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HomeMy WebLinkAboutReports - Drainage - 04/16/2025 v L J L u N U L u L N Switchgrass Crossing Final Drainage Report Prepared for: Doug Snyder Volunteers of America 2660 Larimer St Denver, CO 80205 Prepared by: Ted Swan, PE Shopworks 301 W. 45th Ave Denver, CO 80216 Ted Swan, PE 43903 S r1 C3 P LU tea r- K Page 1 of 12 301 West 45th Avenue,Denver,CO 80216 303 433-4094 v ll u Table of Contents L L u l A. Introduction pg. 3 rg B. Historic Drainage pg. 4 C. Design Criteria pg. 4 D. Drainage Plan pg. 5 E. List of References pg. 8 F. Appendix pg. 9 Page 2 of 12 '!'Avenue,Denver,CO 80216 303 433-4094 v L J A. IntroductionJi v L 1. Location L a. The 1.40 ac (as platted) VOA Switchgrass site (Site) at 3800 S Mason St is bounded by Mason Street on the west, commercial property on the east and south, and Mason Place residential property on the north. The property has been platted as Creger Plaza Third Replat Lot 2 Subdivision Filing No. 1, Lot 1, Blk 1. Please see vicinity map below: VICINITY MAP CREGER DR SITE 0 j J 7 N m w 2-1W O C7 LU a J o Q C/) U COLBOARD DR Scale 1" = 300' b. There are no major drainageways or stormwater facilities. 2. Proposed Development a. The current phase of development proposes (1) four story multifamily residential building with 45 units, private driveways and surrounding amenity areas on 1.40 acres. It is anticipated that the composite percent of impervious area will be 76%. S I1 o P UJ CD f Fi 5 Page 3 of 12 "'Avenue,Denver,CO 80216 303 433-4094 v 3. MDR and Master Drainage Basins a. There is not a Master Drainage Report governing the Site drainage or surrounding areas. The site falls within the Mail Creek Master Drainage Basin. W Li b. No conditional approval comments existed on an approved MDR. L 4. Variances fu 1. No Variances are requested with this project. B. Historic Drainage 1. Overall Basin Description a. The existing 1.4 acre site (as platted) is currently developed with an asphalt parking lot covering the entire site. The site slopes generally to the west at 1-2% to two existing inlets that convey storm water downstream to the storm main within Mason St. Geotechnical analysis has been performed and the soil is anticipated to be mostly comprised of type C and D clayey soils as supported by the NRCS soil data. Groundwater was found at depths of 8+ ft in all borings. The NRCS soil map has been included in Appendix A.As shown on FEMA FIRM Panel 08069CO987G in Appendix A,the site is not located in a FEMA floodplain. b. The Site does not appear to be part of or tributary to a larger master planned drainage basin.As noted previously, it flows directly west to two on site inlets that drain to the storm main within Mason St. c. No irrigation facilities are located near or are impacting the site. d. The residential Mason Place property and a portion of the commercial properties to the east and south drain onto the site and are routed through the onsite water quality ponds along with the rest of the Site drainage. C. Design Criteria 1. Hydrologic Criteria a. The design frequencies used for analysis were as prescribed in the Fort Collins Stormwater Criteria Manual (The Manual): 2yr for the minor storm event and 100 yr for the major storm event. These storm events were used for determining site runoff and pipe capacities. b. The Manual was referenced for anticipated 1-hour rainfall depth in all storm events. The 2 yr 1-hour rainfall depth is 0.82 in and the 100 yr 1-hour depth is 2.86in. c. Given the site area, the rational method was used for determining site runoff flow rate (Q). Per this method, Q is determined using the basin runoff coefficient (C), site acreage (A) and storm intensity (I). Storm intensity is calculated using the Time of Concentration (Tc) for each basin. d. As prescribed in the PDP, detention was not provided for the site due to the fact that the development will be reducing the overall site imperviousness. Onsite Extended Detention Basins (EDB) were utilized to provide water quality treatment for the site. The MHFD-Detention workbook was utilized to determine the Water Quality Capture Volume (WQCV).As prescribed in the workbook WQCV was provided based S I1 o P UJ CD f Fi 5 Page 4 of 12 "'Avenue,Denver CO 80216 303 433-409-1 on the USDCM formula for an extended detention basin with the formula shown below WQCV = a(0.91 I3 - 1.19 I2 + 0.781) W U WQCV= Water Quality Capture Volume (watershed-inches) L a = Coefficient corresponding to BMP type and based on WQCV design drain time I = Imperviousness (percent expressed as a decimal) fu e. Other design criteria was not utilized for hydrologic calculations.Autodesk Hydraflow was used to calculate storm pipe capacity. 2. Hydraulic Criteria a. Private Storm infrastructure was sized to convey runoff from both the 2 year minor storm event and the 100 year major storm event. No public storm infrastructure was required for the project. Hydraulic capacity calculations are shown in Appendix C. b. As noted above, FEMA FIRM Panel 08069CO987G was referenced (and included in Appendix A) and the site does not fall within a jurisdictional floodplain. No LOMR or LOMC is required. c. All storm infrastructure on the plan is privately owned and will be maintained by the property owner d. As part of the storm water management plan to be utilized during construction, the onsite extended detention basins will be temporarily coverted to sediment basins to treat construction stormwater flows prior to discharge to the Mason St storm main. D. Drainage Plan 1. General Concept a. The majority of the Site and the few tributary adjacent areas comprise 3 larger basins that discharge to onsite EDBs for water quality treatment. The northern portion of the site is denoted Basin A. Basin A drains via driveway gutter, storm inlets and storm sewer to EDB-A in the NW corner of the site. The eastern and south eastern portion of the site is denoted Basin B. Basin B sheet flows and drains via driveway gutter and concrete pans to EDB-B in the SE corner of the site. The outfall pipe for Basin B receives offsite flow from the parking lot to the east of the site. The pipe flow from the east has been conservatively modeled as full flow since a drainage report does not exist for the site. The south western portion of the site has been denoted Basin C. Basin C drains via driveway gutter and concrete pan to EDB-C in the SW corner of the site. As mentioned previously, a small portion of the residential property to the north and the commercial properties to the east and south of the Site (totaling 0.09 acres) will drain onto the site. There is a small portion of the site denoted OS-1 that will drain directly offsite to Mason St without being routed through the onsite EDBs. This basin is roughly equivalent to the area of the adjacent sites that are draining onsite. I1 0 P UJ a F Fi S Page 5 of 12 "'Avenue,Denver,CO 80216 303 433-4094 v L J L u 2. Specific Details W U a. As noted above, there are 3 primary onsite basins that drain to extended detention L basins for water quality treatment before being released to storm sewer that drains to the existing storm main within Mason St. Basin A has been further divided into 2 fu subbasins denoted Al and RA1 to allow for the analysis of storm infrastructure serving each subbasin. Similarly, Basin B has also been further divided into 2 subbasins denoted 131 and R131 to allow for the analysis of storm infrastructure serving each subbasin. Basin C is smaller and further division was not deemed necessary. There is also 1 onsite basin denoted OS1 that drains offsite untreated. The subbasins are more particularly described below followed by a runoff summary table showing the local and accumulated flows at each design point: Subbasin RA1 is comprised of the northern section of the building. It is 0.08 ac and is completely impervious rooftop with an impervious percentage of 95%. Major and Minor Storm Runoff from RA1 is directed to a roofdrain location noted as design point R1. The roof drain flows to the northern storm sewer at design point 1 and is routed to eventually outfall at EDB-A. Subbasin Al is comprised of the northernmost portion of the drive lane, parking lot, associated landscape and EDB-C.Al is 0.17 ac and is mostly impervious paving with some pervious landscape and an impervious percentage of 83%. Major and Minor Storm Runoff from Al is directed to a sump inlet at design point 1 and then is routed to storm sewer to outfall into a small concrete forebay at EDB-A. The sump inlet was analyzed for capacity using MHFD criteria found in Appendix C. Subbasin R131 is comprised of the southernmost section of the building. It is 0.20 ac and is completely impervious rooftop with an impervious percentage of 95%. Major and Minor Storm Runoff from R131 is directed to a roof drain at design point R2. The roof drain flows to the courtyard and joins storm flow from Basin 131 to route overland and eventually outfall at EDB-B. Subbasin B1 is comprised of the courtyard, southeastern portion of the drive lane, parking lot, associated landscape and EDB-C. It is 0.79 ac and is split between impervious paving and pervious landscape areas with an impervious percentage of 69%. Major and Minor Storm Runoff from 131 drains overland to a concrete pan on the eastern side of the parking lot and then south to discharge directly to EDB-B at design point 2. Basin C is comprised of the drop off area and drive lane immediately south of the building as well as EDB-C and a small strip of landscape on the southern border of the site. It is 0.16 ac and is split between impervious paving and pervious landscape with an impervious percentage of 70%. Major and Minor Storm Runoff from C is directed to curb and gutter that drain to EDB-C at design point 3. I° ) C P LLY CD f Fi 5 Page 6 of 12 "'Avenue,Denver,CO 80216 303 433-4094 v L J b. See below Runoff Summary Table. ll Runoff Summary Tableu. - Minor Minor Major Major Major Storm Storm Storm Storm m Minor Storm Local Accum Local Accum Design Area Impervious Storm (C (C Flow Flow Flow Flow Basin ID Point (AC) Percentage Value) Value) (cfs) (cfs) (cfs) (cfs) RA1 R1 0.08 95% 0.95 1.00 0.23 0.23 0.80 0.80 Al 1 0.17 83% 0.83 1.00 0.40 0.63 1.41 2.20 RB1 R2 0.20 95% 0.95 1.00 0.54 0.54 1.89 1.89 B1 2 0.79 69% 0.69 0.87 1.57 2.11 5.47 8.19 C1 3 0.16 70% 0.70 0.87 0.31 0.31 1.07 10.09 OSl 4 0.09 58% 0.58 0.73 0.15 0.15 0.64 0.64 c. As discussed during the PDR, the existing site is primarily impervious asphalt and concrete. Therefore, the City allowed the project to waive the detention requirement and only provide water quality treatment for the site. The Project is proposing 