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HomeMy WebLinkAboutWPO201400036 Calculations 2014-04-21 40,:. \TERRA ENGINEERING AND 2374 STUARTS DRAFT HIGHWAY.STUARTS DRAFT VA 24477 LAND SOLUTIONS, PC PH.(540)337-4591 FAX (540)337-5291 The Village at Chestnut Grove Albemarle County, Virginia AS-BUILT Sept 2014 Stormwater Management Cover 14 April 2014 Revised 13 May 2014 The existing basin appears to be roughly a constructed detention basin having steep slopes and excess volume. It is used as a stormwater basin primarily for Sienna Lane runoff,but includes some lot area as well. Rain gardens were approved for lots. Terra Engineering was asked by Cathcart Properties to redesign the basin shape into something acceptable to the Lot 3 property owner,Paul Corridon. To do that,a copy of the previous County approved Stormwater Computations prepared by Kurt Gloeckner dated May 15,2000 was obtained. This report used the rational method for basin design. To the contrary,this redesign uses the 24-hr storm distribution and SCS TR-20(as requested by the County)to comply with changes to the computation methodology as supported by the Department of Environmental Quality. The proposed basin was routed for the 2, 10 and 100-year,24-hour,Type II storms. The computations are attached.The basin contains a primary 15-inch RCP outlet with an 11 V2-inch orifice plate and a higher secondary 15-inch RCP pipe outlet. Both outlets are existing pipes. In summary,the routed 2, 10 and 100-year storms have a peak discharge of 2.90, 8.46 and 17.50 cubic feet per second,respectively. The respective peak stages are 1.17, 3.23 and 5.66 feet. The respective storage volumes are 210, 3380,and 10,057 cubic feet. The pond was enlarged and accommodates the 100-year storm. The basin is designed without a riser,with 3:1 and 4:1 side slopes,including a 4-foot shoulder along the maintenance drive and decorative stone at the pond invert all at the request of the Lot 3 property owner. Nyloplast inlets are used to extend and transition the existing basin inflow pipes and reduce flow velocities. Class I rip-rap(EC-1)is used at the new pipe ends to dissipate energy. i0+14,41•1:61.$47."-Iliiiiire IC: STF\•' �; URNER • Lk.No.019933 4 9/1z/r4-19444 ows, G SIONAL0- PLANNING•CIVIL ENGINEERING•LAND SURVEYING WWW TFRRAFNC:INFFRINW NFT Type II Rainfall=3.70" 2YR 24-hr Storm Routing with 11.5 inch orifice,9-3-14 Prepared by{enter your company name here} Printed 9/9/2014 HydroCAD® 10.00-12 sin 03710 ©2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydragraph Inflow 3 17 cfs 0 Outflow P ry Inflow Area--5.990 5.990 ac ;:::Seconary 2g¢ 2.90 tYS s7 Peak E1ev 988.62 ' 3 Storage 210 cf F. a , 2 ,dam 4 D,Op Ck 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24�25 26 27 28 29 30 Time (hours) 2YR 24-hr Storm Routing with 11.5 inch orifice, 9-3-14 Type 1124-hr Rainfall=3.70" Prepared by{enter your company name here) Printed 9/9/2014 HydroCADe 10.00-12 sin 03710 cp 2014 HydroCAD Software Solutions LLC Summary for Pond 1P: Pond Regraded 11.5" pipe orifice Inflow Area= 5.990 ac, 0.00% Impervious, Inflow Depth= 0.62" Inflow = 3.17 cfs @ 12.16 hrs, Volume= 0.310 of Outflow = 2.90 cfs @ 12.21 hrs, Volume= 0.310 af, Atten= 9%, Lag= 3.4 min Primary = 2.90 cfs @ 