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WPO202200028 Stormwater Management Maintenance Agree. 2022-07-08
SHIMP ENGINEERING, P.C. Design Focused Engineering July 7, 2022 Regarding: Rivers Edge — SWM Calculation Packet Dear Reviewer, Enclosed is the stormwater calculation packet for the Rivers Edge Site Plan in Albemarle County, VA. The purpose of this project is to construct 34 new 3-story multifamily buildings with associated parking and travel ways. This project will disturb a total area of 9.21 acres. The conditions of subsection F of 9VAC25-870-65 Water Quality have been met for this site. The VRRM considers the total limits of disturbance for the project when calculating the required load reductions for the development. Using the DEQ VRRM Re -Development Compliance Spreadsheet, the TP Load Reduction Required for this plan is 6.17 lb/yr. This requirement will be satisfied through the purchase of 6.17 nutrient credits. Two points of analysis were considered for the site Water Quantity (Channel Protection) and Flood Protection. POA 1 The proposed stormwater design meets the Water Quantity requirements set forth in 9VAC25-870-66-B(3) for discharge to a natural stormwater conveyance system through the use of a new underground detention system that releases the 1-yr storm at rates compliant with the Energy Balance Equation. Note that since the 1-yr reduction of the total runoff (including offsite area) is greater than the reduction required by the Energy Balance Equation, runoff at this POA is compliant with the Energy Balance Equation. This runoff will be released to a Level Spreader which will convert the concentrated flow to sheet flow across a 1.77% slope for 112-ft before reaching the river banks. The proposed stormwater design meets the Flood Protection requirements set forth in 9VAC25-870-66-C(3)c where the stormwater conveyance system releases runoff to a mapped floodplain. POA 2 The proposed stormwater design meets the Water Quantity requirements set forth in 9VAC25-870-66-B(3) for discharge to a natural stormwater conveyance system through the use of a new dry detention pond that releases the 1-yr storm at rates compliant with the Energy Balance Equation. The proposed stormwater design meets the Flood Protection requirements set forth in 9VAC25-870-66-C(2)b through the use of a new dry detention pond that releases the 10-yr storm at rates below predevelopment. Predev [cfs] Amax [cfs] Posldev [cfs] POA 1-yr 10-yr 1-yr 1-yr 10-yr 1 2.97 1 42.29 2.06 2.04 56.52 2 3.22 1 20.95 218 2.08 16.13 If you have any questions please do not hesitate to contact me at: Justin@shimp-engineedng.com or by phone at 434-227-5140 ext. 3. Justin Shimp, P.E. Shimp Engineering, P.C. Contents: Pre -Development Runoff Quantity Calculations: Pre-Dev Drainage