3 extended detention basins denoted EDB-A, EDB-B, and EDB-C to treat Water Quality. EDB-A has an upstream tributary area of 0.26 acres with an impervious percentage of 87%. EDB-B has an upstream tributary area of 0.99 acres with an impervious percentage of 75%. EDB-C has an upstream tributary area of 0.16 acres with an impervious percentage of 70%. A summary table of volumes, depths,water surface elevations and discharge is shown below: EDB WQCV (ac ft) WQCV (cu ft) WQ Depth (ft) 100 yr Depth (ft) 100 yr Outflow (cfs) A 0.008 348 2.03 2.6 1.8 B 0.025 1089 1.66 2.5 3.2 C 0.004 174 1.04 1.5 0.6 d. The emergency spillways for each EDB has been sized to provide 1' of freeboard to the top of bank from the emergency spillway WSEL and will direct sheet flows towards the Woodrim Tributary. RGA will be privately maintained and will follow MHFD guidelines for maintenance. See Drainage Plan for maintenance access path. e. Emergency overflow paths and flow cross sections have been provided for all onsite sump inlets and EDB. The locations of each are shown on the Drainage Plan and the calculations for each cross section have been provided in Appendix C. f. One 4' drainage pan (Pan-B) has been provided on site to direct storm runoff downstream to EDB-B. See below table of the design elements of the pan. Calculations for the pan are included in Appendix C. Open Channel Design Element Table Name Long. Slope Minor Q Major Q Velocity Depth Freeboard Pan-B 0.50% 1.57cfs 5.47cfs 2.00ft/s 0.27ft 1.93ft I 0 P UJ CD F Fi S Page 7 of 12 "'Avenue,Denver,CO 80216 303 433-4094 v g. No streets, private driveways or alleys are proposed with the development. 3 h. The permanent SCMs that are proposed with the development are the extended U detention basins EDB-A, EDB-B and EDB-C as discussed previously. Volume L calculations are shown in Appendix C. L U rg E. List of References 1. Fort Collins Stormwater Criteria Manual,Aurora, CO, December 2018. 2. Urban Storm Drainage Criteria Manual,volumes 1, 2, and 3, Urban Drainage and Flood Control District,August 2018, September 2017, and January 2021 (respectively). s n o P SLY a CT H S Page 8 of 12 "; 15"Avenue,Denver,CO 80216 303 433-4094 v 3 ll u 0 U L u l N Appendix A Geotechnical Report Excerpts USGS Soil Survey FEMA FIRM Map NOAA Rainfall Data Existing Drainage Report Excerpts S h o P SLY a CT H S Page 9 of 12 "'Avenue,Denver,CO 80216 303 433-4094 NOTES TO USERS FLOODING EFFECTS FROM LEGEND SPRING CREEK This map is for use in administering the National Flood Insurance Program. It PROFILE BASE LINE SPECIAL FLOOD HAZARD AREAS (SFHAs) SUBJECT TO does not necessarily identify all areas subject to flooding, particularly from local ` INUNDATION BY THE 1% ANNUAL CHANCE FLOOD drainage sources of small size. The community ma repository should be 3115000 FT Drop Structure LL0518 Bridge SPRING PARK DRIVE 3120000 FT g Y p p y 105°05'37.5" g JOINS PANEL 0979 105°03'45.0" The 1% annual chance flood (100-year flood), also known as the base flood, is the flood ,..,, N consulted for possible updated or additional flood hazard information. .. 40133'45.0" that has a 1% chance of being equaled or exceeded in any given year. The Special 40°33 45.0 ::::.::::.::::.;:.:.:. . ......... ...... ...... .... ... .... ...... Bridge e .. ER o K R\v Flood Hazard rd Area is the area subject to flooding b the 1 annual chance flood Are as E T0 obtain more detailed information In areas where Base Flood Elevations ::.::.:,.y,..:..... .:..:. :..:.:.:.:.:.:.:..: .... .:...:.:.:..:.:. .:.:.:....:.:.:.:.:.:. .:.:.:..... .:.:.:.:....:.:.:.:... .:.:.:.:.:. .:.:.:.:..:.:.:..:: : ... .:::.... ...... ..:.: :.:. :. :. . :.. .:.:.:..:.:...:.:..:. of Special Flood Hazard Include Zones A AE AH AO, AR A99 V and VE. The Base F.... >.o :•:»:'. :.: _::::.::::.: .:.:::.>':::.::.;•:::.:::::..:: >'::.::.::: ;:: - :.::.;:.;:::»:::::>:.;:.:':»::.;':>:.;:.;' . ': ::.:::.>:.::. ::.>:.:::.:<.::.::::.<»:.>::: -surface elevation ofthe 1/ annualchance flo od.Elevation is the waterBFEsand/or floodways have been determined users are encouraged to consult WAY DO O V lC 9 the Flood Profiles and Floodway Data and/or Summary y of Stillwater Elevations cr, SP In g E ZONE A No Base Flood Elevations determined. tables contained within the Flood Insurance Study (FIS) report that accompanies N rn U ZONE AE ..: ...:.: ..... ............ ...... ...... ...... ...... ...... .... «:<:::<:>:::<:>' o >i Base Flood Elevations determined. co d. v w Creek cn this FIRM. r should aware h BFE shown n h FIRM represent 0 t s Usessoud bea ae that s so o to = � Cn m rn HI L O L c7 a- rtn r k O m S Creek v Z NE AH ZONE o Flood depths of 1 to 3 feet (usually areas of ondin Base Flood - z ,rounded whole foot elevations. These BFEs are Intended for flood Insurance P ( Y P 9) A G> c m O AE Elevationsrmin U determined.o m ratingpurposes only and should not be used as the sole source of flood D N w P P Y o > Ro a u, D �� +� m 44 OOOm M. CoONE AO elevation information. Accordingly, flood elevation data resented in the FIS «< ::o:::. o,q Flood depths of i to 3 feet (usually sheet flow on sloping terrain); p n � 90 N p ( Y p 9 ) report should be utilized in conjunction with the FIRM for purposes of m m average depths determined. For areas of alluvial fan flooding, velocities construction and/or floodplain management. i also determined. Q Q DARTMO JQ� DARTMOUTH M TRF\L ZONE AR Special Flood Hazard Area formerly protected from the 1% annual Coastal Base Flood Elevations shown on this map apply only landward GT o chance flood by a flood control system that was subsequently of 0.0' North American Vertical Datum of 1988 (NAVD 88). Users of this Q y TRP\� U decertified. Zone AR indicates that the former flood control system is FIRM should be aware that coastal flood elevations are also provided in the IRUTGERS AVENUE o being restored to provide protection from the 1% annual chance or Summary of Stillwater Elevations table in the Flood Insurance Study report w w a greater flood. for this jurisdiction. Elevations shown in the Summary of Stillwater Elevations > > — ZONE A99 Area to be protected from 1% annual chance flood by a Federal table should be used for construction and/or floodplain management purposes o c a OUKE> LANE S°JPP� j flooddete netection system under construction; no Base Flood Elevations when they are higher than the elevations shown on this FIRM. d. Z DUKE � O ZONE V Coastal flood zone with velocity hazard (wave action); no Base Flood Boundaries of the floodways were computed at cross sections and interpolated Q ° ° Elevations determined. between cross sections. The floodways were based on hydraulic considerations a 'o COLUMBIA ROAD Z ZONE VE Coastal flood zone with velocity hazard (wave action); Base Flood with regard to requirements of the National Flood Insurance Program. Floodway Q � J LU o Elevations determined. widths and other pertinent floodway data are provided in the Flood Insurance 23 rimer County Canal No. 2 m ' LU 0 24 in Study report for this jurisdiction. o w co m $ Q FLOODWAY AREAS IN ZONE AE WOR ,APO Certain areas not in Special Flood Hazard Areas may be protected by flood G�� Q J Do CORNELL AVENUE The floodway is the channel of a stream plus any adjacent floodplain areas that must be THINGTpN control structures. Refer to Section 2.4 "Flood Protection Measures" of -ALE WAY $ w CAMBRIDG kept free of encroachment so that the 1% annual chance flood can be carried without the Flood Insurance Study report for information on flood control structures o a U) o E substantial increases in flood heights. for this jurisdiction. 90 ° _ ~n DRIVE w OTHER FLOOD AREAS The projection used in the preparation of this map was Colorado State 9 w Nv2 w V ANDFRg, ZONE X Areas of 0.z% annual chance flood; areas of 1% annual chance flood W Plane north zone (FIPSZONE 0501).The horizontal datum was NAD83, D T > cT N z o o with average depths of less than 1 foot or with drainage areas less than GRS1980 spheroid. Differences in datum, spheroid, projection or State Plane 9 a c 9 N couRT F 1 /o square mile; and areas protected by levees from 1 annual chance y > O AVENUE n w o zones used in the production of FIRMS for adjacent jurisdictions may result in ° F °w Cr slight positional differences in map features across jurisdiction boundaries. o eR 1­_ w flood. am These differences do not affect the accuracy of the FIRM. ¢ „ QUEENS a 0 OTHER AREAS } O COURT Flood elevations on this map are referenced to the North American Vertical �° ZONE X Areas determined to be outside the 0.2% annual chance floodplain. G PRINCETON ROAD Datum of 1988. These flood elevations must be compared to structure and < + w� ground elevations referenced to the same vertical datum. For information 1445000 FT `� j ZONED Areas in which flood hazards are undetermined, but possible. regarding conversion between the National Geodetic Vertical Datum of 1929 0 0 and the North American Vertical Datum of 1988, visit the National Geodetic P°P° < ® COASTAL BARRIER RESOURCES SYSTEM (CBRS) AREAS Survey website at http://www.ngs.noaa.gov/ or contact the National Geodetic PRINCETON BAYLOR STREET Survey at the following address: OTHERWISE PROTECTED AREAS (OPAs) NGS Information Services XLL1032 o CBRS areas and OPAs are normally located within or adjacent to Special Flood Hazard Areas. NOAA, N/NGS12 DRAKE ROAD DRAKE ROAD National Geodetic Survey WD � F oo pain boundary SSMC-3, #9202 m = o Floodway boundary 1315 East-West Highway D DRIVE y M z O Silver Spring, MD 20910-3282 `-o �LU < (nn a > " 44 000m - - Zone D boundary o = a o ~ 0 89 N CBRS and OPA boundary To obtain current elevation, description, and/or location information for bench marks o J �, zFWINCHESTER DRIVE E Boundary dividing Special Flood Hazard Areas of different o w \V rY 9 Pe shown on this map, please contact the Information Services Branch of the � o a � oR m 0 w O O THUNDERBIRD o Base Flood Elevations, flood depths or flood velocities. National Geodetic Surveyat 301 713-3242 or visit its website at Q w U THUNDERBIRD DRIVE m e z O HEATH Cc http://www.ngs.noaa.gov/. > � STREET LU a o o ^^^^^' 513 Base Flood Elevation line and value; elevation in feet* Base map information on this FIRM was provided by the Larimer County GIS and POWDERHORN DRIVE o W RI w m N w � ° (EL 987) Base Flood Elevation value where uniform within zone; Mapping Department. Additional input was provided b the City of Fort Collins > m O CIfFR ��E o ALLE STRAGHAN DRIVE w elevation in feet* pp g p p P Y Y m 9 a DP a w m > Geographic Information Services Division. These data are current as of 2010. o z ° z TREET o w o *Referenced to the North American Vertical Datum of 1988 (NAVD 88) O w p S U 0 0 