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HomeMy WebLinkAboutWPO201700028 Calculations 2018-03-12 HYLAND PARK STORMWATER MANAGEMENT CALCULATIONS PACKET Date of Calculations MARCH 2, 2017 Revised September 20, 2017 APPROVED by the Albemarle County Community Development Department Date v3/izf i8 Fde v/PO LO/ 77o0o z$ PREPARED BY: COLLINS ENGINEERING 200 GARRETT STREET, SUITE K CHARLOTTESVILLE, VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com DEQ Virginia Runoff Reduction Method Water Quality Calculations Virginia Runoff Reduction Method Worksheet DEQ Virginia Runoff Reduction Method New Development Compliance Spreadsheet -Version 3.0 BMP Design Specifications List: 2011 Stds&Specs Site Summary Total Rainfall=43 inches Site Land Cover Summary A soils B Soils C Soils D Soils Totals %of Total Forest/Open(acres) 0.00 1.31 0.00 0.00 1.31 8 Managed Turf(acres) 0.00 10.69 0.00 0.00 10.69 65 Impervious Cover(acres) 0.00 4.38 0.00 0.00 4.38 27 16.38 100 Site Tv and Land Cover Nutrient Loads Site Rv 0.39 Treatment Volume(ft3) 23,008 TP Load(Ib/yr) 14.46 TN Load(Ib/yr) 103.42 Total TP Load Reduction Required(Ib/yr) 7.74 Site Compliance Summary Total Runoff Volume Reduction(ft3) 0 Total TP Load Reduction Achieved(Ib/yr) 0.00 Total TN Load Reduction Achieved(Ib/yr) 0.00 Remaining Post Development TP Load (Ib/yr) 14.46 Remaining TP Load Reduction(Ib/yr) 7.74 Required Summary Print 15 0 0 o S « o 0 H o 0 0 0 F o 0 v t W O O O Q S -6 O O O O O Q p G 0 0 O 0 O O CT: `o Z' O o O E ▪ O O O S Q 0 0 C O O O O C O O N 5 Q o 0 0 S Q O 0 0 0 0 0 0 0 0 0 co Q o 0 o S Q o 0 p o 0 0 0 6 0 0 Q• o 0 o S Q o o0 O 06 0 0 o d d to VI E N V C A � E — E O a a V1 ` lJ f 01 "e a : y w "0., o Q a _° Q y v a) la. a! z a Z a c -am _ A J W C C T fp J 4.2 2 E F 0 F f SCS TR-55 Calculations U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 2:Runoff Curve Number and Runoff Project: Hyland Park Designed By:KKW,PE Date: 9/14/2017 Location: Fontana Drive,Charlottesville,VA Checked By:SRC,PE Date: 9/14/2017 1.Runoff curve Number(CN) Soil name and Cover description(Cover type,treatment,and hydrologic CN(weighted)= Drainage Area Area Product of CN Calculated hydrologic group condition;percent impervious;unconnected/connected CN total product/ Description (Acres) x Area 'S'Value (Appendix A) impervious area ratio) total area DA'A' Impervious Areas 98 0.11 10.5 B Woods in Good Condition 55 4.45 244.6 56 7.75 (Present) Lawns in Good Condition 61 0.30 18.3 Impervious Areas 98 0.00 0.0 DA'B' B Woods in Good Condition 55 2.07 113.9 55 8.15 (Present) Lawns in Good Condition 61 0.03 2.0 DA'A' Impervious Areas 98 2.03 198.9 B Woods in Good Condition 55 0.00 0.0 76 3.07 (Developed) Lawns in Good Condition 61 2.82 172.0 DA'B' Impervious Areas 98 1.17 114.2 (Developed) B Woods in Good Condition 55 0.00 0.0 82 2.26 Lawns in Good Condition 61 0.93 57.0 2.Runoff 1-Year Storm 2-Year Storm 10-Year Storm Drainage Area Description Frequency-years 1 2 10 n/a Rainfall,P(24 hour)-inches 3.5 3.7 5.6 n/a Runoff,Q-inches 0.39 0.47 1.39 DA'A'(Present) Runoff,Q-inches 0.35 0.42 1.30 DA'B'(Present) Runoff,Q-inches 1.40 1.55 3.08 DA'A'(Developed) Runoff,Q-inches 1.75 1.91 3.57 DA'B'(Developed) U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 3:Time of Concentration(T,)or Travel Time(Tt) Project: Hyland Park Designed