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Home My WebLink About20212694.tiffEXHIBIT INVENTORY CONTROL SHEET CASE USR21-0009 - DPOC, LLC Tyler Exhibit Submitted By Page # Description Planning A. Commission Resolution of Recommendation Planning B. Commission C. Planning Services D. Applicant E. Applicant F. G. H. J. K. L. M. N. O. P. Q. R. S. T. U. V. Summary of Hearing (Minutes dated 9/7/2021) PowerPoint Presentation Final Drainage Report (Received 9/21/2021) Division of Water Resources Certificate of Compliance (Received 9/21/2021) 2021-2694 • CASE NUMBER: • APPLICANT: • PLANNER: USR21-0009 DPOC, LLC CHRIS GATHMAN • REQUEST: A SITE SPECIFIC DEVELOPMENT PLAN AND USE BY SPECIAL REVIEW PERMIT FOR OIL AND GAS SUPPORT AND SERVICE (AN OFFICE/SHOP BUILDING FOR AN OIL AND GAS EXPLORATION & PRODUCTION BUSINESS ALONG WITH OUTDOOR STORAGE OF OIL AND GAS PRODUCTION AND EXPLORATION EQUIPMENT) ALONG WITH A COMMUNICATION TOWER UP TO 45 -FEET IN HEIGHT AND WITH MORE THAN THE NUMBER OF CARGO CONTAINERS ALLOWED BY SECTION 23-3-30 OF THE WELD COUNTY CODE (UP TO 10 CARGO CONTAINERS PROPOSED) IN THE A (AGRICULTURAL) ZONE DISTRICT. • LEGAL DESCRIPTION: S2 SECTION 9, T8N, R6OW OF THE 6TH P.M., WELD COUNTY, COLORADO. • LOCATION: WEST OF AND ADJACENT TO CR 103; 0.50 MILES SOUTH OF CR 96. 1 PAGE OF DOCUMENT INCLUDED IN PAPER FILE. REMAINDER RETAINED ELECTRONICALLY IN TYLER. 0 • e %Jt*t 't sEn %niQ •a3 concern 3 rag tP s f n op tf=y w.1 too s tso. .id twrotre ttoo Coca r t Iv Ptsrnning Con amena nfa tl oatri of Coastlty Ccx tea` Ootts hearing; • w f be flat? at W Eta C LI N ' Js ° M I N I S T F? A ri O N E3 CM_ MAW' C roc:,lo-7y. CO SOti_3 •a_s.rs•tart *1• a awe A %Ken' �,�.�. Kfl-+. qv e-1 *tie +.1— rat' a.— a Op. mall a+�. ease a r'y anr%..•A•• aft. e%.r s u r -e .kr.s. S arni ij r1Yr air. SS a�vr�aws v eau a, % - a nt, ..w ..... eI+. ...-s • ..• a e ar• a _*-S µam "" ++�. ' an is • a.��i► alai a ti . - �J'r1w. a•rnwM si t a.. r aarM' girt i a a ' a_ �. • � t a•. - riAl�►'".r a f .�;L. ranee . _e- s Sr .e er + an 7` ,- _fl en ��~-� sle 7r� tales p a M • at 'n .ar•� ea •..a• * aa a -s .a a • aI n a Y a r+ a0�i s _r ea". e asap 111 a % Via* ..�� r v r+ - ear., M. ♦ I. r - ...a.e • s T -a• -mss' a a a� • a�arsu► .res� ago v} •"��►... gl= -w afi •"`a in Ali Sat a.. +4 . - - • a a'.-. isIr[n-OS 0 r..,* S ri SI•Z• illieS avai calskes.Ra_Or." ti .r • 't a` r X ir it /0 '�' p A Weld County Drainage Code Certificate of Compliance Weld County Case Number: USR21 - 0009 Mallard Exploration Field Office Parcel Number: 054109400005 Legal Description, Section/Township/Range: Section 9, Township 8 South, Range 60 West of the 6th PM Date: 09/21/2021 I MICHAEL PALIZZI , Consultant Engineer for Mallard Exploration (Applicant), understand and acknowledge that the applicant is seeking land use approval of the case and parcel in the description above. I have designed or reviewed the design for the proposed land use set for in the application. I hereby certify, on behalf of the applicant, that the design will meet all applicable drainage requirements of the Weld County Code with the exception of the variance(s) described on the attached exhibits. This certification is not a guarantee or warranty either expressed or implied. Engineer's Stamp: ock ..c� A A..:s •P e ' . VN' • • N� 55968 Engineer of Recor S ature 1. 2. 3. Describe List Describe Demonstrate that result the there of design the the the are project. hardship proposed that no criteria granting adverse for of alternative the impacts which of Weld the the variance County with from variance Variance Request (If Applicable) being health, -of requested. the -way intent safety, and/or of the Pc.�'•••..., and offsite FSSi0Np,� Weld general ,,,, `\IA as and a engineering stormwater Code will is still being of adequately which rationale runoff requested. a to variance which the protect public supports is public rights welfare °1\11 Code. properties County Public Works Director/Designee Review (If Applicable) Public Works Director/Designee Name Date of Signature Signature Approved Denied Comments: Department of Public Works I Development Review 1111 H Street, Greeley, CO 80631 I Ph: 970-304-6496 www.weldgov.com/departments/public_works/development_review 08/02/2019 Drainage Report Checklist Project Name: The purpose of this checklist is to assist the applicant's Engineer with developing a drainage report that supports the intent of the Weld County Code using commonly accepted engineering practices and methodologies. Is the project in the MS4? Yes x No If yes, the following requirements in blue apply. See Chapter 8, Article IX of the Weld County Code. Report Content Weld County Case Number X Certificate of Compliance signed and stamped by a Colorado Licensed PE X Description/Scope of Work X Location (County Roads, S -T -R) � Nearby water features and ownership x x x x x ■ x x Total acres vs. developed acres Hydrological soil types/maps FEMA Flood Zones Urbanizing or non -urbanizing Methodologies used for report & analysis (full spectrum is not accepted) Base Design Standard used for permanent control measure design in the MS4 Discussion of offsite drainage routing Conclusion statement indicating that the design will adequately protect public health, safety, and general welfare and have no adverse impacts on public rights -of -way or offsite properties Hydrology and Hydraulic Analysis Design Storm / Rainfall Information (NOM Atlas or Local Data) Release Rate calculations Post construction site imperviousness x Hydrologic calculations (historic & developed basins) x Hydraulic calculations for proposed drainage improvements (swales, culverts, riprap, pond, outlet, spillway, WQCV outlet, etc.) x Detention/WQCV calculations x x Comments: Construction Drawings x x x x x x x x x x x x x x Stamped by PE Engineering scale & north arrow Property lines, rights -of -way, and easements 1' Contours & elevations (existing & proposed) Pre- and post -development drainage basins Arrows depicting flow direction Time of concentration critical path Drainage design points Improvements labeled Permanent control measure and associated drainage features labeled 'No Build/No Storage', include design vo ume Cross sections for open channels, profiles for pipes Elevations for inverts, flow lines, top of grates orifice(s), etc. Pipe specs (size, material, length, slope) Outlet and spillway details Maintenance Plan x x x x x Frequency of onsite inspections Repairs, if needed Cleaning of sediment and debris Vegetation maintenance Manufacturer maintenance specifications, if applicable Other Required Documents (If Applicable) Variance Request and documentation— explain hardship, applicable code section, and proposed mitigation. Variances will not be granted for the Base Design Standard requirement in the MS4. Department of Public Works I Development Review 1111 H Street, Greeley, CO 80631 I Ph: 970-304-6496 I www.weldgov.com/departments/public_works/development_review 8/14/2019 LAMP RYNEARSON 4715 Innovation Dr., Ste. 100 Fort Collins, CO 80525 [P] 970.226.0342 [F] 970.226.0879 LampRynearson com i September 2021 Final Drainage Report Mallard Exploration Field Office Prepared for: vtw twit MALLARD EXPLORATION Project No. 0220014.04 Leaving a Legacy of Enduring Improvements to Our Communities Lamp Rynearson Purpose Statement I I IIai 1 iii I 1 II i Copyright Lamp, Rynearson, Inc., 2020. All rights reserved. FINAL DRAINAGE REPORT Mallard Exploration Field Office Weld County, Colorado CERTIFICATION OF ENGINEER I hereby certify that this preliminary study for the Mallard Exploration Field Office site was prepared by me, or under my direct supervision, in accordance with the provisions of the Weld County Public Works Storm Drainage Criteria for the owners thereof Michael Palizzi, PE State of Colorado Registration No 55968 FINAL DRAINAGE REPORT MALLARD EXPLORATION FIELD OFFICE Weld County, Colorado Table of Contents A General Location & Description 1 Location B HISTORIC DRAINAGE 1 Basin Description 2 Existing Description C DESIGN CRITERIA 1 Hydrologic Criteria 2 Hydraulic Criteria D DRAINAGE FACILITY DESIGN 1 General Concept 2 Specific Details a Rational Method Calculations b Water Quality & Detention Ponds c Erosion Control Maintenance Conclusions E References 1 1 1 1 1 2 2 2 3 3 3 4 4 5 6 7 7 7 Appendices Appendix A — Hydrologic Computations 1 Vicinity Map 2 Future land Use Map 3 Existing Drainage Map 4 Proposed Drainage Map Appendix B — Hydraulic Data 1 FEMA Flood Insurance Rate Map 2 NRCSi Soils Data 3 Commerce City Reference Material 4 Property Report Appendix C — Calculations 1 Impervious Calculations 2 Rational Method Calculations 3 Swale Calculations PRELIMINARY DRAINAGE REPORT MALLARD EXPLORATION FIELD OFFICE WELD COUNTY, COLORADO A. General Location & Description This preliminary drainage report contains details for the overall drainage design for the Mallard field office site The report also includes information on the historic drainage patterns for the site Final drainage design information for the proposed site considers the developed site draining to a proposed detention pond located in the southeast corner of the site Flows will be captured and released into an existing road site ditch 1. Location The proposed Mallard Exploration field office site is located in the Southeast % of Section 9, Township 8 South, Range 60 West of the 6th P M within Weld County, Colorado More specifically, the site is located directly next to County Road 103, approximately 3/4 of a mile South of County road 96 and approximately 2 miles North of Highway 14 It is approximately 2 3 miles Southwest of the abandoned town of Keota located on the prairie in the Pawnee National Grasslands or 2 3 miles Southwest of the intersection of County Road 390 & County Road 103 The proposed site is 35 acres The existing property is the entire south half of section, however, Mallard Exploration is currently in the process of creating a 35 acres parcel through exemption deed for the Field Office site The east 20 acres of the site will be developed for the office, and the remaining acreage to the west will remain undeveloped The property is currently undeveloped and consists of moderately dense weeds and native grasses In general, drainage from the site travels overland towards an existing swale along County Road 103 to the southeast Existing slopes on the site range from 0 to 1% According to the NRCS website, the site consists of predominantly Type B and C soils The Type B soils are classified as Stoneham fine sandy loam The Type C soils are classified as Platner loam See Appendix B for soils data The proposed project is a field office for Mallard Exploration The proposed project will be maintained by Mallard Exploration and will utilize undeveloped land for their field and storage yard The proposed site will consist of a 5,000 square foot building, parking, access roads, gravel storage yard and a detention pond The runoff from the site flows to the proposed detention pond in the southeast corner of the site before discharging offsite into historical paths B. HISTORIC DRAINAGE 1. Basin Description The site is not located within in any Major Drainage Basin Historically, drainage from the site Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 1 meanders overland in a southeasterly direction to a drainage swale parallel to County Road 103. There doesn't appear to be a defined drainage way where storm water collects and flows to the drainage swale along County Road 103. According to the Flood Insurance Rate Map (FIRM) Map No. 08123C1075E with an effective date of March 5, 2007, the proposed development is located completely outside any flood hazard areas (see Appendix B). 