveyance Foam. K. Heavy meadow ?5 Tillage/field 5 Short pasture and lawns 7 Nearly bare ground 10 Glassed waterway 13 Paved areas and shallow paved swabs 20 Table 6-3. Recommended percentage imperviousness -values 1- And Use or Percentage fu ervioncness e Surface Characteristics Business: Downtown Areas 95 Suburban Areas 75 Residential lots (lot area only): Single-family 2.5 acmes or larger 12 035 - 2.5 acres 20 0,25 - 0.75 acres 30 0.25 acres or less 45 Apartments 75 Industrial : Light areas 80 Heavy areas 90 Parks, cemeteries 10 Playgrounds 25 Schools 55 Railroad yard areas 50 Undeveloped Areas: Historic flow analysis --.) Greenbelts, agricultural 2 Off -site flow analysis (Mien land use not defined) 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 2 Lawns,clayey soil 2 Page 1 Supplementary Design Information for UD-Rational Workbook Urban Storm Drainage Criteria Manual (USDCM) Volume 1, Chapter 6 - Runoff (March 2017) Version 2.00 released May 2017 Table 6-5. Runoff coefficients. r To ral or EffectiveNRCS Hydrologic Soil Group A 0.-'v Imperious 2 -Year 5 -Year 30 -Year 25 -Year 50 -Year 100 -Year a00' -Veal '2% 0.01 0.01 0.01 0.01 0.04 0.13 0.27 5% 0.02 0.02 0.02 0.03 0.07 0.15 0.29 10% 0.04 0.05 0.05 0.07 0.11 0.19 0.32 15% 0.07 0.08 0.08 0.1 0.15 0.23 0.35 20% 0.1 0.11 0.12 0.14 0.2 0.27 038 25% 0.14 0.15 0.16 0.19 0.24 0.3 0.42 30% 0.18 0.19 0.7 0.23 0.28 0.34 0.45 35% 0.21 0.23 0.24 0.27 0.32 0.38 0.48 40% 0.25 0.27 0.23 0.32 0.37 0.42 0.51 45% 03 0.31 0.33 ‘ 0.36 0.41 0.46 0.54 50% 0.34 0.36 0.37 0.41 0.45 0.5 0.58 55% 0.39 0.4 0.42 0.45 0.49 0.54 0.61 60% 0.43 0.45 0.47 0.5 0.54 0.58 0.64 65% 0.48 0.5 0.51 0.54 0.58 0.62 0.67 70% 0.53 0.55 0.56 0.59 0.62 0.65 0.71 75% 0 0.58 0.6 0.61 0..64 0.66 0.59 0.74 80% 0.63 0.65 0.66 0.69 0.71 0.73 0.77 85% 0.68 0.7 0.71 0.74 0.75 0.77 0.8 90% 0.73 0.75 0.77 0.79 0.79 0.81 0.84 93% 0.79 0.81 0.82 0.83 0.84 0.85 0.87 100% 0.84 0.86 0.87 0.88 0.88 0.89 0.9 To ral or Effeerrire NRCS Hydrologic Soil Group B i, Lmper rio us 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year 500 -Year 2% 0.01 0.01 4 0.07 0.26 0.34 0.44 0.54 5°'0 0.03 0.0.3 0.1 0.28 0.36 0.45 0.55 10% 0.06 0.07 0.14 0.31 0.38 0.47 0.57 15% 0.09 0.11 0.18 0.34 0.41 0.5 0.59 20% 0.13 0.15 0.22 0.38 0.44 0.52 0.61 25% 0.17 0.19 0.26 0.41 0.47 0.54 0.63 30% 0.1 0.23 0.3 0.44 0.49 0.57 0.65 35% 0.24 0.27 0.34 0.47 0.52 0.59 0.66 40% 0.29 0.32 0.38 0.5 0.55 0.61 0.68 45% 0.33 0.36 0.42 0.53 0.58 0.64 0.7 50% 0.37 0.4 0.46 0.56 0.61 0.66 0.72 55t.V0 0.42 0.45 0.5 0.6 0.63 0.68 0.74 60°- 0 0.46 0.49 0.54 0.63 0.66 0.71 0.76 65° 0 0.5 0.5.4 0.58 0.66 0.69 0.73 0.77 70% 0.55 0.58 0.62 0.69 0.72 0.75 0.79 75% 0.6 0.63 0.66 0.72 0.75 0.78 0.81 80% 0.64 0.67 0.7 0.75 0.77 0.8 0.83 85% 0.69 0.72 0.74 0.78 0.8 0.82 0.85 90% 0.74 0.76 0.78 0.81 0.83 0.84 0.87 95% 0.79 0.81 0.82 0.85 0.86 0.87 0.88 100% 0.84 0.86 0.86 0.88 0.89 0.89 0.9 Total or Effective NRCS Hydrologic Soil Group C ° Imp enious 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year 500 -Year 2% 0.01 0.05 0.15 0.33 0.40 0.49 059 5% 0.03 0.08 0.17 0.35 0.42 0.5 0.6 10% 0.06 0.12 0.21 0_37 0.44 0.52 0.62 15% 0.1 0.16 0.24 0.4 0.47 0.55 0.64 20% 0.14 0.2' 0.28 0.43 0.49 0.57 0.65 25% 0.13 0.24 0.32 0.4-6 0.52 0.59 0.67 30% 0.22 0.28 0.35 0.49 0.54 0.61 0.68 35% 0.26 0.32 0.39 0.51 0.57 0.63 0.7 40% 0.3 0.36 0.43 0.54 0.59 0.65 0.71 45% 0.34 0.4 0.44 0.57 0.62 0.67 0.73 50% 0.38 0.44 0.5 0.6 0.64 0.69 0.75 55% 0.43 0.48 0.54 0.63 0.66 0.71 0.76 60% 047 0.52 0.57 0.65 0.69 0.73 0.78 65% 0.51 0.56 0.61 0.68 0.71 0.75 0.79 70% 0.56 0.61. 0.65 0.71 0.74 0.77 0.31 75% 0.6 0.65 0.68 0.74 0.76 0.79 0.82. 80% 0.65 0.69 0.72 0.77 0.79 0.81 0.34 :85% 0.7 0.73 0.76 0.79 0.81 0.83 0.86 90% 0.74 0.77 0.79 0.8:2 0.84 0.85 0.37 95% 0.79' 0.81 0.83 0.85 0.86 0.87 0.39 100% 0.83 0.85 0.87 0.33 0.89 0.89 0.9 1 00 0.80 w 0.610 U 40 c re Rlri3ff Coefficient, C 0.20 0.00 10 20 30 40 50 60 70 80 Watershed Percentage Irrpervioisness, 'o 90 '1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 1.00 0.00 0.80 0.70 0.60 U X0.60 tl1 0.40 0 0.30 0.20 CC 0.10 0.00 - 6- 2-yr - x- 5-vr -CI- 10-yr -x-25 yr - Or 50-yr Y 100-yr 100 Figure fi-1 _ Runnff coefficient vc watershed imper<-inuctecc NRCS HSG A 10 20 30 40 50 60 70 80 Watershed Percentage Imperviousness., % no 100 —40— 2-yr —x— 5-yr X10 —W-95 yr --O— 50-yr 100-yr Figure 6-2. Runoff coefficient vs. watershed imperviousness MRCS HSG B 0 10 20 30 40 50 6n 7o 80 Watershed Percentzge imperviousness. % 90 100 2-yi -x- 5-y i -t} ' 0-v' -X-25.Vr -O-50-ye x'00-yr figure 6-3. Runoff cuef aieui vs. nvalershed hnpei siumuess NRCS HSG C and D Page 2 Calculation of Peak Runoff using Rational Method Designer: Company: Gustavo Guerrero Golder Associates Date: 3/5/2019 Project: Location: Brahma: Pre -Development 40.9708, -104.4459 Version 2.00 released May 2017 Cells of this color are for required user -input Cells of this color are for optional override values Cells of this color are for calculated results based on overrides 0395(1.1 — Cs.) v c033 i tt=60 isifK, 6 Vt Computed tc = ti + tC Regional tt = F26 — 171) + Lt 60(141+ 9) St tminimum= 5 {urban) tminimum= 10 (non -urban) Selected tc = rnax(tminimum ,rnin(Cornputed tc, Regional tc)} Select UDFCD location for NOAA Atlas 14 Rainfall Depths from the pulidown list OR enter your own depths obtained from the NOAA website (click this link} 2-yr 5•yr 