By: KKW,PE Date: 9/14/2017 Location: Fontana Drive,Charlottesville,VA Checked By: SRC,PE Date: 9/14/2017 Check One: Present X Developed X Check One: I, X Tt DA'A' DA'B' DA'A' DA'B' Segment ID: (Present) (Present) (Developed) (Developed) Sheet Flow:(Applicable to T,only) Woods Light Woods Light 1 Surface description(Table 3-1) Underbrush Underbrush Dense Grass Dense Grass 2 Manning's roughness coeff.,n(Table 3-1 0.4 0.4 0.24 0.24 3 Flow length,L(total L<100)(ft) 100 100 100 95 4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 3.7 3.7 5 Land slope,s(ft/ft) 0.09 0.09 0.09 0.05 6 Compute Tt=[0.007(n*L)08)/p2.5 s°4 0.18 0.18 0.12 0.14 Shallow Concentrated Flow: 7 Surface description(paved or unpaved) Unpaved Unpaved Unpaved Paved 8 Flow Length,L(ft) 380 190 209 126 9 Watercourse slope,s(ft/ft) 0.15 0.12 0.04 0.04 10 Average velocity,V(Figure 3-1)(ft/s) 6.3 5.6 3.2 4 11 Tt=L/3600*V 0.02 0.01 0.02 0.01 Channel Flow: 12 Cross sectional flow area,a(ft2) v sr 0 15 13 Wetted perimeter,Pw(ft) o 0 14 Hydraulic radius,r=a/Pw(ft) a a > a > a 15 Channel Slope,s(ft/ft) z z m m ro 16 Manning's Roughness Coeff,n m fa 17 V=[1.49r2/3ss]/n J J 0 N 18 Flow length,L(ft) `Lnn iD 19 Tt=L/3600*V 0.00 0.00 0.04 0.01 20 Watershed or subarea T,or Tt (Add Tt in steps 6,11 and 19) 0.20 0.19 0.18 0.17 Note:Tc of 0.10 hours is the most conservative SCS TR-55 time of concentration U.S.Department of Agriculture Natural Resources Conservation Service TR 55 Worksheet 4:Graphical Peak Discharge Method Project: Hyland Park Designed By: KKW,PE Location: Fontana Drive,Charlottesville,VA Checked By:SRC,PE Check One: Present X Developed X Drainage Area 1.Data Description Drainage Area Description Drainage Area Description Drainage Area Description DA'A' DA'B' DA'A' DA'B' (Present) (Present) (Developed) (Developed) Drainage Area(Am)in miles2= 0.0076 0.0033 0.0076 0.0033 Runoff curve number CN= 56.3 55.1 76.5 81.5 Time of concentration(Tc)= 0.20 0.19 0.18 0.17 Rainfall distribution type= II II II II Pond and swamp areas spread 0 0 0 0 throughout the watershed= 2.Frequency-years 1 2 10 1 2 10 1 2 10 1 2 10 3.Rainfall,P(24 hour)-inches 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 4.Initial Abstraction,la-inches 1.551 1.551 1.551 1.630 1.630 1.630 0.615 0.615 0.615 0.453 0.453 0.453 5.Compute la/P 0.44 0.42 0.28 0.47 0.44 0.29 0.18 0.17 0.11 0.13 0.12 0.08 6.Unit peak discharge,Qu-csm/in 510 530 740 450 525 755 - - - - - - 7.Runoff,Q from Worksheet 2-inches 0.39 0.47 1.39 0.35 0.42 1.30 1.40 1.55 3.08 1.75 1.91 3.57 8.Pond and Swamp adjustment factor,Fp 1 1 1 1 1 1 1 1 1 1 1 1 9.Peak Discharge,Qp-cfs Routed through SWM Routed through SWM where Qp=Qu Am Q Fp 1.51 1.87 7.80 0.52 0.72 3.23 Facility Facility Note:Qu of 1000 csm/inch is the most conservative SCS TR-55 Qu. Watershed Summary Pre-Development Post-Development DA'A' 4.85 ac. 4.85 ac. • DA'B' 2.10 ac. 2.10 ac. Total= 6.96 ac. 6.95 ac. Outflow Summary: (2-Year Storm Event) Pre-Development Post-Development DA'A' 1.87 cfs 1.78 cfs DA'B' 0.72 cfs 0.55 cfs Total= 2.60 cfs 2.33 cfs Outflow Summary: (10-Year Storm Event) Pre-Development Post-Development DA'A' 7.80 cfs 6.94 cfs DA'B' 3.23 cfs 1.39 cfs Total= 11.02 cfs 8.33 cfs Soils Mapping (Source: NRCS Web Soil Survey Online Database) 3 Soil Map—Albemarle County,Virginia N k 724600 7247C0 724800 724900 725000 725100 725203 725300 725400 725500 725600 38°2'25"N - -.. • —IMF!, I -- I -_ R 38°2'25"N •1" v 1 S v s" -.41111W POD '♦ 71 B 5. + f9B 71Clit 71D t 1(,� ' • 1 71D \ `r e 8 1;11';• . ' /.' : 118§47,411 ' , 5- . vAdliiii . , „ --,It ,A, 40. . 