2. Existing Description The historic runoff from the project area flows northeasterly to an existing drainage swale along County Road 103, and ultimately south where it continues along the drainage swale. Historic basins were delineated considering existing and expected future runoff discharge locations from the project site. The detention basin outlet pipe is designed to outfall to the same existing natural channel mimicking historic conditions. See below for a summary of existing property basin flows: Table 1 — Rational Method Calculations — Existing Conditions EXISTING BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc CS C100 Q5 Q100 EB1 EB1 0.13 26.0% 11.1 0.15 0.31 0.07 0.27 EC1 EC1 0.31 42.0% 10.5 0.28 0.44 0.32 0.93 EC2 EC2 0.37 58.0% 9.3 0.43 0.56 0.61 1.49 EE1 EE1 0.50 47.0% 9.4 0.33 0.48 0.62 1.70 EE2 EE2 0.23 53.0% 13.3 0.38 0.52 0.29 0.74 EE3 EE3 0.13 81.0% 6.1 0.66 0.74 0.38 0.80 EE4 EE4 0.32 64.0% 7.8 0.46 0.61 0.63 1.49 TOTAL 2.00 52.0% 9.6 0.37 0.52 2.82 7.31 EXISTING BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc C10 C100 Q10 Q100 El El 19.44 2.0% 33.3 0.26 0.51 11.57 37.14 E2 E2 15.56 2.0% 47.8 0.26 0.51 7.38 23.70 TOTAL 35.00 2.0% NA NA NA 18.95 60.84 C. DESIGN CRITERIA 1. Hydrologic Criteria Data within the Weld County Charter and County Code: Storm Drainage Criteria and Weld County Engineering & Construction Criteria Manual for the Mallard Exploration Field Office, located in weld County, was used for specific rainfall data for the 2, 5, 10, 25, 50 and 100 -year storms of 0.86, 1.35, 1.54, 2.16, and 2.55 respectively (see Appendix B). Rainfall data of New Raymer was used to represent the Mallard Exploration Field office site due to their close proximity to each other. Since the basins are less than 160 acres, the Rational Method was used to calculate developed stormwater runoff. Composite impervious values for each basin Lamp Rynearson, Inc. Final Drainage Report for Mallard Exploration Field Office Project No. 0220014.01 September 2021 Page 2 were calculated based on site layout Runoff coefficient "C" values were taken from Table RO- 5 of Weld County's Drainage Criteria Manual (V 1) Runoff values were calculated using the Rational Method (see Weld County reference information provided in Appendix B) The imperviousness is determined based on -site layout with the imperviousness values obtained from Table RO-5 of Weld County Drainage Criteria Manual (V 1) The runoff coefficients corresponding to weighted average basin imperviousness and hydrologic soil groups were calculated using UD-Rational V2 00 spreadsheet that was created by Mile High Flood District and is in accordance with Weld County's Drainage Criteria Manual (V 1) The detention basin and outlet structure has been designed to capture and convey the Water Quality Capture Volume (WQCV), 10 -year, and the 100-yr Volume as outlined by the SDDTC 2. Hydraulic Criteria Stormwater will be captured and detained once the site is developed Hydraulic structures and conveyances were designed using techniques developed or adopted by Weld County Charter & Code Chapter 8, articles I - XVI of the Weld County Charter & Code were referenced and are consistent with standard calculation methods typically used for similar developments Water Quality Capture Volume (WQCV) designs were done using the Mile -High Flood District's (MHFD) UD-Detention v4 04 spreadsheet program The results of the detailed calculations are provided in Appendix C The detention pond will be sized to store the stormwater runoff generated by the 1 -hour, 100 - year storm falling on the developed site and release of the detained water at the historic runoff rate of the 1 -hour, 10 -year storm falling on the undeveloped site for non -urbanizing areas The detention pond will include volume for the WQCV This WQCV will be included as a portion of the total 100 -year detention pond volume The water quality capture volume will be set to drain at 40 hours The elevation of the top of the detention pond embankment, except at the spillway, will have a minimum of 1 -foot freeboard above the 100 -year water surface elevation in the detention pond The outlet pipe of the pond will contain a minimum of two concrete cutoff walls embedded at a minimum of 18 inches into the undisturbed soil The cutoff walls will be minimum of 8 inches thick The outlet pipe bedding material will consist of native earthen soil to the daylight point The detention pond will contain an emergency spillway capable of conveying the two times the peak 100 -year storm discharge The invert of the emergency spillway will be equal to, or above, the 100 -year water surface elevation The depth of the flow of the emergency spillway will be 6 inches or less The spillway will have effective erosion protection In order to protect the emergency spillway from catastrophic erosion failure, buried riprap shall be placed from the emergency spillway downhill to the embankment toe of slope and covered with 6 inches of topsoil The riprap will be sized at the time of final engineering design D. DRAINAGE FACILITY DESIGN 1. General Concept The existing conditions have been divided into 2 basins A small ridge in the middle of the site separates the 2 basins The proposed site has been divided into 3 basins, with 2 on site basins and one offsite basin One detention pond is proposed along the southwesterly corner of the Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 3 site Due to the layout of the site and existing slopes 2 swales were designed One to capture water along the west and south of the property and the other in the other next to the access road to capture water coming off the storage yard Both of these swales will be routed east into the pond The overflow spillway has been sized to allow twice the 100 -year flow to be released at incoming rates The goal of the proposed drainage design is to capture the water quality volume in the pond and release at rates that allow for minimum 40 -hour drain time for the WQCV A hydraulic analysis was completed based on calculated discharges to determine the sizes of the proposed drainage structures Detailed design of hydraulic structures, including the detention pond outlet structures, culverts and swales, has been provided in Appendix C 2. Specific Details The following paragraphs outline the calculated runoff for each sub -basin, a description of the basin characteristics and drainage patterns has been provided Basins B1: Basin B1 (20 99 acres) makes up the east half of the site the contains the entire portion that will be developed This basin contains a gravel storage yard, a 5,000 square foot building with a 25' concrete apron and a proposed gravel access road Swales will be constructed to capture site sheet flows A swale is proposed to capture runoff from the west side of the building and directed east into the detention pond, located on the south east corner of the site Another swale is proposed to capture runoff from the sheet flows from the storage yard and will be located next to the access road Flows from this swale will be directed south to the detention pond All flows from the B1 basin are routed to the detention pond outlet structure at the southeast corner of the pond The pond outlet structure will discharge into an existing road side ditch located next to County Road 103 to match historical the flow path Basins B2: Basin B2 (14 01 acres) consists of the western portion of the site that will remain undeveloped Runoff sheet flows to the south where it continues offsite Basin B2 will not be disturbed and flows from this area will follow historic conditions off site Basins B3: Basin B3 (0 49 acres) consists of the east corner of the site on the outer side of the proposed detention pond Runoff from this undeveloped naturally vegetated basin will sheet flow east offsite to the road side ditch next to County Road 103 Basin OS1 Basin OS1 (15 97 acres) is a basin located offsite to the north of basin B1 Basin OS1 is currently an undeveloped area of land that sheet flows across the proposed site Flows from this basin flow directly into basin B1 and will be accounted for in regards to the detention pond spillway calculations a. Rational Method Calculations The runoff from proposed basins were calculated using the Rational Method as they are smaller Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 4 than 90 acres The 10 -year and 100 -year criteria were used for the minor and major storm events Impervious values were assumed based off the SDDTC of weld county requirements The results of the Rational Method analysis for the developed conditions can be found in Appendix C Table 2 — Rational Method Calculations — Proposed Conditions DEVELOPED BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc C10 C100 Q10 Q100 B1 B1 , 20 99;} 33 0% 33 7 0 39 0 57 18 87 45 67 B2 B2 --14:01'' 2 0% 41 3 0 26 0 51 7 15 23 23 OS1 OS1 16'23" 2 0% 48 6 0 26 0 51 7 55 23 67 B3 B3 .s0 49 y 6 0% 25 0 0 28 0 52 0 37 1 13 TOTAL -5172`; 15 0% NA NA NA 33 94 93 70 DEVELOPED BASIN CALCULATIONS DESIGN POINT BASIN AREA Imperviousness % tc C5 C100 Q5 Q100 B1 B1 0 13-': 26 0% 11 1 0 15 0 31 0 07 0 27 Cl Cl _-0-17. ` 36 0% 6 0 0 23 0 40 0 18 0 55 C2 C2 : 0 34 63 0% 6 8 0 46 0 60 0 69 1 63 C3 C3 _0 22 34 0% 12 5 0 22 0 37 0 16 0 53 El El :0 52 " 51 0% 9 1 0 34 0 50 0 72 1 92 E2 E2 _0 23 50 0% 13 8 0 34 0 50 0 26 0 70 E3 E3 0-09 r 80 0% 5 8 0 63 0 73 0 26 0 55 E4 E4 0 30 , 68 0% 8 5 0 51 0 64 0 62 142 TOTAL 2 00;,' 52 0% 9 2 0 36 0 52 2 87 7 46 b. Water Quality & Detention Ponds Stormwater quality will be mitigated onsite during construction with the use of sediment control logs, vehicle tracking devices and inlet/outlet protection devices Long-term stormwater quality will occur by routing the onsite drainage through grass buffers and vegetated swales The detention basin used for this site is classified as an extended detention basin according to the Urban Storm Drainage Criteria Manual Volume 2 This construction will allow for the full, required capture volume of the 100-yr with one foot of freeboard The required volume was calculated utilizing WQCV, 10-yr and 100-yr values obtained from the UD-Detention spreadsheet This spreadsheet can be found within Appendix C and meets county and industry standards For this detention basin, Colorado law requires the WQCV to drain within 40 hours, 99% of the 10 -year event to drain within 72 hours and 99% of the 100 -year event to drain within 120 hours Currently, the WQCV is set to drain in 40 hours For the 10 -year event, time to drain Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 5 97% of inflow volume is 62 hours