Map Pre-Dev HydroCAD Report Post-Dev Runoff Quantity Calculations: Post-Dev Drainage Map Ditch Drainage Map LD-268 Ditch Calculations LD-229 Pipe Capacity Calculations Energy Balance Equation Summary Post-Dev HydroCAD Report Runoff Quality Calculations: VRRM Re -Development Spreadsheet Summary Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Pre -Development Runoff Quantity Calculations: Pre-Dev Drainage Map Pre-Dev HydroCAD Report S DA Ar 1 899 2 339 Total 1,23 200 0 200 400 600 Pre -Development Drainage Area Summary SF AC SF AC SF AC SF AC SF AC min DA Area Area Impervious Impervious C Pervious Pervious Turf Turf Woods Woods TOC 1 899,243 20.64 23,285 0.53 0.32 875,958 20.11 24,500 0.5 851,458 19.55 7.00 2 339,357 7.79 60,887 1.40 0.41 278,470 6.39 115,854 2. 162,616 3.73 7.00 Total 1,238,600 28.43 84,172 1.93 - 1,154,428 26.50 140,354 3. 1,014,074 23.28 - Predevelopment HydroCAD Report Rivers Edge (6S (5S) DA 1 PREDEV DA1 PREDEV UNMANAGED DEVELOPMENT AREA 2L POA 1 Sub4 Reach X 4on Llnk i3S DA2 PREDEV 4L POA 2 Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 2 Time span=5.00-60.00 hrs, dt=0.05 hrs, 1101 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment3S: DA2 PREDEV Runoff Area=7.790 ac 17.97% Impervious Runoff Depth=0.35" Tc=7.0 min UI Adjusted CN=61 Runoff=3.22 cfs 0.227 of Subcatchment5S: DA1 PREDEV Runoff Area=4.880 ac 2.66% Impervious Runoff Depth=0.23" Tc=5.0 min CN=57 Runoff=1.04 cfs 0.095 of Subcatchment6S: DA 1 PREDEV Runoff Area=15.760 ac 2.54% Impervious Runoff Depth=0.21" Tc=7.0 min CN=56 Runoff=2.13 cfs 0.274 of Link 2L: POA 1 Inflow=2.97 cfs 0.369 of Primary=2.97 cfs 0.369 of Link 4L: POA 2 Inflow=3.22 cfs 0.227 of Primary=3.22 cfs 0.227 of Total Runoff Area = 28.430 ac Runoff Volume = 0.596 of Average Runoff Depth = 0.25" 93.21% Pervious = 26.500 ac 6.79% Impervious = 1.930 ac Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here} Printed 5/11/2022 HVdroCAD® 9.10 s/n 07054 ©2010 HVdroCAD Software Solutions LLC Paoe 3 Summary for Subcatchment 3S: DA2 PREDEV Runoff = 3.22 cfs @ 12.01 hrs, Volume= 0.227 af, Depth= 0.35" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Rainfall=2.96" Area (ac) CN Description 1.400 98 Unconnected pavement, HSG B 2.660 61 Turf 3.730 55 Woods 7.790 65 Weighted Average, UI Adjusted CN = 61 6.390 82.03% Pervious Area 1.400 17.97% Impervious Area 1.400 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: DA1 PREDEV DEVELOPMENT AREA Runoff = 1.04 cfs @ 12.01 hrs, Volume= 0.095 af, Depth= 0.23" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Rainfall=2.96" Area (ac) CN Description 0.130 98 Impervious 0.300 61 Turf 4.450 55 Woods 4.880 57 Weighted Average 4.750 97.34% Pervious Area 0.130 2.