79B 72B3 �. 71E N.. 1,0 ‘141111114H ?7' PO Fit_ ..- , •-• ;i.e.:,e... ... . .t,„ • ••,,i,, : ..,,......,. .. -.......,, •, \ r +�� % z ti 796 • . Y�+ �� • j'. . r. ?�. 4 ° .772B3 '� ;Ts ^ '` � " — + � o it p ` r� � I'o � ► a. 38°2'3"N ivN ,.[' -_ . / 38°2'3"N at 724000 724700 724800 724900 725000 725100 725200 725.300 725400 725500 725600 3 3 Map Scale:1:4,840 if printed on A landscape(11"x 8.5")sl net. Meters 'k N 0 50 100 200 300 Feet A 0 200 400 800 1200 Map projection:Web Mercator Corner coo dinates:WGSS4 Edge tics:UTM Zane 17N WG584 USDA Natural Resources Web Soil Survey 2/27/2017 Conservation Service National Cooperative Soil Survey Page 1 of 3 Soil Map—Albemarle County,Virginia MAP LEGEND MAP INFORMATION Area of Interest(AOI) E4 Spoil Area The soil surveys that comprise your AOI were mapped at Area of Interest(AOI) 1:15,800. 6, Stony Spot Soils Very Stony Spot Warning:Soil Map may not be valid at this scale. Soil Map Unit Polygons dq Wet Spot Enlargement of maps beyond the scale of mapping can cause Soil Map Unit Lines " misunderstanding of the detail of mapping and accuracy of soil A Other line placement.The maps do not show the small areas of 0 Soil Map Unit Points Special Line Features contrasting soils that could have been shown at a more detailed Special Point Features scale. V Blowout Water Features Streams and Canals Please rely on the bar scale on each map sheet for map Borrow Pit measurements. Transportation X Clay Spot Rails Source of Map: Natural Resources Conservation Service H-r Closed Depression Web Soil Survey URL: ,..o Interstate Highways Coordinate System: Web Mercator(EPSG:3857) v Gravel Pit US Routes Maps from the Web Soil Survey are based on the Web Mercator Gravelly Spot Major Roads projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the • Landfill Local Roads Albers equal-area conic projection,should be used if more Lava Flow accurate calculations of distance or area are required. Background tom, Marsh or swamp . Aerial Photography This product is generated from the USDA-NRCS certified data as of the version date(s)listed below. .k Mine or Quarry Soil Survey Area: Albemarle County,Virginia © Miscellaneous Water Survey Area Data: Version 10,Dec 11,2013 O Perennial Water Soil map units are labeled(as space allows)for map scales Rock Outcrop 1:50,000 or larger. + Saline Spot Date(s)aerial images were photographed: May 9,2011—Jun 4, 2011 Sandy Spot • • The orthophoto or other base map on which the soil lines were 4g Severely Eroded Spot compiled and digitized probably differs from the background imagery displayed on these maps.As a result,some minor Sinkhole shifting of map unit boundaries may be evident. 