DRitr c� a s Z A A Cross section line z F z ¢ MAE o This map reflects more detailed and up-to-date stream channel configurations Q�� ��� o than those shown on the previous FIRM for this jurisdiction. The floodplains PQP o °P w RUT� STR. ALEXAND 23 ------- 23 Transect line Z Cc and floodways that were transferred from the previous FIRM may have been °� w Geographic coordinates referenced to the North American adjusted to conform to these new stream channel configurations. As a o MORSMPN �, o w a 97`07'30",32°22�30° Datum of 1983 NAD 83 z w CLAIR ROAD OXFORD LANE m O ( ) result, the Flood Profiles and Floodway Data tables in the Flood Insurance � Roc ° J a o a Ky m O Z �� o o a2750oomN 1000-meter Universal Transverse Mercator grid ticks,zone 13 Study report (which contains authoritative hydraulic data) may reflect stream o ANNAg� ° � J channel distances that differ from what is shown on this map. ° MO1NTAIN WAS °°�� NIGHTHAWK DRI�F U_ s� LU 5000-foot grid ticks: Colorado State Plane coordinate 6000000 FT ra w y OOR DRIVE Q system,north zone(FIPSZONE 0501),Lambert Conformal Conic Corporate limits shown on this map are based on the best data available o o w <9 w a- CD at the time of publication. Because changes due to annexations or de-annexations 00 ° Z o �'o W U) may have occurred after this map was published, map users should contact o ° o Z > o z Bench mark see explanation in Notes to users section of CC G z z m DX5510 ( P appropriate community officials to verify current corporate limit locations. Lu o �m N o New Mercer `� ° �P� y v OW ROAD X this FIRM panel) Q " W m Irrigation Canal °F L� N sWALL M1.5 Please refer to the separately printed Map Index for an overview map of the � m °o Z z L 2,� 2G W • River Mile county showing the layout of map panels;community map repository addresses; cn 0 a o ¢ 0 ° o Z_ a a o ° MAP REPOSITORIES and a Listing of Communities table containing National Flood Insurance Program J a w � Z o O a a > z 9G Refer to Map Repositories list on Map Index dates for each community as well as a listing of the panels on which each m O w community is located. w o °PD U_ m m > AqR� M P L� EFFECTIVE DATE OF COUNTYWIDE For information and questions about this map, available products associated with this U' SWALLOW 25 o m g FLOOD INSURANCE RATE MAP w FIRM including historic versions of this FIRM, how to order products or the National Z 26 w � 5 a ° December 19,2006 w J cn 3 � EFFECTIVE DATE(S)OF REVISION(S)TO THIS PANEL Flood Insurance Program in general, please call the FEMA Map Information eXchange ZUNI a w a 3 cn DRIVE May 2,2012-to change Special Flood Hazard Areas, to change floodway, to reflect updated at 1-877-FEMA-MAP (1�377-336-2627) or visit the FEMA Map Service Center website m >_ w �i topographic information, to change Base Flood Elevations,and to incorporate previously issued w w Letters of Map Revision. at http://msc.fema.gov.Available products may include previously issued Letters of Map a Change, a Flood Insurance Study Report, and/or digital versions of this map. Many of Y ° a Larimer County a � these products can be ordered or obtained directly from the website. Users may a Quo � Q determine the current map date for each FIRM panel by visiting the FEMA Map °�° m o Canal No. 2 ¢ Service Center website or by calling the FEMA Map Information eXchange. ��� °� cc W w For community map revision history prior to countywide mapping,refer to the Community E O� elG 0 9 Map History table located in the Flood Insurance Study report for this jurisdiction. oF Y �(i�e/9 FOOTHILLS PARKWN Q = o CT. NOTE: MAP AREA SHOWN ON THIS PANEL IS LOCATED To determine if flood insurance is available in this community, contact your insurance w Fs WITHIN TOWNSHIP 7 NORTH, RANGE 69 WEST. z ° agent or call the National Flood Insurance Program at 1-800-638-6620. J 9 44 88 OOOm N U, J� � o IGUNNISON DP\ Off\ -9�FNUE PLOWMAN WAY Pt } AN 3� MAP SCALE 1" = 500' z0 C°G LL0523 CITY OF FORT COLLINS 80LTZ DRIVE 250 0 500 1000 FEET 00 JUSTICE DR/V, �� ° 080102 METERS 150 0 150 300 O DRIVE O \VE ��ij Z4, \� Lu D MONROE R/G� SYDNEY DRIVE w °FIVE PANEL 0987G 1440000 FT RIVA J°��s oP RIDGLAN < 0 0 0 o oQ O°�Ft� o �Q D z w P OPv 0- LU o m a Z z FIRM a O,�9y9C °P,vz m a c m FLOOD INSURANCE RATE MAP 0 J RIDGE QQQ�� o� ��k o KINGSTON DRIVE ® LARIMER COUNTY, �o� Z Ni1� «y 3: HORSETOOTH ROAD Q�N DRIFTCpURT �PRREN m COLORADO D0 X a O gNDING AVENUE w W LL0525 w a = AND INCORPORATED AREAS ARBOR u~i = w j a A DR\VE a Z m s s/AR PANEL 987 OF 1420 BONITA AVENUE O F- z yy n Q ygVEN w Z O �. ROAD ° > Q = ¢ Y A7pER PO�� (SEE MAP INDEX FOR FIRM PANEL LAYOUT) Q F CREGER DRIVE o 0290 0 o WAY w J w LEEWgRD COURT m CONTAINS: 0 ° AVENUEz WALDEN o �oz o z COMMUNITY NUMBER PANEL SUFFIX U G O g cn m FORT COLLINS,CITY OF 080102 0987 G 9< 0 02 (DBOWLINE CT CO o a ¢ z ~ DENNISON J w 35 0 BOCKMAN DRIVE Sot 36 w l� m WAVENUE z tq� LLLLJJ 729 �O� O COLBOARD DRIVE to 4487000m N 6gsy P�� w q<eION � G sT 9F��0 > Notice to User: The Map Number shown below should be o j �Q BOARDWALK s PAL used when placing map orders; the Community Number shown ca z ORI� �y of above should be used on insurance applications for the subject SAIL LANE � community. MARBLE DRIVE F�o� o9G �pti4A��t�t,o MAP NUMBER F BENTHAVEN SSTIR. Q �ETON Cp 08069CO987G 40131'52.5" �P 40131'52.5" �O �+' JOINS PANEL 1000 105°03'45.0" � 04 MAP REVISED 105105'37.5" 493000m E 494000m E LAND SEC. MAY 2, 2012 Federal Emergency Management Agency Hydrologic Soil Group—Larimer County Area,Colorado 3: 'v a 0 0 4932K 493270 493280 493290 4933W 493310 493320 49.3330 493340 493350 40°32'7"N Ir l I I I I 1 1 40°3Z 7"N gqq�ml w now" o I? W 1 �H o o A oo C V M m O O s a r it � m y not be valid at this scal 40°32'2"N W I 400 32 2 N 493260 493270 493280 411. 4973300 493310 493320 493330 493340 493350 3 3 Map Scale:1:619 if printed on A portrait(8.5"x 11")sheet. c Meters N ° 0 5 10 20 30 Feet 0 30 W 120 180 Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 13N WGS84 USDA Natural Resources Web Soil Survey 3/26/2025 Conservation Service National Cooperative Soil Survey Page 1 of 4 Hydrologic Soil Group—Larimer County Area,Colorado MAP LEGEND MAP INFORMATION Area of Interest(AOI) 0 C The soil surveys that comprise your AOI were mapped at Area of Interest(AOI) 0 CID 1:24,000. Soils © D Warning:Soil Map may not be valid at this scale. Soil Rating Polygons A Not rated or not available Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil F—] AID Water Features line placement.The maps do not show the small areas of Streams and Canals contrasting soils that could have been shown at a more detailed 0 B scale. Transportation B/D *.. Rails Please rely on the bar scale on each map sheet for map 0 C measurements. � Interstate Highways 0 C/D US Routes Source of Map: Natural Resources Conservation Service Web Soil Survey URL: 0 D Major Roads Coordinate System: Web Mercator(EPSG:3857) 0 Not rated or not available Local Roads Maps from the Web Soil Survey are based on the Web Mercator Soil Rating Lines Background projection,which preserves direction and shape but distorts q distance and area.A projection that preserves area,such as the Aerial Photography Albers equal-area conic projection,should be used if more .-.. AID accurate calculations of distance or area are required. ++� B This product is generated from the USDA-NRCS certified data as ti B/D of the version date(s)listed below. C Soil Survey Area: Larimer County Area,Colorado Survey Area Data: Version 19,Aug 29,2024 r.i CID Soil map units are labeled(as space allows)for map scales ... D 1:50,000 or larger. Not rated or not available Date(s)aerial images were photographed: Jul 2,2021—Aug 25, Soil Rating Points 2021 p A The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background E3 AID imagery displayed on these maps.As a result,some minor B shifting of map unit boundaries may be evident. B/D USDA Natural Resources Web Soil Survey 3/26/2025 Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group—Larimer County Area,Colorado Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 76 Nunn clay loam,wet, 1 C 0.5 27.7% to 3 percent slopes 90 Renohill clay loam,3 to D 0.1 7.2% 9 percent slopes 136 Water 1.2 65.1% Totals for Area of Interest 1.9 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D)and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. USDA Natural Resources Web Soil Survey 3/26/2025 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Larimer County Area,Colorado Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Web Soil Survey 3/26/2025 Conservation Service National Cooperative Soil Survey Page 4 of 4 v 3 ll u 01 U L u l N Appendix B Hydrologic Calculations Page 10 of 12 301 v, '!'Avenue,Denver,CO 80216 303 433-4094 Project Name: VOA Switchgrass Project No: 24046 Designed By: TLS Date: 3/13/2025 Reference: Fort Collins Stormwater Criteria Manual Runoff Coefficient Calculations Jurisdiction: Fort Collins Jurisdiction Runoff Coefficient Table (Check Jurisdiction Standards!) NRCS Conveyance Factors Landscape(2-7%) 0.25 Heavy Meadow 2.5 Landscape(>7%) 0.35 Tillage/Field 5 Roof 0.95 Short Pasture and Lav 7 Concrete 0.95 Nearly Bare Ground 10 Asphalt 0.95 Grassed Waterway 15 Gravel 0.50 Paved Areas and Shal 20 Type of Soil C/D Areas By Coverage(SF) Runoff Coefficient(C)By Storm Frequency Basin ID Landscape(2-7%) Landscape(>7%)Roof Concrete lAsphalt IGravel Total Area(SF) Total Area(AC) Impervious% 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr RA1 3669 3669 0.08 95% 0.95 0.95 0.95 1.00 1.00 1.00 Al 1326 1256 4879 7461 0.17 83% 0.83 0.83 0.83 0.91 0.99 1.00 RB1 8706 9706 0.20 95% 0.95 0.95 0.95 1.00 1.00 1.00 B1 8513 4720 7318 13922 34473 0.79 69% 0.69 0.69 0.69 0.76 0.83 0.87 C1 817 1916 1458 2565 6756 0.16 70% 0.70 0.70 0.70 0.76 0.83 0.87 TotaIA 1326 0 3669 1256 4879 0 11130 0.26 87% 0.87 0.87 0.87 0.95 1.00 1.00 TotaIB 8513 4720 8706 7318 13922 0 43179 0.99 75% 0.75 0.75 0.75 0.82 0.90 0.93 OS1 2351 953 523 3827 0.09 58% 0.58 0.58 0.58 0.64 0.70 0.73 Project Name: VOA Switchgrass NRCS Conveyance Factors Project No: 24046 Heavy Meadow 2.5 Designed By: TIS Tillage/Field 5 Date: 3/13/2025 Short Pasture and Lawns 7 Reference: Fort Collins Stormwater Criteria Manual Nearly Bare Ground 10 Grassed Waterway 15 Time of Concentration Calculations Paved Areas and Shallow Paved Swales 20 Overland Flow Time(tJ Channelized Flow Time(tJ Min Time of Concentration t�Calculation Basin ID Overland Travel Length(Li)ft Slope(So)% Imp% Cs-5 yr Coeff ti Length of Travel(LJ ft Slope(S)% NRCS Conveyance(K) ti Total Travel Time(t&tr) Urban Catchment Min Time Equation 6-5 Urban-Rural Min Tc Min T, RAI 46 2.00% 95.00% 0.95 1.51 0 2.00% 20 0.00 1.51 9.85 5.00 5.00 