10-yr 25•yr 50-yr 100-yr 500-yr 1 -hour rainfall depth. P1 (in) _ Rainfall Intensity Equation Coefficients = L 0,89 1.18 1.43 I 1.82 2.13 247 I 3.35 b I 28,50 10.00 0.786 a*Pt kin/hr) — c tc)c Q(c f sl = CIA Subcatchrnent Name Area (ac) NRCS Hydrologic Soil Group Runoff Coefficient, C Overland (Initial) Flow Time Channelized (Travel) Flow Time Time of Concentration Rainfall Intensity, I (inlhr) Peak Flow, CI cfs) Percent Imperviousness 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr Overhand Flow Length L. (ft) IPS Elevation (ft) (Optional) DIS Elevation (ft) (Optional) Overland Flow Slope S (ftlft) Overland Flow Time t, (min) Channelized Flow Length L, (ft) UES Elevation (ft) (Optional) DfS Elevation (ft) (Optional) Channelized Flow Slope SI (ttlft) NRCS Conveyance Factor K Channelized Flow Velocity VI (ftlsec) Channelized Flow Time t: (min) Computed t� (min) Regional t,(min)tc Selected (min) 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 1 3.34 B 0.01 0.01 0.07 0.26 0.34 0.44 0.54 500.00 5492.70 5488.14 0.009 45.26 990.19 5488.14 5482.73 0.005 7.5 5 29.77 75.03 49.72 49.72 1.02 1.35 1.64 2.08 2.44 2.83 3.84 0.03 0.05 0.40 1.82 2.76 4.11 6.95 .: 2 6.19 B 2.0 0-01 0.01 0.07 0.26 0.34 0.44 0.54 500.00 5493.00 3 .6= 0.011 42.95 412.97 5487.65 5481.93 0,014 7.5 7.80 50.74 31.96 31.96 1.3:5 1.78 2.16 2.75 322 173 5.06 0.07 0.13 0.98 4.46 6.76 10.06 17.03 3 0.92 B 2 0 D.01 D.D1 0-07 G.26 34 0.44 D.54 432.47 5487.56 5484,95 D.006 48.27 1.00 C DOE 7.5 0.58 0.03 48.30 25.68 25.8.51.53 2.03 2.45 3.12 3.66 414 5.75 C_01 D.02 0.17 0.75 1.15 1.70 2.89 4 1.94 B 2.C 0.01 1 0.07 0.2c 0.34 0.44 0.54 500.00 5492.72 5488.17 0.009 45.30 331.86 5488.17 5485.46 0.008 7.5 cE' 8.17 53.47 32.26 t2.2c 1.74 1.77 2.15 2/3 3.20 3.71 5.03 0.02 0.04 0.31 1.39 2.11 3.14 5.32 APPENDIX D Post -development Runoff Calculations Calculation of Peak Runoff using Rational Method Designer: Company: SheAna Sadza Golder Associates Date: 311!2019 Project: Location: Brahma: Post -Development 40.9708, -104.4459 Version 2.00 released May 2017 Cells of this color are for required user -input Cells of this color are for optional override values Cells of this color are for calculated results based on overrides 0395(1.1 — Cs] viri 6033 tt 601c S4 60Vt Computed t = ti + tt Regional tc _ (26 — 17) + Lt 60(141+ 9),iSt tminimum= 5 {urban) tminimum= 10 (non -urban) Selected tc = m$9((tminimum ,min(CompLutcd tc, Regional tc)) Select UDFCD location for NOAA Atlas 14 Rainfall Depths from the pulidown list OR enter your own depths obtained from the NOAA website (click this link} 2-yr 5•yr 10-yr 25•yr 50-yr 100-yr 500-yr 1 -hour rainfall depth. P1 (in) _ Rainfall Intensity Equation Coefficients = L 0,89 1.18 1.43 I 1.82 2.13 2.47 I 3.35 b 28,50 10.00 0.786 a*Pt kin/hr) — c tc)c Q(cfs) = CIA Subcatchrnent Name Area (ac) NRCS Hydrologic Sod Group Runoff Coeffl.cient. C Overland (Initial) Flaw Time Channelized (Travel) Flow Time Time of Concentration Rainfall Intensity,I (infhr) Peak Flow, 4 cfs) Percent Imperviousness 2-yr 5-yr 10-yr 25-yr 50-yr 100•yr 500-yr Overhand Flow Length L. (ft) U/S Elevation (tt) (Optional) WS Elevation (ft) (Optional) Overland Flow Slope S, (Rift) Overland Flow Time t, (min) Channelized Flow Length LI (ft) WS Elevation (ft) (Optional) MS Elevation (fit) (Optional) Channelized Flow Slope SI(1t1ft) NRCS Conveyance Factor K Channelized Flow Velocity VI (ftlsec) Channelized Flow Time t. (min) Computed to (min) Regional 4 (min) Selected tc (min) 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 500-yr 1 7.5D B 45.5 0.33 0.36 0.42 0.53 0.58 0.64 0.70 300.00 0.010 23.02 525.00 0.010 20 2.00 38 27.40 23.96 23.96 1.59 2.11 2.55 3.25 3.80 4.41 5.98 3.97 5.75 8.12 13.03 16.59 21.08 31.50 2 2.11 B 2.4 0.01 D.D1 0.07 0.26 D.34 0.44 0.54 500.00 a.a14 39.30 265.00 0.014 7 5.33 44.64 29.68 29.68 1.41 1.86 2.26 2.87 3.36 190 5.29 0.03 0.05 D.35 1.59 2.41 3.58 6.06 3 0.77 B 2.4 0.01 0.D1 0.07 D.26 4.34 0.44 D.54 255.00 0.031 21.59 1.00 0.031 7 1.23 O a1 21.61 25:67 21.61 1.68 2.23 2.70 3.44 4.02 4.66 8.33 0.01 0.02 4.15 0.69 1.05 1.55 2.65 4 0.98 B 2.D 0.01 0.01 0.07 0.26 0.34 0.44 0.54 315.00 0.016 29.85 1.00 0.016 7 0.$9 0.02 29.87 25.67 25.67 1.53 2.03 2.45 3.12 3.66 4.24 5.75 0.01 0.02 0.18 0.80 1.22 1.81 3.06 5 1.04 B 2.D 0.01 D.01 0.07 0.26 D.34 0.44 0.54 500.00 0.908 47.28 455.00 a,G 5 7 G.)=3 12.11 59.39 34.86 34.80 1.28 1.69 2.05 2.51 3.06 3.55 4.81 0.01 0.02 D.16 0.71 1.08 1.61 2.72 APPENDIX E Detention Pond Capacity Demand Calculations wtraarran ;Vale- r Example Zone Configuration (Retention Pond) i _ DETENTION BASIN STAGE -STORAGE TABLE BUILDER UD-Detention. Version 3.07 (February 7017) Rroject BRMBA A Basin ID: 4+:.r ; a -NORF Men! Required !,]dune Calcuation Selected Bh,P Type = 'Watershed Area = Watershed Length = '::falctshud Slope = 'Platershed Irri pe rvicus nes s = Percentage H)t!rdoyic Sal CYvup A = Percentage Hydrulcgic Sal &cup B = Percentage Hydrolcgic Soil Groups C.Cf = DesiredWQCV Drain Time = RP 7.50 325 0.010 45.5CI 0.Cr'•:, 1C0.0'!7;, 1ao Lccalicai feu 1 -hr Rainfall Depths = User Input Water Quality Capture Vclurne ('WQCV; = Excess Urban Runoff Volume (ELRV; = i pr Runoff Volume (P1 = 0.89 in.; = 5-yr Ru non" Volurn a (P1 = 1.18 in.; = 1 C-yr Runoff Volume (P1 = 1.43 in.; = 25 2.r Runoff Volume (P1 = 1.82 in.; = 50-yr RuncTTVolurne (P1 = 2.13 in.; = 100-yr Runoff Volume (P1 = 2.47 in.; = 56C -yr Runoff Volume (P1 = 3.35 in.; = Approdrnale 2-)r Detention Volume = Apprvrirnale 5-)r Detention Volume = Approxirnalte 10-yr DSeuticxr Volume = {.