3, Slide or Slip Sodic Spot USDA Natural Resources Web Soil Survey 2/27/2017 Conservation Service National Cooperative Soil Survey Page 2 of 3 Soil Map—Albemarle County,Virginia Map Unit Legend Albemarle County,Virginia(VA003) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 71B Rabun clay loam,2 to 7 19.9 18.7% percent slopes 71C Rabun day loam,7 to 15 20.6 19.4% percent slopes 71D Rabun clay loam, 15 to 25 21.3 20.0% percent slopes 71E Rabun day loam,25 to 45 16.9 15.8% percent slopes 72B3 Rabun clay,2 to 7 percent 5.8 5.5% slopes,severely eroded 72C3 Rabun day,7 to 15 percent 3.2 3.0% slopes,severely eroded 72D3 Rabun clay, 15 to 25 percent 5.4 5.1% slopes,severely eroded 798 Starr silt loam,2 to 7 percent 13.2 12.4% slopes Totals for Area of Interest 108.4 100.0% tisim Natural Resources Web Soil Survey 2/27/2017 011111-1 Conservation Service National Cooperative Soil Survey Page 3 of 3 Post-Development Routing Calculations Basin A- Detention Only BasinFlow printout INPUT: Basin: Basin A- Detention Cell Routing 5 Contour Areas Elevation(ft) Area(sf) Computed Vol. (cy) 522.00 573.00 0.0 524.00 1799.00 83.6 526.00 3450.00 274.8 528.00 5485.00 602.8 530.00 7803.00 1092.4 Start_Elevation(ft) 522.00 Vol.(cy) 0.00 5 Outlet Structures Outlet structure 0 Orifice name: Riser area (sf) 7.069 diameter or depth (in) 36.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 527.830 multiple 1 discharge into riser Outlet structure 1 Weir name: Emergency Spillway length (ft) 75.000 side angle 75.500 coefficient 3.300 invert (ft) 528.830 multiple 1 discharge through dam Outlet structure 2 Orifice name: Mid-Flow Orifice area (sf) 0.136 diameter or depth (in) 5.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 526.420 multiple 4 discharge into riser Page 1 Basin A- Detention Only Outlet structure 3 Orifice name: Low-Flow Orifice area (sf) 0.136 diameter or depth (in) 5.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 522.000 multiple 1 discharge into riser Outlet structure 4 Orifice name: Barrel area (sf) 1.767 diameter or depth (in) 18.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 522.000 multiple 1 discharge out of riser 4 Inflow Hydrographs Hydrograph 0 SCS name: 1 yr 24hr SCS Method Storm Event Area (acres) 4.850 CN 77.000 Type 2 rainfall, P (in) 3.500 time of conc. (hrs) 0.1800 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 7.740 peak time (hrs) 11.970 volume (cy) 931.899 Hydrograph 1 SCS name: 2 yr 24hr SCS Method Storm Event Area (acres) 4.850 CN 77.000 Type 2 rainfall, P (in) 3.700 time of conc. (hrs) 0.1800 Page 2 Basin A- Detention Only time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 8.553 peak time (hrs) 11.970 volume (cy) 1029.757 Hydrograph 2 SCS name: 10 yr 24hr SCS Method Storm Event Area (acres) 4.850 CN 77.000 Type 2 rainfall, P (in) 5.600 time of conc. (hrs) 0.1800 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 16.948 peak time (hrs) 11.970 volume (cy) 2040.508 Hydrograph 3 SCS name: 100 yr 24hr SCS Method Storm Event Area (acres) 4.850 CN 77.000 Type 2 rainfall, P (in) 9.100 time of conc. (hrs) 0.1800 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 34.044 peak time (hrs) 11.970 volume (cy) 4098.960 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1 yr 24hr SCS Method Storm Event inflow (cfs) 7.740 at 11.96 (hrs) discharge (cfs) 1.163 at 12.32 (hrs) Page 3 Basin A- Detention Only water level (ft) 526.469 at 12.32 (hrs) storage (cy) 338.364 Hydrograph 1 Routing Summary of Peaks: 2 yr 24hr SCS Method Storm Event inflow (cfs) 8.553 at 11.96 (hrs) discharge (cfs) 1.784 at 12.24 (hrs) water level (ft) 526.675 at 12.24 (hrs) storage (cy) 368.836 Hydrograph 2 Routing Summary of Peaks: 10 yr 24hr SCS Method Storm