Al 38 1.00% 82.56% 0.83 3.16 96 0.70% 20 0.96 4.12 12.90 5.00 5.00 RBI 60 2.00% 95.00% 0.95 1.73 0 2.00% 20 0.00 1.73 9.85 5.00 5.00 Bl 50 2.00% 69.50% 0.69 4.26 195 0.50% 20 2.30 6.56 16.64 5.00 5.00 C1 62 1.50% 69.52% 0.70 5.21 20 0.70% 20 0.20 5.41 14.39 5.00 5.00 OSl 35 2.00% 58.14% 0.58 4.56 0 2.00% 20 0.00 4.56 16.12 5.00 5.00 S h O P u Project Name: VOA Switchgrass Project No: 24046 Designed By: TLS Date: 4/4/2025 Reference: Fort Collins Stormwater Criteria Manual Minor Storm Flow Calculations Storm Interval 2 yr 'Check below C Values dependent on storm interval 1 hour Rainfall(in) 0.82 Basin Flow Calcs Accumulative Pipe Flows Pipe Travel Time(min) Flow Rate Revised Accumulative Pipe Flow Pipe Diameter Pipe Velocity Pipe Length Travel Time Basin ID Design Point Area(ac) T. C C x A Intensity(1) (cfs) Revised T, Sum of CA Intensity(1) Flow(cfs) Rate(cfs) (in) (ft/s) (ft) (min) Notes RAS R3 0.08 5.00 0.95 0.08 2.85 0.23 0.23 0.23 8.00 1.31 77.00 0.98 DPRS to DP1 Al 1 0.17 5.00 0.83 0.14 2.85 0.40 5.98 0.22 185 0.63 0.63 12.00 1.61 38.00 0.39 DP1 to EDB-A RB1 R2 0.20 5.00 0.95 0.19 2.85 0.54 0.54 0.54 DPR2+DP2 BS 2 0.79 5.00 0.69 0.55 2.85 1.57 5.00 0.74 185 2.11 2.94 10.00 10.78 48.00 0.07 DP2 to EDB-B plus offsite flow from east CS 3 0.16 5.00 0.70 0.11 2.85 0.31 0.31 4.08 DP2+DP3 plus offsite flow to EDB-C OS1 4 0.09 5.00 0.58 0.05 2.85 0.15 0.15 0.15 Project Name: VOA Switchgrass Project No: 24046 Designed By: TLS Date: 4/4/2025 Reference: Fort Collins Stormwater Criteria Manual Minor Storm Flow Calculations Storm Interval 100 yr Check below C Values dependent on storm interval 1 hour Rainfall(in) 2.86 Basin Flow Calcs Accumulative Pipe Flows Pipe Travel Time(min) Flow Rate Revised Accumulative Pipe Flow Pipe Diameter Pipe Velocity Pipe Length Travel Time Basin ID Design Point Area(ac) T. C C x A Intensity(1) (cfs) Revised T, Sum of CA Intensity(1) Flow(cfs) Rate ids) (in) (ft/s) (ft) (min) Notes RAS RS 0.08 5.00 0.95 0.08 9.95 0.80 0.80 0.80 8.00 4.56 77.00 0.28 DPRS to DPI Al 1 0.17 5.00 0.83 0.14 9.95 1.41 5.28 0.22 9.95 2.20 2.20 12.00 5.61 38.00 0.11 DP1 to EDB-A RBl R2 0.20 5.00 0.95 0.19 9.95 1.99 1.89 1.99 DPR2+DP2 BI 2 0.79 5.00 0.69 0.55 9.95 5.47 5.00 0.74 9.95 7.36 8.19 10.00 30.04 48.00 0.03 DP2 to EDB-B plus offsite flow from east Cl 3 0.16 5.00 0.70 0.11 9.95 1.07 1.07 10.09 DP2+DP3 plus offsite flow to EDB-C 051 4 0.09 5.00 0.73 0.06 9.95 0.64 0.64 0.64 Project Name: VOA Switchgrass Project No: 24046 Designed By: TLS Date: 4/4/2025 Reference: Fort Collins Stormwater Criteria Manual Runoff Summary Table Minor Minor Major Major Minor Major Storm Storm Storm Storm Design Area Impervious Storm (C Storm (C Local Flow Accum Local Flow Accum Basin ID Point (AC) Percentage Value) Value) (cfs) Flow(cfs) (cfs) Flow(cfs) RA1 R1 0.08 95% 0.95 1.00 0.23 0.23 0.80 0.80 Al 1 0.17 83% 0.83 1.00 0.40 0.63 1.41 2.20 RB1 R2 0.20 95% 0.95 1.00 0.54 0.54 1.89 1.89 B1 2 0.79 69% 0.69 0.87 1.57 2.11 5.47 8.19 C1 3 0.16 70% 0.70 0.87 0.31 0.31 1.07 10.09 OS1 4 0.09 58% 0.58 0.73 0.15 0.15 0.64 0.64 v 3 ll u 01 U L u l N Appendix C Hydraulic Calculations Page 11 of 12 301 West 4511 Avenue,Denver,CO 80216 303 433-4094 DETENTIONSTAGE-STORAGE MHFD-Detention,Version 4.04(February 2021) Project:VOASwitchgmw Basin ID:A Depth Increment= 1.00 R Optional p an POOL Example Zone Configuration(Retention Pond) Stage-Storage Stage Ovenide Length Width Area Override Area Volume Volume D S`ion ft Stage k ft R R' Area R' acre ft' (­ft) Watershed Information Top of Micropool -- 0.00 -- -- -- 22 0.000 Selected BMP Type= EDB 5035.5 -- 0.25 -- -- -- 113 0.003 17 0.000 Watershed Area= 0.26 acres 5035.75 -- 0.50 -- -- -- 188 0.004 54 0.001 Watershed Length= 150 R 5036 -- 0.75 -- -- -- 193 0.004 102 0.002 Watershed Length to Centric!= 75 R 5036.25 -- 1.00 -- -- -- 193 0.004 150 0.003 Watershed Slope= 0.010 ft/ft 5036.5 -- 1.25 -- -- -- 193 0.004 199 0.005 Watershed Imperviousness= 87.00% percent 5036.75 -- 1.50 -- -- -- 193 0.004 247 0.006 Percentage Hydrologic Soil Group A= 0.0% percent 5037 -- 1.75 -- -- -- 193 0.004 295 0.007 Percentage Hydrologic Soil Group B= 0.0% percent 5037.25 -- 2.00 -- -- -- 193 0.004 343 0.008 Percentage Hydrologic Soil Groups C/D= 100.0% percent 5037.5 -- 2.25 -- -- -- 193 0.004 392 0.009 Target WQCV Drain Time= 40.0 hours 5037.75 -- 2.50 -- -- -- 193 0.004 440 0.010 Location for 1-hr Rainfall Depths=User Input 5038 -- 2.75 -- -- -- 193 0.004 488 0.011 After providing required inputs above including 1-hour rainfall 5038.25 -- 3.00 -- -- -- 193 0.004 536 0.012 depths,click'Run CUHP'to generate runoff hydrographs using 5038.5 -- 3.25 -- -- -- 193 0.004 585 0.013 the embedded Colorado Urban Hydrograph Procedure. Optional User Overrides 5038.75 -- 3.50 -- -- -- 193 0.004 633 0.015 Water Quality Capture Volume(WQCV)= 0.008 acre-feet .-feet 5039 -- 3.75 -- -- -- 193 0.004 681 0.016 Excess Urban Runoff Volume(EURV)= 0.022 acre-feet .-feet -- -- -- -- 2-yr Runoff Volume(PI=0.87 in.)= 0.015 acre-feet 0.87 inches -- -- -- -- 5-yr Runoff Volume(PI=1.14 in.)= 0.020 acre-feet 1.14 inches -- -- -- -- 10-yr Runoff Volume(P1=1.44 in.)= 0.027 acre-feet 1.44 inches -- -- -- -- 25-yr Runoff Volume(PI=1.95 in.)= 0.038 acre-feet 1.95 inch. -- -- -- -- 50-yr Runoff Volume(PS=2.43 In.)= 0.048 acre-feet 2.43 inches -- -- -- -- 100-yr Runoff Volume(PI=2.98 in.)= 0.060 acre-feet 2.98 inches -- -- -- -- 500-yr Runoff Volume(PI=4.57 in.)= 0.095 acre-feet 4.57 inches -- -- -- -- Approximate 2-yr Detention Volume= 0.015 acre-feet -- -- -- -- Approximate 5-yr Detention Volume= 0.021 acre-feet -- -- -- -- Approximate 10-yr Detention Volume= 0.026 acre-feet -- -- -- -- Approximate 25-yr Detention Volume.= 0.033 acre-feet -- -- -- -- Approximate 50-yr Detention Volume= 0.037 acre-feet -- -- -- -- Approximate 100-yr Detention Volume= 0.042 acre-feet -- -- -- -- Define Zones and Basin Geometry -- -- -- -- Zone 1 Volume(WQCV)= 0.008 acre-feet -- -- -- -- Select Zone 2 Storage Volume(Optional)= acre-feet Total detention Volume -- -- -- -- Select Zone Storage Volume(Optional)= acre-feet is less than 100-year -- -- -- -- Total Detention Basin Volume= 0.008 acre-feet Volume. Initial Surcharge Volume(ISV)= user R3 -- -- -- -- Initial Surcharge Depth(ISD)= user ft -- -- -- -- Total Available Detention Depth(Hm )= user It -- -- -- -- Depth of Trickle Channel(H,c)= user R -- -- -- -- Slope of Trickle Channel(Src)= user ft/ft -- -- -- -- Slopes of Main Basin Sides(Sm,)= user H:V -- -- -- -- Basin Length-to-Width Ratio(Ruw)= -- Initial Surcharge Area(Acv)= R' -- -- -- -- Surcharge Volume Length(Lysv)= user ft -- -- -- -- Surcharge Volume Width(Wsv)= user It -- -- -- -- Depth of Basin Floor(H-R)= user ft -- -- -- -- Length of Basin Floor(LrmoR)= R -- -- -- -- Width of Basin Floor(Wn.00R)= user ft -- -- --Area of Basin Floor(A-11)= user R e -- -- -- -- Volume of Basin Floor(Vaone)- user R3 -- -- -- -- Depth of Main Basin(HnAc,)= ft -- -- -- -- Length of Main Basin(Ln )= user ft -- -- -- -- Width of Main Basin(WM )= user It -- -- --Area of Main Basin(A-)= user RI -- -- -- -- Volume of Main Basin(Vmm)= ft3 -- -- -- -- Calculated Total Basin Volume(Vm,.,i)= user acre-feet -- -- -- -- VOA Switahgrass_MHFD-Detention_A,Basin 4/412025,11:04 AM DETENTIONCASIN STAGE-STORAGE TABLE MHFD-Detention,Version 4.04(February 2021) 20 400 is 300 d 10 200$ a s 100 0 0 0.00 1.00 2.00 3.00 4.00 Stage(ft) —Langth(ft) —Width(ft) —Area(%ft) 0,020 0,020 0.015 0.015 s Z3 molo 0.010 u 2 0.0os o.005 o.000 o.ao0 0.00 100 2,00 3.00 4A0 Stage(ft.) —A—(ames) —V.1.—(.,ft) VOA Switahgtass_MHFO-Oetention_A,Basin 41412025,11:04 AM DETENTION BASIN STRUCTURE MHFD-Detention, Version4.04(February2021) Project:VOA Switchgrass Basin ID:A zouL: Estimated Estimated 2PHE, Stage(ft) Volume(ac-ft) Outlet Type vain eum= Zone 1(WQCV) 2.07 0.008 Orifice Plate -mr,E,.,mz owrY,cE Zone 2 PmrPNexr oPirmes Zone 3 POOL Example Zone Configuration(Retention Pond) Total(all zones) 0.008 User Input:Orifice at Underdrain Outlet(typically used to drain WOCV in a Filtration BMP) Calculated Parameters for Underdrain Underdrain Orifice Invert Depth= N/A ft(distance below the filtration media surface) Underdrain Orifice Area= N/A ft, Underdrain Orifice Diameter=1 N/A linches Underdrain Orifice Centroid=I N/A Ifeet 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) Calculated Parameters for Plate Invert of Lowest Orifice=M0.12 ft(relative to basin bottom at Stage=0 ft) WQ Orifice Area per Row= 8.333E-04 ft' Depth at top of Zone using Orifice Plate= ft(relative to basin bottom at Stage=0 ft) Elliptical Half-Width= N/A feet Orifice Plate:Orifice Vertical Spacing= inches Elliptical Slot Centroid= N/A feet Orifice Plate:Orifice Area per Row= sq.inches(diameter=3/8 inch) Elliptical Slot Area= N/A ftz User Input: Stage and Total Area of Each Orifice Row(numbered from lowest to highest) Row 1(required) I Row 2(optional) Row 3(optional) Row 4(optional) Row 5(optional) Row 6(optional) Row 7(optional) Row 8(optional) Stage of Orifice Centroid(ft)l 0.00 1 2.00 Orifice Area(sq.inches) 0.12 0.12 Row 9(optional) Row 10(optional) Row 11(optional) Row 12(optional) Row 13(optional) Row 14(optional) Row 15(optional) Row 16(optional) Stage of Orifice Centroid(ft) Orifice Area(sq.inches) User Input: Vertical Orifice(Circular or Rectangular) Calculated Parameters for Vertical Orifice Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Area= ftz Depth at top of Zone using Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Centroid= feet Vertical Orifice Diameter= inches User Input: Overflow Weir(Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir(and No Outlet Pipe) Calculated Parameters for Overflow Weir Not Selected Not Selected Not Selected Not Selected Overflow Weir Front Edge Height,Ho= 2.40 ft(relative to basin bottom at Stage=0 ft) Height of Grate Upper Edge,Ht= 2.40 feet Overflow Weir Front Edge Length= 3.00 feet Overflow Weir Slope Length= 3.00 feet Overflow Weir Grate Slope= 0.00 H:V Grate Open Area/100-yr Orifice Area= 7.98 Horiz.Length of Weir Sides= 3.00 feet Overflow Grate Open Area w/o Debris= 6.26 ftz Overflow Grate Type= Type C Grate Overflow Grate Open Area w/Debris= 3.13 ft, Debris Clogging%=1 50% % User Input:Outlet Pipe w/Flow Restriction Plate(Circular Orifice.Restrictor Plate.or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/Flow Restriction Plate Not Selected Not Selected Not Selected Not Selected Depth to Invert of Outlet Pipe= 0.15 ft(distance below basin bottom at Stage=0 ft) Outlet Orifice Area= 0.79 ft, Circular Orifice Diameter= 12.00 inches Outlet Orifice Centroid= 0.50 feet Half-Central Angle of Restrictor Plate on Pipe= N/A N/A radians User Input:Emergency Spillway(Rectangular or