+proxirnale 25-)r Detention Volume = r'f.:proxirnate `0-)r Detention Volume = 4 : roxirnate 1G0. -}r Deleutirxr Volume = Stage -Storage Calculation Zone 1 Velurne ('lWQCtii; = Zone 2Vclurne (1C0 -year - Zcne 1; = Select Zcaie 3 Storage 'Volume (Optimal; = Trial Detenticai Basin Volume = Initial Surcharge Volume (ISV; = Initial Surcharge Depth (ISD; = Total Available DetectUori Depth (�:.l ; = Depth cf Trickle Channel (Hrc; = Slope cf Trickle Channel (Sri; = Sleq:es cf Main Basin Sides (S,,,,;,,; = Basin Length -b -Width Ratio (Rt;,,ti•; = Initial Surcharge Area (A,;,,) = Surcharge Vcturne Lcaiglh (Lry) = Surcharge Volume Width (W13,;) _ Depth cf Basin Flagr (' 4LpoR) = Length of Basin Flcor (Lr1ora) = iiIidlh or Basin Floor (Wrtrtick) = Area or Basin Floor (Astor*) = Vclurrie of Basin Flcor (Vrto-4 = Depth of Main Basin (HF,:;,in) = Length of Main Basin Width cf Main Basin (:'JF: inl = Area cf Main Basin (t 1.:;,Inl = %Jolurrre ci Main Basin (•V.:;,i.l) = Calculated Total Basin Volume (Vr,,,j = 0.097 0.262 0.216 0.313 0.449 0.719 0.903 1.147 1.717 0.202 0.29.4 0.411 0.506 0.550 0.042 0.x997 0.545 0.€42 M'A M'A user ha'A pa'A user user User user User user user user user user user User user user User user -= l x. VLSI! acres R n,n paced percent percent pentad hours acre-feet Opiiaial User Override acre -feel acre-feet inches acre-feet inches acre-feet inches acre-feet inches acre-feet inches acre-feet inches acre -feel inches acre -fee{ acre -fee{ 1 -hr Fter,ipilaborr acre-feet acre-feet acre -feel acre -feel acre-feet acre-feet acre-feet acre-feet R3 a fl n n•n H:V R''L R a R R n Rz RS n R R R acre-feet 0.89 1.18 1.43 1.32 a 13 a47 a35 Depth] lflc reani&IL= Il Stage - Storage DESC; ri{ion Stage R' Optional O erric!e `•ta,`e 1, Lengtti (R' Width (R' Area ((1 2; 4 : ria, _, c!e ''.f ;_ ('1':z; Area (acre,' Volume ((1''3' Vclurne (ac -fl; Permanent Pool -- 0.00 -- -- -- 7.645 0.175 -- 0.56 -- -- -- 10.294 0.226 4.282 0.101 1.50 -- -- -- 17 03 5 a22 12•.664 0.413 - a50 -- -- -- 2.6058 0.575 39.246 0.901 2_70 -- -- -- 25 724 0.613 44.424 1.020 - 3.60 2926 6 0.672 52.823 1.213 Copy of Brahma UD-Oeientirxr_v3 07 R5 xlsrn. Basin 3'5'2019. 3:50 PP.1 5 DETENTION BASIN STAGE -STORAGE TABLE BUILDER UD-Detendan. Version 3.07 (February 2017) 1u &uu 15 340 V U. UU 0.6W 0,50 4410 U.ULU 1.UU —Length (ft) 2.UU Stage (It) Width ;idea (sq.ft.) 3;00 100 0 L220 0.91S 7 W 0.610 7 O U.3U5 n.UU 100 2:00 Stage Nee (IL) V' lUnlre 3,00 L.0U U.000 (acre) (at -ft) i Copy of Brahma UD-Detadion va0i R5.xlsm, Basin (.345:Z419,, 3:50 PM APPENDIX F Outlet Structure Design Calculations Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (February 2017) Project: Basin ID: 1 CO-YR VOLUME EURY I woo/ PERMANENT POOL ZOAE3 ZONE 2 r•ZONE 1 ZONE1 MD 2-/ OHIFICFS -1O0-YLAH ORIFICE Example Zone Configuration (Retention Pond) User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Underd rain Orifice Invert Depth = Underdrain Orifice Diameter = N/A N/A Zone 1 (WQCV) Zone 2 (100 -year) Zone 3 Stage (ft) Zone Volume (ac -ft) Outlet Type 0.48 0.097 Orifice Plate 2.02 0.545 Circular Orifice ft {distance below the filtration media surface) inches U nde rdra in Orifice Centroid = 0.642 Total Calculated Parameters for Underdrain Underd rain Orifice Area = N/A ft2 feet N/A User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EU RV in a sedimentation BM P) Invert of Lowest Orifice = 0.48 ft {relative to basin bottom at Stage = Oft) Depth at top of Zone using Orifice Plate = 2.02 ft {relative to basin bottom at Stage = 0 ft) Orifice Plate: Orifice Vertical Spacing = N/A inches Orifice Plate: Orifice Area per Row = N/A inches User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Stage of Orifice Centroid (ft) Orifice Area (sq. inches) Stage of Orifice Centroid (ft) Orifice Area (sq. inches) Calculated Parameters for Plate WO Orifice Area per Row = Elliptical Half -Width = Elliptical Slot Centroid = Elliptical Slot Area = N/A N/A N/A N/A ft2 feet feet ft2 Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) 0.00 0.34 0.67 1.00 4.00 2.00 1.33 0.75 Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) User Input: Vertical Orifice (Circular or Rectangular) Invert of Vertical Orifice = Depth at top of Zone using Vertical Orifice = Vertical Orifice Diameter = Zone 2 Circular Not Selected ft {relative to basin bottom at Stage = 0 ft) ft {relative to basin bottom at Stage = 0 ft) inches Calculated Parameters for Vertical Orifice Vertical Orifice Area = Vertical Orifice Centroid = Zone 2 Circular Not Selected ft2 feet User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Overflow Weir Front Edge Height, Ho = Overflow Weir Front Edge Length = Overflow Weir Slope = Horiz. Length of Weir Sides = Overflow Grate Open Area %= Debris Clogging %= Not Selected Not Selected ft (relative to basin bottom at Stage = 0 ft) feet H:V (enter zero for flat grate) feet %, grate open area/total area °la User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Depth to Invert of Outlet Pipe = Circular Orifice Diameter = Not Selected Not Selected User Input: Emergency Spillway (Rectangular or Trapezoidal) Spillway Invert Stage= Spillway Crest Length = Spillway End Slopes = Free board above Max Water Surface = ft {distance below basin bottom at Stage = 0 ft) inches ft {relative to basin bottom at Stage = 0 ft) feet H:V feet Calculated Parameters for Overflow Weir Height of Grate Upper Edge, Ht = Over Flow Weir Slope Length = Grate Open Area / 100-yr Orifice Area = Overflow Grate Open Area w/o Debris = Overflow Grate Open Area w/ Debris = Not Selected Not Selected feet feet should be≥4 ft2 ft2 Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Outlet Orifice Area = Outlet Orifice Centroid= Half -Central Angle of Restrictor Plate on Pipe = Not Selected Not Selected N/A N/A Calculated Parameters for Spillway Spillway Design Flow Depth= feet Stage at Top of Freeboard = feet Basin Area at Top of Freeboard = acres ft2 feet radians Routed Hydrograph Results Design. Storm Return Period = One -Hour Rainfall Depth (in) = Calculated Runoff Volume (acre -ft) = OPTIONAL Override Runoff Volume (acre -ft) = Inflow Hydrograph Volume (acre -ft) = Predevelopment Unit Peak Flow, q (cfslacre) Predevelopment Peak O (cfs) _ Peak Inflow Q (cfs) _ Peak Outflow O (cfs) _ Ratio Peak Outflow to Predevelopment Q = Structure Controlling Row = Max Velocity through Grate 1 (fps) = Max Velocity through Grate 2 (fps) = Time to Drain 97% of Inflow Volume (hours) = Time to Drain 99% of Inflow Volume (hours) = Maximum Pond ing Depth (ft) = Area at Maximum Ponding Depth (acres) = Maximum Volume Stored (acre -ft) = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year 0.53 1.07 0.89 1.18 1.43 1.82 2.13 2.47 3.35 0.097 0.362 0.216 0,313 0.449 0.719 0.903 1.147 1.717 0.270 0.390 0.550 0.885 1.135 1.450 2.175 0.097 0.362 0.269 0.389 0.549 0.884 1.134 1.448 2,173 0.00 0,00 0.01 0.01. 0.14 0.53 0.76 1.06 1.72 0.0 0.0 0.1 0.1 1.0 3M 5.7 8.0 12.9 1.5 54 4.0 5.8 8.1 13.0 16.6 21.1 31.5 0.1 0.3 0.2 0.3 03 0.4 0.4 0,4 0.4 N/A N/A N/A 2.5 0.3 0.1 0.1 0.1 0.0 Plate Plate Plate Plate Plate Plate Plate N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 20 33 30 34 39 47 53 59 75 22 37 33 38 43 52 59 66 84 0.41 1.25 0.99 1.32 1.70 2.36 2.77 3.00 3.00 0.23 0.35 0.31 0.36 0.43 0.55 0.63 0.67 0.67 0.082 0.321 0.237 0.349 0.499 0.817 1.057 1.213 1.213 X-axis Left Y -Axis Right Y -Axis Detention Basin Outlet Structure Design UD-Detyention, Version 3.07 (February 2017) 35 30 25 20 S L 15 10 0 0.1 500YR IN - ++ 500YR OUT 100YR IN - a - 100YR OUT 50YR IN - - 50YR OUT r 25YR IN aa6 25YROUT 10YRIN _ - + 10YR OUT SYRIN SYR OUT ZYRIN a. a ZYR OUT EURV IN a. • EURV OUT WQCV IN - WQCV ,,,,-. OUT AI 407407 Aar_ • _. _.. 1 DIME [hr] 10 01 10 DRAIN TIME [hr] User Area ift^2J Interpolated Area ift"2j Summary Area jft^21 Volume Ift"3J ---a -- ::::1umeIft^3J ets' • , .s • - Su rnmary Outflow l.cfsl S -A -V -D Chart Axis Override minimum bound maximum bound 100 Detention Basin Outlet Structure Design Time Interval 5:64 min Hyd rug mph Constant 0.886 Outflow Hydrograph Workbook Filename: Storm Inflow Hydrographs UD-Detention, Version 3.07 (February 2017) The user can override the calct'ated hydregraphs from this workbook with inflow hydrographs developed in a separate program. SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK TIME \WQCV (cfsJ EURV !ifs] 2 Year (cfsJ 5 Year [ifs] 10 Year [cfs] 25 Year (cfsJ 50 Year (cfsJ 100 Year [cis] 500 Year [ifs] 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:05:38 0.00 0,00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:11:17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:16:55 0.07 0.24 0.18 0.26 0.36 0 57 0.72 0.92 1.35 0:22:34 0.18 0.64 0.48 0.69 0.97 1.54 1.96 2.49 3.70 0:28:12 0.46 1.65 1.24 1.78 2.49 3.96 5.04 6.40 9.49 0:33:50 1.26 4.55 3.41 4.89 6.83 10.88 13.85 17.58 26.05 0:39:29 1.46 5.36 4.01 5.77 8.09 12.97 16.58 21.12 31.52 0:45:07 1.38 5.11 3.81 5.50 7.72 12.39 15.85 20.20 30.19 0:50:46 1.26 4.65 3.47 5.00 7.03 11.28 14.43 18.39 27.48 0:56:24 1.11 414 3.08 4.46 6.27 10.09 12.92 16.49 24.68 1:02:02 0.95 3.56 2.65 3.83 5.41 8.73 11.19 14.31 21.48 1:07:41 0.83 3.11 2.31 3.35 4.72 7.60 9.74 12.43 18.67 1:13:19 0.75 2.81 2.09 3.03 4.27 6.89 8.83 11.28 16.92 1:18:58 0.60 2.31 1.71 2.49 3.52 5.70 7.32 9.38 14.12 1:24:36 0.43 1.87 1.39 2.02 2.87 4.67 6.01 7 71 11.65 1:30:14 0.36 1.43 1.05 1.54 2.20 3.61 4.67 6.02 9.14 1:35:53 0 26 1.05 0.77 1.14 1 64 2.70 3 52 4.56 6.98 1:41:31 0.19 0.77 0.56 0.83 1.19 1.95 2.55 3.33 5.15 1:47:10 0.15 0.60 0.44 0.65 0.92 1.51 1.96 2.54 3.90 1:52:48 0.13 0.49 0.36 0.53 0.76 1.24 1.61 2.08 3.17 1:58:26 0.11 0.42 0.31 0.45 0.64 1.05 1.36 1.76 2.67 2:04:05 0.09 0.37 0.27 0.40 0.57 0 92 1.19 1.54 2.34 2:09:43 0.09 0.33 0.25 0.36 0.51 0.83 1.07 1.38 2.09 2:15:22 0.08 0.31 0.23 0.33 0.47 0.76 0.99 1.27 1.92 2:21:00 0.06 0.23 0.17 0.24 0.35 0.56 0.72 0.93 1.42 2:26:38 0.04 0.17 0.12 0.18 0.25 0.41 0.53 0.68 1.03 2:32:17 0.03 0.12 0.09 0.13 0.19 0.30 0.39 0.50 0.76 2:37:55 0.02 0.09 0.07 0.10 0.14 0.22 0.29 0.37 0.56 2:43:34 0.02 0 06 0.05 0.07 0 10 0 16 0.21 0.27 0.41 2:49:12 0 01 0.04 0.03 0.05 0.07 0 11 0.15 0.19 0.29 2:54:50 0.01 0.03 0.02 0.03 0.05 0.08 0.11 0.14 0.21 3:00:29 0.00 0.02 0.01 0.02 0.03 0.05 0.07 0.09 0.15 3:06:07 0.00 0.01 0.01 0.01 0.02 0.03 0.04 0.06 0.09 3:11:46 0.00 0.01 0.00 0.01 0.01 0.02 0.02 0.03 0.05 3:17:24 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.02 3:23:02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:28:41 0 00 0 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:34:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:39:58 