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HomeMy WebLinkAbout05. Drainage, Soils, HydrologyDrainage Report Dunlap Minor Subdivision 591 CR 259 Rifle, Colorado DRAINAGE REPORT October 26, 2018 Prepared for: Joy Dunlap 2233 W. Poinsettia Dr. Phoenix, AZ 85029 Engineer: Nathan Bell, P.E. Bell Consulting LLC P.O. Box 8 Rifle, CO 81650 970/948-3153 Contents introduction DESCRIPTION BASINS METHODOLOGY Off site impacts Developed on site flows conclusions APPENDIX A NRCS Soils Information APPENDIX B PRECIPITATION DATA APPENDIX C Pre -developed Off Site and On Site Hydrology Calculations APPENDIX D Post -developed Hydrology Calculations APPENDIX E Structure Capacity Calculations Dunlap Minor Subd, Drainage Report October 26, 2018 1 Drainage Report — Dunlap Minor Subdivision, Rifle, CO Bell Consulting LLC. has prepared the following Drainage Report for the proposed improvements of the Dunlap Minor Subdivision, a proposed 3 lot single family development northeast of the City of Rifle, Colorado. The purpose of the study is to ascertain the offsite drainage impacts to this site and how development of the site will impact storm runoff from the site. The development consists of low-density single-family residences on large (5+acre) lots. The low density of the development creates a minimal impact to the on-site runoff increases due to the small percentage increase of impervious area to the overall area. Calculations are provided within this report. INTRODUCTION Dunlap Minor Subdivision is located northeast of the City of Rifle within the Silt Mesa area and is accessed via County Road 259 (Jewell Lane). The property is bounded on the east by County Road 259 and on the other 3 sides by single family residential/agricultural parcels. Overall the site is approximately 24.4 acres Regulations require the developer of a parcel to provide mitigation for rain storm events so that the increase in impervious area due to the development does not harm any downstream property. This is accomplished by providing some type of mitigation to allow the rate of runoff to remain at or below historic flow rates. The intent of this report is to provide calculations of the storm events and a description of the methods utilized to mitigate the runoff DESCRIPTION The property topographically is relatively level throughout the eastern and western portions with a relatively steep ridge separating the two. Drainage channels and area for a significant off-site basin (2000 -acres +/-) comprises the eastern area of the property and is shown as having potential inundation from a 100 -yr storm event. Drainage channels for a smaller off- site basin exist on the western portion of the property and flows are contained within these channels for all storm events. Historically the property contained a single family residence along with a several out buildings. The site was served with a gravel driveway with gravel parking areas. BASINS The designation of basin boundaries is shown on the map provided. The offsite area was divided into two basins utilizing aerial and existing topographic maps to delineate the basin boundaries and flow patterns. The onsite area was divided into two basins split by the ridge dividing the overall property for both pre -developed and post improvements flow conditions. Dunlap Minor Subd, Drainage Report October 26, 2018 2 As mentioned above, the site has historically contained improvements that impacted the storm runoff and these were utilized in the current calculations. METHODOLOGY The peak runoff flows for the analysis were determined with the HydroCAD computer program using the methodology given in the Soil Conservation Service's "Technical Release No. 20, Urban Hydrology." Design criteria established by Garfield County require that peak runoff flows be analyzed assuming a 25 -year frequency storm event while keeping in consideration the 100 -year storm event. The 25 -year, 24-hour and the 100 -year, 24-hour precipitation events were estimated to be 1.82 and 2.3 inches respectively. The 2 -year, 24- hour precipitation event was estimated at 1.06 -inches. These data were collected from the online National Weather Service NOAA Atlas 2 interactive program. The NRCS/SCS soils mapping lists the soils in the area primarily in the Hydrologic Group C for both on-site and off-site basins with a mix of A, B, and D throughout. For this reason, a more conservative C grouping was used for the calculations The type of ground cover as well as density also affects the runoff volume from a site. The off-site areas consist primarily of a mix of pinyon/juniper stands in the upper reaches, a sage/brushy mix for the intermediate areas and then pastures in the lower level areas. The onsite areas are a mix of brush and grasses in the eastern and western portions with the central ridge area consisting of medium brush/grass cover. Calculations provided herein and the design of the infrastructure are based upon the 25 -year storm event. The design of the proposed storm drainage culverts has the capacity for 25 -year event flows and is not damaged by 100 -yr events as overtopping of driveways is anticipated. The site was analyzed for the pre -developed, or historic, and post -developed conditions to determine the potential impacts to the area with respect to runoff flows. OFF SITE IMPACTS The two off-site basins flow into the site from the steep area to the north and are the most impactful to development within the site. Basin A is a large basin and flows traverse the eastern portion of the site primarily within channels maintained along the eastern edge. The 25 -yr storm event stays within the channelization creating minimal impact to development. The 100 -yr storm event has the potential to breach the channel and inundate a portion of the lower areas on both Lots 2 and 3. The area of potential inundation is broad and flat, therefore the flows spread out with a flow depth of less than 1 -foot. Basin B is a smaller basin with flows traversing the western portion of the site. Both the 250yr and 100 -yr storm event flows are contained within existing channels. The post improved conditions will continue to direct the off-site flows in much the same way with improvements to be outside of the main channels or inundated areas. Channel crossings should utilize culverts designed for the flows indicated. Dunlap Minor Subd, Drainage Report October 26, 2018 3 Area Runoff Flows BASIN AREA (acres) CN Peak Runoff (cfs) 25 year Peak Runoff (cfs) 100 year A 2058 71 166 450 B 263 79 58 108 DEVELOPED ON SITE FLOWS Development of the site will consist adding 2 single family residences with gravel drives and assorted outbuildings. The anticipated additional impervious areas are small in comparison to the overall area of the project property; therefore, the increased runoff is minimal. Also, the addition of improved vegetation around the residential areas mitigates some of the impervious additions. The site was divided north to south along a ridge that transverses the property. The West and East on-site basins each will have an additional residence and associated improvements. The following table provides a comparison of the flows prior to development (Pre Runoff) and after developed impervious areas are added (Post Runoff). Developed Runoff BASIN AREA (acres) CN Pre to post Pre Runoff (cfs) 25 year Post Runoff (cfs) 25 year West 9.34 77 to 77 4.43 4.43 East 15.04 75 to 75 4.88 4.88 As indicated, flows from these areas does not increase due to the small overall percentage of increased impermeable area. CONCLUSIONS The flows from the proposed improvements to the site by the current development plan are quite minimal and do not effectively increase runoff from the site. The off-site areas add significant flows through the site and need to be taken into consideration during development. The eastern portion of proposed Lots 2 and 3 are subject to potential inundation of less than 1 - ft in depth from a 100 -yr flood event (indicated on the map). Development in these areas should take the potential into account and mitigate accordingly. Driveways crossing the Dunlap Minor Subd, Drainage Report October 26, 2018 - 4 channels on both the eastern and western channels should utilize culverts sized for the 25 -yr storm event. These driveways may overtop during a 100 -yr flood event. Storm water detention is not required as part of this development due to the lack of increased calculated flows. Runoff improvements for the site are indicated on the proposed Site Plan provided by Bell Consulting as part the development application. REG/sl °�.c„AAN Nathan Bell, P.E. 33401 — Bell Consulting LLC. D:\BC jobfiles\1 52 -Dunlap Minor subd\hydro\Drainage Report-Dunlap.docx Dunlap Minor Subd, Drainage Report October 26, 2018 5 8.080 wwarwa`w1ar+Wxl.80 bre +8d detAi i(6oloapAH uoislnipgns JowW deluna POwd u6!sea deluna W W9WJI n \SI 8199 "O 51t6.58904.6 \01 8186-5290[61)10:\ 0198 oo o10J118111 8 808'0, Jll DNLLInSNOJ 1139 v F8 ,508+0 • Q• ti O 73 O 00 O p 2U CD -73 COa)) c CD 00 I I I I I I On-site Basins Existing minor contour Existing major contour Proposed minor contour 0 8 E o e a w Existing overhead electric Ditch Centerline Existing driveway ISDS Profile Hole 1- w z 0w o. C7 -J z 0 N 0 ISDS Percolation Test Hole APPENDIX A NRCS Soils Information 39° 37 31" N 39° 34' 0" N Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties (Dunlap off-site) Map Scale: 1:31,700 if printed on A portrait (8.5" x 11") sheet. ^o N 0 450 900 ■\ 0 1500 3000 6000 Map projection:Web Mercator Comeraoordinates: WGS84 1800 Meters 2700 Feet t_sDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 9000 10/26/2018 Page 1 of 3 39° 3731"N 39° 34' 0" N Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties (Dunlap off-site) MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons 0 A 0 ND B B/D 0 CID . D 0 Not rated or not available Soil Rating Lines " A rior ND B B/D ,y C • C/D n.yr s • Not rated or not available Soil Rating Points • A ▪ A/D • B ▪ B/D ■ I u ▪ I i c C/D D Not rated or not available Water Features Streams and Canals Transportation ++{ Rails owe Interstate Highways ree US Routes Major Roads Local Roads Background - Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 11, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Dec 31, 2009—Oct 12, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/26/2018 Page 2 of 3 Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties Dunlap off-site Hydrologic Soil Group Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 10/26/2018 Page 3 of 3 Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Arvada loam, 1 to 6 percent slopes C 48.2 2.6% 4 Arvada loam, 6 to 20 percent slopes C 59.2 3.2% 9 Badland D 32.3 1.7% 21 Cushman-Lazear stony loams, 15 to 65 percent slopes C 358.9 19.2% 34 Ildefonso stony loam, 25 to 45 percent slopes A 35.3 1.9% 35 Ildefonso-Lazear complex, 6 to 65 percent slopes A 34.9 1.9% 41 Kim loam, 6 to 12 percent slopes A 7.2 0.4% 50 Olney loam, 3 to 6 percent slopes B 163.7 8.8% 51 Olney loam, 6 to 12 percent slopes B 64.7 3.5% 55 Potts loam, 3 to 6 percent slopes C 43.2 2.3% 56 Potts loam, 6 to 12 percent slopes C 142.8 7.6% 58 Potts-Ildefonso complex, 12 to 25 percent slopes C 0.4 0.0% 66 Torriorthents- Camborthids-Rock outcrop complex, steep D 120.9 6.5% 67 Torriorthents-Rock outcrop complex, steep D 754.8 40.4% Totals for Area of Interest 1,866.7 100.0% Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 10/26/2018 Page 3 of 3 Natural Resources N 0 0 0 MAP INFORMATION MAP LEGEND Warning: Soil Map may not be valid at this scale. 0) ca Ta. 0 Eo »222 \CL a>c Eco ° Q)0 03 (0 & ] fa E0 +»m` E&\ 0 L15c a) E Elms 0) 0 IA co 4-, 37/§§ 0 0 o 0 Not rated or not available Streams and Canals Transportation \ / § a)a)2mm ) E : 2/]° 2 E ° a)=wfe \ ) ° 32§2 m § /_a2m5 so m0c=m 2 \ k ƒ$C2 ) G z 2 / 0 $ $$t=0z co 0 \ 00K/m 0 = m a_m% § o0 03 / 0\/(} ±4 2 § 0 2: 2 .° Til / k 0 2 § )$*ee �a m )�� 7§\$t 77 k§E (0ice(0k kƒ \` 45§22 °) ) /7�/18as,0 CO •cov .0'= Eco8-0 6F2 m2 @ X52 2.Qoo om o6 mm) ® y2m a0 0303 WW (07 2 00 oOo (02.00 E E co o t o 8 /\ (Ts Interstate Highways I � 0 0 = i 0= o a c L q Local Roads Not rated or not available I ❑ Background Aerial Photography Soil Rating Lines Rifle Area, Colorado, Parts of Garfield and Version 11, Sep 10, 2018 0 o 0 < i= 2 0 0 0 1 I z Not rated or not available Soil Rating Points < $ = 2 ■ ■ ■ T. ƒ 3 T.0 =0 $± \\ \/ 0 0 z Natural Resources Dunlap Minor Sub Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties Hydrologic Soil Group Map unit symbol Map unit name Rating Acres In AOI Percent of AOI 9.5% 00 in 0 rn o 0 o N 21.0 N N CO N 0 56 Potts loam, 6 to 12 C percent slopes Totals for Area of Interest Arvada loam, 1 to 6 percent slopes CO Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff. None Specified Tie-break Rule: Higher X11 APPENDIX B PRECIPITATION DATA 5/11/2015 Precipitation Frequency Data Server NOAA Atlas 14, Volume 8, Version 2 Location name: Rifle, Colorado, US* Latitude: 39.5646°, Longitude: -107.7706° Elevation: 5522 ft* * source: Google Maps POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOAA, National Weather Service, Silver Spring, Maryland PF tabular 1 PF graphical 1 Maps & aerials PF tabular PDS -based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5 -min 0.123 (0.101-0.152) 0.154 (0.126-0.191) 0.208 (0.169-0.258) 0.256 (0.207-0.320) 0.327 (0.256-0.436) 0.386 (0.292-0.523) 0.449 (0.325-0.629) 0.516 (0.355-0.751) 0.610 (0.400-0.923) 0.685 (0.434-1.05) 10 -min 0.181 (0.148-0.223) 0.226 (0.185-0.279) 0.305 (0.248-0.378) 0.375 (0.303-0.469) 0.479 (0.374-0.638) 0.566 (0.428-0.766) 0.657 (0.476-0.922) 0.755 (0.519-1.10) 0.893 (0.585-1.35) 1.00 (0.635-1.54) 15 -min 0.220 (0.180-0.272) 0.275 (0.225-0.340) 0.371 (0.303-0.461) 0.457 (0.370-0.572) 0.585 (0.456-0.778) 0.690 (0.522-0.934) 0.801 (0.580-1.12) 0.921 (0.633-1.34) 1.09 (0.713-1.65) 1.22 (0.774-1.88) 0.273 0.347 0.473 0.582 0.738 0.864 0.994 1.13 1.32 1.47 30 -min (0.224-0.337) (0.284-0.430) (0.385-0.588) (0.471-0.727) (0.573-0.976) (0.651-1.16) (0.718-1.39) (0.775-1.64) (0.862-1.99) (0.928-2.25) 0.340 0.419 0.553 0.669 0.835 0.970 1.11 1.25 1.46 1.61 60 -min (0.279-0.420) (0.343-0.518) (0.450-0.687) (0.541-0.836) (0.649-1.10) (0.731-1.31) (0.801-1.55) (0.861-1.82) (0.952-2.19) (1.02-2.48) 2 -hr 0.407 (0.336-0.498) 0.491 (0.405-0.601) 0.633 (0.520-0.778) 0.756 (0.616-0.935) 0.933 (0.731-1.22) 1.07 (0.819-1.43) 1.22 (0.892-1.68) 1.38 (0.955-1.97) 1.59 (1.05-2.37) 1.76 (1.13-2.67) 3 -hr i L 0.467 (0.387-0.567) 0.545 (0.452-0.663) 0.680 (0.561-0.831) 0.799 (0.654-0.982) 0.971 (0.766-1.26) 1.11 (0.851-1.47) 1.26 (0.923-1.72) 1.41 (0.985-2.00) 1.63 (1.08-2.40) 1.80 (1.16-2.69) L 6 -hr I J 0.587 (0.491-0.705) 0.675 (0.564-0.813) 0.825 (0.686-0.996) 0.954 (0.788-1.16) 1.14 (0.906-1.45) 1.29 (0.995-1.68) 1.44 (1.07-1.94) 1.60 (1.13-2.24) 1.82 (1.23-2.65) 2.00 (1.30-2.95) 12 -hr 0.743 (0.626-0.884) 0.860 (0.724-1.02) 1.06 (0.885-1.26) 1.22 (1.02-1.47) 1.46 (1.17-1.84) 1.65 (1.28-2.12) 1.84 (1.38-2.44) 2.05 (1.46-2.81) 2.32 (1.58-3.31) 2.53 (1.67-3.68) 24 -hr 0.920 (0.781-1.08) 1.06 (0.903-1.25) 1.31 (1.10-1.55) 1.52 (1.27-1.80) 1.82 (1.47-2.26) 2.06 (1.62-2.60) 2.30 (1.74-3.01) 2.56 (1.84-3.47) 2.91 (2.00-4.09) 3.19 (2.12-4.56) 1.10 1.25 1.53 1.77 2.11 2.39 2.68 2.99 3.41 3.75 2 -day (0.938-1.27) (1.07-1.46) (1.30-1.78) (1.49-2.08) (1.72-2.60) (1.90-2.99) (2.05-3.46) (2.17-4.00) (2.37-4.73) (2.52-5.28) 1.19 1.37 1.67 1.93 2.31 2.61 2.93 3.26 3.72 4.09 3 -day (1.03-1.38) (1.18-1.58) (1.43-1.94) (1.64-2.25) (1.90-2.82) (2.09-3.25) (2.25-3.75) (2.39-4.33) (2.60-5.11) (2.77-5.70) 4 -day 1.27 (1.10-1.46) 1.46 (1.26-1.68) 1.78 (1.53-2.06) 2.06 (1.76-2.39) 2.46 (2.03-2.99) 2.78 (2.23-3.43) 3.11 (2.40-3.96) 3.46 (2.54-4.56) 3.94 (2.77-5.37) 4.32 (2.94-5.99) 7 -day 1.49 (1.29-1.69) 1.69 (1.47-1.93) 2.04 (1.77-2.34) 2.35 (2.01-2.70) 2.77 (2.30-3.33) 3.12 (2.52-3.80) 3.47 (2.69-4.36) 3.84 (2.84-4.98) 4.34 (3.08-5.83) 4.73 (3.25-6.46) 10 -day 1.68 (1.46-1.90) 1.89 (1.65-2.15) 2.26 (1.96-2.57) 2.57 (2.22-2.94) 3.01 (2.51-3.58) 3.36 (2.73-4.07) 3.72 (2.90-4.64) 4.09 (3.05-5.27) 4.60 (3.28-6.13) 5.00 (3.46-6.77) 20 -day 2.21 (1.94-2.48) 2.46 (2.16-2.75) 2.86 (2.50-3.22) 3.20 (2.79-3.62) 3.68 (3.09-4.31) 4.05 (3.31-4.83) 4.43 (3.49-5.43) 4.82 (3.62-6.10) 5.34 (3.85-6.97) 5.74 (4.02-7.64) 2.64 2.93 3.40 3.79 4.33 4.74 5.15 5.56 6.11 6.52 30 -day (2.34-2.94) (2.59-3.27) (2.99-3.80) (3.31-4.26) (3.64-5.01) (3.89-5.58) (4.07-6.24) (4.20-6.96) (4.43-7.89) (4.59-8.59) 45 -day 3.19 (2.83-3.52) 3.56 (3.15-3.93) 4.14 (3.66-4.60) 4.62 (4.06-5.15) 5.26 (4.45-6.04) 5.75 (4.74-6.71) 6.22 (4.95-7.46) 6.68 (5.08-8.27) 7.28 (5.31-9.30) 7.72 (5.48-10.1) 60 -day 3.65 (3.25-4.01) 4.10 (3.65-4.51) 4.82 (4.27-5.32) 5.39 (4.75-5.98) 6.15 (5.21-7.00) 6.71 (5.56-7.78) 7.25 (5.79-8.64) 7.78 (5.93-9.55) 8.44 (6.18-10.7) 8.92 (6.36-11.6) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOM Atlas 14 document for more information. Back to Top http://hdsc.nws.noaa.gov/hdsc/pfds/pfds printpage.htmI?lat=39.5646&Ion=-107.7706&data=depth&units=english&series=pds#table 1/4 APPENDIX C Pre -developed Off Site and On Site Hydrology Calculations Subca (B) offsite Reach 1R Lott R onsite west <A> Offsit 2R East cf'hannel 2d L2 drive onsite east Drainage Diagram for Pre -developed Prepared by Bell Consulting LLC 10/25/2018 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Pre -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap Pre 25yr Page 2 10/25/2018 Area Listing (all nodes) Area (acres) CN Description (subcats) 500.000 63 Sagebrush range, Fair, HSG C (A) 1,058.000 73 Pinyon/juniper range, Fair, HSG C (A) 517.230 74 Pasture/grassland/range, Good, HSG C (1-2,2-3,A) 263.000 79 Pasture/grassland/range, Fair, HSG C (B) 7.150 80 Sagebrush range, Poor, HSG C (1-2,2-3) 2,345.380 Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 3 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Time span=10.00-50.00 hrs, dt=0.05 hrs, 801 points Runoff by SCS TR -20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1-2: onsite west Runoff Area=9.340 ac Runoff Depth=0.36" Flow Length=833' Tc=9.6 min CN=77 Runoff=4.43 cfs 0.276 af Subcatchment 2-3: onsite east Runoff Area=15.040 ac Runoff Depth=0.30" Flow Length=1,145' Tc=12.4 min CN=75 Runoff=4.88 cfs 0.372 af Subcatchment A: Offsite A Runoff Area=2,058.000 ac Runoff Depth=0.20" Flow Length=20,364' Tc=35.8 min CN=71 Runoff=165.69 cfs 33.919 af Subcatchment B: offsite B Runoff Area=263.000 ac Runoff Depth=0.42" Flow Length=8,578' Tc=46.4 min CN=79 Runoff=58.44 cfs 9.218 af Reach 1R: Lot1 R Avg. Depth=1.87' Max Vel=3.94 fps Inflow=58.44 cfs 9.218 af n=0.080 L=700.0' S=0.0314 '/' Capacity=507.81 cfs Outflow=58.10 cfs 9.218 af Reach 2R: East channel Avg. Depth=2.26' Max Vel=6.93 fps Inflow=165.69 cfs 33.919 af n=0.050 L=865.0' S=0.0324 '/' Capacity=528.41 cfs Outflow=164.54 cfs 33.919 af Pond 2d: L2 drive Peak EIev=5,556.90' Inflow=164.54 cfs 33.919 af Outflow=164.54 cfs 33.919 af Total Runoff Area = 2,345.380 ac Runoff Volume = 43.784 af Average Runoff Depth = 0.22" 100.00% Pervious Area = 2,345.380 ac 0.00% Impervious Area = 0.000 ac Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 4 HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment 1-2: onsite west 4.43 cfs @ 12.03 hrs, Volume= 0.276 af, Depth= 0.36" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type 11 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 5.090 74 Pasture/grassland/range, Good, HSG C 4.250 80 Sagebrush range, Poor, HSG C 9.340 77 Weighted Average 9.340 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.7 64 0.0625 0.16 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.1 443 0.0770 6.84 34.21 Trap/Vee/Rect Channel Flow, steep Bot.W=1.00' D=1.00' Z= 4.0'/' Top.W=9.00' n= 0.040 Earth, dense weeds 1.8 326 0.0360 3.02 21.13 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.080 Earth, long dense weeds 9.6 833 Total 0 u_ 2- Subcatchment 1-2: onsite west Hydrograph 4 43 cfs Type II 24 -hr 25 -yr Rainfall=1.82" Runoff Area=9.340 ac Runoff Vo(ume=0.276 af Runoff Depth=0.36" Flow Length=833' Tc=9.6 m i n CN=77 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 5 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment 2-3: onsite east 4.88 cfs @ 12.07 hrs, Volume= 0.372 af, Depth= 0.30" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 12.140 74 Pasture/grassland/range, Good, HSG C 2.900 80 Sagebrush range, Poor, HSG C 15.040 75 Weighted Average 15.040 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 85 0.0500 0.15 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.4 474 0.0370 5.47 16.41 Trap/Vee/Rect Channel Flow, ditch Bot.W=1.00' D=1.00' Z= 2.0'/' Top.W=5.00' n= 0.035 Earth, dense weeds 1.8 586 0.0230 5.52 38.61 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.035 Earth, dense weeds 12.4 1,145 Total Subcatchment 2-3: onsite east Hydrograph 4 88 cfs Type II 24 -hr 25 -yr Rainfall=1.82" Runoff Area=15.040 ac Runoff Volume=0.372 af Runoff Depth=0.30" Flow Length^1 ,145' Tc=12. 4 mi n CN=75 10 11 12 13 1'4-15" '16-1'7-18" 61718 '1'9-26-2'1'2'2-2'3" 920212223 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 6 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment A: Offsite A 165.69 cfs @ 12.45 hrs, Volume= 33.919 af, Depth= 0.20" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type 11 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 1,058.000 73 Pinyon/juniper range, Fair, HSG C 500.000 63 Sagebrush range, Fair, HSG C 500.000 74 Pasture/grassland/range, Good, HSG C 2,058.000 71 Weighted Average 2,058.000 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.9 500 0.2000 4.47 Shallow Concentrated Flow, shallow Nearly Bare & Untilled Kv= 10.0 fps 9.0 10,767 0.1480 19.86 715.03 Trap/Vee/Rect Channel Flow, steep channel Bot.W=3.00' D=3.00' Z= 3.0'/' Top.W=21.00' n= 0.040 Earth, cobble bottom, clean sides 24.9 9,097 0.0400 6.08 310.23 Trap/Vee/Rect Channel Flow, flat channel Bot.W=5.00' D=3.00' Z= 4.0 Top.W=29.00' n= 0.070 Sluggish weedy reaches w/pools 35.8 20,364 Total 0 LL 1801 1701 160=' 150=' 140 130 120 110- 100. 