Trapezoidal) Calculated Parameters for Spillway Spillway Invert Stage= 3.55 ft(relative to basin bottom at Stage=0 ft) Spillway Design Flow Depth= 0.06 feet Spillway Crest Length= 21.00 feet Stage at Top of Freeboard= 4.61 feet Spillway End Slopes= 4.00 H:V Basin Area at Top of Freeboard= 0.00 acres Freeboard above Max Water Surface= 1.00 feet Basin Volume at Top of Freeboard= 0.02 acre-ft Routed Hydrogranh Results The user can override the default CUHP h dro ra hs and runoff volumes by enterinq new values in the Inflow H dro ra hs table Columns W through AF. Design Storm Return Penod= WQCV EURV 2 Year 5 Year SO Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth(In)= N/A N/A 0.87 1.14 1.44 1.95 2.43 2.98 4.57 CUHP Runoff Volume(acre-ft)= 0.008 0.022 0.015 0.020 0.027 0.038 0.048 0.060 0.095 Inflow Hydrograph Volume(acre-ft)= N/A N/A 0.015 0.020 0.027 0.038 0.048 0.060 0.095 CUHP Predevelopment Peak Q(cfs)= N/A N/A 0.0 0.0 0.1 0.2 0.3 0.4 0.8 OPTIONAL Override Predevelopment Peak Q(cfs)= N/A N/A Predevelopment Unit Peak Flow,q(cfs/acre)= N/A N/A 0.00 0.11 0.30 0.79 1..18 1.65 2.91 Peak Inflow Q(cfs)= N/A N/A 0.3 0.4 0.5 0.7 0.8 1.1 1.7 Peak Outflow Q(cfs)= 0.0 3.2 0.1 0.2 0.5 0.9 1.0 1.8 1.7 Ratio Peak Outflow to Predevelopment Q= N/A N/A N/A 7.2 5.8 4.6 3.2 4.1 2.2 Structure Controlling Flow= Plate Plate Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 verflow Weir Max Velocity through Grate 1(fps)= N/A N/A 0.02 0.0 0.1 0.1 0.2 0.3 0.3 Max Velocity through Grate 2(fps)= N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97%of Inflow Volume(hours)= 24 >120 28 27 26 25 23 22 18 Time to Drain 99%of Inflow Volume(hours)= 26 >120 30 30 29 29 28 27 26 Maximum Pending Depth(ft)= 2.03 0.00 2.43 2.45 2.48 2.53 2.54 2.60 2.59 Area at Maximum Ponding Depth(acres)= 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Maximum Volume Stored(acre-ft)= 0.008 0.000 0.010 0.010 0.010 0.010 0.010 0.011 0.010 VOA Switchgrass_MHFD-Detention_A,Outlet Structure 4/4/2025,11:04 AM DETENTIONOUTLET MHFD-Detention Version 4. (February Z ZI 2 I -SOOYR IN I ••••500YR OUT 1.8 �100YR IN 100YR OUT _ 1.6 50YR IN 50YR OUT �25YR IN 1.4 25YR OUT —10YR IN [ A 12 ———lOYR OUT-5YR IN __ [ [ [ _ •• SYR OUT �i 1 —•2YR IN O u ———2YR OUT J 0.8 —EURV IN •EURVOUT •' 'S/ [ '' 0.6 ....wocvouT41 S 0.4 0.2 0 0.1 1 10 TIME[hr] 3 -500YR -100YR ­OYR 2.5 -25" _10YR ­R _YR 2 �EURV �WOOV K x O 1.5 z IN 0 z Is- J NX\ 1 0.5 0 0.1 1 10 100 DRAIN TIME[hr] 10,000 20 O User Area[ft"21 9,000 -Interpolated Area[ft 2] 18 •••0-••Summary Area[ft2] 8,000 -Volume[ft"3] 16 ...0--Summary Volume[W3] 7,000 Outflow[cfs] 14 6,000 ...y..Summary Outflow[cfs] 12 x � 5,000 103. � J j 4,000 8 N 3,000 6 c a 2,000 4 1 1,000 2 0 0 0.00 1.00 2.00 3.DO 4.00 5.00 6.00 PONDING DEPTH[ft] 5-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis minimum bound maximum bound VOA Switchgrass_MHFD-Detention_A,Outlet Structure 4/4/2025,11:04 AM DETENTION BASIN Outflow Hydrograph Workbook Filename: Inflow Hydroaraohs The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP Time Interval 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] 5.00 min 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 0.06 0:15:00 0.00 0.00 0.02 0.05 0.07 0.07 0.10 0.11 0.19 0:20:00 0.00 0.00 0.11 0.16 0.21 0.16 0.21 0.25 0.43 0:25:00 0.00 0.00 0.24 0.33 0.44 0.34 0.44 0.52 0.85 0:30:00 0.00 0.00 0.26 0.35 0.45 0.65 0.83 1.01 1.58 0:35:00 0.00 0.00 0.23 0.30 0.38 0.66 0.83 1.07 1.66 0:40:00 0.00 0.00 0.19 0.25 0.32 0.59 0.75 0.95 1.48 0:45:00 0.00 0.00 0.15 0.20 0.26 0.50 0.63 0.83 1.28 0:50:00 0.00 0.00 0.13 0.17 0.22 0.42 0.53 0.70 1.08 0:55:00 0.00 0.00 0.11 0.15 0.19 0.35 0.44 0.59 0.91 1:00:00 0.00 0.00 0.09 0.12 0.16 0.29 0.37 0.51 0.79 1:05:00 0.00 0.00 0.08 0.10 0.14 0.24 0.31 0.44 0.68 1:10:00 0.00 0.00 0.06 0.09 0.12 0.19 0.24 0.33 0.52 1:15:00 0.00 0.00 0.05 0.08 0.12 0.16 0.20 0.26 0.40 1:20:00 0.00 0.00 0.05 0.07 0.10 0.13 0.16 0.19 0.30 1:25:00 0.00 0.00 0.04 0.07 0.09 0.11 0.14 0.15 0.24 1:30:00 0.00 0.00 0.04 0.06 0.08 0.09 0.12 0.13 0.20 1:35:00 0.00 0.00 0.04 0.06 0.08 0.08 0.10 0.11 0.18 1:40:00 0.00 0.00 0.04 0.05 0.07 0.08 0.10 0.10 0.16 1:45:00 0.00 0.00 0.04 0.05 0.07 0.07 0.09 0.09 0.15 1:50:00 0.00 0.00 0.04 0.05 0.07 0.07 0.09 0.09 0.14 1:55:00 0.00 0.00 0.03 0.04 0.06 0.07 0.08 0.09 0.14 2:00:00 0.00 0.00 0.03 0.04 0.06 0.06 0.08 0.08 0.14 2:05:00 0.00 0.00 0.02 0.03 0.04 0.04 0.06 0.06 0.09 2:10:00 0.00 0.00 0.01 0.02 0.03 0.03 0.04 0.04 0.06 2:15:00 0.00 0.00 0.01 0.01 0.02 0.02 0.03 0.03 0.04 2:20:00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02 0.03 2:25:00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 2:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 2:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:00 0.00 0.00 0.00 1 0.00 0.00 1 0.00 0.00 0.00 1 0.00 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 1 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 0.0o 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 VOA Switchgrass_MHFD-Detention_A,Outlet Structure 4/4/2025,11:04 AM DETENTION BASIN 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. Sta ge-storage stage Area Area Volume Volume Uuotal Description [ft] [ft'] [acres] [ft'] [ac-ft] [cR] 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). VOA Switchgrass_MHFD-Detention_A,Outlet Structure 4/4/2025,11:04 AM DETENTIONSTAGE-STORAGE MHFD-Detention,Version 4.04(February 2021) Project:VOASwitchgmw Basin ID:B Depth Increment= 1.00 R Optional p an POOL Example Zone Configuration(Retention Pond) Stage-Storage Stage Ovenide Length Width Area Override Area Volume Volume Descn lion k Stage k ft R R' Area R' acre ft' (ac-R) Watershed Information Top of Micropool -- 0.00 -- -- -- 12 0.000 Selected BMP Type= EDB 5035.5 -- 0.25 -- -- -- 114 0.003 16 0.000 Watershed Area= 0.99 acres 5035.75 -- 0.50 -- -- -- 278 0.006 65 0.001 Watershed Length= 296 R 5036 -- 0.75 -- -- -- 527 0.012 165 0.004 Watershed Length to Centric!= 150 R 5036.25 -- 1.00 -- -- -- 793 0.018 330 0.008 Watershed Slope= 0.010 ft/ft 5036.5 -- 1.25 -- -- -- 1,127 0.026 570 0.013 Watershed Imperviousness= 75.00% percent 5036.75 -- 1.50 -- -- -- 1,348 0.031 880 0.020 Percentage Hydrologic Soil Group A= 0.0% percent 5037 -- 1.75 -- -- -- 1,362 0.031 1,218 0.028 Pecentage Hire. gk Soil Group B= 0.0% percent 5037.25 -- 2.00 -- -- -- 1,376 0.032 11561 0.036 Percentage Hydrologic Soil Groups C/D= 100.0% percent 5037.5 -- 2.25 -- -- -- 1,391 0.032 1,907 0.044 Target WQCV Drain Time= 40.0 hours 5037.75 -- 2.50 -- -- -- 2,230 0.051 2,359 0.054 Location for 1-hr Rainfall Depths=User Input -- -- -- -- After providing required inputs above including 1-hour minfall -- -- -- -- depths,click'Run CUHP'to generate runoff hydrogmphs using -- -- -- -- the embedded Colorado Urban Hydrogmph Procedure. Optional User Overrides -- -- -- -- Water Quality Capture Volume(WQCV)= 0.025 acre-feet acre-feet -- -- -- -- Excess Urban Runoff Volume(EURV)= 0.073 acre-feet .-feet -- -- -- -- 2-yr Runoff Volume(PI=0.87 in.)= 0.048 acre-feet 0.87 inches -- -- -- -- 5-yr Runoff Volume(PI=1.14 in.)= 0.068 acre-feet 1.14 inches -- -- -- -- 10-yr Runoff Volume(P1=1.44 in.)= 0.091 acre-feet 1.44 inches -- -- -- -- 25-yr Runoff Volume(PI=1.95 in.)= 0.135 acre-feet 1.95 inches -- -- -- -- 50-yr Runoff Volume(PS=2.43 in.)= 0.175 acre-feet 2.43 inches -- -- -- -- 100-yr Runoff Volume(PI=2.98 in.)= 0.222 acre-feet 2.98 inches -- -- -- -- 500-yr Runoff Volume(PI=4.57 in.)= 0.356 acre-feet 4.57 inches -- -- -- -- Approximate 2-yr Detention Volume= 0.048 acre-feet -- -- -- -- Approximate 5-yr Detention Volume= 0.069 acre-feet -- -- -- -- Approximate 10-yr Detention Volume= 0.085 acre-feet -- -- -- -- Approximate 25-yr Detention Volume.= 0.107 acre-feet -- -- -- -- Approximate SD-yr Detention Volume= 0.122 acre-feet -- -- -- -- Approximate 100-yr Detention Volume= 0.142 acre-feet -- -- -- -- Define Zones and Basin Geometry -- -- -- -- Zone 1 Volume(WQCV)= 0.025 acre-feet -- -- -- -- Select Zone 2 Storage Volume(Optional)= acre-feet Total detention Volume -- -- -- -- Select Zone Storage Volume(Optional)= acre-feet is less than 100-year -- -- -- -- Total Detention Basin Volume.= 0.025 acre-feet Volume. Initial Surcharge Volume(ISV)= N/A R3 -- -- -- -- Initial Surcharge Depth(ISD)= N/A It -- -- -- -- Total Available Detention Depth(Hm )= user It -- -- -- -- Depth of In"" Channel(HTc)= N/A ft -- -- -- -- Slope of Trickle Channel(5rc)= N/A ft/ft -- -- -- Slopes of Main Basin Sides(Sm,)= user H:V -- -- -- -- Basin Length-to-Width Ratio(Ruw)= user -- -- -- -- Initial Surcharge Area(Acv)= It -- -- -- -- Surcharge Volume Length(Lysv)= user It -- -- -- -- Surcharge Volume Width(Wsv)= user It -- -- -- -- Depth of Basin Floor(H-R)= user It -- -- -- -- Length of Basin Floor(LrmoR)= It -- -- -- -- Width of Basin Floor(Wn.00R)= user ft -- -- --Area of Basin Floor(A-11)= user ft e -- -- -- -- Volume of Basin Floor(V,,one)= user ft -- -- -- -- Depth of Main Basin(HnAc,)= It -- -- -- -- Length of Main Basin(Ln )= user It -- -- -- -- Width of Main Basin(WM )= user It -- -- --Area of Main Basin(A-)= user It -- -- -- -- Volume of Main Basin(Vnm)= It -- -- -- -- Calculated Total Basin Volume(Vm,.,i)= user acre-feet -- -- -- -- VDA Switahgmss_MHFD-Detention_B,Basin 41412025,11:07 AM DETENTIONCASIN STAGE-STORAGE TABLE MHFD-Detention,Version 4.04(February 2021) 20 2400 is 1500 d 10 1200� a 5 600 0 0 0.00 1AR 2.00 100 4.00 Sorge(ft) —Langth(ft) —Width(ft) —Area(%ft) 0,060 0.060 0.045 0.045 s 3 Q030 0.030 u 0.015 0.015 0.000 0.000 0.00 1.00 2,00 3.00 4.00 suge(ft.) —A—(ames) —V.1.