and time to drain 99% of inflow volume is 71 hours For the 100 -year event, time to drain 97% of inflow volume is 103 hours and time to drain 99% of inflow volume is 116 hours The spillway crest will be placed at the 100-yr water surface elevation and will accommodate the extreme rainfall events The spillway will be nprapped and facilitate flows to continue to adjacent drainage conveyances, ultimately terminating to the road side ditch next to County road 103, following historic patterns The calculations for the detention pond and spillways, along with pond stage -storage information are included in Appendix C Table 3 below provides a summary of the detention pond parameters Table 3 — Parameter for Detention Pond Parameter Proposed Design WQCV (ac -ft) 0 358 10-yr Storage Required (ac -ft) 1 572 100-yr Storage Required (ac -ft) 3 834 Storage Capacity (ac -ft) (Not including 1' freeboard) 4 051 Water Surface Elevation at WQCV (ft) 4904 17 Water Surface Elevation at 10-yr (ft) 4905 19 Water Surface Elevation At 100-yr (ft) 4906 13 Minimum Freeboard (ft) 1 Pond Depth (Bottom to spillway crest (ft) 2 34 Pond Embankment Elevation (Top of pond (ft) 4907 13 Minimum Effective Pond Elevation (Bottom Elevation) (ft) 4903 79 Outlet Pipe Diameter (in) 18 10-yr Historic Outlet Release Rate (cfs) 18 95 100-yr Pond Relese Rate (cfs) 9 7 Spillway Crest Elevation (ft) 4906 13 c. Erosion Control Based on the swale size calculations provided in Appendix C, the average flow velocities for the 100 -year storm event are well below the eroding velocity of 5 feet per second, therefore, Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 6 lining the swales with native vegetation/grass is sufficient to provide protection against any potential erosion and there is no need to provide any hard lining such as riprap for swales As stated within section c above, the ponds during all phases of the process will be protected with nprap See appendix C for supporting calculations Maintenance During all phases of the project, maintenance shall be performed regularly During construction maintenance shall be performed weekly to ensure all BMP's are functioning properly If any repairs are needed, such items shall be repaired or fixed immediately Cleaning of the detention pond shall be done regularly or on a needed basis based on any debris build up Vegetation and seeding shall also be maintained to ensure proper growth During post construction/normal site activities maintenance shall be performed routinely to ensure the BMP's are functioning properly Cleaning of the Detention Pond and outlet structure shall be done on a needed basis based on any debris build up Vegetation and Seeding measures shall also be maintained to ensure growth Conclusions When developed, the site's runoff will increase and be detained, thereby reducing released flows back to historic values The proposed swales will capture the runoff from the site and route the storm flows to the proposed detention pond and eventually into the road side ditch next to County road 103 All drainage design considerations contained in this drainage report are in general accordance with the Weld County Charter and County Code Storm Drainage Cntena, Weld County Eng►neenng & Construction Cntena and the Mile -High Flood Distnct Storm Drainage Cntena Manuals In general, the design presented in this report serves to provide a safe and adequate drainage system for the Mallard Exploration field office development E. References 1 Weld County, Colorado — Charter and County Code Storm Drainage Cntena, 2021 2 Weld County Engineering and Construction Cntena Manual, April 2021 3 Flood Insurance Rate Map, Adams County, Colorado and Incorporated Areas, Panel Number 08123C1075E, FEMA, October, 2020 4 Hydrologic Soil Group — Weld County, Colorado, USDA Natural Resources Conservation Service, March 2021 5 The Mlle High Flood District Storm Drainage Criteria Manual (USDCM), Volumes 1 and 3, published by the Urban Drainage and Flood Control District (UDFCD), Denver, Colorado, updated August 2018 Lamp Rynearson, Inc Final Drainage Report for Mallard Exploration Field Office Project No 0220014 01 September 2021 Page 7 Appendix A i I i i I DER20 / DRAFTER DAS LAMP 4715 INNOVATION DR.. STE.100 FORT COLLINS. CO 80525 RVNEARSON 50215.0542 Lam5Ryneerson.com REVIEWER NICKEL P411ZD PRO,ECT NUMBER 0220014.01 DATE 03/24/2021 MALLARD FIELD OFFICE WELD COUNTY COLORADO VICINITY MAP DARFACE LOCATION SE/4 55 385 RSV BOCK AND PAGE KIT(BALL LARAMIE Comprehensive Plan Map r Q f.. — t ....1., J.I COPS •...... e_. . Nees —p fO -.Peer Zia . .. tARIMER GDU vY .Iifo .1191 �> " W.''/ RRES1006 E •� ?RIGMON LOCSOHUE TERM Or JR. Ilia prim ha Sum • ndpp•. .sr/ Iw gas es. .." ti VIM C.srt be cat .a., Cpl. rr. •s dMa mat Is •ra t is moron Is raise War sod .l. ex..ald alcpalae COMM br aM a pr /rr.r•.r0. ft twlfpat..s ts-pet Oh to lad in i.e. dflas Ao•.a1 I•IO Oa tit kin .t pa orb NeeISOM ammeter*. it Ned as cat.,W spOlkOS a. o Cash MOIR NO COSLYLf1AOCf Witt ANY Plat ON WIOOVCI fI( ft it0 FOR•AW Of SCR PURPOSE S. NNW Cater NW I NOIlORMT S wit (ANNUMIt' S. (ITN(O NPNI WOOR RiI1OAS TO INf COWL ITN" VI ACCORACI. CM COMIC IM SS a SUCH p70O.8CI NON ACCIPI SW IYRlt1 AN11Mi IKrit MIT ./C OROtr. I Wet! 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WILL ELEV 00.,VULVLVV.V.VaLLL 0 an OUTLET PIPE CLVIIETER GERM, WES No w uEaq ETaR„apgcE My EMI NV �_-E 4°�SIMIDE a as IMMO MOIVIALLBEp_ ____ ValibLAILLITOLI Im1a IT/MEW MEL NE..mnME AM ICIIMMO1OOLAO ECAI E0.MS IE ACCESS EMMA S MEV 0. 400101.41 SE STMiSEESE,FELMU4MV4Cq OEM S,E6TPwv, ASTELICALVIVOIVELL MM., ela MEET 5 a S Appendix B I I I I i I i 1 I 1 National Flood Hazard Layer FIRMette FEMA Legend 104°5'40'W 40°40'27"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT 0 250 500 Feet 1:6,000 1,000 1,500 2.000 Basemap: USGS National Map: Orthoimagery: Data refreshed October. 2020 104°52'W 40°3959"N SPECIAL FLOOD HAZARD AREAS OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS Without Base Flood Elevation (BFE) Zone A, With BFE or Depth Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Future Conditions 1% Annual Chance Flood Hazard Area with Reduced Flood Risk due to Levee. See Notes. Area with Flood Risk due to Levee NO SCREEN Area of Minimal Flood Hazard Effective LOMRs Area of Undetermined Flood Hazard - Channel, Culvert, or Storm Sewer I I I I i I Levee, Dike, or Floodwall 0 20.2 Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation 8— — — Coastal Transect •••• •tr,.•-, Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary Coastal Transect Baseline Profile Baseline Hydrographic Feature Digital Data Available No Digital Data Available Unmapped The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on .. 16/2021 at 12:45 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. 40' 40'24"N 104° 9 421 W 576480 a} 0 576480 575640 / Soil rids) nmy not be vdIRI tit Mk scale I 576590 I 575640 5/bral Map Sole: 1:3,690 if printed on A landscape (11" x 8.5") sheet. g N 0 50 100 Soil Map —Weld County, Colorado, Northern Part 576800 576800 200 Meters 300 Feet A 0 150 300 600 900 Map proles: WIb Mernr Corner coordinates: W384 Edge tics: UTM Zone 13N WGS84 USDA Natural Resources a Conservation Service 576880 576880 57®80 577040 577120 Straw) J I I I I I 576890 577040 577120 Strati 577280 to Zn Web Soil Survey National Cooperative Soil Survey 0 3/15/2021 Page 1 of 3 40' 40 24" N 40. 40' TN Soil Map —Weld County Colorado. Northern Part Area of Interest (AOI) n Soils O MAP LEGEND Area of Interest (AOI) Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout 3t •.s 0 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 Spat • Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation +-+-4 Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography MAP INFORMATION The so I 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 15 Jun 5. 2020 Soil map units are labeled (as space allows) for map scales 1 50,000 or larger. Cate(s) aerial images were photographed Jul 19, 2018 -Aug 10, 2018 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 sniffing of map unit boundaries may be evident. t. SI);1 SSE Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 3/15/2021 Page 2 of 3 Soil Map Weld County, Colorado, Northern Part Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 54 Platner loam. 0 to 3 percent slopes 49.4 88.0% 61 Stoneham fine sandy to 6 percent slopes loam. 0 6.7 12.0% Totals for Area of Interest 56.1 100.0% t \ Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 3/15/2021 Page 3 of 3 Map Unit Description: Platner loam. 0 to 3 percent slopes Weld County, Colorado, Northern Part Weld County, Colorado, Northern Part 54—Platner loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2tIn0 Elevation: 4,000 to 4,930 feet Mean annual precipitation: 14 to 17 inches Mean annual air temperature: 46 to 50 degrees F Frost -free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Platner and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Platner Setting Landform: I nterfl uves Landform position (two-dimensional): Summit Landform position (three-dimensional): Irterfluve Down -slope shape: Linear Across -slope shape: Linear Parent material: Mixed eolian deposits over tertiary aged alluvium derived from igneous, metamorphic and sedimentary rock Typical profile Ap - 0 to 6 inches: loam Bt1 - 6 to 11 inches: clay Bt2 - 11 to 20 inches: clay Bk1 - 20 to 27 inches: loam Bk2 - 27 to 37 inches: sandy clay loam C - 37 to 80 inches: sandy clay loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline (0.0 to 1.0 mmhos/cm) Available water capacity: Moderate (about 8.1 inches) t \ Natural Resources Web Soil Survey a Conservation Service National Cooperative Soil Survey 3/15/2021 Page 1 of 2 Map Unit Description: Platner loam, 0 to 3 percent slopes Weld County, Colorado, Northern Par, Interpretive groups Land capability classification (irrigated): 3s Land capability classification (nonirrigated): 4s Hydrologic Soil Group: C Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Minor Components Ascalon Percent of map unit: 10 percent Landform: Interfluves Landform position (two-dimensional): Summit, shoulder Landform position (three-dimensional): Interfluve Down -slope shape: Linear Across -slope shape: Linear Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Rago, rarely flooded Percent of map unit: 4 percent Landform: Drainageways Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope, head slope Down -slope shape: Linear Across -slope shape: Concave Ecological site: R067BY036CO - Overflow Hydric soil rating: No Rago, ponded Percent of map unit: 1 percent Landform: Playas Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Concave Across -slope shape: Concave Ecological site: R067BY010CO - Closed Upland Depression Hydric soil rating: No Data Source Information Soil Survey Area: Weld County. Colorado. Northern Part Survey Area Data: Version 15, Jun 5, 2020 USDA Natural Resources Web Soil Survey a Conservation Service National Cooperative Soil Survey 3/15/2021 Page 2 of 2 Map Unit Description: Stoneham fine sandy loam, 0 to 6 percent slopes --Weld County, Colorado, Northern Part Weld