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA 1 PREDEV UNMANAGED Runoff = 2.13 cfs @ 12.04 hrs, Volume= 0.274 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 1-yr Rainfall=2.96" Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 4 Area (ac) CN Description 0.400 98 Impervious 0.260 61 Turf 15.100 55 Woods 15.760 56 Weighted Average 15.360 97.46% Pervious Area 0.400 2.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Link 2L: PDA 1 Inflow Area = 20.640 ac, 2.57% Impervious, Inflow Depth = 0.21" for 1-yr event Inflow = 2.97 cfs @ 12.03 hrs, Volume= 0.369 of Primary = 2.97 cfs @ 12.03 hrs, Volume= 0.369 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Summary for Link 4L: PDA 2 Inflow Area = 7.790 ac, 17.97% Impervious, Inflow Depth = 0.35" for 1-yr event Inflow = 3.22 cfs @ 12.01 hrs, Volume= 0.227 of Primary = 3.22 cfs @ 12.01 hrs, Volume= 0.227 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 5 Time span=5.00-60.00 hrs, dt=0.05 hrs, 1101 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment3S: DA2 PREDEV Runoff Area=7.790 ac 17.97% Impervious Runoff Depth=1.62" Tc=7.0 min UI Adjusted CN=61 Runoff=20.95 cfs 1.053 of Subcatchment5S: DA1 PREDEV Runoff Area=4.880 ac 2.66% Impervious Runoff Depth=1.33" Tc=5.0 min CN=57 Runoff=11.12 cfs 0.541 of Subcatchment6S: DA 1 PREDEV Runoff Area=15.760 ac 2.54% Impervious Runoff Depth=1.26" Tc=7.0 min CN=56 Runoff=31.60 cfs 1.655 of Link 2L: POA 1 Inflow=42.29 cfs 2.195 of Primary=42.29 cfs 2.195 of Link 4L: POA 2 Inflow=20.95 cfs 1.053 of Primary=20.95 cfs 1.053 of Total Runoff Area = 28.430 ac Runoff Volume = 3.248 of Average Runoff Depth = 1.37" 93.21% Pervious = 26.500 ac 6.79% Impervious = 1.930 ac Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 6 Summary for Subcatchment 3S: DA2 PREDEV Runoff = 20.95 cfs @ 11.99 hrs, Volume= 1.053 af, Depth= 1.62" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Rainfall=5.41" Area (ac) CN Description 1.400 98 Unconnected pavement, HSG B 2.660 61 Turf 3.730 55 Woods 7.790 65 Weighted Average, UI Adjusted CN = 61 6.390 82.03% Pervious Area 1.400 17.97% Impervious Area 1.400 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: DA1 PREDEV DEVELOPMENT AREA Runoff = 11.12 cfs @ 11.97 hrs, Volume= 0.541 af, Depth= 1.33" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Rainfall=5.41" Area (ac) CN Description 0.130 98 Impervious 0.300 61 Turf 4.450 55 Woods 4.880 57 Weighted Average 4.750 97.34% Pervious Area 0.130 2.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA 1 PREDEV UNMANAGED Runoff = 31.60 cfs @ 12.00 hrs, Volume= 1.655 af, Depth= 1.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 10-yr Rainfall=5.41" Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 7 Area (ac) CN Description 0.400 98 Impervious 0.260 61 Turf 15.100 55 Woods 15.760 56 Weighted Average 15.360 97.46% Pervious Area 0.400 2.