—(ao-ft) VOA Switahgrass_MHFO-Oetention_B,Basin 4/412025,11 07AM DETENTION BASIN STRUCTURE MHFD-Detention, Version4.04(February2021) Project:VOA Switchgrass Basin ID:B zouL: Estimated Estimated 2PHE, Stage(ft) Volume(ac-ft) Outlet Type vain eum= Zone 1(WQCV) 1.65 0.025 Orifice Plate -mr,E,.,mz owrY,cE Zone 2 PmrPNexr oPirmes Zone 3 POOL Example Zone Configuration(Retention Pond) Total(all zones) 0.025 User Input:Orifice at Underdrain Outlet(typically used to drain WOCV in a Filtration BMP) Calculated Parameters for Underdrain Underdrain Orifice Invert Depth= N/A ft(distance below the filtration media surface) Underdrain Orifice Area= N/A ft, Underdrain Orifice Diameter=1 N/A linches Underdrain Orifice Centroid=I N/A Ifeet 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) Calculated Parameters for Plate Invert of Lowest Orifice= 0.00 ft(relative to basin bottom at Stage=0 ft) WQ Orifice Area per Row= 8.889E-04 ft' Depth at top of Zone using Orifice Plate= 1.65 ft(relative to basin bottom at Stage=0 ft) Elliptical Half-Width= N/A feet Orifice Plate:Orifice Vertical Spacing= 8.20 inches Elliptical Slot Centroid= N/A feet Orifice Plate:Orifice Area per Row= 0.13 sq.inches(diameter=3/8 inch) Elliptical Slot Area= N/A ftz User Input: Stage and Total Area of Each Orifice Row(numbered from lowest to highest) Row 1(required) I Row 2(optional) Row 3(optional) Row 4(optional) Row 5(optional) Row 6(optional) Row 7(optional) Row 8(optional) Stage of Orifice Centroid(ft)l 0.00 1 0.55 1 1.10 Orifice Area(sq.inches) 0.13 0.13 0.13 Row 9(optional) Row 10(optional) Row 11(optional) Row 12(optional) Row 13(optional) Row 14(optional) Row 15(optional) Row 16(optional) Stage of Orifice Centroid(ft) Orifice Area(sq.inches) User Input: Vertical Orifice(Circular or Rectangular) Calculated Parameters for Vertical Orifice Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Area= ftz Depth at top of Zone using Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Centroid= feet Vertical Orifice Diameter= inches User Input: Overflow Weir(Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir(and No Outlet Pipe) Calculated Parameters for Overflow Weir Not Selected Not Selected Not Selected Not Selected Overflow Weir Front Edge Height,Ho= 2.50 ft(relative to basin bottom at Stage=0 ft) Height of Grate Upper Edge,Ht= 2.50 feet Overflow Weir Front Edge Length= 3.00 feet Overflow Weir Slope Length= 0.00 feet Overflow Weir Grate Slope= 0.00 H:V Grate Open Area/100-yr Orifice Area= 0.00 Horiz.Length of Weir Sides= 0.00 feet Overflow Grate Open Area w/o Debris= 0.00 ftz Overflow Grate Type= Type C Grate Overflow Grate Open Area w/Debris= 0.00 ft, Debris Clogging%=1 50% % User Input:Outlet Pipe w/Flow Restriction Plate(Circular Orifice.Restrictor Plate.or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/Flow Restriction Plate Not Selected Not Selected Not Selected Not Selected Depth to Invert of Outlet Pipe= 0.10 ft(distance below basin bottom at Stage=0 ft) Outlet Orifice Area= 1.23 ftz Circular Orifice Diameter= 15.00 inches Outlet Orifice Centroid= 0.63 feet Half-Central Angle of Restrictor Plate on Pipe= N/A N/A radians User Input:Emergency Spillway(Rectangular or Trapezoidal) Calculated Parameters for Spillway Spillway Invert Stage= 2.59 ft(relative to basin bottom at Stage=0 ft) Spillway Design Flow Depth= 0.39 feet Spillway Crest Length= 2.00 feet Stage at Top of Freeboard= 3.98 feet Spillway End Slopes= 12.00 H:V Basin Area at Top of Freeboard= 0.05 acres Freeboard above Max Water Surface= 1.00 feet Basin Volume at Top of Freeboard= 0.05 acre-ft Routed Hydrogrranh Results The user can override the default CUHP h dro ra hs and runoff volumes by enterinq new values in the Inflow H dro ra hs table Columns W through AF. Design Storm Return Penod= WQCV EURV 2 Year 5 Year SO Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth(In)= N/A N/A 0.87 1.14 1.44 1.95 2.43 2.98 4.57 CUHP Runoff Volume(acre-ft)= 0.025 0.073 0.048 0.068 0.091 0.135 0.175 0.222 0.356 Inflow Hydrograph Volume(acre-ft)= N/A N/A 0.048 0.068 0.091 0.135 0.175 0.222 0.356 CUHP Predevelopment Peak Q(cfs)= N/A N/A 0.0 0.1 0.3 0.8 1.2 1.6 2.9 OPTIONAL Override Predevelopment Peak Q(cfs)= N/A N/A Predevelopment Unit Peak Flow,q(cfs/acre)= N/A N/A 0.01 0.12 0.31 0.79 1.17 1.65 2.90 Peak Inflow Q(cfs)= N/A N/A 0.8 1.1 1.5 2.2 2.9 3.7 5.9 Peak Outflow Q(cfs)= 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Ratio Peak Outflow to Predevelopment Q= N/A N/A N/A 0.2 0.1 0.0 0.0 0.0 0.0 Structure Controlling Flow= Plate N/A Plate N/A N/A N/A N/A N/A N/A Max Velocity through Grate 1(fps)= N/A N/A N/A N/A N/A N/A N/A N/A N/A Max Velocity through Grate 2(fps)= N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97%of Inflow Volume(hours)= 37 67 53 64 78 104 >120 >120 >120 Time to Drain 99%of Inflow Volume(hours)= 40 72 57 70 84 112 >120 >120 >120 Maximum Pending Depth(ft)= 1.66 2.50 2.30 2.50 2.50 2.50 2.50 2.50 2.50 Area at Maximum Ponding Depth(acres)= 0.03 0.05 0.04 0.05 0.05 0.05 0.05 0.05 0.05 Maximum Volume Stored(acre-ft)= 0.025 0.054 0.045 0.054 0.054 0.A 0.054 0.054 0.054 VOA Switchgrass_MHFD-Detention_B,Outlet Structure 4/4/2025,11:44 AM DETENTIONOUTLET MHFD-Detention Version 4. (February Z ZI 7 —500YR IN ••••500YR OUT �100YR IN 6 —100YR OUT �50YR IN — —50YR OUT 5 _YRIN --25YR OUT ­GYR IN ---10YR OUT 4 —5YR IN ••••5YR OUT �•2YR IN u 3 ---2YR OUT EURU IN EURU OU �WQCV IN 2 ••••WqN OUT 1 0 0.1 1 SO TIME[hr] 3 —500YR —100YR ­OYR 2.5 —25VR �lOVR �SYR —2YR 000, 2 V �WQCV K x z 1.5 z 0 z 0 1 0.5 0 0.1 1 10 100 DRAIN TIME[hr] 10,000 10 O User Area[ft"21 9,000 -Interpolated Area[ft^2] 9 •••0-••Summary Area[ft"2] 8,000 -Volume[ft"3] 8 •••►••Summary Volume[W3] 7,000 Outflow[cfs] 7 6,000 ••~••Summary Outflow[cfs] 6 x � 5,000 5 30 � J j 4,000 4 N 3,000 3 c a 2,000 2 1,000 -- - 1 0 0 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 PONDING DEPTH[ft] 5-A-V-D Chart Axis Override X-axis Left Y-Axis Ri ht Y-Axis minimum bound maximum bound VOA Switchgrass_MHFD-Detention_B,Outlet Structure 4/4/2025,11:44 AM DETENTION BASIN Outflow Hydrograph Workbook Filename: Inflow Hydroaraohs The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP Time Interval 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] 5.00 min 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 0.03 0.04 0.17 0:15:00 0.00 0.00 0.05 0.13 0.20 0.19 0.27 0.31 0.56 0:20:00 0.00 0.00 0.32 0.45 0.59 0.46 0.60 0.74 1.30 0:25:00 0.00 0.00 0.70 0.99 1.36 1.01 1.37 1.66 2.82 0:30:00 0.00 0.00 0.80 1.12 1.49 2.13 2.78 3.40 5.45 0:35:00 0.00 0.00 0.72 1.00 1.31 2.25 2.89 3.73 5.91 0:40:00 0.00 0.00 0.63 0.85 1.12 2.09 2.69 3.44 5.44 0:45:00 0.00 0.00 0.52 0.72 0.95 1.81 2.33 3.07 4.84 0:50:00 0.00 0.00 0.43 0.61 0.79 1.59 2.03 2.66 4.20 0:55:00 0.00 0.00 0.37 0.52 0.69 1.30 1.67 2.25 3.55 1:00:00 0.00 0.00 0.33 0.46 0.61 1.12 1.43 1.98 3.13 1:05:00 0.00 0.00 0.29 0.40 0.54 0.97 1.25 1.78 2.80 1:10:00 0.00 0.00 0.23 0.35 0.48 0.80 1.03 1.41 2.24 1:15:00 0.00 0.00 0.19 0.29 0.42 0.65 0.84 1.12 1.77 1:20:00 0.00 0.00 0.16 0.25 0.37 0.51 0.65 0.82 1.31 1:25:00 0.00 0.00 0.15 0.23 0.32 0.41 0.54 0.62 1.00 1:30:00 0.00 0.00 0.14 0.21 0.28 0.34 0.44 0.50 0.82 1:35:00 0.00 0.00 0.14 0.20 0.26 0.30 0.38 0.42 0.70 1:40:00 0.00 0.00 0.13 0.18 0.24 0.26 0.34 0.37 0.61 1:45:00 0.00 0.00 0.13 0.17 0.23 0.74 0.31 0.33 0.56 1:50:00 0.00 0.00 0.13 0.15 0.22 0.23 0.29 0.31 0.52 1:55:00 0.00 0.00 0.11 0.14 0.21 0.22 0.28 0.29 0.49 2:00:00 0.00 0.00 0.10 0.13 0.19 0.21 0.27 0.28 0.48 2:05:00 0.00 0.00 0.07 0.10 0.13 0.15 0.20 0.20 0.34 2:10:00 0.00 0.00 0.05 0.07 0.09 0.11 0.14 0.15 0.25 2:15:00 0.00 0.00 0.04 0.05 0.07 0.08 0.10 0.10 0.18 2:20:00 0.00 0.00 0.02 0.03 0.05 0.05 0.07 0.07 0.12 2:25:00 0.00 0.00 0.02 0.02 0.03 0.04 0.05 0.05 0.08 2:30:00 0.00 0.00 0.01 0.01 0.02 0.02 0.03 0.03 0.05 2:35:00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02 0.03 2:40:00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 2:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 2:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:00 0.00 0.00 0.00 1 0.00 0.00 1 0.00 0.00 0.00 1 0.00 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 1 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 1 0.00 0.00 0.00 0.00 0.00 VOA Switchgrass_MHFD-Detention_B,Outlet Structure 4/4/2025,11:44 AM DETENTION BASIN 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. Sta ge-storage stage Area Area Volume Volume Uuotal Description [ft] [ft'] [acres] [ft'] [ac-ft] [cR] 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). VOA Switchgrass_MHFD-Detention_B,Outlet Structure 4/4/2025,11:44 AM DETENTIONSTAGE-STORAGE MHFD-Detention,Version 4.04(February 2021) Project:VOASwitchgmw Basin ID:C Depth Increment= 1.00 R Optional p an POOL Example Zone Configuration(Retention Pond) Stage-Storage Stage Ovenide Length Width Area Override Area Volume Volume Descn lion ft Stage k ft R R' Area R' ft' (­ft) Watershed Information Top of Micropool -- 0.00 -- -- -- 8 0.000 Selected BMP Type= EDB 5035 -- 0.25 -- -- -- 69 0.002 10 0.000 Watershed Area= 0.16 acres 5035.25 -- 0.50 -- -- -- 154 0.004 37 0.001 Watershed Length= 88 R 5035.5 -- 0.75 -- -- -- 246 0.006 87 0.002 Watershed Length to Centric!= 44 R 5035.75 -- 1.00 -- -- -- 345 0.008 161 0.004 Watershed Slope= 0.015 ft/ft 5036 -- 1.25 -- -- -- 440 0.010 259 0.006 Watershed Imperviousness= 70.00% percent 5036.25 -- 1.50 -- -- -- 527 0.012 380 0.009 Percentage Hydrologic Soil Group A= 0.0% percent 5036.5 -- 1.75 -- -- -- 644 0.015 527 0.012 Percentage Hydrologic Soil Group B= 0.0% percent 5036.75 -- 2.00 -- -- -- 652 0.015 689 0.016 Percentage Hydrologic Soil Groups C/D= 100.0% percent 5037 -- 2.25 -- -- -- 661 0.015 853 0.020 Target WQCV Drain Time= 40.0 hours -- -- -- -- Location for 1-hr Rainfall Depths=User Input -- -- -- -- After providing required inputs above including 1-hour minfall -- -- -- -- depths,click'Run CUHP'to generate runoff hydrogmphs using -- -- -- -- the embedded Colorado Urban Hydrogmph Procedure. Optional User Overrides -- -- -- -- Water Quality Capture Volume(WQCV)= 0.004 acre-feet acne-feet -- -- -- -- Excess Urban Runoff Volume(EURV)= 0.011 acre-feetacre-feet -- -- -- -- 2-yr Runoff Volume(PI=0.87 in.)= 0.007 acre-feet 0.87 inches -- -- -- -- 5-yr Runoff Volume(PI=1.14 in.)= 0.010 acre-feet 1.14 inches -- -- -- -- 10-yr Runoff Volume(P1=1.44 in.)= 0.013 acre-feet 1.44 inches -- -- -- -- 25-yr Runoff Volume(PI=1.95 in.)= 0.020 acre-feet 1.95 inches -- -- -- -- 50-yr Runoff Volume(PS=2.43 In.)= 0.026 acre-feet 2.43 inches -- -- -- -- 100-yr Runoff Volume(PI=2.98 in.)= 0.034 acre-feet 2.98 inches -- -- -- -- 500-yr Runoff Volume(PI=4.57 in.)= 0.054 acre-feet 4.57 inches -- -- -- -- Approximate 2-yr Detention Volume= 0.007 acre-feet -- -- -- -- Approximate 5-yr Detention Volume= 0.010 acre-feet -- -- -- -- Approximate 10-yr Detention Volume= 0.013 acre-feet -- -- -- -- Approximate 25-yr Detention Volume.= 0.016 acre-feet -- -- -- -- Approximate 50-yr Detention Volume= 0.018 acre-feet -- -- -- -- Approximate 100-yr Detention Volume= 0.022 acre-feet -- -- -- -- Define Zones and Basin Geometry -- -- -- -- Zone 1 Volume(WQCV)= 0.004 acre-feet -- -- -- -- Select Zone 2 Storage Volume(Optional)= acre-feet Total detention Volume -- -- -- -- Select Zone Storage Volume(Optional)= acre-feet is less than 100-year -- -- -- -- Total Detention Basin Volume= 1.114 acre-feet Volume. Initial Surcharge Volume(ISV)= R3 -- -- -- -- Initial Surcharge Depth(ISD)= user ft -- -- -- -- Total Available Detention Depth(Hm )= user It -- -- -- -- Depth of In"" Channel(H,c)= user R -- -- -- -- Slope of Trickle Channel(5rc)= user ft/ft -- -- -- -- Slopes of Main Basin Sides(Sm,)= user H:V -- -- -- -- Basin Length-to-Width Ratio(Ruw)= -- Initial Surcharge Area(Acv)= R' -- -- -- -- Surcharge Volume Length(Lysv)= user ft -- -- -- -- Surcharge Volume Width(Wsv)= user It -- -- -- -- Depth of Basin Floor(H-R)= user ft -- -- -- -- Length of Basin Floor(LrooR)= R -- -- -- -- Width of Basin Floor(Wn.00R)= user ft -- -- --Area of Basin Floor(A-11)= user R e -- -- -- -- Volume of Basin Floor(Vaone)- user R3 -- -- -- -- Depth of Main Basin(HnAc,)= ft -- -- -- -- Length of Main Basin(Ln )= user ft -- -- -- -- Width of Main Basin(WM )= user It -- -- --Area of Main Basin(A-)= user RI -- -- -- -- Volume of Main Basin(Vmm)= ft3 -- -- -- -- Calculated Total Basin Volume(Vm,.,i)= user acre-feet -- -- -- -- VOA Switahgrass_MHFD-Detention_C,Basin 41412025,11:10 AM DETENTIONCASIN STAGE-STORAGE TABLE MHFD-Detention,Version 4.04(February 2021) 20 800 is 600 d 10 400� a 5 200 0 0 0.00 1.00 200 300 4.00 stage(ft) —Length(ft) —Wi@h(ft) —Area Is9.k) 0,020 0,020 0.015 11 0.015 s Z3 molo 0.010 u 2 o.00s 0.005 o.000 0.goo 0.00 100 2,00 3.00 4.00 Stage(ft.) —Area(xres) —V.1.