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:45:36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:51:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:56:53 0.00 0.00 0.00 0.00 0.00 0.00 0 00 0.00 0.00 4:02:31 0.00 0 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:08:10 0 00 0 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:13:48 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:19:26 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:30:43 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:36:22 0.00 0.00 0.00 0.00 0.00 0 00 0 00 0.00 0.00 4:42:00 0 00 0.00 0.00 0.00 0 00 0 00 0 00 0 00 0.00 4:47:38 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:53:17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:58:55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:04:34 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:10:12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:15:50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:21:29 0.00 0 00 0.00 0.00 0 00 0 00 0.00 0 00 0.00 5:27:07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:32 :46 0 00 0 00 0.00 0.00 0 00 0.00 0.00 0.00 0.00 5:38:24 0.00 0.00 0.00 0.00 0 00 0 00 0.00 0 00 0.00 5:44:02 0.00 0 00 0.00 0.00 0 00 0 00 0.00 0 00 0.00 5:49:41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:55:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:00:58 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:06:36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:12:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:17,53 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:23:31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:29:10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:34:48 0.00 0.00 0.00 0.00 0.00 0.00 0 00 0.00 0.00 6:40:26 0 00 0.00 0.00 0.00 0 00 0 00 0 00 0 00 0.00 6:46:05 0.00 0.00 0.00 0.00 0 00 0 00 0.00 0 00 0.00 APPENDIX G Overflow Weir Design Calculations Weir Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Brahma Overflow Weir Trapezoidal Weir Crest Bottom Length (ft) Total Depth (ft) Side Slope (z:1) Calculations Weir Coeff. Cw Compute by: Known Q (cfs) Depth (ft) 2.00 1.50 1.00 0.50 0.00 -0.50 Sharp 6.00 1.00 too = 8.10 Known Q = 3.58 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (fits) Top Width (ft) Brahma Overflow Weir Wednesday, Mar 6 2019 0.33 3.580 2.09 171 6.66 2 Weir W.S. 10 12 14 16 18 Depth (ft) 2.00 1.50 1.00. 0.50 0.00 -0.50 Length (ft) golder.com DRAINAGE REPORT REVIEW CHECKLIST Design storm ❑ Release rate — See #2 Below URBANIZING or NON -URBANIZING Overall post construction site imperviousness Soils types ❑ Discuss how the offsite drainage is being routed — See #3 Below Conclusion statement must also include the following: xl xl Indicate that the historical flow patterns and run-off amounts will be maintained in such a manner that it will reasonably preserve the natural character of the area and prevent property damage of the type generally attributed to run-off rate and velocity increases, diversions, concentration and/or unplanned ponding of storm run-off for the 100 -year storm. How the project impacts are mitigated. Construction Drawings ❑ Drawings stamped by PE, (scanned electronic PDF preferred) Drainage facilities ❑outlet details — See #2 Below ❑Spillway — See #4 Below Maintenance Plan ❑ Frequency of onsite inspections ❑Repairs, if needed ❑Cleaning of sediment and debris from drainage facilities ❑Vegetation maintenance ❑ Include manufacturer maintenance specifications, if applicable Comments: 1. The basins change acreage between pre- and post -development. Please compare basins of the same acreage or if the runoff will be routed to a different design point, please compare design points before and after development. 2. T.O. Basin elevation on the Drain Basin Perforation Detail shows the top of the basin being at 5485.33 and the stage storage table for the pond shows the 100 year storm elevation being at 5485.5. The spillway elevation shows being at an elevation of 5485.00. The outlet and spillway will overtop before the 100 year storm volume is detained. These releases are not accounted for on the UD-Detention outlet worksheet. The UD-Detention worksheet orifice information and the perforation details do not match. The elevations are different as well as X Project Name: USRI9-0026 CAM Brahma Compressor The purpose of this checklist is to provide the applicant's Engineer a basic list of items that County Staff will review in regards to a drainage report. The drainage design shall meet the requirements of the Weld County Code and commonly accepted engineering practices and methodologies. A detention pond design (or other stormwater mitigation design) is appropriate for projects which have a potential to adversely affect downstream neighbors and public rights -of -way from changes in stormwater runoff as a result of the development project. The design engineer's role is to ensure adjacent property owners are not adversely affected by stormwater runoff created by development of the applicant's property. REPORT (© = complete, ❑ = required) Stamped by PE, scanned electronic PDF acceptable Certification of Compliance ❑ Variance request, if applicable Description/Scope of Work ❑ Number of acres for the site - See #1 Below ❑ Methodologies used for drainage report & analysis Design Parameters xi Xl xl xi X xl 4/11/2018 Weld County Department of Public Works' Development Review 1111 H Street, Greeley, Co 80631 I Ph: 970-400-3750 I Fax: 970-304-6497 www.weldgov.com/departments/public_works/development_review/ DRAINAGE REPORT REVIEW CHECKLIST the total area of each row. An outlet structure with an orifice for water quality and a separate plate/orifice for detention release may be required. 