County, Colorado, Northern Part 61 Stoneham fine sandy loam, 0 to 6 percent slopes Map Unit Setting National map unit symbol: 360k Elevation: 4,000 to 6,500 feet Mean annual precipitation: 12 to 16 inches Mean annual air temperature: 48 to 52 degrees F Frost -free period: 130 to 170 days Farmland classification: Farmland of statewide importance Map Unit Composition Stoneham and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Stoneham Setting Landform: Alluvial fans. plains Down -slope shape: Linear Across -slope shape: Linear Parent material: Calcareous loamy alluvium Typical profile H1 - 0 to 5 inches: fine sandy loam H2 - 5 to 8 inches: clay loam H3 - 8 to 14 inches: loam H4 - 14 to 60 inches: sandy loam, gravelly sandy loam H4 - 14 to 60 inches: Properties and qualities Slope: 0 to 6 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water capacity: High (about 11.2 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B SDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 3/15/2021 Page 1 of 2 Map Unit Description: Stoneham fine sandy loam, 0 to 6 percent slopes ---Weld County, Colorado, Northern Part Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Minor Components Kim Percent of map unit: 5 percent Hydric soil rating: No Mitchell Percent of map unit: 5 percent Hydric soil rating: No Data Source Information Soil Survey Area: Weld County, Colorado, Northern Part Survey Area Data: Version 15, Jun 5, 2020 \ Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 3/15/2021 Page 2 of 2 Table 5-1 Weld County Design Storm Rainfall Comparison 1 -Hour Frequency Storm Longmont Depth 1 (in) Greeley2 Depth (in) New Depth Raymer3 (in) I-25 &Tri-Town4 Depth (in) 2 -year (50% chance) 1.02 1.04 0.86 0.98 5 -year (20% chance) 1.46 1.49 1.35 1.39 10 -year (10% chance) 1.75 1.76 1.54 1.68 25 -year (4% chance) 2.07 1.80 2.04 50 -year (2% chance) 2.42 2.51 2.16 2.37 100 -year (1% chance) 2.72 2.78 2.55 2.68 2 -Hour Frequency Storm Longmont Depth 1 (in) Greeley2 Depth (in) New Depth Raymer3 (in) I-25 &Tri-Town4 Depth (in) 2 -year (50% chance) 1.20 1.16 1.05 1.16 5 -year (20% chance) 1.66 1.60 1.55 1.60 10 -year (10% chance) 2.00 1.91 1.77 1.91 25 -year (4% chance) 2.37 2.10 2.32 50 -year (2% chance) 2.74 2.65 2.45 2.67 100 -year (1% chance) 3.08 2.99 2.82 3.03 6 -Hour Frequency Storm Longmont Depth 1 (in) Greeley2 Depth (in) New Depth Raymer3 (in) I-25 &Tri-Town4 Depth (in) 2 -year (50% chance) 1.56 1.38 1.44 1.50 5 -year (20% chance) 2.05 1.80 1.95 2.00 10 -year (10% chance) 2.47 2.22 2.25 2.35 25 -year (4% chance) 2.95 2.58 2.75 2.87 50 -year (2% chance) 3.35 2.94 3.05 3.25 100 -year (1% chance) 3.77 3.42 3.42 3.70 1. From UDFCD Manual 2. From City of Greeley Manual 3. From NOAA Atlas (nomograph projection) 4. From I-25 and Tri-Town Study, Volume 2, Chapter 2, page 20 5.4.3 Larger Basin Rainfall Methods As noted above, the Rational Method should not be used to determine runoff for basins larger than 160 acres. In areas located in the southwest portion of Weld County and where areas are larger than 160 acres that have drainage characteristics similar to an urban area, the Colorado Urban Hydrograph Procedure (CUHP) is an acceptable model for determining runoff amounts. The CUHP model can be used for basins from 0 to 3,000 acres. The parameter adjustments provided in the runoff chapter of the UDFCD Manual (Volume 1) should be used when dealing with basins that are larger than 160 acres. The CUHP model is not applicable in non -urban areas, including those areas in Weld County that are outside of the Denver metropolitan area. The U.S. Army Corps of Engineers (USACE) HEC-HMS model is more applicable for mixed suburban -agricultural areas. The HEC-HMS model can be used on watersheds and drainage basins larger than 160 acres provided the modeling follows the parameters in the HEC- HMS User's Manual, the HEC-HMS Technical Reference Manual, and the HEC-HMS Application's Guide. WELD COUNTY ENGINEERING & CONSTRUCTION CRITERIA Page j38 DRAINAGE CRITERIA MANUAL (V 1) RUNOFF 2 0 RATIONAL METHOD For urban catchments that are not complex and are generally 160 acres or less in size, it is acceptable that the design storm runoff be analyzed by the Rational Method This method was introduced in 1889 and is still being used in most engineering offices in the United States Even though this method has frequently come under academic criticism for its simplicity, no other practical drainage design method has evolved to such a level of general acceptance by the practicing engineer The Rational Method properly understood and applied can produce satisfactory results for urban storm sewer and small on -site detention design 21 Rational Formula The Rational Method is based on the Rational Formula Q=CIA in which Q= the maximum rate of runoff (cfs) (RO-1) C = a runoff coefficient that is the ratio between the runoff volume from an area and the average rate of rainfall depth over a given duration for that area I = average intensity of rainfall in inches per hour for a duration equal to the time of concentration, tc A = area (acres) Actually, Q has units of inches per hour per acre (in/hr/ac), however, since this rate of in/hr/ac differs from cubic feet per second (cfs) by less than one percent, the more common units of cfs are used The time of concentration is typically defined as the time required for water to flow from the most remote point of the area to the point being investigated The time of concentration should be based upon a flow length and path that results in a time of concentration for only a portion of the area if that portion of the catchment produces a higher rate of runoff The general procedure for Rational Method calculations for a single catchment is as follows 1 Delineate the catchment boundary Measure its area 2 Define the flow path from the upper -most portion of the catchment to the design point This flow path should be divided into reaches of similar flow type (e g , overland flow, shallow swale flow, gutter flow, etc ) The length and slope of each reach should be measured 3 Determine the time of concentration, tc, for the catchment 2007-01 Urban Drainage and Flood Control Distnct RO-3 RUNOFF DRAINAGE CRITERIA MANUAL (V 1) 4 Find the rainfall intensity, I, for the design storm using the calculated t, and the rainfall intensity - duration -frequency curve (See excerpts from "Rainfall" Chapter at the end of this document and NOAA Atlas 14 website https //hdsc nws noaa gov/hdsc/pfds/pfds_map_cont html) 5 Determine the runoff coefficient, C 6 Calculate the peak flow rate from the watershed using Equation RO-1 22 Assumptions The basic assumptions that are often made when the Rational Method is applied are 1 The computed maximum rate of runoff to the design point is a function of the average rainfall rate during the time of concentration to that point 2 The depth of rainfall used is one that occurs from the start of the storm to the time of concentration, and the design rainfall depth during that time period is converted to the average rainfall intensity for that period 3 The maximum runoff rate occurs when the entire area is contributing flow However, this assumption has to be modified when a more intensely developed portion of the catchment with a shorter time of concentration produces a higher rate of maximum runoff than the entire catchment with a longer time of concentration 2.3 Limitations The Rational Method is an adequate method for approximating the peak rate and total volume of runoff from a design rainstorm in a given catchment The greatest drawback to the Rational Method is that it normally provides only one point on the runoff hydrograph When the areas become complex and where sub -catchments come together, the Rational Method will tend to overestimate the actual flow, which results in oversizing of drainage facilities The Rational Method provides no direct information needed to route hydrographs through the drainage facilities One reason the Rational Method is limited to small areas is that good design practice requires the routing of hydrographs for larger catchments to achieve an economic design Another disadvantage of the Rational Method is that with typical design procedures one normally assumes that all of the design flow is collected at the design point and that there is no water running overland to the next design point However, this is not the fault of the Rational Method but of the design procedure The Rational Method must be modified, or another type of analysis must be used, when analyzing an existing system that is under -designed or when analyzing the effects of a major storm on a system designed for the minor storm RO-4 2007-01 Urban Drainage and Flood Control Distnct DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF 2.4 Time of Concentration One of the basic assumptions underlying the Rational Method is that runoff is a function of the average rainfall rate during the time required for water to flow from the most remote part of the drainage area under consideration to the design point. However, in practice. the time of concentration can be an empirical value that results in reasonable and acceptable peak flow calculations. The time of concentration relationships recommended in this Manual are based in part on the rainfall -runoff data collected in the Denver metropolitan area and are designed to work with the runoff coefficients also recommended in this Manual. As a result, these recommendations need to be used with a great deal of caution whenever working in areas that may differ significantly from the climate or topography found in the Denver region. For urban areas, the time of concentration, tt., consists of an initial time or overland flow time, t,, plus the travel time, t,, in the storm sewer, paved gutter, roadside drainage ditch, or drainage channel. For non - urban areas, the time of concentration consists of an overland flow time, t,, plus the time of travel in a defined form, such as a swale, channel, or drainageway. The travel portion, t,, of the time of concentration can be estimated from the hydraulic properties of the storm sewer, gutter, swale, ditch, or drainageway. Initial time, on the other hand, will vary with surface slope, depression storage, surface cover, antecedent rainfall, and infiltration capacity of the soil, as well as distance of surface flow. The time of concentration is represented by Equation RO-2 for both urban and non -urban areas: in which: t� = time of concentration (minutes) t, = initial or overland flow time (minutes) t, = travel time in the ditch, channel, gutter, storm sewer, etc. (minutes) 2.4.1 Initial Flow Time The initial or overland flow time, t1, may be calculated using equation RO-3: 0.3951.1- c5 0.33 ksi in which: = initial or overland flow time (minutes) = runoff coefficient for 5 -year frequency (from Table RO-5) 2007-01 Urban Drainage and Flood Control District (RO-2) (RO-3) RO-5 RUNOFF DRAINAGE CRITERIA MANUAL (V. 1) L = length of overland flow (500 ft maximum for non -urban land uses, 300 ft maximum for urban land uses) S = average basin slope (ft/ft) Equation RO-3 is adequate for distances up to 500 feet. Note that, in some urban watersheds. the overland flow time may be very small because flows quickly channelize. 