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HomeMy WebLinkAboutWPO201400092 Calculations WPO VSMP 2016-06-29 FOOTHILL CROSSING II STORMWATER MANAGEMENT CALCULATIONS PACKET Date of Calculations June 5, 2015 Revised September 24, 2015 Revised June 29, 2016 (Minor revisions noted in yellow) PREPARED BY: COLLINS 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 (Revised per updated SCS Worksheet 2) Virginia Runoff Reduction Method New Development Worksheet -v2.8 -June 2014 To be used w/2011 BMP Standards and Specifications Site Data Pro ect Name The Villas at Foothills Date 6/29/16-Updated per revised SCS Worksheet 2 data input cells calculation cells constant values 1. Post-Development Pro ect Land Cover Information Constants - - Annual Rainfall(inches) 43 Target Rainfall Event(inches) 1.00 Phosphorus EMC(mg/L) 0.26 Nitrogen EMC(mg/L) 1.86 Target Phosphorus Target Load(Ib/acre/yr) 0.41 Pj 0.90 Land Cover (acres) A soils B Soils C Soils D Soils Totals Forest/Open Space(acres)--undisturbed, protected forest/open space or reforested land 0.00 0.00 0.00 0.00 0.00 Managed Turf(acres)--disturbed,graded for yards or other turf to be mowed/managed 0.00 9.31 5.96 0.00 15.27 Impervious Cover(acres) 0.00 14.65 5.04 0.00 19.69 Total 34.96 Rv Coefficients A soils B Soils C Soils D Soils Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 Land Cover Summary Forest/Open Space Cover(acres) 0.00 Weighted Rv(forest) 0.00 Forest 0% Managed Turf Cover(acres) 15.27 Weighted Rv(turf) 0.21 Managed Turf 44% Impervious Cover(acres) 19.69 Rv(impervious) 0.95 %Impervious 56% Total Site Area(acres) 34.96 Site Rv 0.63 Post-Development Treatment Volume(acre-ft) 1.82 Post-Development Treatment Volume(cubic feet) 79,420 Post_Development Load(TP)(Ib/yr) 49.90 Post_Development Load(TN)(Ib/yr) Total Load(TP)Reduction Required(Ib/yr) 35.57 Y 0 W V Y Y Y Y Q 0 0 0 0 W IX a 1 o 0 Q 0 0 0 0 0 0 W fi < Y ❑ 0000 < 0000 U 0 m J aO J O ❑ i m z O I- a 0 v 0 U LI 0 o o-ok 0 W U K i- < O o ❑ ix 1- w W S v v O co co co cc, W O W CO W Q Y U O W ❑ m O m 0o o U[i aU) U) co a, o1 M N a m o Ig z _._ L___, 10 -c- al W 1.1.1 IL U Q' U Ce T W V C)ce T Q4 W W Z d ❑ W z } _� 1 V Q LL W QQ ,,E- 0-) w 0 J O(Q•F a O CC w CC m m j W ~ O j W F- O 1)�l Q F W w W ❑Q Y >I- ❑ W < ce Z re K x 00 Co- Z o x 0 '.., W 0 LL '�!W 7 w 0 W w 0 ay C E0 w < v) z 2 w < Z 'A] 0 F W O Z O 0 I- 0 Z LU 0 H I<6 z 0 6 F < Z O 0 I., C Lu CC z0 ac) a ? H tt U z W �',J - = ❑ — a <U ❑ o L 4 0 Z 1 2 11-7 W x H W I-- 10 0 6 a 0 y 0 CC Z I FC 0 ~ N ~ ❑ <00 av < z 0 0 a CO 0 ce zO 0xa JaO❑ >tit r = al I wa 0aCOt < LU 0zw7Oa0ww❑ cc IL I-z 0 a 0a 0 0 w ❑ ��',, ',.. a ❑ cn z N ay = o aLy mCC 0. < co N r O O` (n d Z Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method New Development Worksheet-v2.8-June 2014 Site Data Summary Total Rainfall= 43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 9.31 5.96 0.00 15.27 43.68 Impervious(acres) 0.00 14.65 5.04 0.00_ 19.69 56.32 34.96 100.00 Site Rv 0.63 Post Development Treatment Volume(ft3) 79420 Post Development TP Load(Ib/yr) 49.90 Post Development TN Load(Ib/yr) _ 356.97 Total TP Load Reduction Required(lb/yr) 35.57 Total Runoff Volume Reduction(ft') 0 Total TP Load Reduction Achieved(Ib/yr) 36 Total TN Load Reduction Achieved(Ib/yr) 138.17 Adjusted Post Development TP Load(Ib/yr) 13.68 Remaining Phosphorous Load Reduction(Lb/yr)Required 0.00 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 5.67 8.15 1.45 0.00 0.00 15.27 Impervious(acres) 10.84 8,45 0.40 0.00 0.00 19.69 34.96 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(Ib/yr) 19.62 16.59 0.00 0.00 0.00 36.21 TN Load Red.