1 5.69 10=100_ 90 80=" 70 60=' 50-E 40= 30 20= 10 Subcatchment A: Offsite A Hydrograph 165.69 cfs I/ i I. 0 . . . . . . . . . . . . . . . . . . . . . 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) Type II r 25 -yr Rainfall=1.82" 00 R Area=ac2,058.000 Runoff � 0� . Runoff e 9 un Vols' � 33 1 9 af --, nioff Dept 4 20 R� h ..' Flaw Len 9 th=2 0,364` Tc=358 min CN=71 Runoff Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 7 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Subcatchment B: offsite B Runoff = 58.44 cfs @ 12.52 hrs, Volume= 9.218 af, Depth= 0.42" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 263.000 79 Pasture/grassland/range, Fair, HSG C 263.000 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.8 100 0.1400 24.2 2,270 0.0500 1.6 1,527 0.1200 12.8 4,681 0.0380 0.21 Sheet Flow, Grass: Short n= 0.150 P2= 1.06" 1.57 Shallow Concentrated Flow, shallow Short Grass Pasture Kv= 7.0 fps 16.15 290.63 TrapNee/Rect Channel Flow, steep Bot.W=3.00' D=2.00' Z= 3.0'1' Top.W=15.00' n= 0.035 Earth, dense weeds 6.11 293.37 TrapNee/Rect Channel Flow, flat Bot.W=4.00' D=4.00' Z= 2.0'1' Top.W=20.00' n= 0.080 Earth, long dense weeds 46.4 8,578 Total 65 60 55 50 45 40 u 35 LL 30 25 20 15 10 5 0 Subcatchment B: offsite B Hydrograph 58.44 cfs 1011 IA Type H 24 -hr 25 -yr i 1 Runoffi Runoff Rainfall=1 82 Area=263: QOOac VOlume 9.218 af Runo F Qepth=Q.4 f low Length^8, Th=46..4 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 8 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 1R: Lot1 R Inflow Area = 263.000 ac, Inflow Depth = 0.42" for 25 -yr event Inflow = 58.44 cfs @ 12.52 hrs, Volume= 9.218 of Outflow = 58.10 cfs @ 12.60 hrs, Volume= 9.218 af, Atten= 1%, Lag= 5.1 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 3.94 fps, Min. Travel Time= 3.0 min Avg. Velocity = 1.56 fps, Avg. Travel Time= 7.5 min Peak Storage= 10,336 cf @ 12.55 hrs, Average Depth at Peak Storage= 1.87' Bank -Full Depth= 6.00', Capacity at Bank -Full= 507.81 cfs 6.00' x 6.00' deep channel, n= 0.080 Earth, long dense weeds Side Slope Z -value= 1.0'/' Top Width= 18.00' Length= 700.0' Slope= 0.0314 '1' Inlet Invert= 5,580.00', Outlet Invert= 5,558.00' 65- 60- 55 50 - 45 40- 0 35- c 30 - LL 25 20 15 10 0 Reach 1R: Lot1 R Hydrograph 58.44 cfs 58.10 cfs ���������������� /A:'. papityT n=0.080 L=700.0' 0314 X8-1 cfs 10 11 12 13 14 15 1617 18 19 20 2122 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 3839 40 41 42 4344 45 46 4748 49 50 Time (hours) ■ Inflow ❑ Outflow Dunlap Pre 25yr Pre -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 9 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 2R: East channel Inflow Area = 2,058.000 ac, Inflow Depth = 0.20" for 25 -yr event Inflow = 165.69 cfs @ 12.45 hrs, Volume= 33.919 of Outflow = 164.54 cfs @ 12.51 hrs, Volume= 33.919 af, Atten= 1%, Lag= 3.7 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 6.93 fps, Min. Travel Time= 2.1 min Avg. Velocity = 3.25 fps, Avg. Travel Time= 4.4 min Peak Storage= 20,590 cf @ 12.47 hrs, Average Depth at Peak Storage= 2.26' Bank -Full Depth= 4.00', Capacity at Bank -Full= 528.41 cfs 6.00' x 4.00' deep channel, n= 0.050 Scattered brush, heavy weeds Side Slope Z -value= 2.0'/' Top Width= 22.00' Length= 865.0' Slope= 0.0324 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,552.00' 180 170 160= 150= 140= 130= 120- 110= N o 100 90 0 u_ 80 70= 60 50= 40 30= 20 10= 0 Reach 2R: East channel Hydrograph 165.69 cfs 10 11 12 1314 15 16 17 18 19 20 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 40 41 42 4344 45 46 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Pre -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap Pre 25yr Type 11 24 -hr 25 -yr Rainfall=1.82" Page 10 10/25/2018 Inflow Area = Inflow = Outflow = Primary = Pond 2d: L2 drive 2,058.000 ac, Inflow Depth = 0.20" for 164.54 cfs @ 12.51 hrs, Volume= 164.54 cfs @ 12.51 hrs, Volume= 164.54 cfs @ 12.51 hrs, Volume= 25 -yr event 33.919 af 33.919 af, Atten= 0%, Lag= 0.0 min 33.919 af Routing by Stor-Ind method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 5,556.90' © 12.51 hrs Flood Elev= 5,558.00' Device Routing Invert Outlet Devices #1 Primary 5,552.00' 24.0" x 30.0' long Culvert CMP, end -section conforming to fill, Ke= 0.500 Outlet Invert= 5,551.00' S= 0.0333 '/' Cc= 0.900 n= 0.010 PVC, smooth interior #2 Primary 5,556.00' 60.0' long x 20.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=164.08 cfs @ 12.51 hrs HW=5,556.90' (Free Discharge) t1=Culvert (Inlet Controls 29.86 cfs © 9.50 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 134.22 cfs © 2.50 fps) Pond 2d: L2 drive Hydrograph 80 1 70 60= 50=' 40-E 30= 20=' 10- 00= 90-E 80- 70 = 60- 50= 40= 30= 20 10 0 164.54 cfs 164.54 cfs Inflow Area=2, 58.000 ac PeakEtev=5, 556 90' 10 1112 1314 15 1617 1819 20 2122 2324 25 2627 2829 30 3132 3334 35 3637 3839 40 4142 4344 45 4647 4849 50 Time (hours) ❑ Inflow ❑ Primary Subca (B) offsite Reach 1R Lott R onsite west <A> Offsit 2R East cf'hannel 2d L2 drive onsite east Drainage Diagram for Pre -developed Prepared by Bell Consulting LLC 10/25/2018 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Pre -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap Pre -develop Page 2 10/25/2018 Area Listing (all nodes) Area (acres) CN Description (subcats) 500.000 63 Sagebrush range, Fair, HSG C (A) 1,058.000 73 Pinyon/juniper range, Fair, HSG C (A) 517.230 74 Pasture/grassland/range, Good, HSG C (1-2,2-3,A) 263.000 79 Pasture/grassland/range, Fair, HSG C (B) 7.150 80 Sagebrush range, Poor, HSG C (1-2,2-3) 2,345.380 Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 3 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Time span=10.00-50.00 hrs, dt=0.05 hrs, 801 points Runoff by SCS TR -20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1-2: onsite west Runoff Area=9.340 ac Runoff Depth=0.62" Flow Length=833' Tc=9.6 min CN=77 Runoff=8.41 cfs 0.481 af Subcatchment 2-3: onsite east Runoff Area=15.040 ac Runoff Depth=0.54" Flow Length=1,145' Tc=12.4 min CN=75 Runoff=10.23 cfs 0.673 af Subcatchment A: Offsite A Runoff Area=2,058.000 ac Runoff Depth=0.40" Flow Length=20,364' Tc=35.8 min CN=71 Runoff=449.50 cfs 67.754 af Subcatchment B: offsite B Runoff Area=263.000 ac Runoff Depth=0.71" Flow Length=8,578' Tc=46.4 min CN=79 Runoff=108.20 cfs 15.483 af Reach 1 R: Lot1 R Avg. Depth=2.65' Max Vel=4.69 fps Inflow=108.20 cfs 15.483 af n=0.080 L=700.0' S=0.0314 '1' Capacity=507.81 cfs Outflow=107.61 cfs 15.483 af Reach 2R: East channel Avg. Depth=3.70' Max Vel=9.04 fps Inflow=449.50 cfs 67.754 af n=0.050 L=865.0' S=0.0324 '1' Capacity=528.41 cfs Outflow=446.34 cfs 67.754 af Pond 2d: L2 drive Peak Elev=5,557.90' Inflow=446.34 cfs 67.754 af Outflow=446.34 cfs 67.754 af Total Runoff Area = 2,345.380 ac Runoff Volume = 84.391 af