2.4.2 Overland Travel Time For catchments with overland and channelized flow, the time of concentration needs to be considered in combination with the overland travel time, t,, which is calculated using the hydraulic properties of the swale, ditch, or channel. For preliminary work, the overland travel time, t,, can be estimated with the help of Figure RO-1 or the following equation (Guo 1999): C o� V = C k ,t. in which: = velocity (ft/sec) = conveyance coefficient (from Table RO-2) S,, = watercourse slope (ft/ft) Table RO-2 Conveyance Coefficient, C,. (RO-4) Type of Land Surface Conveyance Coefficient, ('i. Heavy meadow 2.5 Tillage/field 5 Short pasture and lawns 7 Nearly bare ground 10 Grassed waterway 15 Paved areas and shallow paved swales 20 The time of concentration, tc, is then the sum of the initial flow time, t,, and the travel time, t,, as per Equation RO-2. 2.4.3 First Design Point Time of Concentration in Urban Catchments Using this procedure, the time of concentration at the first design point (i.e., initial flow time, t,) in an urbanized catchment should not exceed the time of concentration calculated using Equation RO-5. in which: RO-6 L t = +10 180 (RO-5) t, = maximum time of concentration at the first design point in an urban watershed (minutes) 2007-01 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF 1. = waterway length (ft) Equation RO-5 was developed using the rainfall -runoff data collected in the Denver region and, in essence, represents regional "calibration" of the Rational Method. The first design point is the point where runoff first enters the storm sewer system. An example of definition of first design point is provided in Figure RO-2. Normally, Equation RO-5 will result in a lesser time of concentration at the first design point and will govern in an urbanized watershed. For subsequent design points, the time of concentration is calculated by accumulating the travel times in downstream drainageway reaches. 2.4.4 Minimum Time of Concentration Should the calculations result in a , of less than 10 minutes, it is recommended that a minimum value of 10 minutes be used for non -urban watersheds. The minimum ti recommended for urbanized areas should not be less than 5 minutes and if calculations indicate a lesser value, use 5 minutes instead. 2.4.5 Common Errors in Calculating Time of Concentration A common mistake in urbanized areas is to assume travel velocities that are too slow. Another common error is to not check the runoff peak resulting from only part of the catchment. Sometimes a lower portion of the catchment or a highly impervious area produces a larger peak than that computed for the whole catchment. This error is most often encountered when the catchment is long or the upper portion contains grassy parkland and the lower portion is developed urban land. 2.5 Intensity The rainfall intensity. I. is the average rainfall rate in inches per hour for the period of maximum rainfall of a given recurrence frequency having a duration equal to the time of concentration. After the design storm's recurrence frequency has been selected, a graph should be made showing rainfall intensity versus time. The precipitation-intesity curve can be found on the NOAA Atlas 14 website for site specific rain gages. The intensity for a design point may be taken from the graph or calculated through the use of Equation RA -3 using the calculated r . and the 1 -hour point rainfall depth (inches). 2.6 Watershed Imperviousness All parts of a watershed can be considered either pervious or impervious. The pervious part is that area where water can readily infiltrate into the ground. The impervious part is the area that does not readily allow water to infiltrate into the ground, such as areas that are paved or covered with buildings and sidewalks or compacted unvegetated soils. In urban hydrology, the percentage of pervious and impervious land is important. The percentage of impervious area increases when urbanization occurs 2007-01 Urban Drainage and Flood Control District RO-7 RUNOFF DRAINAGE CRITERIA MANUAL (V. 1) and the rainfall -runoff relationships change significantly. The total amount of runoff volume normally increases, the time to the runoff peak rate decreases. and the peak runoff rates increase. Photograph RO 2 —Urbanization (impervious area) increases runoff volumes, peak discharges, frequency of runoff, and receiving stream degradation. When analyzing a watershed for design purposes. the probable future percent of impervious area must be estimated. A complete tabulation of recommended values of the total percent of imperviousness is provided in Table RO-3 and Figures RO-3 through RO-5, the latter ceveloped by the District after the evolution of residential growth patterns since 1990. 2.7 Runoff Coefficient The runoff coefficient, C, represents the integrated effects of infiltration, evaporation, retention, and interception, all of which affect the volume of runoff. The determination of C requires judgment and understanding on the part of the engineer. Based in part on the data collected by the District since 1969, an empirical set of relationships between C and the percentage imperviousness for the 2 -year and smaller storms was developed and are expressed in Equations RO-6 and RO-7 for Type A and C/D Soil groups (Urbonas, Guo and Tucker 1990). For Type B soil group the impervious value is found by taking the arithmetic average of the values found using these two equations for Type A and Type C/D soil groups. For larger storms (i.e., 5-, 10. 25-. 50- and 100 -year) correction factors listed in Table RO-4 are applied to the values calculated using these two equations. RO-8 2007-01 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF Table RO-3 Recommended Percentage Imperviousness Values Surface Land Characteristics Use or Imperviousness Percentage Business: Commercial areas 95 Neighborhood areas 85 Residential: Single-family * Multi -unit (detached) 60 Multi -unit (attached) 75 Half -acre lot or larger * Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off (when -site flow land analysis use not defined) 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 * See Figures RO-3 through RO-5 for percentage imperviousness. + 1.31i -1.4412 +1.135i - 0.12 for c4 ≥ 0, otherwise CA = 0 (RO-6) Cc,D = K. + 0.858i 3 - 0.786i2 + 0.774i + 0.04) (RO-7) CB _(CA +CH))/2 2007-01 Urban Drainage and Flood Control District RO-9 RUNOFF in which: DRAINAGE CRITERIA MANUAL (V. 1) i = % imperviousness/100 expressed as a decimal (see Table RO-3) C,1= Runoff coefficient for Natural Resources Conservation Service (NRCS) Type A soils CH Runoff coefficient for NRCS Type B soils Cc,, Runoff coefficient for NRCS Type C and D soils Correction factor for Type A soils defined in Table RO-4 K(7) Correction factor for Type C and D soils defined in Table RO-4 Table RO-4—Correction Factors K, and Ku) for Use with Equations RO-6 and RO-7 NRCS Soil Type Storm Return Period 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year C and D 0 -0.101+0.11 -0.181+0.21 -0.281+0.33 -0.331+0.40 -0.391+0.46 A 0 -0.08i + 0.09 -0.14i + 0.17 -0.19/ + 0.24 -0.221+ 0.28 -0.25/ + 0.32 The values for various catchment imperviousnesses and storm return periods are presented graphically in Figures RO-6 through RO-8, and are tabulated in Table RO-5. These coefficients were developed for the Denver region to work in conjunction with the time of concentration recommendations in Section 2.4. Use of these coefficients and this procedure outside of the semi -arid climate found in the Denver region may not be valid. The UD-Rational spreadsheet performs all the needed calculations to find the runoff coefficient given the soil type and imperviousness and the reader may want to take advantage of this macro -enabled Excel workbook that is available for download from the Weld County website. See Examples 7.1 and 7.2 that illustrate the Rational method. RO-10 2007-01 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V 1) Table RO-5— Runoff Coefficients, C RUNOFF Percentage Imperviousness Type C and D NRCS Hydrologic Soil Groups 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 0% 0 04 0 15 0 25 0 37 0 44 0 50 5% 0 08 0 18 0 28 0 39 0 46 0 52 10% 011 021 030 041 047 053 15% 014 024 032 043 049 054 20% 0 17 0 26 0 34 0 44 0 50 0 55 25% 020 028 036 046 051 056 30% 022 030 038 047 052 057 35% 0 25 0 33 0 40 0 48 0 53 0 57 40% 0 28 0 35 0 42 0 50 0 54 0 58 45% 031 037 044 051 055 059 50% 0 34 0 40 0 46 0 53 0 57 0 60 55% 0 37 0 43 0 48 0 55 0 58 0 62 60% 041 ' 046 051 057 060 063 65% 0 45 0 49 0 54 0 59 0 62 0 65 70% 0 49 0 53 0 57 0 62 0 65 0 68 75% 054 058 062 066 068 071 80% 0 60 0 63 0 66 0 70 0 72 0 74 85% 0 66 0 68 0 71 0 75 0 77 0 79 90% 073 075 077 080 082 083 95% 0 80 0 82 0 84 0 87 0 88 0 89 100% 089 090 092 094 095 096 TYPE B NRCS HYDROLOGIC SOILS GROUP 0% 002 008 015 025 030 035 5% 004 010 019 028 033 038 10% 006 014 022 031 036 040 15% 0 08 0 17 0 25 0 33 0 38 0 42 20% 012 020 027 035 040 044 25% 015 022 030 037 041 046 30% 018 025 032 039 043 047 35% 020 027 034 041 044 048 40% 023 030 036 042 046 050 45% 026 032 038 044 048 051 50% 029 035 040 046 049 052 55% 033 038 043 048 051 054 60% 037 041 046 051 054 056 65% 041 045 049 054 057 059 70% 0 45 0 49 0 53 0 58 0 60 0 62 75% 051 054 058 062 064 066 80% 0 57 0 59 0 63 0 66 0 68 0 70 85% 0 63 0 66 0 69 0 72 0 73 0 75 90% 071 073 075 078 080 081 95% 079 081 083 085 087 088 100% 089 090 092 094 095 096 2007-01 Urban Drainage and Flood Control Distnct RO-11 RUNOFF RO-12 DRAINAGE CRITERIA MANUAL (V 1) TABLE RO-5 (Continued) —Runoff Coefficients, C Percentage Imperviousness Type A NRCS Hydrologic Soils Group 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 0% 000 000 005 012 016 020 5% 000 002 010 016 020 024 10% 000 006 014 020 024 028 15% 0 02 0 10 0 17 0 23 0 27 0 30 20% 0 06 0 13 0 20 0 26 0 30 0 33 25% 009 016 023 029 032 035 30% 0 13 0 19 0 25 0 31 0 34 0 37 35% 016 022 028 033 036 039 40% 019 025 030 035 038 041 45% 022 027 033 037 040 043 50% 0 25 0 30 0 35 0 40 0 42 0 45 55% 029 033 038 042 045 047 60% 033 037 041 045 047 050 65% 0 37 0 41 0 45 0 49 0 51 0 53 70% 0 42 0 45 0 49 0 53 0 54 0 56 75% 0 47 0 50 0 54 0 57 0 59 0 61 80% 0 54 0 56 0 60 0 63 0 64 0 66 85% 061 063 066 069 070 072 90% 0 69 0 71 0 73 0 76 0 77 0 79 95% 0 78 0 80 0 82 0 84 0 85 0 86 100% 089 090 092 094 095 096 2007-01 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V 1) WATERCOURSE SLOPE IN PERCENT 5O 3O 2O 1O 5 3 2 1 5 RUNOFF p3 v °o it 3 * h y 1 `q; NI Ir CO °qr 4 Id a eAd ? "Arks? 4Q Qe We f /,I, / 1 2 .3 5 1 2 3 5 VELOCITY IN FEET PER SECOND 1O 2O Figure RO-1—Estimate of Average Overland Flow Velocity for Use With the Rational Formula 2007-01 RO-13 Urban Drainage and Flood Control Distnct RUNOFF DRAINAGE CRITERIA MANUAL (V 1) RO-14 CATCHMENT A CATCHMENT B CATCHMENT C INLET 1 STORM SEWER X CATCHMENT D CATCHMENT E INLET 2 STORM SEWER Y CATCHMENT F INLET 3 NOTE INLETS 1, 2, 3 AND STORM SEWER X ARE EACH THE "FIRST DESIGN POINT" AND THE REGIONAL Tc SHOULD BE CHECKED STORM SEWER Y IS NOT THE FIRST DESIGN POINT Figure RO-2.