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Link 2L: PDA 1 Inflow Area = 20.640 ac, 2.57% Impervious, Inflow Depth = 1.28" for 10-yr event Inflow = 42.29 cfs @ 11.99 hrs, Volume= 2.195 of Primary = 42.29 cfs @ 11.99 hrs, Volume= 2.195 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Summary for Link 4L: PDA 2 Inflow Area = 7.790 ac, 17.97% Impervious, Inflow Depth = 1.62" for 10-yr event Inflow = 20.95 cfs @ 11.99 hrs, Volume= 1.053 of Primary = 20.95 cfs @ 11.99 hrs, Volume= 1.053 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 8 Time span=5.00-60.00 hrs, dt=0.05 hrs, 1101 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment3S: DA2 PREDEV Runoff Area=7.790 ac 17.97% Impervious Runoff Depth=4.11" Tc=7.0 min UI Adjusted CN=61 Runoff=54.28 cfs 2.670 of Subcatchment5S: DA1 PREDEV Runoff Area=4.880 ac 2.66% Impervious Runoff Depth=3.63" Tc=5.0 min CN=57 Runoff=31.90 cfs 1.475 of Subcatchment6S: DA 1 PREDEV Runoff Area=15.760 ac 2.54% Impervious Runoff Depth=3.51" Tc=7.0 min CN=56 Runoff=93.55 cfs 4.606 of Link 2L: POA 1 Inflow=123.97 cfs 6.082 of Primary=123.97 cfs 6.082 of Link 4L: POA 2 Inflow=54.28 cfs 2.670 of Primary=54.28 cfs 2.670 of Total Runoff Area = 28.430 ac Runoff Volume = 8.752 of Average Runoff Depth = 3.69" 93.21% Pervious = 26.500 ac 6.79% Impervious = 1.930 ac Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here} Printed 5/11/2022 HVdroCAD® 9.10 s/n 07054 ©2010 HVdroCAD Software Solutions LLC Paoe 9 Summary for Subcatchment 3S: DA2 PREDEV Runoff = 54.28 cfs @ 11.99 hrs, Volume= 2.670 af, Depth= 4.11" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Rainfall=8.86" Area (ac) CN Description 1.400 98 Unconnected pavement, HSG B 2.660 61 Turf 3.730 55 Woods 7.790 65 Weighted Average, UI Adjusted CN = 61 6.390 82.03% Pervious Area 1.400 17.97% Impervious Area 1.400 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: DA1 PREDEV DEVELOPMENT AREA Runoff = 31.90 cfs @ 11.96 hrs, Volume= 1.475 af, Depth= 3.63" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Rainfall=8.86" Area (ac) CN Description 0.130 98 Impervious 0.300 61 Turf 4.450 55 Woods 4.880 57 Weighted Average 4.750 97.34% Pervious Area 0.130 2.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA 1 PREDEV UNMANAGED Runoff = 93.55 cfs @ 11.99 hrs, Volume= 4.606 af, Depth= 3.51" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 100-yr Rainfall=8.86" Rivers Edge Pre Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here} Printed 5/11/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 10 Area (ac) CN Description 0.400 98 Impervious 0.260 61 Turf 15.100 55 Woods 15.760 56 Weighted Average 15.360 97.46% Pervious Area 0.400 2.