(Ib/yr) 74.87 63.30 0.00 0.00 0.00 138.17 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area A Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 3.03 2.64 0.00 5.67 34.34 Impervious(acres) 0.00 7.62 3.22 0.00 10.84 65.66 16.51 BMP Selections Practice Credit Area(acres) Downstream Practice 13.c.Wet Pond#2(Spec#14) Impervious: 10.84 Turf(Pervious): 5.67 Total Impervious Cover Treated(acres) 10.84 Total Turf Area Treated(acres) 5.67 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 19.62 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 74.87 Drainage Area B Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 5.50 2.65 0.00 8.15 49.10 Impervious(acres) 0.00 6.69 1.76 0.00 8.45 50.90 16.60 BMP Selections Practice Credit Area(acres) Downstream Practice 13.c.Wet Pond#2(Spec#14) impervious: 8.45 Turf(Pervious): 8.15 Total Impervious Cover Treated(acres) 8.45 Total Turf Area Treated(acres) 8.15 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 16.59 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 63.30 Drainage Area C Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 0.78 0.67 0.00 1.45 78.38 Impervious(acres) 0.00 0.34 0.06 0.00 0.40 21.62 1.85 BMP Selections Practice Credit Area(acres) Downstream Practice Total Impervious Cover Treated(acres) 0.00 Total Turf Area Treated(acres) 0.00 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 0.00 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 0.00 Summary Print Virginia Runoff Reduction Method Worksheet Channel and Flood Protection Weighted CN 1-year 2-year storm 10-year storm Adjusted CN storm Adjusted Adjusted CN CN Target Rainfall Event(in) 3.50 3.70 5.60 D.A.A CN 87 87 87 87 D.A.B CN 82 82 82 82 D.A.C CN 74 74 74 74 D.A.D CN 0 #N/A #N/A #N/A D.A.E CN 0 #N/A #N/A #N/A Summary Print Soils Mapping (Source: NRCS Web Soil Survey Online Database) 1 ,. y� "mil x , k = ` i� i" 11,7 VWyy...� �. . A 1.- y1ali 11 i 4 4 4 4 4 4 + + t , t + f _ 14 t t V ..... 4 4 4 f f— 4—�s i i —+_+,_r-_t-+�--�^'� —1- 1 r t t 1- t+ t t F f 4 jt,k 41 N 1 t 1 i It + // a, :"i F � ; / *SSC s _#a . 37 3 4,a ., ,,,......,.. . ,,..,,,, 4.0„Iv','., ,. ,,, .: _" . , .. ...1,.. T , + ' . r 3 4,,,,t...., ' 36C a SCS TR-55 Calculations (Revised) U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 2:Runoff Curve Number and Runoff Project: Foothill Crossing II Designed By:KKW,PE Date: 6/29/2016 Location: Crozet,VA Checked By:FGM,PE Date: 6/29/2016 Check One: Present X Developed X 1.Runoff curve Number(CN) Revisions are limited to those shown in yellom Drainage Area Soil name and Cover description CN(weighted)= hydrologic rou Area Product of CN Calculated 1S1 Description group (Cover type,treatment,and hydrologic condition;percent CN total