12.21 hrs, Volume= 0.310 of Secondary= 0.00 cfs @ 5.00 hrs, Volume= 0.000 of Routing by Stor-Ind method,Time Span= 5.00-30.00 hrs, dt=0.05 hrs Peak Elev= 988.62' @ 12.21 hrs Surf.Area= 822 sf Storage=210 cf Plug-Flow detention time= 0.2 min calculated for 0.309 af(100% of inflow) Center-of-Mass det. time=0.2 min (912.7- 912.5 ) Volume Invert Avail.Storage Storage Description #1 987.44' 13,484 cf Surface Storage(Irregular)Listed below(Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 987.44 0 0.0 0 0 0 988.00 27 26.0 5 5 54 988.76 1,163 132.0 346 351 1,388 989.00 1,260 136.0 291 642 1,480 991.00 2,194 174,0 3,411 4,053 2,467 993.00 3,474 219.0 5,619 9,672 3,928 994.00 4,159 237.0 3,811 13,484 4,620 Device Routing Invert Outlet Devices #1 Primary 987.44' 15.0" Round RCP_Round 15" L= 112.2' RCP, end-section conforming to fill, Ke= 0.500 Inlet I Outlet Invert= 987.44'1 978.49' S= 0.0798'P Cc= 0.900 n= 0.013 Concrete pipe, straight& clean, Flow Area 1.23 sf #2 Device 1 987.44' 11.5"Vert. Orifice/Grate C= 0.600 #3 Secondary 989.85' 15.0" Round 15" RCP wl FES L= 106.3' RCP, end-section conforming to fill, Ke=0,500 Inlet/Outlet Invert= 989.85'!978,38' S= 0.1079'P Cc= 0.900 n= 0.013 Concrete pipe, straight& clean, Flow Area= 1.23 sf Primary OutFlow Max=2.88 cfs @ 12.21 hrs HW=988.61' (Free Discharge) t- RCP Round 15" (Passes 2.88 cfs of 4.39 cfs potential flow) 2=Orifice/Grate (Orifice Controls 2.88 cfs @ 4.00 fps) ;secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=987.44' (Free Discharge) 3=15'" RCP w/FES ( Controls 0,00 cfs) 10YR 24-hr Storm Routing with 11.5 inch orifice, 9-3-14 Type 1124-hr Ratinfa11=5.6O Prepared by{enter your company name here} Printed 9/9/2014 HydroCAD®10.00-12 sin 03710 Q 2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydragra ph / CI Inflow 10Sa cts 0 Outflow Ea Primary Inflow Area=5.990 ec €SeoondarY 11-':' , . - Sp. : Poak Elev 990.E 10� � _ 646ds _ ,.0,1-,:N s� Storage--35380 cf t— - ,. w - snas V i 6_ E Q a 5 l `> fez . v 0: : ' ' --- ,���� � � 1 sy �6�61t► sa° 5 8 7 8 9 10 11 124 13 14 15 16 17 18 19 20 21 22 23 24 25 28 27 28 29 30 Time (hours) 10YR 24-hr Storm Routing with 11.5 inch orifice, 9.3-14 Type 1124-hr Rainfall=5.60" Prepared by{enter your company name here} Printed 9/9/2014 HydroCADO 10.00-12 sin 03710 ©2014 HydroCAD Software Solutions LLC Summary for Pond 1P: Pond Regraded 11.5" pipe orifice Inflow Area= 5.990 ac, 0.00% Impervious, Inflow Depth= 1.67" Inflow = 10.58 cfs @ 12.13 hrs, Volume= 0.831 af Outflow = 8.46 cfs @ 12.24 hrs, Volume= 0.831 af, Atten=20%, Lag= 6.3 min Primary = 5.77 cfs @ 12.24 hrs, Volume= 0.784 af Secondary= 2.69 cfs @ 12.24 hrs, Volume= 0.047 af Routing by Stor-Ind method, Time Span=5.00-30.00 hrs, dt=0.05 hrs Peak Elev=990.68' @ 12.24 hrs Surf.Area=2,028 sf Storage=3,380 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time=2.6 min (878.8- 876.11 ) Volume Invert Avail.Storage Storage Description #1 987.44' 13,484 cf Surface Storage(Irregular)Listed below(Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 987.44 0 0.0 0 0 0 988.00 27 26.0 5 5 54 988.76 1,163 132.0 346 351 1,388 989.00 1,260 136.0 291 642 1,480 991.00 2,194 174.0 3,411 4,053 2,467 993.00 3,474 219.0 5,619 9,672 3,928 994.00 4,159 237.0 3,811 13,484 4,620 