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Link 2L: PDA 1 Inflow Area = 20.640 ac, 2.57% Impervious, Inflow Depth = 3.54" for 100-yr event Inflow = 123.97 cfs @ 11.98 hrs, Volume= 6.082 of Primary = 123.97 cfs @ 11.98 hrs, Volume= 6.082 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Summary for Link 4L: PDA 2 Inflow Area = 7.790 ac, 17.97% Impervious, Inflow Depth = 4.11" for 100-yr event Inflow = 54.28 cfs @ 11.99 hrs, Volume= 2.670 of Primary = 54.28 cfs @ 11.99 hrs, Volume= 2.670 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-60.00 hrs, dt= 0.05 hrs Post-Dev Runoff Quantity Calculations: Post-Dev Drainage Map Ditch Drainage Map LD-268 Ditch Calculations Storm Structure Drainage Map LD-204 Inlet Calculations LD-229 Pipe Capacity Calculations Energy Balance Equation Summary Post-Dev HydroCAD Report ------------------------------ °DA-DA2 UNMANAGED 5.66 AC C=0.39 TOC=7 min .W RIVER'S EDGE POSTDEVELOPMENT DRAINAGE AREA MAP 0 Q i DA-DEV TO DRY POND 1.88 AC C=0.51 TOC=5 min 0 i Energy Balance Equation Summary For POA 1 Rivers Edge POA 1 2yr,2CHrsrormdormarame: 1-TEAR STORM ANALYSIS To meet Energy Balance Requirements, Cull I.E.'(ovR�; Rv.To..a.x)/Rv�„!, Reduce Flow @ POA M: Achieved Total Runoff (including Offsite) (Q,ad-Max Qom.) = required reduction@POA PREHEV POST➢EV Pre Onsite Drainage Area = 688 ac 106 - 013 = 0.91 c& requiretl 1-TR Qpre= 2W Qrpoet= 21M Post One its Drainage Area = d8A ac ACHIEVED i-yr REDUCTION AT POA 1: 2TR Qpre= tp.22 Qspost= 692 Or�ea.q�e = 1.Of I = OB o.93 c& 10 TR Qpre= 6229 Qmpost= 5652 RVp wi- 0.035 Ms. C.- - 0.13 ch ACHIEVED 1 TR Retluction 10 TR Retlutlion RV�p=e 0.9J -tares Runoff to tM1le point le compliant with 9VAC2G3]O 6FC(21b because tM1e total ,anoRto tM1le point le Note_ Bince tM1e 1 yr retluctlon of tM1e total runoff (including oRzlte are Is greeter than the reduction reduced 0y an amount exceeding the reduction requiretl 0y the enter9y 0elena. equation. requiretl 5y tM1e EnerOY Balance Equation. Runoff at this POA is compliant with the Energy Belence Site<om lies with 9VAC2iBiD-B6c2E decadee tM1e 111 r eak runoff ie retlucetl. E uation Rivers Edge POA 2 �e...we•e51.F.'Inc.s.,.w•e'RVr..w,.r+wel/Rve...wre Cewediae5 (Qy..uiRV,wewd)/Rve•..°e•e Pre-0ev CA= 1.19 ac Post-0ev �A= Q.-raw-bled = 7.16 ac RVr..w..wee = 0.22] Max Qe.,- R19 ds am Aerated Poill Max Runoff OW a 2,011 Site carrplies MIT 9VAC258]R88-(3A M aximum Outer 20.96oh(predee) Achieted Q10yr as 16.166h DA-DA1 UNMANAGED 16.14 AC C=0.31 TOC=7 min �T4 a, A,� o - < 6 SF AC SF AC AC SF AC SF AC SF AC (MIN) 0 !� o o DA 1 Area Area Impervious Impervious C A Pervious Pervious Turf Turf Woods Woods TO DETENTION (PIPE) 212,617 4.88 139,738 3.21 0.69 4.88 72,880 1.67 72,880 1.67 0 0.00 5.00 DA 1 UNMANAGED 702,853 16.14 450 0.30 16.14 7OZ403 16.12 92,770 2. 