3. Please provide a drawing showing off -site basins as well as calculations and a detailed grading plan showing how off -site flows will be routed around the site. Include design information for any swales or berms utilized. Page 6 of the report indicates that CR 65 will stop off -site flows from entering the site. The weir report for the spillway shows a total 0 of 3.58 cfs. The total 100 -year storm runoff amount from the site is 21.1 cfs. The spillway must be able to pass this quantity with less than 6" of depth over the spillway. See #2 above in reference to the spillway elevation. The emergency spillway elevation must be tied back into the top of the embankment using a maximum slope of 4:1. It appears from the provided detail that the current slope is 1:1. The UD-Detention worksheet shows the pond overtopping at 3 feet in depth. Please clarify whatis going on at this elevation. A 40 hour drain time is required for the WQCV. The type of pond that was chosen on the UD-Detention worksheet is a retention pond. This pond would be an extended detention basin. Weld County Code Section 23-12-90.A.5 states "The outlet pipe must contain a minimum of two concrete cutoff wal s embedded a minimum of 18 inches into undisturbed earthen soil. The cutoff walls must be a minimum of 8 inches thick. The outlet pipe bedding material must consist of native earthen soil, not granular bedding material, to at least the first downstream manhole or daylight point." Show these anti -see collars on the construction drawings. 9. Please designate the top of berm elevation. Ensure that the detention pond has 1' of freeboard above the 100 - year stormwater elevation. 10. Once the revised design and drainage report have been submitted, the County may provide additional comments in addition to the ones listed above. Depending on the complexity of the changes made, a full 28 -day review period may be required. 11. Please provide a written response on how the above comments have been addressed when resubmitting the drainage report. Thank -you. 4/11/2018 Weld County Department of Public Works' Development Review 1111 H Street, Greeley, CO 80631 I Ph: 970"400-3750 I Fax: 970304-6497 www.weldgov.com/departments/public_works/development_review/ SOUND MODELING REPORT BRAHMA COMPRESSOR STATION SUMMIT MIDSTREAM NIOBRARA, LLC WELD COUNTY, CO Prepared by 6SGM 118 West Sixth Street, Suite 200 Glenwood Springs, CO 81601 970.945.1004 970.945.5948 fax Brahma Compressor Station June 2019 TABLE OF CONTENTS 1.0 Introduction 2.0 Sound Fundamentals 3.0 Existing Conditions 4.0 CRS 25-12-103 Sound Standards 5.0 Brahma Compressor Station Sound Modeling 5.1 Sound Modeling Methodology 5.2 Sound Sensitive Receptors 5.3 Sound Modeling Results 6.0 Conclusion LIST OF TABLES Table 3-1: Existing Sound Levels at Proposed Brahma CS Table 4-1: CRS 25-12-103 Sound Standards Table 5-1: Sound (dB(A)) levels at Different Frequencies for Proposed Equipment Table 5-2: Modelling Scenarios Employed Table 5-3: Sound Reception Locations LIST OF FIGURES Figure 1-1: Brahma Compressor Station Vicinity Map Figure 3-1: Brahma — Existing Sound Levels (dB(A)) Figure 5-1: Brahma Compressor Station Site Plan Figure 6-1: Scenario 1 Modelling Results LIST OF APPENDICES Appendix A - Site Photos 1 3 3 5 5 5 6 8 8 4 5 5 8 8 2 4 7 9 Sound Modeling Report j Brahma Compressor Station June 2019 1.0 Introduction This report provides a sound modeling assessment of the proposed Brahma Compressor station operated by Summit Midstream Niobrara, LLC (summit) in relation to surrounding lands, existing sound levels, and how the proposed compressor station would adhere to guidance in the Colorado Revised Statutes (CR5) 25-12-103. The sound modeling process includes currently proposed mechanical equipment, specifically the specified compressor engines. The Brahma Compressor Station (4O05814.15 N, 104°26'46.77" W) is located 7.3 miles west of Hereford, Colorado, and miles south of the Wyoming border. The site is surrounded by rangeland, agricultural fields, with oil and gas operations to the east; the nearest single-family home (associated with ranching) is approximately 1.4 miles to the east. Figure 1.1 identifies the site. To assess the predicted sound levels or the proposed operations, engine manufacturer sound data of the proposed equipment was used. The following is provided in this report: • A brief introduction to the fundamentals of sound • A brief review of applicable state and county sound standards • Existing conditions • Discussion of sound modeling methodology and results Sound Modeling Report 'I Brahma Compressor Station June 2019 Figure 14: Brahma Compressor Station Vicinity Map Proposed Brahma Compressor Station VICINITY MAP PROPOSED BRAHMA COMPRESSOR. STATION r1Proposed Brahma Compressor Site County Road Stream Township/Range/Section L_ I Slab Bu.ylt_3dry Disclaimer: ih s prod.tct is for irfcrnttiand :)urµoses end mat FIR have bees preparac for, or be