Average Runoff Depth = 0.43" 100.00% Pervious Area = 2,345.380 ac 0.00% Impervious Area = 0.000 ac Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 4 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Subcatchment 1-2: onsite west Runoff = 8.41 cfs @ 12.02 hrs, Volume= 0.481 af, Depth= 0.62" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 5.090 74 Pasture/grassland/range, Good, HSG C 4.250 80 Sagebrush range, Poor, HSG C 9.340 77 Weighted Average 9.340 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.7 64 0.0625 0.16 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.1 443 0.0770 6.84 34.21 Trap/Vee/Rect Channel Flow, steep Bot.W=1.00' D=1.00' Z= 4.0 7' Top.W=9.00' n= 0.040 Earth, dense weeds 1.8 326 0.0360 3.02 21.13 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.080 Earth, long dense weeds 0 9.6 833 Total Subcatchment 1-2: onsite west Hydrograph 8 41 cfs i no 11 4 hr 100 -yr° Rainfa-IIT2.30" 4rea=9 340 ac RrunoVolt unoff Flow 11100.481 of epth-Q.62 Lrengt-h 833' 1c=9:6 -mirth C N=77 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) 0 Runoff r Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 5 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment 2-3: onsite east 10.23 cfs @ 12.06 hrs, Volume= 0.673 af, Depth= 0.54" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 12.140 74 Pasture/grassland/range, Good, HSG C 2.900 80 Sagebrush range, Poor, HSG C 15.040 75 Weighted Average 15.040 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 85 0.0500 0.15 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.4 474 0.0370 5.47 16.41 TrapNee/Rect Channel Flow, ditch Bot.W=1.00' D=1.00' Z= 2.0 '/' Top.W=5.00' n= 0.035 Earth, dense weeds 1.8 586 0.0230 5.52 38.61 TrapNee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0 '/' Top.W=8.00' n= 0.035 Earth, dense weeds 12.4 1,145 Total 0 Subcatchment 2-3: onsite east Hydrograph '1 10.23 cfs Type 11 24- Ru unol no Ru F r 100 -yr 1=2.3 `' ainfal f Area=15.040 ac 1/o me=0.673 af noff Depth=0.54.' low Length^1,145' Tc=12 4 min cN=75 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 6 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment A: Offsite A 449.50 cfs @ 12.39 hrs, Volume= 67.754 af, Depth= 0.40" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 1,058.000 73 Pinyon/juniper range, Fair, HSG C 500.000 63 Sagebrush range, Fair, HSG C 500.000 74 Pasture/grassland/range, Good, HSG C 2,058.000 71 Weighted Average 2,058.000 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.9 500 0.2000 4.47 Shallow Concentrated Flow, shallow Nearly Bare & Untilled Kv= 10.0 fps 9.0 10,767 0.1480 19.86 715.03 Trap/Vee/Rect Channel Flow, steep channel Bot.W=3.00' D=3.00' Z= 3.0'/' Top.W=21.00' n= 0.040 Earth, cobble bottom, clean sides 24.9 9,097 0.0400 6.08 310.23 Trap/Vee/Rect Channel Flow, flat channel Bot.W=5.00' D=3.00' Z= 4.0 Top.W=29.00' n= 0.070 Sluggish weedy reaches w/pools 35.8 20,364 Total Subcatchment A: Offsite A Hydrograph 500/ 449.50 cfs 450= 400- 350- 300- To - 250= 250_ o - 200- 150= 100 50 0 Type II 24 -hr 100 -yr Rainfall=2.30" Runoff Area=2,058.000 ac Runoff Volume=67.754 of Runoff Qepth=0A0'' - lowLength=2 Tc=35 0,364 8 min CN=71 1011 12 1314 1516 1718 1920 2122 23 2425 26 2728 29 3031 3233 34 3536 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 7 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment B: offsite B 108.20 cfs @ 12.49 hrs, Volume= 15.483 af, Depth= 0.71" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 263.000 79 Pasture/grassland/range, Fair, HSG C 263.000 Pervious Area Tc (min) Length Slope Velocity Capacity (feet) (ft/ft) (ft/sec) (cfs) Description 7.8 100 0.1400 0.21 24.2 2,270 0.0500 1.57 1.6 1,527 0.1200 16.15 290.63 12.8 4,681 0.0380 6.11 293.37 Sheet Flow, Grass: Short n= 0.150 P2= 1.06" Shallow Concentrated Flow, shallow Short Grass Pasture Kv= 7.0 fps Trap/Vee/Rect Channel Flow, steep Bot.W=3.00' D=2.00' Z= 3.0'/' Top.W=15.00' n= 0.035 Earth, dense weeds Trap/Vee/Rect Channel Flow, flat Bot.W=4.00' D=4.00' Z= 2.0'/' Top.W=20.00' n= 0.080 Earth, long dense weeds 46.4 8,578 Total 0 LL 12 11 11 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 Subcatchment B: offsite B Hydrograph 5 0, 5_ 0- 5- 0 5_ 0= 5. 0- 5- 0- 5= 0- 5- 0- 5- 0= =5-0-5-0- 5- 0 5- 0 5 108.20 cfs Type II 24 -hr 140 -yr Rainfall=2.30" Runoff Ara 263.000 ac runoff V 5.483 af Runoff Qe h,71" Flow LenT�464i5,7 ' min N=79 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3031 32 33 34 35 36 37 38 39 4041 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 8 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 1R: Lot1 R Inflow Area = 263.000 ac, Inflow Depth = 0.71" for 100 -yr event Inflow = 108.20 cfs @ 12.49 hrs, Volume= 15.483 of Outflow = 107.61 cfs @ 12.56 hrs, Volume= 15.483 af, Atten= 1%, Lag= 4.4 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 4.69 fps, Min. Travel Time= 2.5 min Avg. Velocity = 1.77 fps, Avg. Travel Time= 6.6 min Peak Storage= 16,081 cf @ 12.52 hrs, Average Depth at Peak Storage= 2.65' Bank -Full Depth= 6.00', Capacity at Bank -Full= 507.81 cfs 6.00' x 6.00' deep channel, n= 0.080 Earth, long dense weeds Side Slope Z -value= 1.0'/' Top Width= 18.00' Length= 700.0' Slope= 0.0314 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,558.00' 12 11 10 9i 81 7 0 6i 0 LL 5 Reach 1R: Lot1 R Hydrograph 4, 3, 22 11 r 1 108.20 cfs 107.61 cfs 1 Inflow Area=263.000 ac Avg. Depth+2.65' Marc- Vel=4-.69 fps n=0 080 0.0314 V' Capaci yre507.81 cis 10 11 12 1314 15 16 17 18 19 20 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 40 41 42 4344 45 46 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Dunlap Pre -develop Pre -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 9 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 2R: East channel Inflow Area = 2,058.000 ac, Inflow Depth = 0.40" for 100 -yr event Inflow = 449.50 cfs @ 12.39 hrs, Volume= 67.754 of Outflow = 446.34 cfs @ 12.44 hrs, Volume= 67.754 af, Atten= 1%, Lag= 2.9 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 9.04 fps, Min. Travel Time= 1.6 min Avg. Velocity = 3.86 fps, Avg. Travel Time= 3.7 min Peak Storage= 42,911 cf @ 12.41 hrs, Average Depth at Peak Storage= 3.70' Bank -Full Depth= 4.00', Capacity at Bank -Full= 528.41 cfs 6.00' x 4.00' deep channel, n= 0.050 Scattered brush, heavy weeds Side Slope Z -value= 2.0'/' Top Width= 22.00' Length= 865.0' Slope= 0.0324 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,552.00' 50 45 40 35 30 w 25 0 LL 20 15 10 Reach 2R: East channel Hydrograph 449.50 cfs 446.34 cfs 507 inflow Anea2,058.000 ac Avg Max . bepth=3.70" Vel=9:04 fps rr-8:450, Capacit • 32# '1' 528.41 cfs 10 11 12 1314 15 1617 18 1920 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 4041 42 4344 4546 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Pre -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap Pre -develop Type 11 24 -hr 100 -yr Rainfall=2.30" Page 10 10/25/2018 Inflow Area = Inflow = Outflow = Primary = Pond 2d: L2 drive 2,058.000 ac, Inflow Depth = 0.40" 446.34 cfs © 12.44 hrs, Volume= 446.34 cfs © 12.44 hrs, Volume= 446.34 cfs © 12.44 hrs, Volume= for 100 -yr event 67.754 af 67.754 af, Atten= 0%, Lag= 0.0 min 67.754 af Routing by Stor-Ind method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 5,557.90' © 12.44 hrs Flood Elev= 5,558.00' Device Routing Invert Outlet Devices #1 Primary #2 Primary 5,552.00' 24.0" x 30.0' long Culvert CMP, end -section conforming to fill, Ke= 0.500 Outlet Invert= 5,551.00' S= 0.0333 '/' Cc= 0.900 n= 0.010 PVC, smooth interior 5,556.00' 60.0' long x 20.