Device Routing Invert Outlet Devices #1 Primary 987.44' 15.0" Round RCP_Round 15" L= 112.2' RCP,end-section conforming to fill, Ke= 0.500 Inlet/Outlet Invert= 987.44'/978.49' S= 0.0798'/' Cc=0.900 n= 0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf #2 Device 1 987.44' 11.5"Vert.Orifice/Grate C= 0.600 #3 Secondary 989.85' 15.0" Round 15" RCP w/FES L= 112.3' RCP, end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert= 989.85'1 980.89' S= 0.0798'1' Cc= 0.900 n=0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf Primary OutFlow Max=5.76 cfs @ 12.24 hrs HW=990.67' (Free Discharge) L1=RCP_Round 15" (Passes 5.76 cfs of 9.54 cfs potential flow) Z2=OrificelGrate (Orifice Controls 5.76 cfs @ 7.98 fps) §e econdary OutFlow Max=2.63 cfs @ 12.24 hrs HW=990.67' (Free Discharge) 3=15"RCP wI FES (Inlet Controls 2.63 cfs @ 3.08 fps) 100YR 24-hr Storm Routing with 11.5 inch orifice, 9-3-14 Type /I 24-hr Rainfall-8.50" Prepared by{enter your company name here} Printed 91412014 HydroCADY 10.00-12 sin 03710 O 2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydrograph Inflow 125°3441. 28- I �y {{�� Primary nflow Area=5.w}1+90 � .. 7-...°Seutcflo°wnclary 26= Peak Elev=993.'I'L1. 24 22= Storage--10,057 cf ,. 17,SO cis. 20-a s 18_' 16- C 3 14: ' a u 12j - I9 9 cis �. � 10= fay , , 8= / o_. _ 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours} 100YR 24-hr Storm Routing with 11.5 inch orifice, 9-3-14 Type 1124-hr Rainfall=8.50" Prepared by{enter your company name here) Printed 9/4/2014 HydroCADO 10.00-12 sin 03710 ©2014 HydroCAD Software Solutions LLC Summary for Pond 1P: Pond Regraded 11.5" pipe orifice Inflow Area= 5.990 ac, 0.00% Impervious, Inflow Depth= 3.71" Inflow = 25.08 cfs @ 12.12 hrs, Volume= 1.853 of Outflow = 17.50 cfs @ 12.26 hrs, Volume= 1.853 af, Atten=30%, Lag=8.1 min Primary = 7.91 cfs @ 12.26 hrs, Volume= 1.458 af Secondary= 9.59 cfs @ 12.26 hrs, Volume= 0.395 af Routing by Stor-Ind method,Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 993.11'@ 12.26 hrs Surf.Area=3,546 sf Storage=10,057 of Plug-Flow detention time=4.2 min calculated for 1.850 af(100%of inflow) Center-of-Mass det. time=4.2 min (855.9-851.7) Volume Invert Avail.Storage Storage Description #1 987.44' 13,484 cf Surface Storage(Irregular)Listed below(Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 987.44 0 0.0 0 0 0 988.00 27 26.0 5 5 54 988.76 1,163 132.0 346 351 1,388 989.00 1,260 136.0 291 642 1,480 991.00 2,194 174.0 3,411 4,053 2,467 993.00 3,474 219.0 5,619 9,672 3,928 994.00 4,159 237.0 3,811 13,484 4,620 Device Routing Invert Outlet Devices #1 Primary 987:44' 15.0" Round RCP Round 15" L= 112.2' RCP, end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert=987.44'/978.49' S= 0.0798'I' Cc=0.900 n= 0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf #2 Device 1 987.44' 11.5"Vert. Orifice/Grate C=0.600 #3 Secondary 989.85' 15.0" Round 15"RCP wI FES L= 112.3' RCP, end-section conforming to fill, Ke= 0.500 Inlet/Outlet Invert= 989.85'/980.89' S= 0.0798'1' Cc= 0.900 n=0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf Primary OutFlow Max=7.90 cfs @ 12.26 hrs HW=993.10' (Free Discharge) Z-1=RCP_Round 15" (Passes 7.90 cfs of 13.26 cfs potential flow) t2=OrificelGrate (Orifice Controls 7.90 cfs @ 10.96 fps) §econdary OutFlow Max=9.57 cfs @ 12.26 hrs HW=993.10' (Free Discharge) '7--:3=15" RCP w/FES (Inlet Controls 9.57 cfs @ 7.80 fps) \TERRA ENGINEERING AND 2374 STGa1RTS[Ott,,"r HIGIMAY,S'Pt7AR:1'S bRAris vA244 7 s /LAND SOLUTIONS,PG PH.