Event inflow (cfs) 16.948 at 11.96 (hrs) discharge (cfs) 6.944 at 12.14 (hrs) water level (ft) 528.366 at 12.14 (hrs) storage (cy) 679.741 Hydrograph 3 Routing Summary of Peaks: 100 yr 24hr SCS Method Storm Event inflow (cfs) 34.044 at 11.96 (hrs) discharge (cfs) 33.404 at 11.96 (hrs) water level (ft) 529.000 at 11.96 (hrs) storage (cy) 826.177 Mon Sep 18 16:46:48 EDT 2017 Page 4 Basin B- Detention Only BasinFlow printout INPUT: Basin: Basin B- Detention Cell Routing 4 Contour Areas Elevation(ft) Area(sf) Computed Vol.(cy) 590.00 1552.00 0.0 592.00 2740.00 156.9 594.00 4241.00 413.4 596.00 5994.00 790.6 Start_Elevation(ft) 590.00 Vol.(cy) 0.00 4 Outlet Structures Outlet structure 0 Orifice name: Riser area (sf) 7.069 diameter or depth (in) 36.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 593.900 multiple 1 discharge into riser Outlet structure 1 Weir name: Emergency Spillway length (ft) 85.000 side angle 75.500 coefficient 3.300 invert (ft) 594.900 multiple 1 discharge through dam Outlet structure 2 Orifice name: Low-Flow Orifice area (sf) 0.087 diameter or depth (in) 4.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 590.000 multiple 1 discharge into riser Page 1 Basin B- Detention Only Outlet structure 3 Orifice name: Barrel area (sf) 1.767 diameter or depth (in) 18.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 590.000 multiple 1 discharge out of riser 4 Inflow Hydrographs Hydrograph 0 SCS name: 1 yr 24hr SCS Method Storm Event Area (acres) 2.100 CN 82.000 Type 2 rainfall, P (in) 3.500 time of conc. (hrs) 0.1700 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 4.237 peak time (hrs) 11.961 volume (cy) 502.811 Hydrograph 1 SCS name: 2 yr 24hr SCS Method Storm Event Area (acres) 2.100 CN 82.000 Type 2 rainfall, P (in) 3.700 time of conc. (hrs) 0.1700 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 4.632 peak time (hrs) 11.961 volume (cy) 549.775 Hydrograph 2 SCS name: 10 yr 24hr SCS Method Storm Event Area (acres) 2.100 Page 2 Basin B- Detention Only CN 82.000 Type 2 rainfall, P (in) 5.600 time of conc. (hrs) 0.1700 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 8.605 peak time (hrs) 11.961 volume (cy) 1021.355 Hydrograph 3 SCS name: 100 yr 24hr SCS Method Storm Event Area (acres) 2.100 CN 82.000 Type 2 rainfall, P (in) 9.100 time of conc. (hrs) 0.1700 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 16.422 peak time (hrs) 11.961 volume (cy) 1949.063 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1 yr 24hr SCS Method Storm Event inflow (cfs) 4.236 at 11.96 (hrs) discharge (cfs) 0.531 at 12.32 (hrs) water level (ft) 592.471 at 12.40 (hrs) storage (cy) 207.452 Hydrograph 1 Routing Summary of Peaks: 2 yr 24hr SCS Method Storm Event inflow (cfs) 4.632 at 11.96 (hrs) discharge (cfs) 0.553 at 12.38 (hrs) water level (ft) 592.660 at 12.42 (hrs) storage (cy) 229.384 Hydrograph 2 Routing Summary of Peaks: 10 yr 24hr SCS Method Storm Event Page 3 Basin B- Detention Only inflow (cfs) 8.605 at 11.96 (hrs) discharge (cfs) 1.390 at 12.30 (hrs) water level (ft) 594.164 at 12.30 (hrs) storage (cy) 439.545 Hydrograph 3 Routing Summary of Peaks: 100 yr 24hr SCS Method Storm Event inflow (cfs) 16.420 at 11.96 (hrs) discharge (cfs) 12.272 at 12.02 (hrs) water level (ft) 594.942 at 12.02 (hrs) storage (cy) 574.897 Tue Sep 19 11:29:25 EDT 2017 