product/ p (Acres) x Area Value (Appendix A) impervious;unconnected/connected impervious area ratio) total area B Impervious Areas 98 0.00 0.0 B Woods in Good Condition 55 9.12 501.6 D.A#1 B Lawns in Good Condition(75%+Groundcover) 61 1.93 117.7 61 6.37 (Present) C Impervious Areas 98 0.00 0.0 C Woods in Good Condition 70 4.94 345.8 C Lawns in Good Condition(75%+Groundcover) 74 0.92 68.1 B Impervious Areas 98 0.17 16.7 B Woods in Good Condition 55 5.20 286.0 D.A#2 B Lawns in Good Condition (Reduced by 2.87 ac.) 61 7.59 463.0 63 5.86 (Present) C Impervious Areas 98 0.00 0.0 C Woods in Good Condition 70 1.14 79.8 C Lawns in Good Condition(75%+Groundcover) 74 3.95 292.3 B Impervious Areas (Increased from 7.30 ac.to 7.62 ac.) 98 7.62 746.8 (Excess capacity reduced from 5.7ac.to 5.38 ac.of Imp.Area) D.A#1A B Woods in Good Condition 55 0.00 0.0 (Developed) B Lawns in Good Condition (Reduced by 0.32ac.) 61 3.03 184.8 87 1.45 C Impervious Areas(+Excess Capacity for 2.82 ac Imp.) 98 3.22 315.6 C Woods in Good Condition 70 0.00 0.0 C Lawns in Good Condition(75%+Groundcover) 74 2.64 195.4 B Impervious Areas (Reduced from 7.36ac.to 6.69ac.) 98 6.69 655.6 (Excess capacity increased from 0.46 ac.to 1.13 ac.of Imp.Area) D.A#2B 8 Woods in Good Condition 55 0.00 0.0 (Developed) B Lawns in Good Condition (Reduced by 2.2 ac.) 61 5.50 335.5 82 2.21 C Impervious Areas(+Excess Capacity for 0.39 ac Imp.) 98 1.76 172.5 C Woods in Good Condition 70 0.00 0.0 C Lawns in Good Condition(75%+Groundcover) 74 2.65 196.1 B Impervious Areas 98 0.34 33.3 B Woods in Good Condition 55 0.00 0.0 D.A#2C B Lawns in Good Condition(75%+Groundcover) 61 0.78 47.6 74 3.57 (Developed) C Impervious Areas 98 0.06 5.9 C Woods in Good Condition 70 0.00 0.0 C Lawns in Good Condition(75%+Groundcover 74 0.67 49.6 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 0.58 0.67 1.75 D.A#1(Present) Runoff,0-inches 0.66 0.76 1.90 D.A#2(Present) Runoff,Q-inches 2.21 2.40 4.17 D.A#1A(Developed) Runoff,Q-inches 1.78 1.94 3.61 D.A#28(Developed) Runoff,Cl-inches 1.22 1.36 2.82 D.A#2C(Developed) TR 55 Worksheet 3:Time of Concentration(Ta)or Travel Time(T,) Project: Foothill Crossing II Designed By:KKW,PE Date: 6/2/2015 Location: Crozet,VA Checked By:KKW,PE Date: 6/2/2015 Check One: Present X Developed X Check One: T, X T, Through subarea D.A#1 D.A#2 D.A#1A D.A#2B D.A#2C Segment ID: (Present) (Present) (Developed) (Developed) (Developed) Sheet Flow:(Applicable to T,only) 1 Surface description(Table 3-1) Dense Grass Dense Grass Dense Grass Dense Grass Dense Grass 2 Manning's roughness coeff.,n(Table 3-1 0.24 0.24 0.24 0.24 0.24 3 Flow length,L(total L<100)(ft) 100 100 100 100 100 4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 3.7 3.7 3.7 5 Land slope,s(ft/ft) 0.01 0.02 0.02 0.04 0.03 6 Compute Tt=[0.007(n*L)°'8]/P20.5 2'5 s°'4 0.29 0.22 0.22 0.17 0.19 Shallow Concentrated Flow: 7 Surface description(paved or unpaved) Unpaved Unpaved Unpaved Unpaved Unpaved 8 Flow Length,L(ft) 952 755 117 96 237 9 Watercourse slope,s(ft/ft) 0.041 0.066 0.026 0.042 0.059 10 Average velocity,V(Figure 3-1)(ft/s) 3.2 4.2 2.6 3.3 4.5 11 Tt=L/3600*V I 0.08 I 0.05 I 0.01 I 0.01 I 0.01 I Channel