suitahlc for legal, enailcerirq• cr sun:eyinq purposes. Users of this information L:har.lc renew or consult the primary data and i ifcwin &tion 5c.0 ies tt, osccrt5ii •i tie usaiiliry & the infouraticn. The rnaps zr€ distr but2c "AS -IS- without warranties Df any f?ird, either exprrnssec cr i n�lied, in iitrcirg bit rt)t li-nitcd to w;rrantias cif suitability to a partictdar pu•pozeor use. 5GM IIaVs' bin M,:,uIneiri Oki -woad Spnn:, CO 81 bD1 S7C.3349040 ' •.hvm.5Q IfFI-C.CCin D.55 1 Ca:e: CVl4rf2019 Location: 4O.9706a, Anil. 4 462 Createc By SCf1MJ Urawr Dy: 'Dr 2 SCALE: 1 ' = miles Miles Sound Modeling Report 2 Brahma Compressor Station June 2019 2.0 Sound Fundamentals Sound is most commonly experienced by people as pressure waves passing through the air. These rapid changes in air pressure are processed by the human ear as the sensation of sound. The rate at which the pressure fluctuates is called the frequency. Frequency is measured as the number of oscillations per second, or Hertz (Hz). Audible frequencies range from 20 — 20,000 Hz for a healthy human ear. Pitches at the lower end of this range are commonly experienced as a "rumble" or "boom." Pitches at the higher end or the range might be described as a "screech" or a "hiss". Lower frequencies can have other impacts, such as causing windows to rattle and similar effects. Sound can vary in volume as well as in pitch. This volume is usually expressed as decibels (dB). The sound you hear generally comes in two forms. Environmental sound generally comes from a variety of distant sources, such as distant traffic, wind in trees, and distant industrial or farming activities. Distant sound sources such as these create a low-level "background sound" in which no individual source is identifiable. Background sound stays relatively constant moment to moment but can vary through the day in accordance with natural forces or the daily pattern of human activity. Superimposed on this background sound is a succession of distinct, identifiable noisy events of brief duration. This can include the passing of single vehicles, aircraft flyovers, and the passage of sirens. Detailed acoustical terms have been provided in Appendix A — Glossary of Acoustical Terms. 3.0 Existing Conditions on May 29, 2019, existing sound levels were collected at the proposed Brahma Compressor Station location. Sound monitoring occurred at the four cardinal directions from the proposed pad, approximately 350 -feet from the pad center. At each location, approximately 14 minutes of sound levels were collected to establish average daytime sound levels. Conditions during the study were sunny, approximately 550 F, and winds were 10-15 mph from a southerly direction. Average existing sound levels were 54.59 dB(A) (see Table 3-1: Existing Sound Levels at Proposed Brahma CS, and Figure 2: Brahma- Existing Sound Levels (dBA)). See Appendix BA— Site Photos for conditions at sampling locations. Most sounds were associated with truck traffic on the adjacent road. Sound Modeling Report 3 Brahma Compressor Station June 2019 Table 3-1: Existing Sound Levels at Proposed Brahma CS Existing Sound Levels (dB(A)) on 5/29/2019 Interval South West East North 0:00:00 46.3 67.5 60.1 46.3 dB(A) 0:00:59 43.7 61 61.6 43.7 dB(A) 0:01:58 43.3 52.9 64.8 43.3 dB(A) dB(A) 0:02:57 40.5 63 51.9 40.5 0:03:56 54.6 60.5 56.5 54.6 dB(A) 0:04:55 54.8 61.6 56.5 54.8 dB(A) dB(A) dB(A) 0:05:54 53.6 68.5 61.6 53.6 0:06:53 46 60.3 53.4 46 0:07:52 46.3 69.7 59.7 46.3 dB(A) 0:08:51 51.4 61.5 52.2 51.4 dB(A) 0:09:50 45.4 53 52.8 45.4 dB(A) 0:10:49 56.7 56.6 61.7 56.7 dB(A) 0:11:48 54.8 67.1 49.5 54.8 dB(A) 0:12:47 56.4 68.9 53.8 56.4 dB(A) 0:13:46 54.2 65.5 51.5 54.2 dB(A) AVG 49.87 62.51 56.51 49.87 54.69 Figure 3-1: Brahma - Existing Sound Levels (dB(A)) 75 70 65 60 55 50 45 40 35 Bra hma - Existing Sound Levels (dB(A)) w1� .6s a'V,.+,, a ` 1 • r l Si.w a",f l . ` l'�1 a ` r • fi{„ ' . a `'V a ` —West s • J •CSC{ 1 ` East l L ' ` (�'1, a J 4.0 , IQ) 1 h'YSouth North .10 ` N t N`i` atiti\ �l a ♦V + el,' ® Sound Modeling. Report 4 Brahma Compressor Station June 2019 4.0 CRS 25-12-103 Sound Standards The modeling analysis was developed to predict operational sound levels at adjacent properties and verify compliance or operations with the CRS 25-12-103 sound standards. The CRS code establishes permissible sound levels by type of property and time of day. For the purposes of the law, sound is measured as "Levels of sound radiating from a property line at a distance of twenty-five feet" and any sound "In excess of the d8('A) established for the following time periods and zones shall constitute prima facie evidence that such sound is a public nuisance". Defined sound levels are provided in Table 4-1. Table 4-1: CRS 25-12-103 Sound Standards Zone 7:00 a: m. to next 7:00 p.m. 7:00 p.m. to next 7:00 a.m. Residential 55 dB (A) 50 dB (A) Commercial 60 dB (A) 55 dB (A) Light Industrial 70 dB (A) 65 dB (A) Industrial 80 dB (A) 75 dB (A) The stringency of the sound requirements depends on the zoning of the site, which, based on reference information, is zoned as Light Industrial. 