Page 4 Channel Adequacy Channel Adequacy D.A.'A'Outfall to Existing Riprap Ditch Adequate Outfall • Existing riprap ditch at 27%slope(two-sections) o STA.0+00(6.8'wide,and 4.3' deep existing channel): • Overland D.A. =0.21 ac., Cw=0.50,Tc=5 min. (2-year=0.8 cfs; 10-year= 1.0 cfs) • Plus SWM Basin 'A' outflows(2-year= 1.78 cfs, 10-year= 6.94 cfs) • Total Flows: 2-year= 2.58 cfs, 10-year= 7.94 cfs • Flow remains within the channel,velocity appropriate for riprap channel (0.73 ft max, 8.5 fps max 2-year) o STA 1+15 (6'wide, 5'deep existing channel): • Overland D.A. =0.20 ac., Cw=0.50,Tc=5 min. (2-year=0.50 cfs; 10-year=0.60 cfs) • Plus STA 0+00 flow • Flow remains within the channel,velocity is appropriate for riprap channel (0.93 ft, 6.6 fps max 2-year) Project Name: Hyland Park Channel Adequacy Job Number. Designed By: KKW Road Name: Riprap Channel MaxS=5.0% NAG SC150 MaxV=sips Side: N/A Max V=2.0 fps NAG SC250 Max V=9.0fps GREEN ARMOI Max V=12.0fps Sta Sta T. C Area CA 12 Q= Slope Earth(n=0.02) n=0.05 17u Qs) Depth iu Min.Des ign From To (min) Value (ac.) accun- (in/hr) (cfs) (ft/ft) VeL I Depth VeL I Depth (ut/hr) (cfs) (ft) (Depth)I(Type) Ditch 1 UPLAND 0+00 5.0 0.45 0.34 0.15 5.2 2.6 0.2700 8.5 fps 0.41 ft 6.7 7.9 0.73 ft 5"NAC$C250 0+00 1+15 5.0 0.45 0.20 0.09 5.2 3.0 0.2700 6.6 fps 0.65 ft 6.7 8.5 0.93 ft 8"NAGSC250 EXISTING RIPRAP DITCH GEOMETRY ADEQUATE FOR OVERLAND FLOW AND SWM BASIN OUTFLOW Complex Channel(STA.0+00,2—year) Input: Slope 0.270 Flow(given) 2.600 line x y n 0 0.000 4.300 0.050(first n value not used) 1 2.920 0.000 0.050 2 3.540 0.000 0.050 3 6.870 4.300 0.050 Output: Depth 0.408 (y) ( 0.408) Channel bed segment output: line QV A P 1 0.21 3.64 0.06 0.49 2 2.15 8.49 0.25 0.62 3 0.25 3.86 0.06 0.52 Mon Sep 18 14:57:47 EDT 2017 Complex Channel (STA.0+00, 10—year) Input: Slope 0.270 Flow(given) 7.900 line x y n 0 0.000 4.300 0.050(first n value not used) 1 2.920 0.000 0.050 2 3.540 0.000 0.050 3 6.870 4.300 0.050 Output: Depth 0.734 (y) ( 0.734) Channel bed segment output: line QV A P 1 0.99 5.39 0.18 0.89 2 5.72 12.57 0.46 0.62 3 1.19 5.71 0.21 0.93 Complex Channel (STA. 1+15,2—year) Input: Slope 0.270 Flow(given) 3.000 line x y n 0 0.000 5.450 0.050(first n value not used) 1 1.700 0.690 0.050 2 2.920 0.000 0.050 3 6.040 5.450 0.050 Output: Depth 0.647 (y) ( 0.647) Channel bed segment output: line QV A P 1 0.00 0.00 0.00 0.00 2 2.45 6.63 0.37 1.31 3 0.55 4.56 0.12 0.75 Mon Sep 18 16:50:05 EDT 2017 Complex Channel(STA. 1+15, 10—year) Input: Slope 0.270 Flow(given) 8.501 line x y n 0 0.000 5.450 0.050(first n value not used) 1 1.700 0.690 0.050 2 2.920 0.000 0.050 3 6.040 5.450 0.050 Output: Depth 0.931 (y) ( 0.931) Channel bed segment output: line Q V A P 1 0.02 1.82 0.01 0.26 2 7.04 9.85 0.71 1.40 3 1.44 5.82 0.25 1.07 Mon Sep 18 16:50:57 EDT 2017 D.A. `B'Outfall to Existing 15"CMP Culvert Adequate Outfall • Existing 15" CMP culvert: Invert In=574.40; Invert Out=573.01; L=24.3';S=5.72% o Overland D.A. = 1.73 ac., Cw=0.57,Tc=5 min. (2-year= 5.13 cfs; 10-year= 6.61 cfs) o Plus SWM Basin 'B'outflows(2-year=0.55 cfs, 10-year= 1.39 cfs) o Total Flows: 2-year=5.68 cfs, 10-year=8.00 cfs • Culvert maximum capacity 8.4 cfs at 2.07 fps • Two-year(60%of capacity)—5.68 cfs>8.40 cfs maximum,velocity=2.24 cfs ✓ • Ten-year(78%of capacity)—8.00 cfs>8.40 cfs maximum ✓