Flow: `w `w w 12 Cross sectional flow area,a(ft2) w 3 v E E E 13 Wetted perimeter,Pw(ft) o o `o 14 Hydraulic radius,r=a/Pw(ft) N/A N/A •c o .E o E o 15 Channel Slope,s(ft/ft) cu 0• v E ov E ov 16 Manning's Roughness Coeff,n To Tu Z 17V=[1.49rV3s°'5]/n 18 Flow length,L(ft) it F- it 19 T,=L/3600*V 0.00 0.00 0.00 I 0.00 I 0.00 I 20 Watershed or subarea T,or T, (Add T,in steps 6,11 and 19) I 0.37 I 0.27 I 0.23 I 0.18 I 0.20 I U.S.Department of Agriculture Natural Resources Conservation Service TR 55 Worksheet 4:Graphical Peak Discharge Method Project: Foothill Crossing II Designed By: KKW,PE Date: 6/29/2016 Location: Crozet,VA Checked By: FGM,PE Date: 6/29/2016 Check One: Present X Developed X Revisions are limited to those shown in yellow Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area 1.Data Description Description Description Description Description D.A#1 D.A#2 D.A#1A D.A#2B D.A#2C (Present) (Present) (Developed) (Developed) (Developed) Drainage Area(Am)in miles?= 0.0264 0.0282 0.0258 0.0259 0.0029 Runoff curve number CN= 61 63 87 82 74 Time of concentration(Tc). 0.37 0.27 0.23 0.18 0.20 Rainfall distribution type= II II II II II Pond and swamp areas spread 0 0 0 0 0 throughout the watershed= 2.Frequency-years 1 2 10 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 3.5 3.7 5.6 4.Initial Abstraction,la-inches 1.273 1.273 1.273 1.173 1.173 1.173 0.289 0.289 0.289 0.442 0.442 0.442 0.713 0.713 0.713 5.Compute la/P 0.36 0.34 0.23 0.34 0.32 0.21 0.08 0.08 0.05 0.13 0.12 0.08 0.20 0.19 0.13 6.Unit peak discharge,Qu-csm/ir 450 480 550 560 595 655 - - - - - 740 755 800 7.Runoff,Q from Worksheet 2-inches 0.58 0.67 1.75 0.66 0.76 1.90 2.21 2.40 4.17 1.78 1.94 3.61 1.22 1.36 2.82 8.Pond and Swamp adjustment factor,Fp 1 1 1 1I. 1 1 1 1 1 9.Peak Discharge,Qp-cfs 6.86 8.49 25.44 10.44 12.77 35.18 ROUTED ROUTED 2.61 2.97 6.53 These pre-dev.flows are smaller/more conservative Summary of Watersheds Summary of Drainage Areas 1-Year 2-Year 10-Year Predevelopment Post-Development Predevelopment(cfs) 'ost-Development(cfs) Predevelopment{cfs) 'ost-Development(cfs)'Predevelo ment(cfs)'ost-Development(cfsj D.A.#1 16.91 D.A.#1A 16.51 D.A.#1 6.86 D.A.#1A 1.48 D.A.41 8.49 D.A.#1A _ 1.61 D.A.#1 25.44 D.A.#1A 2.39 D.A.#2B 16.60 D.A.#2B 0.93 D.A.#28 0.97 D.A.#2 D.A.#2B 15.74 D.A.#2 18.05 D.A.#21 1.85 DA.#2 10.44 D.A.#2C 2.61 D.A.#2 12.77 D.A.#2C 2.97 35.18 D.A.#2C 6.53 Totals: 34.96 34.96 Totals: 17.30 5.02 Totals: 21.26 5.55 Totals: 60.62 24.66 Post-Development Routing Calculations (Revised per updated Basin B Routings) villas Level II wet Pond-A-new BasinFlow printout INPUT: Basin: Foothills Crossing II - Wet Pond Level II 'A' Design 12 Contour Areas Elevation(ft) Area(sf) Computed Vol . (cy) 626.00 1409.00 0.0 628.00 3497.00 175.9 629.00 4762.00 328.3 630.00 6141.00 529.7 631.00 9357.00 814.6 632.00 13497.00 1235.5 632.40 20122.00 1482.9 634.00 24142.00 2792.6 636.00 28144.00 4727.2 638.00 32372.00 6966.7 640.00 36827.00 9527.9 641.50 40316.00 11670.0 Start_Elevation(ft) 632.00 vol . (cy) 1235.46 6 Outlet Structures Outlet structure 0 Orifice name: Low-Flow Orifices area (sf) 0.087 diameter or depth (in) 4.