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=445.14 cfs @ 12.44 hrs HW=5,557.90' (Free Discharge) t1=Culvert (Inlet Controls 33.47 cfs © 10.65 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 411.68 cfs © 3.62 fps) 45 40 35 30 u 25 20 15 10 5 Pond 2d: L2 drive Hydrograph 1 446.34 cfs 446.34 cfs Inflow Area =2,058.000 ac Peak EIev=5,557.90" 10 1112 1314 15 1617 1819 20 2122 2324 25 2627 2829 30 3132 3334 35 3637 3839 40 4142 4344 45 4647 4849 50 Time (hours) ❑ Inflow ❑ Primary APPENDIX D Post -developed Hydrology Calculations /ubca B offsite Reach 1R Lott R and onsite west <A> Offsit 2R East cf'hannel 2d L2 drive onsite east Drainage Diagram for Post -developed Prepared by Bell Consulting LLC 10/25/2018 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 25 -yr Page 2 10/25/2018 Area Listing (all nodes) Area (acres) CN Description (subcats) 500.000 63 Sagebrush range, Fair, HSG C (A) 1,058.000 73 Pinyon/juniper range, Fair, HSG C (A) 517.130 74 Pasture/grassland/range, Good, HSG C (1-2,2-3,A) 263.000 79 Pasture/grassland/range, Fair, HSG C (B) 6.950 80 Sagebrush range, Poor, HSG C (1-2,2-3) 0.300 98 Paved parking & roofs (1-2,2-3) 2,345.380 Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 3 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Time span=10.00-50.00 hrs, dt=0.05 hrs, 801 points Runoff by SCS TR -20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1-2: onsite west Runoff Area=9.340 ac Runoff Depth=0.36" Flow Length=833' Tc=9.6 min CN=77 Runoff=4.43 cfs 0.276 af Subcatchment 2-3: onsite east Runoff Area=15.040 ac Runoff Depth=0.30" Flow Length=1,145' Tc=12.4 min CN=75 Runoff=4.88 cfs 0.372 af Subcatchment A: Offsite A Runoff Area=2,058.000 ac Runoff Depth=0.20" Flow Length=20,364' Tc=35.8 min CN=71 Runoff=165.69 cfs 33.919 af Subcatchment B: offsite B Runoff Area=263.000 ac Runoff Depth=0.42" Flow Length=8,578' Tc=46.4 min CN=79 Runoff=58.44 cfs 9.218 af Reach 1R: Lot1 R Avg. Depth=1.87' Max Vel=3.94 fps Inflow=58.44 cfs 9.218 af n=0.080 L=700.0' S=0.0314 '/' Capacity=507.81 cfs Outflow=58.10 cfs 9.218 af Reach 2R: East channel Avg. Depth=2.26' Max Vel=6.93 fps Inflow=165.69 cfs 33.919 af n=0.050 L=865.0' S=0.0324 '/' Capacity=528.41 cfs Outflow=164.54 cfs 33.919 af Pond 2d: L2 drive Peak EIev=5,556.90' Inflow=164.54 cfs 33.919 af Outflow=164.54 cfs 33.919 af Total Runoff Area = 2,345.380 ac Runoff Volume = 43.784 af Average Runoff Depth = 0.22" 99.99% Pervious Area = 2,345.080 ac 0.01% Impervious Area = 0.300 ac Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 25 -yr Type 11 24 -hr 25 -yr Rainfall=1.82" Page 4 10/25/2018 Runoff Subcatchment 1-2: onsite west = 4.43 cfs @ 12.03 hrs, Volume= 0.276 af, Depth= 0.36" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 5.090 74 Pasture/grassland/range, Good, HSG C 4.150 80 Sagebrush range, Poor, HSG C 0.100 98 Paved parking & roofs 9.340 9.240 0.100 77 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity (min) (feet) (ft/ft) (ft/sec) Capacity Description (cfs) 6.7 64 0.0625 0.16 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.1 443 0.0770 6.84 34.21 Trap/Vee/Rect Channel Flow, steep Bot.W=1.00' D=1.00' Z= 4.0'/' Top.W=9.00' n= 0.040 Earth, dense weeds 1.8 326 0.0360 3.02 21.13 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.080 Earth, long dense weeds 9.6 833 Total Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 5 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 0 Subcatchment 1-2: onsite west Hydrograph ell 24 -hr 25 -yr` Rainfall=1.82" Runoff 4rea=9.340 ac Runoff VoIume=0.276 of Runoff depth=0.36" Flow Length=$33 7c=9.6 min N=77 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 6 HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment 2-3: onsite east = 4.88 cfs @ 12.07 hrs, Volume= 0.372 af, Depth= 0.30" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type 11 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 12.040 74 Pasture/grassland/range, Good, HSG C 2.800 80 Sagebrush range, Poor, HSG C 0.200 98 Paved parking & roofs 15.040 75 Weighted Average 14.840 Pervious Area 0.200 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 85 0.0500 0.15 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.4 474 0.0370 5.47 16.41 Trap/Vee/Rect Channel Flow, ditch Bot.W=1.00' D=1.00' Z= 2.0'/' Top.W=5.00' n= 0.035 Earth, dense weeds 1.8 586 0.0230 5.52 38.61 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.035 Earth, dense weeds 12.4 1,145 Total Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 7 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 0 LL 0 Subcatchment 2-3: onsite east Hydrograph 48 Type 1124 -hr 25 -yr Rai nfal 11.82" Runoff Area=15.040 ac Runoff Volume=0.372 of Runoff Depth=0.30" Flow Len th^1,145 12.4 mi c= n CN=75 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 25 -yr Type 11 24 -hr 25 -yr Rainfall=1.82" Page 8 10/25/2018 Runoff Subcatchment A: Offsite A 165.69 cfs @ 12.45 hrs, Volume= 33.919 af, Depth= 0.20" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type 11 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 1,058.000 500.000 500.000 73 Pinyon/juniper range, Fair, HSG C 63 Sagebrush range, Fair, HSG C 74 Pasture/grassland/range, Good, HSG C 2,058.000 71 Weighted Average 2,058.000 Pervious Area Tc (min) Length Slope Velocity Capacity (feet) (ft/ft) (ft/sec) (cfs) Description 1.9 500 0.2000 4.47 Shallow Concentrated Flow, shallow Nearly Bare & Untilled Kv= 10.0 fps 9.0 10,767 0.1480 19.86 715.03 Trap/Vee/Rect Channel Flow, steep channel Bot.W=3.00' D=3.00' Z= 3.0'/' Top.W=21.00' n= 0.040 Earth, cobble bottom, clean sides 6.08 310.23 Trap/Vee/Rect Channel Flow, flat channel Bot.W=5.00' D=3.00' Z= 4.0'/' Top.W=29.00' n= 0.070 Sluggish weedy reaches w/pools 24.9 9,097 0.0400 35.8 20,364 Total 0 LL 1801 1701 160-1 150-1 140 130 120 110- 100. 1 5.69 10=100_ 90 80=" 70 60-1 50-1 40= 30 20= 10 Subcatchment A: Offsite A Hydrograph 165.69 cfs I/ i I. 0 . . . . . . . . . . . . . . . . . . . . . 