609,633 00 /.00 - DA 1TOTAL 915,470 21.02 140,188 0.99 21.02 775,283 17.80 165.650 609,633 14.00 "• SF AC SF AC AC SF AC SF AC SF AC (MIN) DA 2 Area Area Impervious Impervious C A Pervious Pervious Turf Turf Woods Woods TOC DETENTION (POND) 65,687 L51 27,696 0.55 1.51 37,991 0.87 37,991 0 5.00 DA2 Unmanaged 263,053 6.04 36,689 0.38 6.04 226,364 5.20 66,195 160169 7.00 DA2TOTAL 328,740 7.55 64,385 0.42 7.55 264,355 6.07 104,186 160,169 DA-DEV 4.88 AC ��=0.69 TOC=5 min Rivers Edge Post -Development Drainage Area Summary SF AC SF AC AC SF AC SF AC SF AC (MIN) DA 1 Area Area Impervious Impervious C A Pervious Pervious Turf Turf Woods Woods TOC DETENTION (PIPE) 212,617 4.88 139,738 3.21 0.69 4.88 72,880 1.67 72,880 1.67 0 0.00 5.00 DA 1 UNMANAGED 702,853 16.14 450 0.01 0.30 16.14 702,403 16.12 92,770 2.13 609,633 14.00 7.00 DA 1 TOTAL 915,470 21.02 140,188 3.22 0.99 21.02 775,283 17.80 165,650 3.80 609,633 SF AC SF AC AC SF AC SF AC SF AC (MIN) DA2 Area Area Impervious I Impervious C A Pervious Pervious Turf Turf Woods I Woods TOC DETENTION (POND) 65,687 1.51 27,696 0.55 1.51 37,991 0.87 37,991 0.87 0 5.00 DA2 Unmanaged 263,053 6.04 1 36.689 0.38 1 6.04 1 226,364 5.20 66,195 1.52 160169 7.00 DA2 TOTAL 328,740 7.55 64,385 0.42 1 7.55 1 264,355 6.07 104,186 2.39 160,169 6110i o' ttl\`tlr r' i \ lilliil N`�ell it `\ iifllil \1.3lii\ _ l'•i \ .,�'d` t .1 nil I' °rli ``\ -------__-' \ e \ , .��h�;\,� SCC - -- - \ \IDA=O:, C ; \ 01 \ `�`. \ \` \`PI\\ \ \ 'Inn,OWF i \ \ �. xil `t i liii \ ` i . \�:�. ``��`\`.` :Illi �> i(it Jiri I\ilil �I '� \� \�.`��1\`J \\\ `r \�llii .. 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""�l`i\ `N ♦ t t t 1 �\ 1` r t \ t t 1 I \` . ` O\\`�.`` `� `111\\t` \` .xt ttr 1b .. �`�`�• ` tttt\�. .`\� xx ' \1 ' x\ f 'r I'�t, t\I; \\\ `\\\`'i`\\J' t t \txt ttt t \` xxl ��. -It t t t 1 1 1 t t 1\ .Ir 1 i I t \♦ \ \ \. 1 tt N \ r r UH tl I li I I i i t\ 1 1111W, i (1 ,x\In \`�Pt �`i `.`} / i ` I \ \ - \♦ \ ll il'ii \I'li'li'li l <II)♦lrl >. \.11\ i `�`�,``. �\` ♦\ ' \\Ills \`\ \\ l 1li`t 11 i i I i li11i\lx Itllil;liil i >`t\\\Ill l l l /�<\\ Hilt \ `\�` 1 i II I; i;Iiili !i`\\�� `x\ \ \ ( \`\` i'i' \ \\ \ r` 1111111\\.`\I(11;\\ \ \ \ ( ;i\\ i/ l l` `\ C(tit ,\\ \\\` iil'r "F. . `I\\\ tr \ttlt 111 1 / \\ =- RIVER'S EDGE POST DEVELOPMENT DITCH DRAINAGE AREA MAP SCC 3 DA=0.36AC Rivers Edge Modified LD-268 Roadside and Median Ditch Design Fonn Sal. Slope Min_ Max Earth Ditch C A To 12 110 02 010 - 1 L - 1 R Slope Ft/Ft Slope Ft/Ft Alowable Velocity n= 03 Vall.- 2yr Wdocity l"r "Depth Matting Type Freehoam ehannel oepm INCR ACC 1 0.44 0.25 0.11 0.11 5.0 5.39 7.05 0.61 0.79 2 2 0.02 0.07 4.0 2.33 0.50 EC-2 TYPE 1 0.50 1.00 2 0.55 0.64 0.35 0.35 5.0 5.39 7.05 1.89 2.47 2 2 0.01 0.10 4.0 3.54 0.88 EC-2 TYPE 1 0.12 1.00 3 0.63 0.36 0.22 0.22 5.0 5.39 7.05 1.20 1.57 2 2 0.01 0.08 4.0 2.91 0.74 EC-2 TYPE 0.26 1.00 4 ' • • • • 1.06 26.70 1 2 2 0.13 0.23 7.0 4.95 1.22 EC-3 TYPEI 0.78 2.00 2-yr