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 632.000 multiple 1 discharge into riser Outlet structure 1 Orifice name: Mid-Flow Orifices area (sf) 0.087 diameter or depth (in) 4.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 635.000 multiple 1 discharge into riser outlet structure 2 weir name: Emergency Spillway length (ft) 30.000 side angle 71.500 coefficient 3.300 invert (ft) 640.000 multiple 1 discharge through dam Outlet structure 3 Curve name: Anti-vortex Device multiple 1 Invert (ft) 638.500 discharge into riser file: thirtysix.txt Page 1 Villas Level II Wet Pond-A-new Outlet structure 4 Culvert name: Barrel multiple 1 discharge out of riser D (in) 30.000 h (in) 0.000 Length (ft) 166.000 Slope 0.012 Manning's n 0.013 Inlet coeff. Ke 0.500 Equation constant set 3 Invert (ft) 626.000 Outlet structure 5 Orifice name: Inverted Pipe area (sf) 0.049 diameter or depth (in) 3.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 631.000 multiple 1 discharge into riser 4 inflow Hydrographs Hydrograph 0 SCS name: 1-Year 24-Hour SCS Method Storm Area (acres) 16.510 CN 87.000 Type 2 rainfall , P (in) 3.500 time of conc. (hrs) 0.2300 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 37.621 peak time (hrs) 11.991 volume (cy) 4839.119 Hydrograph 1 SCS name: 2-Year 24-Hour SCS Method Storm Area (acres) 16.510 CN 87.000 Type 2 rainfall , P (in) 3.700 time of conc. (hrs) 0.2300 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 40.733 peak time (hrs) 11.991 volume (cy) 5239.494 Hydrograph 2 SCS name: 10-Year 24-Hour SCS Method Storm Area (acres) 16.510 Page 2 villas Level II wet Pond-A-new CN 87.000 Type 2 rainfall , P (in) 5.600 time of conc. (hrs) 0.2300 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 71.287 peak time (hrs) 11.991 volume (cy) 9169.618 Hydrograph 3 SCS name: 100-Year 24-Hour SCS Method Storm Area (acres) 16.510 CN 87.000 Type 2 rainfall , P (in) 9.100 time of conc. (hrs) 0.2300 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 129.695 peak time (hrs) 11.991 volume (cy) 16682.513 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-Year 24-Hour SCS Method Storm inflow (cfs) 37.434 at 11.98 (hrs) discharge (cfs) 1.475 at 13.80 (hrs) water level (ft) 635.449 at 13.96 (hrs) storage (cy) 4164.447 Hydrograph 1 Routing Summary of Peaks: 2-Year 24-Hour SCS Method Storm inflow (cfs) 40.531 at 11.98 (hrs) discharge (cfs) 1.606 at 13.92 (hrs) water level (ft) 635.709 at 13.94 (hrs) storage (cy) 4426.913 Hydrograph 2 Routing Summary of Peaks: 10-Year 24-Hour SCS Method Storm inflow (cfs) 70.933 at 11.98 (hrs) discharge (cfs) 2.386 at 14.40 (hrs) water level (ft) 638.176 at 14.40 (hrs) storage (cy) 7178.537 Hydrograph 3 Routing Summary of Peaks: 100-Year 24-Hour SCS Method Storm inflow (cfs) 129.051 at 11.98 (hrs) discharge (cfs) 51.479 at 12.18 (hrs) water level (ft) 640.195 at 12.18 (hrs) storage (cy) 9795.943 Tue Aug 25 12:31:39 EDT 2015 Page 3 villas Level II Wet Pond-B-alternate BasinFlow printout INPUT: Basin: Foothills Crossing II - Wet Pond Level II 'B' Design 11 Contour Areas Elevation(ft) Area(sf) Computed Vol . (cy) 648.00 1673.00 0.0 649.00 2446.00 75.8 650.00 3361.00 182.9 652.00 5618.00 511.9 653.00 7641.00 756.5 654.00 11691.00 1111.8 654.40 17012.00 1323.2 656.00 19772.00 2412.1 658.00 23291.00 4005.2 660.00 27037.00 5867.5 662.00 31008.00 8015.7 Start_Elevation(ft) 654.00 Vol . (cy) 1111.84 6 Outlet Structures Outlet structure 0 orifice name: Low-Flow Orifices area (sf) 0.049 diameter or depth (in) 3.