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) Type II r 25 -yr Rainfall=1.82" 00 R Area=ac2,058.000 Runoff � 0� . Runoff e 9 un Vols' � 33 1 9 af --, nioff Dept 4.20 R� h ..' Flaw Len 9 th=2 0,364` Tc=358 min CN=71 Runoff Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 9 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Subcatchment B: offsite B Runoff = 58.44 cfs @ 12.52 hrs, Volume= 9.218 af, Depth= 0.42" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 25 -yr Rainfall=1.82" Area (ac) CN Description 263.000 79 Pasture/grassland/range, Fair, HSG C 263.000 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.8 100 0.1400 24.2 2,270 0.0500 1.6 1,527 0.1200 12.8 4,681 0.0380 0.21 Sheet Flow, Grass: Short n= 0.150 P2= 1.06" 1.57 Shallow Concentrated Flow, shallow Short Grass Pasture Kv= 7.0 fps 16.15 290.63 TrapNee/Rect Channel Flow, steep Bot.W=3.00' D=2.00' Z= 3.0'1' Top.W=15.00' n= 0.035 Earth, dense weeds 6.11 293.37 TrapNee/Rect Channel Flow, flat Bot.W=4.00' D=4.00' Z= 2.0'1' Top.W=20.00' n= 0.080 Earth, long dense weeds 46.4 8,578 Total 65 60 55 50 45 40 u 35 LL 30 25 20 15 10 5 0 Subcatchment B: offsite B Hydrograph 58.44 cfs 1011 IA Type H 24 -hr 25 -yr i 1 Runoffi Runoff Rainfall=1 82 Area=263: QOOac VOlume 9.218 af Runo F Qepth=Q.4 f low Length^8, Th=46..4 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 10 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 1R: Lot1 R Inflow Area = 263.000 ac, Inflow Depth = 0.42" for 25 -yr event Inflow = 58.44 cfs @ 12.52 hrs, Volume= 9.218 of Outflow = 58.10 cfs @ 12.60 hrs, Volume= 9.218 af, Atten= 1%, Lag= 5.1 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 3.94 fps, Min. Travel Time= 3.0 min Avg. Velocity = 1.56 fps, Avg. Travel Time= 7.5 min Peak Storage= 10,336 cf @ 12.55 hrs, Average Depth at Peak Storage= 1.87' Bank -Full Depth= 6.00', Capacity at Bank -Full= 507.81 cfs 6.00' x 6.00' deep channel, n= 0.080 Earth, long dense weeds Side Slope Z -value= 1.0'/' Top Width= 18.00' Length= 700.0' Slope= 0.0314 '1' Inlet Invert= 5,580.00', Outlet Invert= 5,558.00' 65- 60- 55 50 - 45 40- 0 35- 30- E 25 20 15 10 0 Reach 1R: Lot1 R Hydrograph 58.44 cfs 58.10 cfs ���������������� /A:'. papityT n=0.080 L=700.0' 0314 X8-1 cfs 10 11 1213 14 15 1617 18 19 20 2122 23 24 2526 27 28 29 30 31 32 33 34 35 36 37 3839 40 41 42 4344 45 46 4748 49 50 Time (hours) ■ Inflow ❑ Outflow Dunlap post 25 -yr Post -developed Type 11 24 -hr 25 -yr Rainfall=1.82" Prepared by Bell Consulting LLC Page 11 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 2R: East channel Inflow Area = 2,058.000 ac, Inflow Depth = 0.20" for 25 -yr event Inflow = 165.69 cfs @ 12.45 hrs, Volume= 33.919 of Outflow = 164.54 cfs @ 12.51 hrs, Volume= 33.919 af, Atten= 1%, Lag= 3.7 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 6.93 fps, Min. Travel Time= 2.1 min Avg. Velocity = 3.25 fps, Avg. Travel Time= 4.4 min Peak Storage= 20,590 cf @ 12.47 hrs, Average Depth at Peak Storage= 2.26' Bank -Full Depth= 4.00', Capacity at Bank -Full= 528.41 cfs 6.00' x 4.00' deep channel, n= 0.050 Scattered brush, heavy weeds Side Slope Z -value= 2.0'/' Top Width= 22.00' Length= 865.0' Slope= 0.0324 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,552.00' 180 170 160= 150= 140= 130= 120- 110= N o 100 90 0 u_ 80 70= 60 50= 40 30= 20 10= 0 Reach 2R: East channel Hydrograph 165.69 cfs 10 11 12 1314 15 16 17 18 19 20 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 40 41 42 4344 45 46 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 25 -yr Type 11 24 -hr 25 -yr Rainfall=1.82" Page 12 10/25/2018 Inflow Area = Inflow = Outflow = Primary = Pond 2d: L2 drive 2,058.000 ac, Inflow Depth = 0.20" for 164.54 cfs @ 12.51 hrs, Volume= 164.54 cfs @ 12.51 hrs, Volume= 164.54 cfs @ 12.51 hrs, Volume= 25 -yr event 33.919 af 33.919 af, Atten= 0%, Lag= 0.0 min 33.919 af Routing by Stor-Ind method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 5,556.90' © 12.51 hrs Flood Elev= 5,558.00' Device Routing Invert Outlet Devices #1 Primary 5,552.00' 24.0" x 30.0' long Culvert CMP, end -section conforming to fill, Ke= 0.500 Outlet Invert= 5,551.00' S= 0.0333 '/' Cc= 0.900 n= 0.010 PVC, smooth interior #2 Primary 5,556.00' 60.0' long x 20.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=164.08 cfs @ 12.51 hrs HW=5,556.90' (Free Discharge) t1=Culvert (Inlet Controls 29.86 cfs © 9.50 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 134.22 cfs © 2.50 fps) 0 LL Pond 2d: L2 drive Hydrograph 80 i 701 0(' 50_" / 40 =" 20 _ 111, 90" : li _ .. i i 80" 70: 50-' 40_' 40,,,_ 44 1/� 164.54 cfs 164.54 cfs Inflow Area=2, 58.000 ac PeakEtev=5, 556 90' :=p _ 0 illrfil�ilii�/i 10 1112 1314 15 1617 1819 20 2122 2324 25 2627 2829 30 3132 3334 35 3637 3839 40 4142 4344 45 4647 4849 50 Time (hours) ❑ Inflow ❑ Primary /ubca B offsite Reach 1R Lott R and onsite west <A> Offsit 2R East cf'hannel 2d L2 drive onsite east Drainage Diagram for Post -developed Prepared by Bell Consulting LLC 10/25/2018 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 100 -yr Page 2 10/25/2018 Area Listing (all nodes) Area (acres) CN Description (subcats) 500.000 63 Sagebrush range, Fair, HSG C (A) 1,058.000 73 Pinyon/juniper range, Fair, HSG C (A) 517.130 74 Pasture/grassland/range, Good, HSG C (1-2,2-3,A) 263.000 79 Pasture/grassland/range, Fair, HSG C (B) 6.950 80 Sagebrush range, Poor, HSG C (1-2,2-3) 0.300 98 Paved parking & roofs (1-2,2-3) 2,345.380 Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 3 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Time span=10.00-50.00 hrs, dt=0.05 hrs, 801 points Runoff by SCS TR -20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1-2: onsite west Runoff Area=9.340 ac Runoff Depth=0.62" Flow Length=833' Tc=9.6 min CN=77 Runoff=8.41 cfs 0.481 af Subcatchment 2-3: onsite east Runoff Area=15.040 ac Runoff Depth=0.54" Flow Length=1,145' Tc=12.4 min CN=75 Runoff=10.23 cfs 0.673 af Subcatchment A: Offsite A Runoff Area=2,058.000 ac Runoff Depth=0.40" Flow Length=20,364' Tc=35.8 min CN=71 Runoff=449.50 cfs 67.754 af Subcatchment B: offsite B Runoff Area=263.000 ac Runoff Depth=0.71" Flow Length=8,578' Tc=46.4 min CN=79 Runoff=108.20 cfs 15.483 af Reach 1R: Lot1 R Avg. Depth=2.65' Max Vel=4.69 fps Inflow=108.20 cfs 15.483 af n=0.080 L=700.0' S=0.0314 '/' Capacity=507.81 cfs Outflow=107.61 cfs 15.483 af Reach 2R: East channel Avg. Depth=3.70' Max Vel=9.04 fps Inflow=449.50 cfs 67.754 af n=0.050 L=865.0' S=0.0324 '/' Capacity=528.41 cfs Outflow=446.34 cfs 67.754 af Pond 2d: L2 drive Peak EIev=5,557.90' Inflow=446.34 cfs 67.754 af Outflow=446.34 cfs 67.754 af Total Runoff Area = 2,345.380 ac Runoff Volume = 84.391 af Average Runoff Depth = 0.43" 99.99% Pervious Area = 2,345.080 ac 0.01% Impervious Area = 0.300 ac Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 100 -yr Type 11 24 -hr 100 -yr Rainfall=2.30" Page 4 10/25/2018 Runoff Subcatchment 1-2: onsite west = 8.41 cfs @ 12.02 hrs, Volume= 0.481 af, Depth= 0.62" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 5.090 74 Pasture/grassland/range, Good, HSG C 4.150 80 Sagebrush range, Poor, HSG C 0.100 98 Paved parking & roofs 9.340 9.240 0.100 77 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity (min) (feet) (ft/ft) (ft/sec) Capacity Description (cfs) 6.7 64 0.0625 0.16 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.1 443 0.0770 6.84 34.21 Trap/Vee/Rect Channel Flow, steep Bot.W=1.00' D=1.00' Z= 4.0'/' Top.W=9.00' n= 0.040 Earth, dense weeds 1.8 326 0.0360 3.02 21.13 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.080 Earth, long dense weeds 9.6 833 Total Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 5 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 0 u_ 4- 0 Subcatchment 1-2: onsite west Hydrograph i 1 Type 1124-hr100-yr Rainfa-I,IT2.30" Ru noff Area=9.340 ac Runoff Volume=q. 481 of unoff Flow e p Lrength=833 Tc=9.6 c 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 6 HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment 2-3: onsite east = 10.23 cfs @ 12.06 hrs, Volume= 0.673 af, Depth= 0.54" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 12.040 74 Pasture/grassland/range, Good, HSG C 2.800 