—(.,ft) VOA Switahgrass_MHFO-Oetention_C,Basin 4/412025,11:10 AM DETENTION BASIN STRUCTURE MHFD-Detention, Version4.04(February2021) Project:VOA Switchgrass Basin ID:C Estimated Estimated 2PHE, Stage(ft) Volume(ac-ft) Outlet Type vain eum= Zone 1(WQCV) 1.00 0.004 Orifice Plate -mr,E,.,mz owrY,cE Zone 2 PmrPNexr oPirmes Zone 3 POOL Example Zone Configuration(Retention Pond) Total(all zones). 0.004 User Input:Orifice at Underdrain Outlet(typically used to drain WOCV in a Filtration BMP) Calculated Parameters for Underdrain Underdrain Orifice Invert Depth= N/A ft(distance below the filtration media surface) Underdrain Orifice Area= N/A ft, Underdrain Orifice Diameter=1 N/A linches Underdrain Orifice Centroid=I N/A Ifeet 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) Calculated Parameters for Plate Invert of Lowest Orifice=ED.. ft(relative to basin bottom at Stage=0 ft) WQ Orifice Area per Row= 8.333E-04 ft' Depth at top of Zone using Orifice Plate= ft(relative to basin bottom at Stage=0 ft) Elliptical Half-Width= N/A feet Orifice Plate:Orifice Vertical Spacing= inches Elliptical Slot Centroid= N/A feet Orifice Plate:Orifice Area per Row= sq.inches(diameter=3/8 inch) Elliptical Slot Area= N/A ft User Input: Stage and Total Area of Each Orifice Row(numbered from lowest to highest) Row 1(required) I Row 2(optional) Row 3(optional) Row 4(optional) Row 5(optional) Row 6(optional) Row 7(optional) Row 8(optional) Stage of Orifice Centroid(ft)l 0.00 1 0.33 1 0.67 Orifice Area(sq.inches) 0.12 0.12 0.12 Row 9(optional) Row 10(optional) Row 11(optional) Row 12(optional) Row 13(optional) Row 14(optional) Row 15(optional) Row 16(optional) Stage of Orifice Centroid(ft) Orifice Area(sq.inches) User Input: Vertical Orifice(Circular or Rectangular) Calculated Parameters for Vertical Orifice Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Area= ftz Depth at top of Zone using Vertical Orifice= ft(relative to basin bottom at Stage=0 ft) Vertical Orifice Centroid= feet Vertical Orifice Diameter= inches User Input: Overflow Weir(Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir(and No Outlet Pipe) Calculated Parameters for Overflow Weir Not Selected Not Selected Not Selected Not Selected Overflow Weir Front Edge Height,Ho= 1.33 ft(relative to basin bottom at Stage=0 ft) Height of Grate Upper Edge,Ht= 1.33 feet Overflow Weir Front Edge Length= 3.00 feet Overflow Weir Slope Length= 0.00 feet Overflow Weir Grate Slope= 0.00 H:V Grate Open Area/100-yr Orifice Area= 0.00 Horiz.Length of Weir Sides= 0.00 feet Overflow Grate Open Area w/o Debris= 0.00 ft, Overflow Grate Type= Type C Grate Overflow Grate Open Area w/Debris= 0.00 ft, Debris Clogging%=1 50% % User Input:Outlet Pipe w/Flow Restriction Plate(Circular Orifice.Restrictor Plate.or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/Flow Restriction Plate Not Selected Not Selected Not Selected Not Selected Depth to Invert of Outlet Pipe= 0.60 ft(distance below basin bottom at Stage=0 ft) Outlet Orifice Area= 1.23 ftz Circular Orifice Diameter= 15.00 inches Outlet Orifice Centroid= 0.63 feet Half-Central Angle of Restrictor Plate on Pipe= N/A N/A radians User Input:Emergency Spillway(Rectangular or Trapezoidal) Calculated Parameters for Spillway Spillway Invert Stage= 2.25 ft(relative to basin bottom at Stage=0 ft) Spillway Design Flow Depth= 0.15 feet Spillway Crest Length= 2.00 feet Stage at Top of Freeboard= 3.40 feet Spillway End Slopes= 14.00 H:V Basin Area at Top of Freeboard= 0.02 acres Freeboard above Max Water Surface= 1.00 feet Basin Volume at Top of Freeboard= 0.02 acre-ft Routed Hydrogranh Results The user can override the default CUHP h dro ra hs and runoff volumes by enterinq new values in the Inflow H dro ra hs table Co/urns W through AF. Design Storm Return Penod= W CV EURV 2 Year 5 Year SO Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth(In)= N/A N/A 0.87 1.14 1.44 1.95 2.43 2.98 4.57 CUHP Runoff Volume(acre-ft)= 0.004 0.011 0.007 0.010 0.013 0.020 0.026 0.034 0.054 Inflow Hydrograph Volume(acre-ft)= N/A N/A 0.007 0.010 0.013 0.020 0.026 0.034 0.054 CUHP Predevelopment Peak Q(cfs)= N/A N/A 0.0 0.0 0.1 0.2 0.2 0.3 0.6 OPTIONAL Override Predevelopment Peak Q(cfs)= N/A N/A Predevelopment Unit Peak Flow,q(cfs/acre)= N/A N/A 0.00 0.15 0.41 1.05 1..54 2.14 3.76 Peak Inflow Q(cfs)= N/A N/A 0.1 0.2 0.3 0.4 0.6 0.7 1.1 Peak Outflow Q(cfs)= 0.0 0.7 0.0 0.0 0.1 0.3 0.5 0.6 1.3 Ratio Peak Outflow to Predevelopment Q= N/A N/A N/A 1.5 1.7 1.9 2.2 1.9 2.1 Structure Controlling Flow= Plate Overflow Weir 1 Plate Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 Overflow Weir 1 verflow Weir Max Velocity through Grate 1(fps)= N/A N/A N/A N/A N/A N/A N/A N/A N/A Max Velocity through Grate 2(fps)= N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97%of Inflow Volume(hours)= 8 10 12 13 12 11 11 10 9 Time to Drain 99%of Inflow Volume(hours)= 9 12 13 14 14 13 13 13 12 Maximum Pending Depth(ft)= 1.04 1.68 1.19 1.35 1.38 1.44 1.48 1.50 1.60 Area at Maximum Ponding Depth(acres)= 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Maximum Volume Stored(acre-ft)= 0.004 0.011 0.005 0.007 0.007 0.008 0.008 0.009 6.010 VOA Switchgrass_MHFD-Detention_C,Outlet Structure 4/4/2025,11:10 AM DETENTIONOUTLET MHFD-Detention Version 4. (February Z ZI 1.4 —500YR IN ••••500YR OUT �100YR IN 1.2 100YR OUT �50YR IN 50YR OUT 1 —YRIN 25YR OUT —10YR IN 10YR OUT 0.8 —5YR IN Y+ .. .5YR OUT 3 —2YR IN 0 ———2YR OUT LL 0.6 EURU IN •EURU OU _wQCV IN 0.4 ••`•WQN our NL �• 0.2 \ \ U — _ ...—...—.. .. 0.1 1 10 TIME[hr] 1.8 —500YR —100YR 1.6 —WYR —25YR 1.4 —1OYR —SYR _2YR 000 1.2 �EURV _WccV 00, x � 1 0 z p 0:8 z 0 0.6 0.4 0.2 0 0.1 1 10 100 DRAIN TIME[hr] 10,000 SO O User Area[ft"21 9,000 —Interpolated Area[ft^2] 9 •••0-••Summary Area[ft"2] 8,000 —Volume[ft"31 8 •••►••Summary Volume[W3] 7,000 Outflow[cfs] 7 6,000 ..y..Summary Outflow[cfs] 6 x � 5,000 5 3r � J j 4,000 4 N 3,000 3 c a 2,000 2 1 1,000 1 0 0 0.00 0.50 1.D0 1.50 2.DO 2.50 3.00 3.50 4.00 PONDING DEPTH[ft] 5-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis minimum bound maximum bound VOA Switchgrass_MHFD-Detention_C,Outlet Structure 4/4/2025,11:10 AM DETENTION BASIN Outflow Hydrograph Workbook Filename: Inflow Hydroaraohs The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP CUHP Time Interval 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] 5.00 min 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 0.04 0:15:00 0.00 0.00 0.01 0.03 0.04 0.04 0.06 0.06 0.11 0:20:00 0.00 0.00 0.07 0.09 0.12 0.09 0.12 0.15 0.26 0:25:00 0.00 0.00 0.14 0.19 0.27 0.20 0.27 0.34 0.58 0:30:00 0.00 0.00 0.15 0.20 0.27 0.43 0.57 0.70 1.11 0:35:00 0.00 0.00 0.12 0.16 0.21 0.41 0.53 0.70 1.10 0:40:00 0.00 0.00 0.09 0.12 0.16 0.35 0.45 0.58 0.92 0:45:00 0.00 0.00 0.07 0.09 0.13 0.27 0.34 0.47 0.74 0:50:00 0.00 0.00 0.05 0.08 0.10 0.22 0.29 0.38 0.60 0:55:00 0.00 0.00 0.04 0.06 0.08 0.17 0.21 0.30 0.47 1:00:00 0.00 0.00 0.03 0.05 0.06 0.12 0.16 0.24 0.37 1:05:00 0.00 0.00 0.03 0.04 0.06 0.10 0.13 0.20 0.32 1:10:00 0.00 0.00 0.02 0.04 0.06 0.08 0.10 0.15 0.24 1:15:00 0.00 0.00 0.02 0.04 0.06 0.07 0.09 0.12 0.19 1:20:00 0.00 0.00 0.02 0.03 0.05 0.06 0.07 0.08 0.14 1:25:00 0.00 0.00 0.02 0.03 0.04 0.05 0.06 0.06 0.11 1:30:00 0.00 0.00 0.02 0.03 0.04 0.04 0.05 0.05 0.09 1:35:00 0.00 0.00 0.02 0.03 0.03 0.04 0.05 0.05 0.08 1:40:00 0.00 0.00 0.02 0.02 0.03 0.03 0.04 0.04 0.07 1:45:00 0.00 0.00 0.02 0.02 0.03 0.03 0.04 0.04 0.07 1:50:00 0.00 0.00 0.02 0.02 0.03 0.03 0.04 0.04 0.07 1:55:00 0.00 0.00 0.01 0.02 0.03 0.03 0.04 0.04 0.07 2:00:00 0.00 0.00 0.01 0.02 0.02 0.03 0.04 0.04 0.07 2:05:00 0.00 0.00 0.01 0.01 0.01 0.02 0.02 0.02 0.04 2:10:00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.02 2:15:00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 2:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 2:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:25:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:30:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:35:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:40:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:45:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:50:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3:55:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:05:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:10:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:15:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:20:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4:25:00 0.00 0.00 0.00 1 0.00 0.00 1 0.00 0.00 0.00 1 0.00 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 1 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 VOA Switchgrass_MHFD-Detention_C,Outlet Structure 4/4/2025,11:10 AM DETENTION BASIN 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. Sta ge-storage stage Area Area Volume Volume Uuotal Description [ft] [ft 11 [acres] [ft 11 [ac-ft] [cR] 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). VOA Switchgrass_MHFD-Detention_C,Outlet Structure 4/412025,11:10 AM Storm Sewer Summary Report Pagel Line Line ID Flow Line Line Line Invert Invert Line HGL HGL Minor HGL Dns Junction No. rate Size shape length EL Dn EL Up Slope Down Up loss Junct Line Type (cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) (ft) No. 1 B01 9.26 15 Cir 30.409 5033.76 5034.14 1.251 5035.01* 5035.64' 0.13 5035.77 End Manhole 2 B02 8.19 18 Cir 152.000 5034.34 5035.10 0.500 5035.84* 5036.77* 0.05 5036.82 1 Manhole 3 EXMH-B03 0.83 6 Cir 66.874 5036.87 5038.15 1.914 5037.33 5038.60 0.30 5038.91 2 Manhole 4 A02 2.20 12 Cir 7.420 5035.70 5035.73 0.401 5036.70 5036.72 0.11 5036.83 End Manhole 5 A03 2.20 12 Cir 31.131 5035.73 5035.89 0.514 5036.83* 5036.95* 0.04 5036.98 4 Manhole 6 A04 0.80 8 Cir 76.716 5036.22 5036.61 0.508 5036.98 