---Diagram of First Design Point 2007-01 Urban Drainage and Flood Control Distnct DRAINAGE CRITERIA MANUAL (V 1) 90 80 70 60 e o & 50 E C v b 40 A N 30 20 10 0 RUNOFF 15,000 04 • homes! sq ft honest / 14,000 sq ft • • / • / / (3000 sq ft homes r ♦ ♦ ♦ • / ° • / ♦ • 12,000 sq ft. homes L. . • 1 i / /° 0 a r 0 0 if • . / / s / ♦ / 0 11,000 sq ft homes • ° �. / / O O 0 1 2 3 4 Single Family Dwelling Units per Acre 5 6 Figure RO-3— Watershed Imperviousness, Single -Family Residential Ranch Style Houses 2007-01 Urban Drainage and Flood Control District RO-15 RUNOFF DRAINAGE CRITERIA MANUAL (V 1) 90 5,000 sq it homes . 0 00 0 ° 14,000 sq ft. homes I 70 60 O �50 b 4o ex. 30 0 0 0 0 0 D 00/ © O 0 009 ® 13,000 sq ft. homes r f� p 20 --- -0 °® 10 0 1 0 0 ° 0 0 ® ® o oos 0 0 0 0 0 '2,000 sq ft homes nzoo 1,000 sq ft homes 0 1 2 3 4 5 6 Single Family Dwelling Units per Acre Figure RO- —Watershed Imperviousness, Single -Family Residential Split -Level Houses RO-16 2007-01 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V 1) RUNOFF so 80 70 0 60 s 0 E50 e ti40 a 73 i- 30 20 10 0 j5,000 sq ft homes /1 • 00 sq ft. homes I' / + + / • - 3 000 sq ft homes I o • • - + + + • / + +• + • - I2,000 sq ft homes I / • ® • ' • r 1,000 sq it homes, 140 • / •+ • .ate 0 1 2 3 4 Single Family Dwelling Units per Acre 5 6 Figure RO-5—Watershed Imperviousness, Single -Family Residential Two -Story Houses 0 E u i 'o 0 0 e K Watershed Percentage Imperviousness —.-100yr i-0-50•yr 1 —&-25-yr I --s- 10-yr -P-5-yr -o-2 yr 1 Figure RO-6—Runoff Coefficient, C, vs Watershed Percentage Imperviousness NRCS Hydrologic Soil Group A 2007-01 Urban Drainage and Flood Control Distnct RO-17 RUNOFF Runoff Coefficient C 1 00 0 90 0 80 0 70 0 60 0 50 0 40 0 30 0 20 0 10 0 00 0% DRAINAGE CRITERIA MANUAL (V 1) � 1 � Hffi I i 10% 20% 30% 40% 50% 60% 70% Watershed Percentage Imperviousness 80% 90% 100% - 100-yr -- 50-yr t25 yr , —x-10 yr 1 —4-5-yr `0--2-yrj Figure RO-7—Runoff Coefficient, C, vs. Watershed Percentage Imperviousness NRCS Hydrologic Soil Group B U C O 1 00 0 90 0 80 0 70 0 60 g 0 0 50 U 0 s 0 40 re 0 30 0 20 010 0 00 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Watershed Percentage Imperviousness — o— 100-yr , —0-50 yr —0-25 yr x— 10-yr —x— 5-yr ,—o--2 yr Figure RO-8—Runoff Coefficient, C, vs Watershed Percentage Imperviousness NRCS Hydrologic Soil Groups C and D RO-18 2007-01 Urban Drainage and Flood Control Distnct RAINFALL DRAINAGE CRITERIA MANUAL (V. 1) 4.0 INTENSITY -DURATION CURVES FOR RATIONAL METHOD To develop depth -duration curves or intensity -duration curves for the Rational Method of runoff analysis take the 1 -hour depth(s) obtained from the NOAA Atlas website and multiply by the factors in Table RA -4 to determine rainfall depth and rainfall intensity at each duration. The intensity can then be plotted as illustrated in Figure RA -15. Actual rainfall intensities from the NOAA Atlas website may also be used in the calculations. TABLE RA -4 —Factors for Preparation of Intensity -Duration Curves 5 10 15 30 60 Duration (minutes) Rainfall Depth at Duration (inches) 0.29P, 0.45P, 0.57P, 0.79P, 1.0P, Intensity (inches per hour) 3.48P, 2.70P, 2.28P, 1.58P, 1.0P, Alternatively, the rainfall intensity for the area within the District can be approximated by the equation: I= �l 0 + T.)° 28.5 P1 in which: / = rainfall intensity (inches per hour) P, = 1 -hour point rainfall depth (inches) T, = time of concentration (minutes) RA -6 (RA -3) 01/2004 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V 1) RAINFALL Rainfall Intensity (inches per hour) 10 9 8 7 6 5 4 3 2 0 .. 100-yr rainfall = 2 6 inch . . .' \ • . • % �, 10-yr rainfall = 1 55 inch 2-yr rainfall = 0 95 inch �,, ...' 1 ..____ —...m 0 10 20 30 Time (minutes) 40 50 Figure RA -15 —Rainfall Intensity -Duration Curves 60 Rev 01/2004 RA -27 Urban Drainage and Flood Control Distnct sin Weld County PROPERTY PORTAL Property Information (970) 400-3650 Technical Support (970) 400-4357 Account: R0545086 March 16, 2021 Account Information Account Parcel Space Type Account Tax Year Buildings Actual Value Assessed Value R0545086 054109000004 Agricultural 2021 38,941 11,290 1 Legal 3112S29860(4R) Subdivision Block Lot Land Economic Area NE ECON 7 RURAL Property Address Property City Zip Section Township Range 09 08 60 Owner(s) Account Owner Name Address R0545086 HITZ GROUP FINANCIAL LLC 1001 410 A FORT E HARMONY COLLINS, ROAD CO 805253354 UNIT Document History Reception Rec Date Type Grantor Grantee Doc Fee Sale Date Sale Price 03-07-1979 USR USE BY SPECIAL REVIEW SUP -333 POWER LINES 345 KV 0 00 0 02043650 02-20-1986 SWDN 0 00 01-01-1900 0 02181688 06-06-1989 PRDN 0 00 06-05-1989 0 1628202 01-14-1974 WDN 0 00 01-14-1974 0 1751074 04-11-1978 SHD 0 00 04-11-1978 0 1770655 10-24-1978 WDN 0 00 10-24-1978 0 1792796 06-06-1979 SWDNE 0 00 06-06-1979 0 1839844 10-27-1980 OTH 0 00 10-27-1980 0 1921438 03-28-1983 WDN 0 00 03-28-1983 0 2573083 10-07-1997 WD THOMAS RAYMOND W & RONALD W SHIVELY RICHARD H & ROSEMARY 22 00 10-01-1997 220,000 3775026 06-20-2011 WD SHIVELY RICHARD H HITZ FINANCIAL GROUP LLC 14 30 06-10-2011 143,000 Building Information No buildings found Valuation Information Type Code Description Actual Value Assessed Value Acres Land SqFt Land 4127 DRY FARM LAND- AGRICULTURAL 38,859 11,270 306 000 13,329,360 Land 4167 WASTE LAND 82 20 10 000 435,600 Totals - - 38,941 11,290 316 000 13,764,960 Comparable sales for your Residential property may be found using our SALES SEARCH TOOL Tax Authorities Area ax ID District District Name Current Levy Mill 1007 0700 AIMS JUNIOR COLLEGE 6.305 1007 0524 BRIGGSDALE FIRE 4.002 1007 1050 HIGH PLAINS LIBRARY 3.181 1007 0210 SCHOOL BRIGGSDALE DIST RE10J- 19.690 1007 0100 WELD COUNTY 15.038 1007 1200 WEST CONSERVATION GREELEY 0.414 Total - - 48.63 Photo NO PHOTO Sketch NO SKETCtyright © 2021 Weld County, Colorado. All rights reserved. Privacy Policy & Disclaimer I Accessibility Information Appendix C I I 1 ii 1 II it li I II i i I i Imperviousness Mallard Field Office Design Point Basin Pond Area (acres) Concrete Area (acres) Gravel (acres) Roofs (acres) Lawns (acres) Total Area Percent Imperviousness (I = 100) (1= 100) (I = 40) (1= 90) (I = 2) (acres) EXISTING El EB1 0.00 0.00 0.00 0.00 19.44 19.44 2% E2 EC1 0.00 0.0C 0.00 0.00 15.56 15.56 2% Total 0 1, . 0.00 _ 35.00 2% PROPOSED B1 B1 1.64 0,23 11.54 0.ic b./8 20.67 33% B2 B2 0.00 0.00 0.00 0.00 13.84 13.84 2% O51 OS1 0.00 0.00 0.00 0.00 16.23 16.23 2% B3 B3 0.00 0.00 0.05 D 00 0.44 0.49 6% Total B 1 64 0.23 i 1.8c4 0.18 21.06 35.00 21% Total 1.64 0 23 1.S . 18 51 23 15% Notes: Percent Impervious Values per Table 501, Commerce City Storm Drainage Design and Techincal Criteria GLF RECOMMENQED RUNOFF COEFFICIENTAND PERCENT IMPERVIOUS LANE) USE OR PERCENT SURFACE CHARACTERISTICS IMPERVIOUS FREQUENCY 2 s 10 1E)0 BUSINESS; Commwczal Ann NepMatw+oA Ann RESIOFMTAL, ye• F omry 1.40117 Un,t idatachee) MutlrUtut ; UKftet7) 1/2 Acts Lot or UMW Aaartmenh INDUSTRIAL Lint Nays moony Aron PARKS. CEMETARIES PLAYCAQUNDS: SCfOCLS• RAILROAD YARD AREAS UNDEVELOPED AREAS. NNtor1C Row Amity%a Creeapetts, Aqc,trvai rxla4 Flo* Anatyuu (wiwl IanC v!a viol aar'nwj) STREETS: PevsO envoi DRIVE AND WALKS ROOFS LAWNS. SANDY SOIL LAWNS, CLAYEY SOIL 95 a? 67 a6 89 70 60 63 70 tt0 43 40 45 50 40 SO 4S 50 60 70 70 00 05 70 lb 40 30 35 40 oo 70 85 70 70 AD a0 71 72 76 90 00 a0 S5 7 10 10 35 13 15 25 35 50 45 SO 80 40 40 45 Sn 7 1Sea laM8i 45 43 47 y5 87 970 50 b', In 100 17 lib w 43 13 '5 `15 IS 65 96 91 81 8.8 88 90 an 6; 90 90 0 .Ju 0: 05 to 0 }5 10 21) 40 NOTE Thom* Rational Fctmu.a coefficients may not bit valid Inc tarps bssins Rational Method (FOR IMPERVIOUSNESS VALUES ONLY).xlsx 3/25/2021 Calculation of Peak Runoff using Rational Method Designer: DAS Company- uwf R5c.ewtart Date: 125/2021 hgect MALLARD FIE LO OFFICE - E°sang L ocdwn: WELD COUNTY ree wen 200 ..leased May 2247 of In cab w e 1e 'tslf ed ata+npol chit coke web *tonal ovend. t ;f of ies cols we I 'levW ed results �entdes 0..14; 1.1 — C. _r ;; .IY. Ct 5111', Ceapotrd e, = 1. - t.1 R p.wai t l76 -17S)♦ 601141 1 4, St SIseb 'I • 10 (t.oeurben) sse.e.d t, -. malts,..,,., mtn(C,unputed 1. . Repmrlt,)) 200 Syr 1000 $i0e 5► -1. 1000. SNOT 14tour ,a.44 depth. Pi Jai I e tie I 1.15 I t.SE I la 1 2.' E I 2.55 I s ► c aY Ramisi buenwty Equ an on Coefficients = 28.50 I 19.00 I 0.700 I;.u/hci ;b . 1 T :r.j-^eer:-. ,, emart. i_.. _.t►n4 Subcatchmem Name Area Jac) MRCS N5'ieM.lc Sal Group Percent bnpeneteusness Rand( Coell.c amt. C Overland Orate?, Flow rime - Chau.dted {Trae4 Flow hue I Ina. S Concentration A Weil 0 tensttrz l ¢n/n1 Peak Flow. 0 (ds) r'Yt Syt 107r )Syr 50.4, 100yr Sr Ny Overland w neLength L. RI UIS Mermen fn aIII Ial Dig oaten (wl 40wrrtndl Overt.,d Res Ova1.nd Flier Time I. Owl Ol Chastised Plow Length L, MI UPI Bevdw. 411 -- ' dt " 04 Onedie.. 011 'Cob pad; Clvv.eit.d Flew liege R IAI MRCS Conveyance !rise Factor I( Ch.nnrred Vaunt V.IR/e.c1 Che nred d Flew MIN 1. (null nu Computed 1, (stn) Reversal 7% t, hnnl Selected I. (non) r Syr 10Or lSyr Sop /0►W 3.03.00495. 00 7. SM layr isyr Sap 100Or keep e One 1 RVRI 10.t4 C :.0 0.01 1.05 C.'5 C33 0.40 043 CSi 300.00 A 0.005 t 5122 r '00.00 0 305 5 035 ' 4 ' 4 33 2S 57.35 1]10 •27 IN 2.2? Lai 3.75 1.,0 02E 1N Sd0 ' r04 24.95 35.00 0...-5 0.1: 11.57 37.14 E: IS SS c. 10 C'S 0.1] 040 '2•1 v � 0.002550.00 77.0t C. A: S 0.17 40 N 113.00 47 75 U >5 • 0, I Si 1 01 �. : Sa 1DC 7.6 27 4.t] ': 17 4201 22.0E ',L'3D5 8 ..;.7.10 7370 e Calculation of Peak Runoff using Rational Method Des,pier: DAS CornnawY' LwT Rameetai Date: 3/25/2021 Protect: Woad Fill Oita - Proposed Fbw lo: a,on' Wad Catty 91...aon 774,714101.1440 144-4 255. LCds al On cdOr solo, ftoure use-Input t o d/!a'Qier we for apainl commit valuer delis toe we tor Seated !nuts Dosed co everrid80. ti 3.1115,,.! • - 3- 1 11 _ tt 60L 601'. Cmputrdl, !i-ti kermal t =126-171)4 La 60(144 4 91 tea S 'utt.n, 10 (ra.artenl Selected t<< salt tma(Cmputd t, .'lepoeali.)) 14io4r !area depth. M (Ira s lye Syr +Gyt 2.v SOr 'Ifyr Sad 9.16 1 1.35 I 1.54 I Leo I 2.i• I 2.55 I a t c asp R..04 oaana.t' Equate Cortland; a 2450 I 1100 0.706 I,im/tr) „ 4414 (KO s) w clA Sua<stchmenl Mane Area (a<I MRCS Hydrologic Oal Goss Percent Land Coolness'*. C Overland Irma aT Flow Tore Chwwdrrd (Travel) Flow Time Tmne of Concentration Rwig 4A Intemnri I$SIW) Peak FSos. 0 cis) Syr 11149 254! SO- r 150yr S11d-6r Overland Flew Leith LIPI UPI Elevates Ely • opo-rndl 011 Elnahon AI ,Optiemdi Overland Res den RRrtI Ovtt.M Flom Time ltmnl CM.vNwtad Flee Lope L*) WI Bevwasn /91 I One snarl 04 ESevaa.. let) Op„' .. Channel zed Flew Slope 40tAt1 MRCS Genveyaacs Facts: K CMniad Flow Velocity V. Otaatl Chrwdleed Flow Time ;(an) Computed Computed744 t, semi Regond t. (mnl ede<1d I. Omni Sep lbw 2Sylr Sd4. SleepS6O 1T S-yr 111 -ye 1ST 51149 14049 506.44 St 20.17 C 33.0 0.2s 1.10 0.37 n SC 0.56 0.52 152 :00.00 9.091 31 N 550:)0 0.905 IO 0.71 7501 46.61 31 3'. Si 1.31 2.05 1.14 174 311 381 6.50 1280 1413 2450 11.74 49.60 0.39 057 tail 4567 B2 13.14 C 2.0 0.3! 1.05 0.15 0.33 0.40 Oat 151 500.00 0.Q05 55:2 55090 0.004 S 0.32 flAt 52.11 41.21 4'.. Y ! 