Velocity calculations performed using steepest slope 82-yr flow 10-yr Depth calculation performed using shallowest slope 8 I0yr 1= ' Flmnnes taken from HydnnCAD mortal SCC sf ac Imp (sf) Imp (ac) Turf (sf) Turf (ac) C 1 11099 0.25 2599 0.06 8500 0.20 0.44 2 27751 0.64 11545 027 16206 0.37 0.55 3 15490 0.36 8432 0.19 7058 0.16 0.63 I I I I \ cc\\11II I I I 1 � a f l l f u I ! \ \ \ \ It \ \ \ \ f W I II 1 J W II La -cc 1 wo I zi I � 1 I w 1 I 1;0 0 80 160 240 ► a:0 777 Scale: 1 Rivers Edge Modified LD-268 Roadside and Median Ditch Design Form Side Slope Min. Max Earth Ditch C A CA Tc 12 110 Q2 010 :1 L .1 R Slope FVFt Slope Ft/Ft Allowable Velocity nw.03 Vel.' 2-yr *Velocity 10-yr "Depth Matting Type rremoem Channel Depth INCR I ACC 1 0.44 0.25 0.11 0.11 5.0 5.39 7.05 0.61 0.79 2 2 0.02 0.07 4.0 2.33 0.50 EC-2 TYPE 1 0.50 1.00 2 0.55 0.64 0.35 0.35 5.0 5.39 7.05 1.89 2.47 2 2 0.01 0.10 4.0 3.54 0.88 EC-2 TYPE 1 0.12 1.00 3 0.63 0.36 0.22 0.22 5.0 5.39 7.05 1.20 1.57 2 2 0.01 0.08 4.0 2.91 0.74 EC-2 TYPE 1 0.26 1.00 4 1.06 26.70 2 2 0.13 0.23 7.0 4.95 1.22 EC-3 TYPE 1 0.78 2.00 2-yr Velocity calculations performed using steepest slope & 2-yr flow 10-yr Depth calculation performed using shallowest slope & 10-yr flow Fbwrates taken from HydroCAD model ----- ------ _____--- __---- _--_ `-� - �_-----_______ `-_\ \� `\ \�- -_� �- �i=i ii -- --_ _--_____-- =_ -` _� - _ ----- - -_ _ _rT-___ __ ___ ___ _`-_ _____--_-__��` �� ���___-�-_�_ �_____-_ �_--_ �_�_�� -- `� ---_ -_ --- ______ __ = _= RIVER'S EDGE _ ; - ; - _ _ __ _ _ - -_------ --- -- -- ;_--- - - ---- -- - _ _- _-_- - - -- ;______________________ _ __ STORM STRUCTURE - ; \\ -----------`---_ ___ _ = - `--- -- _ _ = =_ - DRAINAGE AREA MAP - -\\ <;c ___ --- - ---- --- \ -- It IN, IN NN . ♦ \ \ \ \ ��\ ` `\ `` ` `- - O \ 1 1 \ 1 1 1 1 1 1 1 \ \ \` \ \ \ \ . \ `\ \` \ \\ \\ \ ♦ \ \ 1 1 � I�� \`� \\ ` `` \ \r.`. . `. \\ \ • m ` \ 1 1 \ I 1 \ 1 1 1 I i `. \ \ \ / ash \ \. ♦ +♦ \ \ \\ \ ♦ \ \ .......\.,. _\ :..::.T.�.::ikk.:.. ` \ \ \ ` 3 ` 0 `— ka�, � \ 1 I 1 1 ,</\`���C��7ry / 1 \— \ \ \ \ \ ♦ `� "•':: `::ki#.:::`:`:::. :::::. \ \ . `. `�, �\ ``` 1 \ e �./! r i i i li IIA \tT LP�I ,/ Y I 1 / CIt a , . / : / �'. :: , / : : '� -.ter \ \ \' % \`a I / � �• r / / / / \ \ \ 1 \ \ Pm UO IN I \\\`\\\\�\\\\; \.; •'°\\`.``�``—,_``— _\\�—\�```--_ __— — _ � _ F_. �-'/ / 11y��/ "�, / IN �`--- ---- - -------------- 6`¢,! / ------------ _ 9 AC \ \ \ \ � `�\ `\`` \ � .� �-- e•c '•ew-- i/2 � — � ��"" \ i' "may\ .'