5.0 Brahma Compressor Station Sound Modeling 5.'1 Sound Modeling Methodology The sound modeling was completed with the use of 3D computer sound modeling software. All models in this report were developed with SoundPlan Essentials 4.1 software using the ISO 9613-2 standard. Sound levels are predicted based on the locations, sound levels, and frequency spectra of the sound sources, and the geometry and reflective properties of the local terrain, buildings, and barriers. The predicted sound levels only take into consideration the sound produced by the compressor engines and no other sources, such as traffic, other site operations, neighboring operations, other human activity, or environmental factors. The proposed compressor engine equipment's sound level data used in the Brahma Compressor Station modeling were sourced from equipment manufacturer data (caterpillar Inc.), relying on proposed project design documentation. The modeling results predicted are dependent on equipment and mitigation orientation as indicated on current project documentation. Table 5-1 lists the modeled equipment for the site. Table 5-1: Sound (dB(A)) levels at Different Frequencies for Proposed Equipment Frequency (Hz) 125 250 500 1000 2000 4000 Caterpillar G3608 Levels (dB(A)) Sound 114 112.8 114.9 116 119.8 120.3 As the exact location of compressors and effectiveness of any potential exhaust systems are not precisely known, results are considered preliminary. Similarly, none of the other equipment at the Sound Modeling Report 5 Brahma Compressor Station June 2019 compression station (dehydration units, etc.) was modeled, either as a static building or a source for sound due to the lack of information about those factors. However, exhaust systems generally produce sounds in the 85-dB(A) range, which is much less than the 115-dB(A) range of the actual engines. In this model, the compressor building listed in the provided site plan did not include any height details. Therefore, the building was modeled as a uniform, 4m tall building containing the two listed compressor engines, and otherwise conforming to the dimensions specified. Figure 5-1 shows the Brahma Compressor Station plot plan and mechanical equipment layouts used in the model. 5.2 Sound Sensitive Receptors The Nosie sensitive receptor locations were chosen to be consistent with the requirements of CRS 25-12-10 , specifically that sound levels radiating from the site perimeter (property boundary) at 25 feet or more, in excess of the dB(A) established for the established time and zone shall constitute evidence that the sound is a public nuisance. As such, receptor locations were chosen to give the largest sound level reading at 25 ft from the site, representing potential regulatory measurement points, should a complaint be made. Of note, the actual property boundaries are variable in distance from the compressor building. 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' I - - _ I. d'RAIRN;G2(15/1 GI BRAHMA VICINITY PI_vT Y1ti' COMP: PLiI.Nr SUMMIT COMPRESSOR MIDSTREAM AND LOCATION AND NOTES STA1ION FIAT'S, — UT I CULOF1DC' 9-N1N s L.s1ry i { AS ra TED EWG NO, I DESCRIPTION NO: REVISION BY CIIIs° a APP7D DATE a EstE..rcti trot IS]wt 9'e :Ills ske utivia CHECtiEG. aI I9 ..-. �_ 1 046 CAM IYnailli Till aoL,T a- I �'t': COIF � 2I �{i �I KRA+ Hr. Nil BRA —SW -00111 FerV 0 ?tit is • J Sound Modeling Report ? Brahma Compressor Station June 2019 5.3 Sound Modeling Results One scenario was modeled, as the site plan already included an enclosure around the compressor engines. The description is found in Table 5-2, and the results of the sound modeling is found in Table 5-3 Table 5-2: Modelling Scenarios Employed Modeled Scenario Description Scenario 1 Compressor Compressor rating of Engines' mechanical sounds a Sound are modeled inside Transmission Class the (SIC) Building, which has 25. Table 54: Sound Reception Locations 1 SCENARIO Location 1, 25 ft West of Property Line 57.9 Location 2, 25 ft North of Property Line 50.3 Location 3, 25 of Property Line 50.6 ft East Location 4, 25 ft South of Property Line 64.2 A verage dB( A) 55.75 Allowable Sound Level, 25 ft from the Property Line 70.0 Day / 65.0 Night 6.0 Conclusion Predictive sound models were created to represent the proposed operations at the Brahma Compressor Station. Sound sensitive receptors locations included in the models were placed in accordance with the sound standards of CRS 25-12-103. The numerical and graphical sound modeling results for Scenario I (compressor building rated to STC 25) indicate that the proposed operations at the Brahma Compressor Station are predicted to fall within the CRS sound limits at all 4 receiver locations. Sound Modeling Report Brahma Compressor Station June 2019 Figure 64: Scenario 41 Modelling Results Sound Modeling Report 9 Brahma Compressor Station June 2019 Appendix A Site Photos Sound Modeling Report 10 6SGM Project Name: Site Brahma Sound Study Proposed Photo Point 1 (P1) North sampling location • Photo Point 2 (P2) East sampling location Location: Task Brahma CS 1 oft.' Jr } -j ,'•'_'N^L l �- 1� y• .-.a eta` " �n7N�� •an nA t - .a ._p 6y�,!y h - - •: ' 1 !1.4a �• I . T 'r,, y,. L I _ ., "t.'hy� I I •;iIf , < _ w.ii ..�-,� �{.a^ �`r, a..{.tiY i* st a y:l py�,Fs' _ * •'e • 'y ��.r 1 h' Y"t^ L' •A ?',� .4 n"y. eaW y^.• •i: a T.r Y1 r�1�� ,'Li�;4 _ R ,'. ) 1J G • r .) {!''1 1 r_ J.�f•f.t{ 1 l.jnyty ', r< .•'rf ill- A L ` �5M Q ti ^ • .% 7 . t .Y.!1 % ♦:4:f f f I '�A. •R' f> 1J 1. r�r, 1 t"'>.• �z d •-.• . 9k •11 j'; ..• ' r C ,}1t ,�! ar rt ... e ,As . 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