11 - 1.74 1.00 2.32 2.75 111 0.15 1.24 4.04 10.12 1155 22.42 t3�s11 O.it 7,15 ?3,23 ,.,. 1423 C 2.0 9.9' 3.05 O.1S 0.33 0.40 0.49 1. S9 5013.09 0.003 6299 '00.90 0903 5 027 4280 '0S S9 01617-SS.57 48S' 100 '.57 1.79 1.00 251 386 0.17 1.31 4.26 '1.21 13.41 23.67 0.41 0.51 i S 21 1.11 0.40 C 6.0 0.34 3.06 O..e 03_4 042 O.il 25' 45.03 0.005 4592 0.30 0.005 • S 0.35 200 4191 24.91 1412 ' 50 235 248 3.14 177 4.45 0.03 0.10 113 00 54 0.75 1 n 028 032 • 0„33 1.11tl . • I i DETENTION BASIN STAGE -STORAGE TABLE BUILDER MHFD-Detention, Version 4.04 (February 2021) Project: Mallard Field Office Basin ID: Detention Pond l oriX fiCiallION1 { & �1 �6M.aIa owancc ""`" Example Zone Configuration (Retention Pond) Watershed Information Selected BMP Type = Watershed Area = Watershed Length = Watershed Length to Centroid = Watershed Slope = Watershed Imperviousness = Percentage Hydrologic Soil Group A = Percentage Hydrologic Soil Group B = Percentage Hydrologic Soil Groups C/D = Target WQCV Drain Time = EDB 35.00 1,500 800 0.005 21.00% 0.0% 10.0% 90.0% 40.0 acres ft ft ft/ft percent percent percent percent hours Location for 1 -hr Rainfall Depths = Denver - Capitol Building After providing required inputs above including 1 -hour rainfall depths, dick 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. Water Quality Capture Volume (WQCV) = Excess Urban Runoff Volume (EURV) = 2-yr Runoff Volume (P1 = 0.86 in.) = 5-yr Runoff Volume (P1 = 1.35 in.) = 10-yr Runoff Volume (P1 = 1.54 in.) = 25-yr Runoff Volume (P1 = 1.8 in.) = 50-yr Runoff Volume (P1 = 2.16 in.) = 100-yr Runoff Volume (P1 = 2.55 in.) = 500-yr Runoff Volume (P1 = 3.14 in.) = Approximate 2-yr Detention Volume = Approximate 5-yr Detention Volume = Approximate 10-yr Detention Volume = Approximate 25-yr Detention Volume = Approximate 50-yr Detention Volume = Approximate 100-yr Detention Volume = Define Zones and Basin Geometry Zone 1 Volume (WQCV) = Zone 2 Volume (10 -year - Zone 1) = Zone 3 Volume (100 -year - Zones 1 & 2) = Total Detention Basin Volume = Initial Surcharge Volume (ISV) = Initial Surcharge Depth (ISD) = Total Available Detention Depth (Htotr) = Depth of Trickle Channel (Hip) = Slope of Tridde Channel (Sic) Slopes of Main Basin Sides (Sma,n) Basin Length -to -Width Ratio (Ri-;;) Initial Surcharge Area (A5) = Surcharge Volume Length (Lisv) _ Surcharge Volume Width (Wisp,) = Depth of Basin Floor (HFLooP) = Length of Basin Floor (LFLo a) = Width of Basin Floor (WFLoos,) = Area of Basin Floor (AFcoca) = Volume of Basin Floor (VFwoR) = Depth of Main Basin (HMApi) = Length of Main Basin (14.44) = Width of Main Basin (WM,un) = Area of Main Basin (AM, s) = Volume of Main Basin (VMAp4) = Calculated Total Basin Volume (Vic,) = 0.349 0.657 0.405 1.351 1.835 2.760 3.799 5.129 6.904 0.392 0.881 1.057 1.258 1.407 1.893 0.349 0.708 0.835 1.893 user user user user User user user user user user user user user user user user user user user user user acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet acre-feet ft ft ft ft ft/ft H:V ft - ft ft ft ft ft ft2 ft3 ft ft ft ft' ft' acre-feet Optional User Overrides ace -feet ace -feet inches inches inches inches inches inches inches 0.86 1.35 1.54 1.80 2.16 2.55 Depth Increment = 0.10 ft Stage - Storage Description Stage (ft) Optional Override Stage (ft',, Length (ft) Wdth (ft) Area (ft 2) Optional Ovemde Area (ft 2) Area (acre) Volume (ft 3) Volume (ac -ft) Top of Micropool -- 0.00 -- -- -- 39,529 0.907 4903.9 -- 0.10 -- -- -- 40,287 0.925 3,991 0.092 4904 -- 0.20 -- -- -- 41,075 0.943 8,059 0.185 4904.1 -- 0.30 -- -- -- 41,904 0.962 12,208 0.280 4904.2 -- 0.40 -- -- -- 42,790 0.982 16,443 0.377 4904.3 -- 0.50 -- -- -- 43,773 1.005 20,771 0.477 4904.4 -- 0.60 -- -- -- 44,917 1.031 25,205 0.579 4904.5 -- 0.70 -- -- -- 46,409 1.065 29,771 0.683 4904.6 -- 0.80 -- -- -- 48,161 1.106 34,500 0.792 4904.7 -- 0.90 -- -- -- 50,270 1.154 39,422 0.905 4904.8 -- 1.00 -- -- -- 52,808 1.212 44,575 1.023 4904.9 -- 1.10 -- -- -- 55,818 1.281 50,007 1.148 4905 -- 1.20 -- -- -- 59,356 1.363 55,755 1.280 4905.1 -- 1.30 -- -- -- 63,481 1.457 61,907 1.421 4905.2 -- 1.40 -- -- -- 68,245 1.567 68,494 1.572 4905.3 -- 1.50 -- -- -- 73,622 1.690 75,587 1.735 4905.4 -- 1.60 -- -- -- 79,622 1.828 83,249 1.911 4905.5 -- 1.70 -- -- -- 86,540 1.987 91,557 2.102 4905.6 -- 1.80 -- -- -- 94,591 2.172 100,614 2.310 4905.7 -- 1.90 -- -- -- 104,109 2.390 110,549 2.538 4905.8 -- 2.00 -- -- -- 114,856 2.637 121,497 2.789 4905.9 -- 2.10 -- -- -- 125,674 2.885 133,523 3.065 4906 -- 2.20 -- -- -- 136,960 3.144 146,655 3.367 4906.1 -- 2.30 -- -- -- 148,889 3.418 160,947 3.695 4906.2 -- 2.40 -- -- -- 161,528 3.708 176,468 4.051 MHFD-Detention v4 04.:dsm Basin 3/25/2021 434 PM DETENTION BASIN STAGE -STORAGE TABLE BUILDER MHFD-Detention, Version 4.04 (February 2021) 20 15 t 10 • • J 5 0 • 161600 0.00 1.00 2M0 Stage (ft) Length (ft) Width (ft) —Area (sq.ft.) 3.720 2.790 pN G 1.860 • 3.00 4.00 121200 80800 40400 0 • I 4.060 3.045 a • 2.030 • 0 0.930 1.015 0.000 0.00 1.00 2.00 Stage (ft.) — Area (acres) Volume (ac -ft) 3.00 4.00 0.000 MHFD-Detention v4 04.4m. Basin 3/25/2021. 4:34 PM ON BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.04 (February 2021) Project: Mallard Field Office Basin ID: Detention Pond VOLUME EURVI wOCV PERMANENT - POOL ZONE ZONE 2 -ZONE 1 ZONE 1 AND 2 ORIFICES --100•YEAR ORIFICE Example Zone Configuration (Retention Pond) Zone 1 (WQCV) Zone 2 (10 -year) Zone 3 (100 -year) Estimated Stage (ft) Estimated Volume (ac -ft) Outlet Type 0.38 0.349 Orifice Plate 1.03 0.708 Circular Orifice 1.59 0.835 Weir&Pipe (Restrict) Total (all zones) User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Diameter = N/A inches 1.893 Underdrain Orifice Area = Underdrain Orifice Centroid = Calculated Parameters for Underdrain ft2 feet N/A N/A User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir typically used to drain WOCV and/or EURV in a sedimentation BMP; Invert of Lowest Orifice = Depth at top of Zone using Orifice Plate = Orifice Plate: Orifice Vertical Spacing = Orifice Plate: Orifice Area per Row = 0.00 0.38 1.50 7.61 ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches sq. inches (use rectangular openings) 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) WQ Orifice Area per Row = Elliptical Half -Width = Elliptical Slot Centroid = Elliptical Slot Area = Calculated Parameters for Plate 5.285E-02 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 0.13 0.25 7.61 7.61 7.61 Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Ro++. 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 0.38 N/A 1.03 N/A 2.00 N/A ft (relative to basin bottom at Stage = 0 ft) ft (relative to basin bottom at Stage = 0 ft) inches Vertical Orifice Area = Vertical Orifice Centroid = Calculated Parameters for Vertical Orifice Zone 2 Circular Not Selected 0.02 N/A 0.08 N/A ft` feet User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir (and No Outlet Pipe; Overflow Weir Front Edge Height, Ho = Overflow Weir Front Edge Length = Overflow Weir Grate Slope = Horiz. Length of Weir Sides = Overflow Grate Type = Debris Clogging % = Zone 3 Weir Not Selected 1.03 N/A 3.00 N/A 4.00 N/A 3.00 N/A Type C Grate N/A 50% N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, Ht = feet Ove-flow Weir Slope Length = H:V Grate Cpen Area / 100-yr Orifice Area = feet Overflow Grate Open Area w/o Debris = Overflow Grate Open Area w/ Debris = User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Depth to Invert of Outlet Pipe = Outlet Pipe Diameter = Restrictor Plate Height Above Pipe Invert = Zone 3 Restrictor Not Selected 0.00 N/A 18.00 N/A 18.00 User Input: Emergency Spillway (Rectangular or Trapezoidal) Spillway Invert Stage= Spillway Crest Length = Spillway End Slopes = Freeboard above Max Water Surface = Calculated Parameters for Overflow Weir Zone 3 Weir Not Selected 1.78 N/A 3.09 N/A 3.65 N/A 6.46 N/A 3.23 N/A feet feet Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = inches Outlet Orifice Centroid = inches Half -Central Angle of Restrictor Plate on Pipe = ft (relative to basin bottom at Stage = 0 ft) feet H:V feet Spi'Iway Design Flow Depth= Stage at Top of Freeboard = Easin Area at Top of Freeboard = Basin Volume at Top of Freeboard = Zone 3 Restrictor Not Selected 1.77 N/A 0.75 N/A 3.14 N/A Calculated Parameters for Spillway feet feet acres acre -ft ft` feet radians Routed Hydrograph Resu is Design Storm Return Period = One -Hour Rainfall Depth (in) = CUHP Runoff Volume (acre -ft) = Inflow Hydrograph Volume (acre -ft) = CUHP Predevelopment Peak Q (cfs) = OPTIONAL Override Predevelopment Peak Q (cfs) = Predevelopment Unit Peak Flow, q (cfs/acre) = Peak Inflow Q (cfs) = Peak Outflow Q (cfs) = Ratio Peak Outflow to Predevelopment Q = Structure Controlling Flow = 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 Ponding Depth (ft) = Area at Maximum Ponding Depth (acres) = Maximum Volume Stored (acre -ft) = The user ran override the default CUHP hvdroaraphs and runoff volumes by enter'nn no v vaIvec in the inflow Hvdroacc,nhc table 'Columns V/ thin/oh 4F' M WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year N/A N/A 0.86 1.35 1.54 1.80 2.16 2.55 3.14 0.349 0.657 0.405 1.351 1.835 2.760 3.799 5.129 6.904 N/A N/A 0.405 1.351 1.835 2.760 3.799 5.129 6.904 N/A N/A 0.3 8.4 11.9 22.0 30.9 42.5 57.6 N/A N/A N/A N/A 0.01 0.24 0.34 0.63 0.88 1.21 1.65 N/A N/A 3.8 13.3 17.1 27.4 37.0 49.2 65.3 0.4 0.6 0.4 0.9 1.8 4.0 6.6 9.7 10.4 N/A N/A N/A 0.1 0.1 0.2 0.2 0.2 0.2 Plate Vertical Orifice 1 Plate Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 N/A N/A N/A N/A 0.0 0.1 0.5 0.8 1.3 1.4 N/A N/A N/A N/A N/A N/A N/A N/A N/A 35 39 38 46 46 44 41 39 37 40 45 42 53 55 55 54 53 51 0.38 0.68 0.37 1.13 1.40 1.77 2.06 2.34 2.40 0.98 1.06 0.97 1.31 1.57 2.10 2.76 3.53 3.71 0.358 0.662 0.338 1.187 1.572 2.224 2.924 3.834 4.051 MHFD-Detention_v4 04.xlsm, Outlet Structure 3/25/2021, 6:22 PM DETENTION BASIN OUTLET STRUCTURE DESIGN Mf /FD -Detention, Version 4.04 (February 2021) 70 SO 40 rr 2 30 20 10 • 0 SOOYR IN 500YR OUT 100YR IN a 100YR OUT SOYRIN SOYR OUT +--r 25YR IN — — 25YR OUT 10YR IN 0 10YR OUT SYR IN SYR OUT 2YR IN 2YR OUT EURV IN EURV OUT WQCV IN wQcv OUT TIME [lid :_- eon — r �— glib ga ` ` 1 a laIIIIII a a .. d 0.1 10 3 2.5 2 0.5 0 �- 500YR 100YR aaSOYR 2SYR 10YR SYR 2YR EURV ci.WQCV 0.1 1 10 DRAIN TIME [SI 100 AREA (ft^2(, VOLUME (ft^3) 180,000 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 0.00 O User Area (ft^2J Interpolated Area (ft^2J • • ♦ • • Summary Area (ft^2] Volume [ft^3] • • ••• • • Summary Volume [ft^3] Outflow (cfs] • • •• • • Summary Outflow [cfs] 0.50 1.00 1.50 • 2.00 PONDING DEPTH [ft] 2.50 3.00 3.50 4.00 20 18 16 14 12 7E- 10 O J 85 O 6 4 2 0 S -A -V -D Chart Axis Override minimum bound maximum bound X-axis Left Y -Axis Right Y -Axis MHFD-Detention_v4 04.xtsm, Outlet Structure 3/25/2021, 6:22 PM Time Interval 5.00 min DETENTION BASIN OUTLET STRUCTURE DESIGN Outflow Hydrograph Workbook Filename: Inflow Hydrograph The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate progia SOURCE CUHP CUHP ....�. CUHP CUHP ` I H iT CUNP v" r-CUHP..