80 Sagebrush range, Poor, HSG C 0.200 98 Paved parking & roofs 15.040 75 Weighted Average 14.840 Pervious Area 0.200 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 85 0.0500 0.15 Sheet Flow, sheet Range n= 0.130 P2= 1.06" 1.4 474 0.0370 5.47 16.41 Trap/Vee/Rect Channel Flow, ditch Bot.W=1.00' D=1.00' Z= 2.0'/' Top.W=5.00' n= 0.035 Earth, dense weeds 1.8 586 0.0230 5.52 38.61 Trap/Vee/Rect Channel Flow, flat Bot.W=6.00' D=1.00' Z= 1.0'/' Top.W=8.00' n= 0.035 Earth, dense weeds 12.4 1,145 Total Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 7 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Subcatchment 2-3: onsite east Hydrograph 11 10.23 cfs w = 6- 0 U. 5- 0 e 11 r 100 -yr 1=2.3n" ainfal u uno orea=� 5.u4u ac olume=q.673 of Runoff Depth ----=Q 54" Flow Liength^1i'45, 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ■ Runoff Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 100 -yr Type 11 24 -hr 100 -yr Rainfall=2.30" Page 8 10/25/2018 Runoff Subcatchment A: Offsite A 449.50 cfs @ 12.39 hrs, Volume= 67.754 af, Depth= 0.40" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 1,058.000 500.000 500.000 73 Pinyon/juniper range, Fair, HSG C 63 Sagebrush range, Fair, HSG C 74 Pasture/grassland/range, Good, HSG C 2,058.000 71 Weighted Average 2,058.000 Pervious Area Tc (min) Length Slope Velocity Capacity (feet) (ft/ft) (ft/sec) (cfs) Description 1.9 500 0.2000 4.47 9.0 10,767 0.1480 19.86 715.03 24.9 9,097 0.0400 6.08 310.23 Shallow Concentrated Flow, shallow Nearly Bare & Untilled Kv= 10.0 fps Trap/Vee/Rect Channel Flow, steep channel Bot.W=3.00' D=3.00' Z= 3.0'/' Top.W=21.00' n= 0.040 Earth, cobble bottom, clean sides Trap/Vee/Rect Channel Flow, flat channel Bot.W=5.00' D=3.00' Z= 4.0 Top.W=29.00' n= 0.070 Sluggish weedy reaches w/pools 35.8 20,364 Total 500 450 400- 350- 4 9.50 00_350- Subcatchment A: Offsite A Hydrograph 449.50 cfs 300- w 250= 200- 150- 100' 50 0 1011 12 1314 1516 1718 1920 2122 23 2425 26 2728 29 3031 3233 34 3536 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) Type II 24 -hr 100 -yr Rainfall=2.30" Runoff Area=2,058.000 ac Runoff Volume=67.754 of Runoff Depth 0A01 -- lowLength=2 Tc=35 0,364 min C 71 ❑ Runoff Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 9 HydroCAD® 8.00 sin 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Runoff Subcatchment B: offsite B 108.20 cfs @ 12.49 hrs, Volume= 15.483 af, Depth= 0.71" Runoff by SCS TR -20 method, UH=SCS, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Type 11 24 -hr 100 -yr Rainfall=2.30" Area (ac) CN Description 263.000 79 Pasture/grassland/range, Fair, HSG C 263.000 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.8 100 0.1400 0.21 Sheet Flow, Grass: Short n= 0.150 P2= 1.06" 24.2 2,270 0.0500 1.57 Shallow Concentrated Flow, shallow Short Grass Pasture Kv= 7.0 fps 1.6 1,527 0.1200 16.15 290.63 Trap/Vee/Rect Channel Flow, steep Bot.W=3.00' D=2.00' Z= 3.0'/' Top.W=15.00' n= 0.035 Earth, dense weeds 12.8 4,681 0.0380 6.11 293.37 Trap/Vee/Rect Channel Flow, flat Bot.W=4.00' D=4.00' Z= 2.0'/' Top.W=20.00' n= 0.080 Earth, long dense weeds 46.4 8,578 Total 0 LL 12 11 11 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 Subcatchment B: offsite B Hydrograph 5 0, 5_ 0- 5- 0 5_ 0= 5. 0- 5- 0- 0- 5- 0- 5- 0= -5-0-0=5-0-5-0- 5- 0 5- 0 5 108.20 cfs Type II 24 -hr 140 -yr Rainfall=2.30" Runoff Ara 263.000 ac runoff V 5.483 af Runoff Qe h,71" Flow LenT�464i5,7 ' min N=79 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Time (hours) ❑ Runoff Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 10 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 1R: Lot1 R Inflow Area = 263.000 ac, Inflow Depth = 0.71" for 100 -yr event Inflow = 108.20 cfs @ 12.49 hrs, Volume= 15.483 of Outflow = 107.61 cfs @ 12.56 hrs, Volume= 15.483 af, Atten= 1%, Lag= 4.4 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 4.69 fps, Min. Travel Time= 2.5 min Avg. Velocity = 1.77 fps, Avg. Travel Time= 6.6 min Peak Storage= 16,081 cf @ 12.52 hrs, Average Depth at Peak Storage= 2.65' Bank -Full Depth= 6.00', Capacity at Bank -Full= 507.81 cfs 6.00' x 6.00' deep channel, n= 0.080 Earth, long dense weeds Side Slope Z -value= 1.0'/' Top Width= 18.00' Length= 700.0' Slope= 0.0314 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,558.00' 12 11 10 9i 81 7 0 6i 0 LL 5 Reach 1R: Lot1 R Hydrograph 4, 3, 22 11 r 1 108.20 cfs 107.61 cfs 1 Inflow Area=263.000 ac Avg. Dept -h+2.65' Marc- Vel=4-.69 fps n=0 080 1_,= 0.Q 0.0314 V' Capaci yre507.81 cis 10 11 12 1314 15 16 17 18 19 20 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 40 41 42 4344 45 46 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Dunlap post 100 -yr Post -developed Type 11 24 -hr 100 -yr Rainfall=2.30" Prepared by Bell Consulting LLC Page 11 HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC 10/25/2018 Reach 2R: East channel Inflow Area = 2,058.000 ac, Inflow Depth = 0.40" for 100 -yr event Inflow = 449.50 cfs @ 12.39 hrs, Volume= 67.754 of Outflow = 446.34 cfs @ 12.44 hrs, Volume= 67.754 af, Atten= 1%, Lag= 2.9 min Routing by Stor-Ind+Trans method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 9.04 fps, Min. Travel Time= 1.6 min Avg. Velocity = 3.86 fps, Avg. Travel Time= 3.7 min Peak Storage= 42,911 cf @ 12.41 hrs, Average Depth at Peak Storage= 3.70' Bank -Full Depth= 4.00', Capacity at Bank -Full= 528.41 cfs 6.00' x 4.00' deep channel, n= 0.050 Scattered brush, heavy weeds Side Slope Z -value= 2.0'/' Top Width= 22.00' Length= 865.0' Slope= 0.0324 '/' Inlet Invert= 5,580.00', Outlet Invert= 5,552.00' 50 45 40 35 30 w 25 0 LL 20 15 10 Reach 2R: East channel Hydrograph 449.50 cfs 446.34 cfs 507 inflow Anea2,058.000 ac Avg Max . bepth=3.70" Vel=9:04 fps rr-8:450, Capacit • 32# '1' 528.41 cfs 10 11 12 1314 15 1617 18 1920 21 2223 2425 26 2728 2930 31 3233 34 35 36 37 38 39 4041 42 4344 4546 47 4849 50 Time (hours) ■ Inflow ❑ Outflow Post -developed Prepared by Bell Consulting LLC HydroCAD® 8.00 s/n 005531 © 2006 HydroCAD Software Solutions LLC Dunlap post 100 -yr Type 11 24 -hr 100 -yr Rainfall=2.30" Page 12 10/25/2018 Inflow Area = Inflow = Outflow = Primary = Pond 2d: L2 drive 2,058.000 ac, Inflow Depth = 0.40" 446.34 cfs © 12.44 hrs, Volume= 446.34 cfs © 12.44 hrs, Volume= 446.34 cfs © 12.44 hrs, Volume= for 100 -yr event 67.754 af 67.754 af, Atten= 0%, Lag= 0.0 min 67.754 af Routing by Stor-Ind method, Time Span= 10.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 5,557.90' © 12.44 hrs Flood Elev= 5,558.00' Device Routing Invert Outlet Devices #1 Primary #2 Primary 5,552.00' 24.0" x 30.0' long Culvert CMP, end -section conforming to fill, Ke= 0.500 Outlet Invert= 5,551.00' S= 0.0333 '/' Cc= 0.900 n= 0.010 PVC, smooth interior 5,556.00' 60.0' long x 20.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=445.14 cfs @ 12.44 hrs HW=5,557.90' (Free Discharge) t1=Culvert (Inlet Controls 33.47 cfs © 10.65 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 411.68 cfs © 3.62 fps) 45 40 35 30 u 25 20 15 10 5 Pond 2d: L2 drive Hydrograph 1 446.34 cfs 446.34 cfs Inflow Area =2,058.000 ac Peak EIev=5,557.90" 10 1112 1314 15 1617 1819 20 2122 2324 25 2627 2829 30 3132 3334 35 3637 3839 40 4142 4344 45 4647 4849 50 Time (hours) ❑ Inflow ❑ Primary