(5403 337 4591 1:1A1 (54O 337 5291 The Village at Chestnut Grove Albemarle County,Virginia Stormwater Management Cover 14 April 2014 Revised 13 May 2014 The existing basin appears to be roughly a constructed detention basin having steep slopes and excess volume. It is used as a stormwater basin primarily for Sienna Lane runoff,but includes some lot area as well.Rain gardens were approved for lots. Terra Engineering was asked by Cathcart Properties to redesign the basin shape into something acceptable to the Lot 3 property owner,Paul Corridon.To do that,a copy of the previous County approved Stormwater Computations prepared by Kurt Gloeckner dated May 15,2000 was obtained. This report used the rational method for basin design.To the contrary,this redesign uses the 24-hr storm distribution and SCS TR-20(as requested by the County)to comply with changes to the computation methodology as supported by the Department of Environmental Quality. The proposed basin was routed for the 2, 10 and 100-year,24-hour,Type 11 storms. The computations are attached.The basin contains a primary 15-inch RCP outlet with an 11Y2-inch orifice plate and a higher secondary 15-inch RCP pipe outlet. Both outlets are existing pipes. In summary,the routed 2, 10 and 100-year storms have a peak discharge of 3.11,7.27 and 17.89 cubic feet per second,respectively.The respective peak stages are 1.26,4.61 and 7.28 feet.The respective storage volumes are 81,3149,and 9628 cubic feet. The pond was enlarged and accommodates the 100-year storm. The basin is designed without a riser,with 3:1 and 4:1 side slopes,including a 4-foot shoulder along the maintenance drive and decorative stone at the pond invert all at the request of the Lot 3 property owner. Nyloplast inlets are used to extend and transition the existing basin inflow pipes and reduce flow velocities. Class 1 rip-rap(EC-1) is used at the new pipe ends to dissipate energy. sikLT 4:11,\ er CEVEN 4ir RIV ER Z Lic.No.019933 4 /t` a/i4 SS � IaNAL� �� PLANNING•CIVIL ENGINEERING.LAND SURVEYING W W W.TERRAENGINEERING.NET 2YR 24-hr Storm Routing with 11.5 inch orifice Type 1124-hr Rainfal1=3.70" Prepared by Terra Engineering and Land Solutions, PC HydroCADO 10.00-11 s/n 03710 ©2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydrograph M Inflow 3.17 crf 41118 hro 0 Outflow j� � ((�� �1� Primary 3,11cIo 12.18133 -- Inflow Area=5.99O-ac_..- 1 sB00tldary 3.11th i21Hh» ; y ,. Peak Elegy=986.71' 3- a Storage 81 cf 2-' !s 1"°o oar7, '�. � � ;;1 'r' 6 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 2YR 24-hr Storm Routing with 11.5 inch orifice Type II 24-hr Rainfall=3.70" Prepared by Terra Engineering and Land Solutions, PC HydroCADO 10.00-11 sin 03710 0 2014 HydroCAD Software Solutions LLC Summary for Pond 1P: Pond Regraded 11.5" pipe orifice Inflow Area= 5.990 ac, 0.00% Impervious, Inflow Depth= 0.62" Inflow = 3.17 cfs @ 12.16 hrs, Volume= 0.310 at Outflow = 3.11 cfs @ 12.18 hrs, Volume= 0.310 af, Atten=2%, Lag= 1.4 min Primary = 3.11 cfs @ 12.18 