5037.27 0.08 5037.35 5 Manhole 7 D01 1.41 12 Cir 32.029 5035.02 5035.10 0.250 5036.02 5036.06 0.05 5036.11 End Manhole -71 Project File: VOA Switchgrass_100 year Hydraulics.stm Number of lines: 7 Run Date: 4/4/2025 NOTES: Known Qs only ; *Surcharged(HGL above crown). Storm Sewers v2024.00 Storm Sewer Profile Proj. file: VOA Switchgrass_1 00 year Hydraulics.stm LO CD � o c pS c pc E p p o 0 J 10 N^^ D OD N J OR OD OR O p L N 0)L6(n (n r 6(6 C4 O(6 p M NMM (() OM ) (V CM Elev. (ft)0 w o rLDLO M CLOL LOLO o -o w o Lu o www ww m - > a E » c E » 66 cn it (n R S S (n WE 5048.00 5048.00 5045.00 5045.00 5042.00 5042.00 5039.00 5039.00 5036.00 1% 1 5036.00 „ o 5033.00 5033.00 0 10 20 30 40 50 60 70 80 90 100 110 120 HGL EGL Reach (ft) Storm Sewers Storm Sewer Profile Proj. file: New.stm N M = M C C O S C O S C O J J J O ^ C^D �-M n Cn CROC O p M CDO V 4 O r-M CO aD O QO p to CO CMM CMMM N 'TM Elev. (ft) o w LO M ��� 0 �Ln� �� ) p W O WWW - wWW N WW CO > :° E» cc cnU' cn Esc fn WEE fn E 5051.00 5051.00 5047.00 5047.00 5043.00 5043.00 5039.00 5039.00 .8740 5035.00 5035.00 LT 5031.00 5031.00 0 25 50 75 100 125 150 175 200 225 250 HGL EGL Reach (ft) Storm Sewers Storm Sewer Profile Proj. file: New.stm =3 _ = O Oho J �o CD CDLO N CO O to (`') O O COElev. (ft) o w M to W) o -p W o W W co = > E 65 <n WE 5048.00 .5048 00 5045.00 5045.00 5042.00 5042,00 5039.00 5039.00 5036.00 50J6 00 3 .029U-12"@ 0.25% 5033.00 5033.00 0 10 20 30 40 50 60 70 80 90 100 HGL EGL Reach (ft) Storm Sewers Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday,Apr 4 2025 <Name> Circular Highlighted Diameter (ft) = 0.50 Depth (ft) = 0.45 Q (cfs) = 0.828 Area (sqft) = 0.19 Invert Elev (ft) = 36.87 Velocity (ft/s) = 4.45 Slope (%) = 1.92 Wetted Perim (ft) = 1.25 N-Value = 0.013 Crit Depth, Yc (ft) = 0.45 Top Width (ft) = 0.30 Calculations EGL (ft) = 0.76 Compute by: Known Depth Known Depth (ft) = 0.45 Elev (ft) Section 38.00 37.50 37.00 36.50 36.00 0 1 2 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday,Apr 4 2025 <Name> Triangular Highlighted Side Slopes (z:1) = 50.00, 25.00 Depth (ft) = 0.27 Total Depth (ft) = 1.00 Q (cfs) = 5.470 Area (sqft) = 2.73 Invert Elev (ft) = 5037.30 Velocity (ft/s) = 2.00 Slope (%) = 0.50 Wetted Perim (ft) = 20.26 N-Value = 0.013 Crit Depth, Yc (ft) = 0.27 Top Width (ft) = 20.25 Calculations EGL (ft) = 0.33 Compute by: Known Q Known Q (cfs) = 5.47 Elev (ft) Section Depth (ft) 5039.00 1.70 5038.50 1.20 5038.00 0.70 5037.50 - 0`.20 5037.00 -0.30 5036.50 -0.80 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 Reach (ft) MHFD Inlet, Version 5.03 Au Ust 2023 (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Project:Switchgrass Crossing Inlet ID:A03 T T T,- W T. STREET JE a CROWN _j GutterGeometry: Maximum Allowable Width for Spread Behind Curb TRACK= 2.0 ft Side Slope Behind Curb(leave blank for no conveyance credit behind curb) SencK= 0.020 ft/ft Manning's Roughness Behind Curb(typically between 0.012 and 0.020) nsACK= 0.013 Height of Curb at Gutter Flow Line HNRB= 6.00 inches Distance from Curb Face to Street Crown TCRoWN= 26.0 ft Gutter Width W= 2.00 ft Street Transverse Slope Sx= 0.020 ft/ft Gutter Cross Slope(typically 2 inches over 24 inches or 0.083 ft/ft) SW= 0.083 ft/ft Street Longitudinal Slope-Enter 0 for sump condition So= 0.000 ft/ft Manning's Roughness for Street Section(typically between 0.012 and 0.020) nS`rREET= 0.013 Minor Storm Major Storm Max.Allowable Spread for Minor&Major Storm TMnx= 10.0 26.0 ft Max.Allowable Depth at Gutter Flowline for Minor&Major Storm dMAx= 6.0 12.0 inches Check boxes are not applicable in SUMP conditions r r- MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm MANOR STORM Allowable Capacity is not applicable to Sump Condition Q.11-= SUMP F SUMP cfs 1 INLET IN A SUMP OR SAG LOCATION MHFD-Inlet, Version 5.03(August 2023) dLo(C) H-Curb H-Vert - Wo W Lo(G) Design Information nut Denver No.16 CombinationMINOR MAJOR Type of Inlet Type=1 Denver No.16 Combination Local Depression(additional to continuous gutter depression'a'from above) ai_i= 2.00 2.00 inches Number of Unit Inlets(Grate or Curb Opening) No= 1 1 Water Depth at Flowline(outside of local depression) Ponding Depth= 3.9 7.8 inches Grate Information MINOR MAJOR r Override Depths Length of a Unit Grate La(G)= 3.00 3.00 feet Width of a Unit Grate W.= 1.73 1.73 feet Open Area Ratio for a Grate(typical values 0.15-0.90) Aaeo= 0.31 Clogging Factor for a Single Grate(typical value 0.50-0.70) Cf(G)= 0.50 0.50 Grate Weir Coefficient(typical value 2.15-3.60) C. (G)= 3.60 -60 Grate Orifice Coefficient(typical value 0.60-0.80) Co(G)= 0.60 0.60 Curb Opening Information MINOR MAIOR Length of a Unit Curb Opening L.(C)= 3.00 3.00 feet Height of Vertical Curb Opening in Inches Het= 6.50 6.50 inches Height of Curb Orifice Throat in Inches Hthr�= 5.25 5.25 inches Angle of Throat Theta= 0.00 0.00 degrees Side Width for Depression Pan(typically the gutter width of 2 feet) W,= 2.00 2.00 feet Clogging Factor for a Single Curb Opening(typical value 0.10) Cf(C)= 0.10 0.10 Curb Opening Weir Coefficient(typical value 2.3-3.7) C.(C)= 3.70 3.70 Curb Opening Orifice Coefficient(typical value 0.60-0.70) Co(C)_ ,,h Low Head Performance Reduction(Calculated) MINOR MAIOR Depth for Grate Midwidth dc.te= 0.35 0.67 ft Depth for Curb Opening Weir Equation dcurb= 0.16 0.48 ft Grated Inlet Performance Reduction Factor for Long Inlets RF�te= 0.61 1.00 Curb Opening Performance Reduction Factor for Long Inlets RFcurb= N/A N/A Combination Inlet Performance Reduction Factor for Long Inlets RFC-bi anrn= 0.61 1.00 MINOR MAJOR Total Inlet Interception Capacity(assumes clogged condition) Qa= 7.4 cfs Inlet Capacity IS GOOD for Minor and Major Storms > 1.7 Peak Q cEaK aeQmaeo= cfs 1 ll u 0 U L u l N Appendix C Drainage Map 5 f`I P uj o r- K S Page 12 of 12 301 West 4511 Avenue,Denver,CO 80216 303 433-4094 5 4 3 I 2 1 nl � lJJ rn 0 M BENCHMARK: AURORA BENCHMARK POINT NO. 09-070B, 3" DIAMETER BRASS CAP EXTENDED DETENTION BASIN WATER QUALITY VOLUME TABLE L m ATOP THE NORTH EDGE OF A CURB OPENING INLET & CENTERED THEREON BEING m EDB WQCV (ac ft) WQCV (cu ft) WQ Depth (ft) 100 yr Depth (ft) 100 yr Outflow (cfs) ON THE WEST SIDE OF S. CHAMBERS ROAD & 40' MORE/LESS NORTH OF THE JEWELL 0 LANDLINE AS EVIDENCED BY THE RANGE BOX IN S. CHAMBERS ROAD. PUBLISHED A 0.008 348 2.03 2.6 1.8 ELEVATION = 5535.38 (NAVD 88) B 0.025 1089 1.66 2.5 3.2 N C 0.004 174 1.04 1.5 0.6 U 00 0 w, U LU w �j � % / / STORM MH NOTES z / _ RMD o aRCP Nvs=5o3a.a5 OFFSITE STORMWATER 1 ALL STORM INFRASTRUCTURE SHOWN IS PRIVATE UNLESSOTHERWISE NOTED AND WILL BE MAINTAINED BY THE D - 12"RCP INV W=5034.65 FLOWS • 18"RCP INV N=5034.45 -�_ UTILITY cABiIVET_. PROPERTY OWNER - VOLUNTEERS OF AMERICA. STORM INFRASTRUCTURE HAS BEEN DESIGNED TO ACCOMMODATE 0w l LOT 1 CREGER 3RD REPEAT THE 100 YEAR STORM a OFFSITE STORMWATER (PLAT-REC. NO. o� UTILITY 20190044858) U _ VAULT / F E OWNER:MASON PLACE LLLP - - ''' / E E Ill- E - E E- - EZC _ L UTILITY '��' - '�p� F� o -. VAULT STMH-A02 STINLET-AO3 9 ' �,°� m �- ro 2' NYLOPLAST TYPE 16 COMBO INLET 1 r �' BASIN Al 1► - 0.17 0.83 STCO-A04 503�" 1 AO 1 .00 Storm Cleanout 12 PVC Flee 8°PVC Pipe c I Q� 3 I / 110 I -E �. I T OFFSITE STORMWATER Q FLOWS SANITARY MH � - RIM=5039.00 12�� � _ 10°PVC INV S=5031.85 I EXISTING PVC PIP - - - - - I Runoff Summary Table 10"PVC INV N=5031.70 E EMERGENCY I - \ II ti I I I I Minor Minor Major Major OVERFLOW \ I o Minor Major Storm Storm Storm Storm CM STORM MH I SPILLWAY I STORM INLET * rRA1 BUILDING FFE �o * I 44 � ,�, Design Area Impervious Storm (C Storm (C Local Flow Accum Local Flow Accum RIM=5038.87 ELEV 5038.80 III Tpe= 3 •9q 1 o.�a °ao 5039.50 1 15"RCP INV E=5035.02 12"PV I V iv=5035. I I Basin ID Point (AC) Percentage Value) Value) (cfs) Flow(cfs) (cfs) Flow(cfs) 18"RCP INV S=5034.17 I WSEL 5038 86 / d = 0 - RA1 R1 0.08 95% 0.95 1.00 0.23 0.23 0.80 0.80 18"RCP INV NE=5034.17 ■ �' cz SS 5SI �� I Al 1 0.17 83% 0.83 1.00 0.40 0.63 1.41 2.20 STINLET-D01 l �► �' R131 R2 0.20 95% 0.95 1.00 0.54 0.54 1.89 1.89 � MODIFIED TYPE C I � � � - � C OUTLET STRUCTURE O EXTENDED DETENTION BASIN B1 2 0.79 690 0.69 0.87 1.57 2.11 5.47 8.19 cz ' EDB-A (WATER QUALITY ONLY) C1 3 0.16 70% 0.70 0.87 0.31 0.31 1.07 10.09 III j 051 4 0.09 58% 0.58 0.73 0.15 0.15 0.64 0.64 C pM C Ll c0 II - --- -_- -- c�v � • TILITY ULT a� 4 ' UL ♦- 1► O r I it O * / RBI I I �-- �20OO , OS1 ' LL 4-1 AC OJ3 �p 4'CONCRETE PAN W W IN III ®` �, o '� LOT2MORELAND DRAINAGE PLAN LEGEND CD III q : SUBDIVISION � I W -�-- W W - (PLAT-REC. NO. 91030712) - �► OWNER:D AND M � ^^ °° I �' --_- I - AUTOMOTIVE BOUNDARY LINE w ) T O III B1 EXISTING CURB AND GUTTER v ) U L L 0.79 069 AC 0.87 EXISTING STORM LINE M® Cn m ~ II EXISTING STORM MANHOLE IJ_ I BUILDING FFE: O +� 5039.50 A /�' � EXISTING STORM INLET Ip �' ❑� v � R2 I EXISTING MINOR CONTOUR 5281 o Cn I I T OFFSITE STORMWATER EXISTING MAJOR CONTOUR 5280 e ( I� II FLOWS B V CV �-- I -J +5 15 15 15 ram LC7 `VVV/JJJ, PROPOSED CURB AND GUTTER � O ' %* co o I s / � % ( PROPOSED SIDEWALK ® O -�a--- L7I ------ -- -, _-- ----n-' / PROPOSED STORM LINE Q CU PROPOSED STORM MANHOLE C1 � I � , III I ♦- - � , � .�, O = = z - � I o � _ �, � _ � 1 PROPOSED STORM INLET � � � � J (T J p 1� o w I 5039 w r U �, 1 1 PROPOSED MINOR CONTOUR 5281 � I � � o O I C1 nni �`� e♦ PROPOSED MAJOR CONTOUR 5280 _ 6 6 0,0 � / PROPOSED RETAINING WALL O DC Q ,r I 00 ® I 3: o F" 1 1 A� 0.87 ,( h��� �► 2 BASIN DELINEATION v J M {�� OFFSITE STORMWATER C-p FLOWS FROM EASTERN FLOW ARROW 5p38 0 � 0 0 � � w EMERGENCY � I�� I � I PARKING LOT ASSUMED O � � Ri � �p"� 3 ®� OVERFLOW � � FULL FLOW FOR PIPE � Y LET SPILLWAY - BASIN ID CV EMERGENCY _ __ _ 0.83 CFS OVERFLOW - - �-ELEV 5037.87 XX XX 0 -h--`n1IV 1 �1 WSEL 5038.26 6 SPILLWAY T EXTENDED DETENTION I BASIN LABEL 2 YR C-VALUE REV: V ELEV 5037.00 I I � \ BASIN EDB-B (WATER XX 1 2024 Revision 1 CD WSEL 5037.15 !I I 503$ QUALITY ONLY) 2 2024 Revision 2 tf I � / t AREA 3 2024 Revision 3 � 15" EXISTING RCP ( 18"RCP 6"EXISTING PVC Pipe 100 YR i ST S -� - - �� - _ � � C-VALUE Q I I / �50 g RO� 0� \ TOG=5040.38 EXTENDED DETENTION BASIN - s"PVC INV W=5038.15Ille DESIGN POINT LABEL XX EDB-C (WATER QUALITY ONLY) O -- Q �� � - _ V - � DRAWN: TS LOT 1 PLAT OF MASON STREET PUD STINLET B02 REVIEWED: TS STINLET B01 PLAT-REC. N0. 520208) DATE: 03/16/2024 MODIFIED TYPE C A I I MODIFIED TYPE C �OFFSITE STORMWATER ( OUTLET STRUCTURE N A U I OUTLET STRUCTURE FLOWS OWNER:RCA MASON LLC I u CONSTRUCTION DOCUMENTS _ _ PROJECT#: 24046 � SANITARY MH� _'� FILE: 24046 Drainage Plan RIM=5038.02 V 8"PVC INV S=5032.52 SHEET TITLE: 10"PVC INVN=5032.32 DRAINAGE PLAN C- 0 i a� i Cf) SCALE: REF PLAN CD 0 20' 40' v � NO. DR1 SCALE:1" = 20' Q 5 4 3 I 2 I 1 F_