-- �__. Ct1HP CUHP CUHP TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs] 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.07 0:15:00 0.00 0.00 0.06 0.25 0.31 0.21 0.31 0.33 0.48 0:20:00 0.00 0.00 0.44 1.29 1.70 0.64 1.04 1.45 2.29 0:25:00 0.00 0.00 1.92 6.14 8.89 2.99 4.48 6.95 12.29 0:30:00 0.00 0.00 3.20 11.28 14.80 14.81 21.12 27.18 38.22 0:35:00 0.00 0.00 3.68 13.11 16.81 22.71 31.29 41.05 55.49 0:40:00 0.00 0.00 3.81 13.35 17.06 26.57 36.04 47.09 62.91 0:45:00 0.00 0.00 3.64 12.76 16.45 27.44 37.03 49.18 65.28 0:50:00 0.00 0.00 3.42 12.02 15.47 27.14 36.51 48.64 64.49 0:55:00 0.00 0.00 3.22 11.22 14.58 25.76 34.76 47.00 62.37 1:00:00 0.00 0.00 3.04 10.44 13.74 24.26 32.89 45.33 60.20 1:05:00 0.00 0.00 2.87 9.69 12.95 22.82 31.06 43.67 58.03 1:10:00 0.00 0.00 2.68 9.08 12.37 20.98 28.77 40.48 54.07 1:15:00 0.00 0.00 2.50 8.54 11.91 19.40 26.85 37.45 50.28 1:20:00 0.00 0.00 2.33 7.96 11.20 17.87 24.77 34.26 46.06 1:25:00 0.00 0.00 2.17 7.38 10.34 16.40 22.73 31.13 41.86 1:30:00 0.00 0.00 2.01 6.80 9.45 14.92 20.67 28.19 37.89 1:35:00 0.00 0.00 1.85 6.24 8.57 13.48 18.67 25.37 34.07 1:40:00 0.00 0.00 1.69 5.59 7.73 12.07 16.72 22.65 30.41 1:45:00 0.00 0.00 1.55 5.01 7.03 10.72 14.87 20.11 27.05 1:50:00 0.00 0.00 1.46 4.56 6.52 9.61 13.37 18.05 24.36 1:55:00 0.00 0.00 1.36 4.22 6.08 8.78 12.24 16.45 22.24 2:00:00 0.00 0.00 1.27 3.91 5.63 8.09 11.30 15.09 20.43 2:05:00 0.00 0.00 1.17 3.57 5.13 7.38 10.31 13.72 18.56 2:10:00 0.00 0.00 1.06 3.24 4.64 6.71 9.35 12.42 16.78 2:15:00 0.00 0.00 0.95 2.92 4.17 6.07 8.45 11.19 15.11 2:20:00 0.00 0.00 0.86 2.61 3.72 5.46 7.59 10.05 13.55 2:25:00 0.00 0.00 0.76 2.32 3.30 4.89 6.78 8.99 12.09 2:30:00 0.00 0.00 0.67 2.03 2.90 F 4.33 6.00 7.97 10.71 2:35:00 0.00 0.00 0.59 1.76 2.52 3.79 5.25 6.98 9.36 2:40:00 0.00 0.00 0.51 1.49 2.15 3.26 4.52 6.01 8.04 2:45:00 0.00 0.00 0.43 1.23 1.79 2.74 3.80 5.04 6.73 2:50:00 0.00 0.00 0.35 0.98 1.44 2.23 3.08 4.09 5.44 2:55:00 0.00 0.00 0.27 0.74 1.10 1.72 2.38 3.14 4.17 3:00:00 0.00 0.00 0.20 0.53 0.82 1.24 1.72 2.26 3.01 3:05:00 0.00 0.00 0.15 0.39 0.64 0.85 1.20 1.58 2.15 3:10:00 0.00 0.00 0.13 0.31 0.52 0.61 0.88 1.15 1.58 3:15:00 0.00 0.00 0.10 0.25 0.43 0.45 0.66 0.84 1.17 3:20:00 0.00 0.00 0.09 0.21 0.35 0.34 0.51 0.61 0.87 3:25:00 0.00 0.00 0.07 0.17 0.29 0.26 0.39 0.44 0.63 3:30:00 0.00 0.00 0.06 0.14 0.23 0.20 0.30 0.32 0.45 3:35:00 0.00 0.00 0.05 0.11 0.18 0.15 0.23 0.22 0.32 3:40:00 0.00 0.00 0.04 0.09 0.14 0.12 0.17 0.17 0.24 3:45:00 0.00 0.00 0.03 0.07 0.11 0.09 0.13 0.13 0.19 3:50:00 0.00 0.00 0.03 0.05 0.08 0.07 0.10 0.10 0.15 3:55:00 0.00 0.00 0.02 0.04 0.06 0.06 0.08 0.08 0.12 4:00:00 0.00 0.00 0.02 0.03 0.05 0.04 0.06 0.06 0.09 4:05:00 0.00 0.00 0.01 0.02 0.03 0.03 0.05 0.05 0.06 4:10:00 0.00 0.00 0.01 0.01 0.02 0.02 0.03 0.03 0.04 4:15:00 0.00 0.00 0.00 0.01 0.01 0.01 0.02 0.02 0.03 4:20:00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 4:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 4:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 MHFD-Detention_v4 04.xlsm. Outlet Structure 3/25/2021, 6 22 PM DETENTION BASIN OUTLET STRUCTURE DESIGN MHFD-Detention, Version 4.04 (February 2021) Summary Stage -Area -Volume -Discharge Relationships The user can create a summary S -A -V -D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S -A -V -D table to the full S -A -V -D table in the chart to confirm it captures all key transition points. Stage - Storage Description Stage [ft] Area [ft2] Area [acres] Volume [ft) Volume [ac -ft] Total Outflow [cis] WQCV - 4904.17 0.38 42,613 0.978 15,589 0.358 138 10-YR - 4905.19 1.40 68,245 1.567 68,494 1.572 1.77 100-YR - 4906.13 2.34 153,945 3.534 167,004 3.834 9.72 i For best results, include the stages of all grade slope changes (e.g. ISV and Floor) from the S -A -V table on Sheet 'Basin'. Also include the inverts of all outlets (e.g. vertical orifice, overflow grate, and spillway, where applicable). MHFD-Detention_v4 04.xlsm, Outlet Structure 3/25/2021, 6:22 PM Weir Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. 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 Q B1 + Q OS1. = Sharp = 127.00 - 1.00 = 4.00 = 3.10 Known Q = 140.00 Highlighted \ Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Top Width (ft) OVERFLOW WEIR Thursday, Mar 25 2021 = 0.50 = 140.00 64.50 = 2.17 = 131.00 I 0 10 20 Weir 30 40 50 60 ;_- W.S. 70 80 90 100 110 120 130 140 150 160 Depth (ft) 2.00 1.50 1.00 0.50 0.00 -0.50 Length (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. NORTH SWALE Triangular Side Slopes (z:1) Total Depth (ft) Invert Elev (ft) Slope (%) N -Value Calculations Compute by: Known Q (cfs) Elev (ft) 14.00 13.00 12.00 11.00 10.00 9.00 = 19.00, 22.00 = 3.00 10.00 = 0.50 = 0.025 Known Q = 59.00 Section Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ftls) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Thursday, Mar 25 2021 1.04 59.00 22.17 - 2.66 = 42.69 = 0.88 = 42.64 1.15 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Depth (ft) 4.00 3.00 2.00 1.00 0.00 -1.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. SOUTH SWALE Triangular Side Slopes (z:1) Total Depth (ft) Invert Elev (ft) Slope (%) N -Value Calculations Compute by: Known Q (cfs) Elev (ft) 14.00 13.00 12.00 11.00 10.00 9.00 = 54.00, 5.00 = 3.00 = 10.00 = 0.50 = 0.025 Known Q = 35.00 Section Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ftls) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Thursday. Mar 25 2021 = 0.75 = 35.00 = 16.59 2.11 = 44.33 = 0.62 = 44.25 = 0.82 41/ 0 20 40 60 80 100 120 140 160 180 200 220 Depth (ft) 4.00 3.00 2.00 1.00 0.00 -1.00 Reach (ft) ile COLORADO Division of Water Resources Department of Natural Resources WELL PERMIT NUMBER 321955 - RECEIPT NUMBER 1001 0769 ORIGINAL PERMIT APPLICANT(S) APPROVED WELL LOCATION DPOC LLC (MCLLVAIN, JAMISON) AUTHORIZED AGENT LAMP RYNEARSON (PALIZZI, MICHAEL) PERMIT TO CONSTRUCT A NEW WELL Water Division: 1 Designated Basin: Management District: County: Parcel Name: Water District: 1 NA N., A WELD NIA Physical Address: 0 WCR 103 BRIGGSDALE, CO 80611 SE 1/4 SE 1/4 Section 9 Township 8.0 N Range 60M W Sixth P.M. UTM COORDINATES (Meters, Zone:13, NAD83) Easting: 576855.7 Northing: 41502608.2 ISSUANCE OF THIS PERMIT DOES NOT CONFER A WATER RIGHT CONDITIONS OF APPROVAL This well shall be used in such a way as to cause no material injury to existing water rights. The issuance of this permit does not ensure that no injury will occur to another vested water right or preclude another owner of a vested water right from seeking relief in a civil court action. The construction of this well shall be in compliance with the Water Well Construction Rules 2 CCR 402-2, unless approval of a variance has been granted by the State Board of Examiners of Water Well Construction and Pump Installation Contractors in accordance with Rule 18. Approved pursuant to CRS 37-92-602(3)(b)(I) and the policy of the State Engineer dated April 9, 1985 for appropriation of groundwater tributary to the South Platte River system. The use of groundwater from this well is limited to drinking and sanitary facilities as described in CRS 37-92-602(1)(c), for a commercial business. Water from this well shall not be used for lawn/landscape/greenhouse irrigation, domestic animal/livestock watering, or for any other purpose outside the business building structure(s). 5 y Approved as the only well on a tract of land of 35.00 acres described as that portion of the S 1/2 of Sec. 9, Twp. 8 N, Rng. 60 W, S P.M., Weld County, more particularly described as Lot A on Exhibit A in the well permit file. 64 The pumping rate of this well shall not exceed 15 GPM. The annual amount of groundwater to be withdrawn by this well shall not exceed 1/3 acre-foot (108,600 gallons). Si The return flow from the use of this well must be through an individual wastewater disposal system of the non -evaporative type where the water is returned to the same stream system in which the well is located. 9 This well shall be constructed not more than 200 feet from the location specified on this permit. 131 A totalizing flow meter must be installed on this well and maintained in good working order. Permanent records of all diversions must be maintained by the well owner (recorded at least annually) and submitted to the Division Engineer upon request. 11 1 ADVANCE NOTICE REQUIRED - Pursuant to Construction Rule 6.2.2.1 (2 CCR 402-2), licensed or private drillers and pump installers must provide advanced notification (at least 24 hours) to the State Engineer prior to each of the following for this well: well construction, the initial installation of the pump, and initial installation of a cistern connected to the water well supply system. Any change in the anticipated date of construction/ installation must be re -noticed (at least 24 hours prior to revised anticipated date). Information regarding the notification process and a link to the electronic notification form can be found on the the Division of Water Resource website. NOTE: At the proposed well location, the White River formation is located at or near the ground surface and extends to a depth of approximately 105 feet. Wells completed in the White River formation must be constructed in accordance with Well Construction Rule 10.4.6 (2 CCR 402-2) for a Type II aquifer. NOTE: At the proposed well location, the Laramie formation is located approximately 105 feet below ground surface and extends to a depth of approximately 140 feet. Wells completed in the Laramie formation must be constructed in accordance with Well Construction Rule 10.4.6 (2 CCR 402-2) for a Type II aquifer. Printed 05-19-2021 For questions about this permit call 303.866.3581 or go to www.water.state.co.us Page 1 of 2 WELL PERMIT NUMBER 321955 - RECEIPT NUMBER 10010769 NOTE At the proposed well location, the Laramie -Fox Hills aquifer is located approximately 140 feet below grobnd surface and extends to a depth of approximately 580 feet Wells completed in the Laramie -Fax Hills aquifer must be constructed with solid steel casing and grouted in accordance with Well Construction Rule 10 4 8 (2 CCR 402-2) NOTE At the proposed well location, the Upper Pierre aquifer is located approximately 865 feet below ground surface and extends to a depth of approximately 1620 feet. Wells completed in the Upper Pierre aquifer must be constructed in accordance with Well Construction Rule 10 4 5 2 (2 CCR 402-2) for a Type l aquifer overlain by multiple confining layers NOTE A hydrogeologic aquifer evaluation has been completed for this permit and the details of the evaluation can be viewed in the hydrogeologic aquifer evaluation imaged document and the original permit file NOTE This permit will expire on the expiration date unless the well is constructed by that date A Well Construction and Yield Estimate Report (GWS-31) must be submitted to the Division of Water Resources to verify the well has been constructed An extension of the expiration date may be available Contact the DWR for additional information or refer to the extension request form (GWS-64) available at, dwr colorado gov Issued By BRIAN NA KRAUSER Date Issued: 5/19/2021 Expiration Date' 5/19/2023 Printed 05-19-2021 For questions about this permit call 303 866 3581 or go to www water state co us Page 2 of 2 Hello