hrs, Volume= 0.310 at Secondary= 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span=5.00-30.00 hrs, dt=0.05 hrs Peak Elev=986.71'@ 12.18 hrs Surf.Area= 190 sf Storage=81 cf Plug-Flow detention time=0.1 min calculated for 0.309 af(100% of inflow) Center-of-Mass det. time=0.1 min (912.6-912.5) Volume Invert Avail.Storage Storage Description #1 985.43' 10,609 cf Surface Storage(Irregular)Listed below(Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 985.43 0 0.0 0 0 0 987.00 285 66,0 149 149 350 989.00 1,260 136.0 1,429 1,579 1,494 991.00 2,194 174.0 3,411 4,990 2,481 993.00 3,474 219.0 5,619 10,609 3,942 Device Routing Invert Outlet Devices #1 Primary 985.43' 15.0" Round RCP_Round 15" L= 112.2' RCP, end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert=985.43'/976.48' S=0.0798?' Cc=0.900 n=0.013 Concrete pipe, straight&clean, Flow Area 1.23 sf #2 Device 1 985.43' 11.5"Vert.Orifice/Grate C=0.600 #3 Secondary 989.85' 16.0" Round 16"RCP w/FES L= 106.3' RCP,end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert=989.85'/978.38' S=0.1079'.1' Cc=0.900 n=0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf Primary OutFlow Max=3.08 cfs @ 12.18 hrs HW=986.691 (Free Discharge) T-1RCP_Round 15" (Passes 3.08 cfs of 4.72 cfs potential flow) T-2=Orifice/Grate (Orifice Controls 3.08 cfs @ 4.26 fps) §econdary OutFlow Max=0.00 cfs @ 5.00 hrs HW=985.43' (Free Discharge) T-3=15"RCP w/FES (Controls 0.00 cfs) Type 1124-hr Rainfall=5.60" 10YR 24-hr Storm Routing with 11.5 inch orifice Prepared by Terra Engineering and Land Solutions, PC HydroCAD®10.00-11 s/n 03710 ©2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydrograph inflow i 10 58 de 1213 ha ®Outflow Area=5.990 ac' se , r, 11 Peak E1ev=99006 10 sf+ rage=3,149 cf 9 7.270egiuncre 8 .._... 7.07 cis,�12.27hrs 6 0 iry 4 3 A19 efa- 0 ,� ' ... v a 5 6 7 8 9 10 11 12 13 14 15 17 8 19 20 21 22 23 24 25 26 27 28 29 30 T16 ime (h1ours) 10YR 24-hr Storm Routing with 11.5 inch orifice Type 1124-hr Rainfall=5.60" Prepared by Terra Engineering and Land Solutions, PC HydroCADV 10.00-11 sin 03710 2014 HydroCAD Software Solutions LLC Summary for Pond 1P: Pond Regraded 10" pipe orifice Inflow Area = 5.990 ac, 0.00% Impervious, Inflow Depth = 1.67" Inflow = 10.58 cfs @ 12.13 hrs, Volume= 0.831 at Outflow = 7.27 cfs @ 12.27 hrs, Volume= 0.831 af, Atten= 31%, Lag=8.3 min Primary = 7.07 cfs @ 12.27 hrs, Volume= 0.830 at Secondary= 0.19 cfs @ 12.27 hrs, Volume= 0.001 at Routing by Stor-Ind method, Time Span=5.00-30.00 hrs, dt=0.05 hrs Peak Elev=990.06'@ 12.27 hrs Surf.Area= 1,722 sf Storage=3,149 cf Plug-Flow detention time=2.1 min calculated for 0.829 at(100%of inflow) Center-of-Mass det. time=2.1 min( 878.2-876.1 ) Volume Invert Avail.Storage Storage Description #1 985.43' 10,609 cf Surface Storage(Irregular)Listed below(Recaic) Elevation Surf.Area Perim. lnc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 985.43 0 0.0 0 0 0 987.00 285 66.0 149 149 350 989.00 1,260 136.0 1,429 1,579 1,494 991.00 2,194 174.0 3,411 4,990 2,481 993.00 3,474 219.0 5,619 10,609 3,942 Device Routing Invert Outlet Devices #1 Primary 985.43' 15.0" Round RCP...Round 15" L= 112.2' RCP, end-section conforming to fill, Ke=0.500 Inlet Outlet Invert=985.43'/976.48' S=0.0798'P Cc=0,900 n=0.013 