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 654.000 multiple 1 discharge into riser Outlet structure 1 Orifice name: Mid-Flow Orifices area (sf) 0.087 diameter or depth (in) 4.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 658.000 multiple 1 discharge into riser Outlet structure 2 weir name: Emergency Spillway length (ft) 35.000 side angle 78.460 coefficient 3.300 invert (ft) 660.250 multiple 1 discharge through dam Outlet structure 3 Curve name: Anti-Vortex Device multiple 1 Invert (ft) 659.000 discharge into riser file: fortyeight.txt Page 1 Villas Level II Wet Pond-B-alternate Outlet structure 4 Culvert name: Barrel multiple 1 discharge out of riser D (in) 30.000 h (in) 0.000 Length (ft) 100.000 Slope 0.005 Manning's n 0.013 Inlet coeff. Ke 0.500 Equation constant set 3 Invert (ft) 653.000 Outlet structure 5 orifice name: Inverted Pipe area (sf) 0.049 diameter or depth (in) 3.000 width for rect. (in) 0.000 coefficient 0.600 invert (ft) 653.000 multiple 1 discharge into riser 4 Inflow Hydrographs Hydrograph 0 SCS name: 1-Year 24-Hour SCS Method Storm Area (acres) 16.600 CN 82.000 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) 33.012 peak time (hrs) 11.970 volume (cy) 3974.645 Hydrograph 1 SCS name: 2-Year 24-Hour SCS Method Storm Area (acres) 16.600 CN 82.000 Type 2 rainfall , P (in) 3.700 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) 36.093 peak time (hrs) 11.970 volume (cy) 4345.638 Page 2 villas Level II Wet Pond-B-alternate Hydrograph 2 scS name: 10-Year 24-Hour SCS Method Storm area (acres) 16.600 CN 82.000 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) 67.055 peak time (hrs) 11.970 volume (cy) 8073.432 Hydrograph 3 SCS name: 100-Year 24-Hour SCS Method Storm area (acres) 16.600 CN 82.000 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) 127.960 peak time (hrs) 11.970 volume (cy) 15406.399 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-Year 24-Hour SCS Method Storm inflow (cfs) 33.012 at 11.96 (hrs) discharge (cfs) 0.930 at 14.88 (hrs) water level (ft) 657.511 at 14.94 (hrs) storage (cy) 3591.360 Hydrograph 1 Routing Summary of Peaks: 2-Year 24-Hour SCS Method Storm inflow (cfs) 36.093 at 11.96 (hrs) discharge (cfs) 0.968 at 14.48 (hrs) water level (ft) 657.841 at 15.14 (hrs) storage (cy) 3868.869 Hydrograph 2 Routing Summary of Peaks: 10-Year 24-Hour SCS Method Storm inflow (cfs) 67.055 at 11.96 (hrs) discharge (cfs) 15.737 at 12.22 (hrs) water level (ft) 659.637 at 12.22 (hrs) storage (cy) 5508.693 Hydrograph 3 Routing Summary of Peaks: 100-Year 24-Hour SCS Method Storm inflow (cfs) 127.960 at 11.96 (hrs) discharge (cfs) 115.628 at 12.02 (hrs) water level (ft) 660.846 at 12.02 (hrs) storage (cy) 6740.742 wed Jun 29 14:17:50 EDT 2016 Page 3 r , / F 1 UC SEE . t '' ' r` ''' i1 f�; j -4., I 1 K_.�, 1 ' qV,41e. 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