Concrete pipe, straight& clean, Flow Area= 1.23 sf #2 Device 1 985.43' 11.5"Vert.Orifice/Grate C=0.600 #3 Secondary 989.85' 15.0" Round 15"RCP w/FES L= 112.3' RCP, end-section conforming to fill, Ke=0.500 Inlet Outlet Invert= 989.85'!980.89' S=0.0798'P Cc= 0.900 n=0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf frimary OutFlow Max=7.05 cfs 12.27 hrs HW=990.04' (Free Discharge) T--1=RCP_Round 16" (Passes 7.05 cfs of 11.79 cfs potential flow) T-2Orifice/Grate (Orifice Controls 7.05 cfs @ 9.78 fps) §econdary OutFlow Max=0.17 cfs @ 12.27 hrs HW=990.04' (Free Discharge) 7-3=15"RCP w/FES (Inlet Controls 0.17 cfs @ 1.47 fps) 100YR 24-hr Storm Routing with 11.5 inch orifice Type fl 24-hr Rainfall=8.50" Prepared by Terra Engineering and Land Solutions, PC HydroCAD®10,00-11 s/n 03710 ©2014 HydroCAD Software Solutions LLC Pond 1P: Pond Regraded 11.5" pipe orifice Hydrograph , , inflow 2506ck 1212hn ( Oulflow 4 a- miry 26 __ inflow are - .9' 0� ac Secondary 26 - v=99-2.7 24 . v- 2.7 24 1' . 17.89dsi2251us tor�tg = 20 18 4 16 14 r� ' it 12-i _ :.9.Obth sss;;;11.2bbra rg__ti_- 10 863 oft• 12 25 tin - - 8 6 t 4; ' '/;/'/,.....,.„. „„.,„., ' .-/ iiiibilas ,..5e..,,,,,, ... - ,-., *' 2 s 6 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 100YR 24-hr Storm Routing with 11.5 inch orifice Type 1124-hr Rainfall=8.50" Prepared by Terra Engineering and Land Solutions, PC HydroCAD )10.00-11 s/n 03710 ©2014 HydroCAD Software Solutions LLC Summary for Pond 1?: Pond Regraded 11.5" pipe orifice Inflow Area= 5.990 ac, 0.00% Impervious, Inflow Depth= 3.71" Inflow = 25.08 cfs @ 12.12 hrs, Volume= 1.853 af Outflow = 17.89 cfs @ 12.25 hrs, Volume= 1.853 af, Atten=29%, Lag=7.8 min Primary = 9.06 cfs @ 12.25 hrs, Volume= 1.550 af Secondary= 8.83 cfs 12.25 hrs, Volume= 0.304 af Routing by Stor-Ind method,Time Span=5.00-30.00 hrs, dt=0.05 hrs Peak Elev=992,71'c 12,25 hrs Surf.Area=3,269 sf Storage=9,628 cf Plug-Flow detention time= 3.8 min calculated for 1.850 af(100%of inflow) Center-of-Mass det. time=3.8 min (855.5-851.7) Volume Invert Avail,Storage Storage Description #1 985.43' 10,609 of Surface Storage(Irregular)Listed below(Recalc) Elevation Surf.Area Perim. Inc.Store Cum,Store WetArea (feet) (so-ft) (feet) (cubic-feet) (cubic-feet) (so-ft) 985.43 0 0.0 0 0 0 987,00 285 66.0 149 149 350 989.00 1,260 136.0 1,429 1,579 1,494 991.00 2,194 174.0 3,411 4,990 2,481 993.00 3,474 219.0 5,619 10,609 3,942 Device Routing Invert Outlet Devices #1 Primary 985.43' 15.0" Round RCP_Round 15" L= 112.2' RCP, end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert=985.43'!976,48' S=0.0798 V' Cc=0.900 n=0.013 Concrete pipe, straight&clean, Flow Area= 1.23 sf #2 Device 1 985.43' 11.5"Vert.Orifice/Grate C=0,600 #3 Secondary 989.85' 15.0" Round 15" RCP w/FES L= 112.3' RCP, end-section conforming to fill, Ke=0.500 Inlet/Outlet Invert=989.85'/980.89' S.=0.0798 V' Cc=0.900 n=0.013 Concrete pipe, straight& clean, Flow Area= 1.23 sf rrimary OutFlow Max=9.06 cfs 12.25 hrs HW=992.71' (Free Discharge) T-1=RCP Round 16" (Passes 9.06 cfs of 15.24 cfs potential flow) T-2=Orifice/Grate (Orifice Controls 9.06 cfs© 12.55 fps) §econdary OutFlow Max=8.83 cfs(41 12.25 hrs HW=992.71' (Free Discharge) T-3=15"RCP w/FES (Inlet Controls 8.83 cfs©7.19 fps)