�, �' � _ / � / \\ \♦`\\ `\\ `\ \♦ `♦♦ ` \ \ ``� �—______ —`— — -- \ \ � —_ l 1 -- - - \\\\ \ 1\ - `-` ----- ScOale: 1"=200' 200 � 400 600 Rivers Edge Storm Structure Drainage Area Summary Inlet Area (st) Area (ac) Read (sf) Other Impervious (sf) Impervious (sf) Impervious (ac) Turf (sf) Turf (ac) c F7 7368 0.17 2777 0 2777 0.06 4591 0.11 0.53 F6 4214 0.10 3031 165 3196 0.07 1018 0.02 0.76 F5 14208 0.33 8196 1024 9220 0.21 4988 0.11 0.69 F4 14910 0.34 7126 1297 8423 0.19 6487 0.15 0.64 F3 11107 0.25 5176 0 5176 0.12 5931 0.14 0.58 F2B 20417 0.47 11371 1042 12413 0.28 8004 0.18 0.66 F2A 3473 0.08 2029 449 2478 0.06 995 0.02 0.73 F2 7506 0.17 3467 0 3467 0.08 4039 0.09 0.58 E3 14704 0.34 7572 758 8330 0.19 6374 0.15 0.64 E2 14771 0.34 7397 1041 8438 0.19 6333 0.15 0.64 D2 8342 0.19 5033 611 5644 0.13 2698 0.06 0.71 C3 12988 0.30 5981 569 6550 0.15 6438 0.15 0.60 C2 16430 0.38 7388 1063 8451 0.19 7,979 0.18 0.61 B2 10836 0.25 5274 636 5910 0.14 4926 0.11 0.63 J3 38850 0.89 14144 0 14144 0.32 24706 0.57 0.52 Rivers Edge LD-204 Stormwater Inlet Computations Inlets on Grace Only Sag Inlets Only wLE O£Z mxxUa ooa< 13� - irc U E 11 1 1 o. <5 1 E1 2 2'1 2 35 fi 8 9 9 19 1 11 12 13 ib 16 1] 1 18 1 19 2 20 22 23 24(R) (im60 (cls) (cts) (c1s) ff) Pr) V) f) Pf) (ft) (R) (cts) (cts) (fl) 01 (R) (fl) F7 DI-3C 8 7368 0.17 0.53 0.09 4.0 0.36 0.00 0.36 0.015 0.015 0.020 0.020 - - - - - 0.09 0.5 0.18 2.83 6.6 0.58 0.00 0.58 0.015 0.015 0.020 0.020 - - - - - 0.11 0.5 0.21 3.90 F6 DI-3B 10 4214 0.10 0.76 0.07 4.0 0.29 0.00 0.29 0.015 0.040 0.015 0.083 1.40 0.12 100.0% 0.29 0.00 - - - - 6.5 0.47 0.00 0.47 0.015 0.040 0.015 0.83 1.68 0.14 100.0% 0.47 0.00 - - - - F5 DI-3B 10 14208 0.33 0.69 0.22 4.0 0.90 0.00 0.90 0.015 0.040 0.015 0.083 2.78 0.18 100.0% 0.90 0.00 - - - - 6.5 1.46 0.00 1.46 0.015 0.040 0.015 0.83 4.82 0.21 100.0% 1.46 0.00 - - - - F4 DI-3B 10 14910 0.34 0.64 0.22 4.0 0.87 0.00 0.87 0.015 0.040 0.015 0.083 - - - - - 0.18 0.5 0.35 1.11 6.5 1.42 0.00 1.42 0.015 0.040 0.015 0.83 - - - - - 0.21 0.5 0.41 1.53 F3 DI-3B 12 11107 0.25 0.58 0.15 4.0 0.59 0.00 0.59 0.015 0.100 0.020 0.083 1.54 0.13 100.0% 0.59 0.00 - - - - 6.5 0.96 0.00 0.96 0.015 0.100 0.020 0.83 1.85 0.15 100.0% 0.96 0.00 - - - - F2 DI-3B 14 7506 0.17 0.58 0.10 4.0 0.40 0.00 0.40 0.015 0.100 0.020 0.020 3.24 0.8 100.0% 0.40 0.00 - - - - 6.5 0.65 0.00 0.65 0.015 0.100 0.020 0.020 3.89 0.08 100.0% 0.65 0.00 6.5 2.03 0.00 2.03 0.015 0.030 0.010 0.010 - - - - - 0.12 0.5 0.23 13.2] F2 DI-3B 10 34]3 0.08 0.73 0.06 4.0 0.23 0.00 0.23 0.015 0.030 0.010 0.010 5.09 0.05 100.0% 0.23 0.00 - - - - 6.5 1.40 0.00 1.40 0.015 0.008 0.050 0.83 E2 DI-3B 10 14M 0.38 0.64 0.24 4.0 0.97 0.00 0.97 0.015 0.08 0.050 0.083 0.28 0.5 0.% 1.52 0.24 0.5 0.49 1.19 02 DI-3B 10 8342 0.19 0.71 0.14 6.5 0,88 0.00 0.88 0.015 0.008 0.050 0.083 3.40 0.24 100.0% 0. 8 0.00 - - - - C2 DI-3B 10 16430 0.38 0.61 0.23 6.5 6.5 1.1] 0.92 1.49 0.00 0.00 0.00 1.17 0.92 1.49 0.015 0.015 0.015 0.008 0.0 0.0080 0.008 0.050 0.050 0.050 0.83 0.083 0.83 - - - - - - - - - 0.26 0.24 0.28 0.5 0.5 0.5 0.52 0.48 0.57 1.36 1.15 1.58 B2 DI-3B 10 10836 0.25 0.63 0.16 4.0 6.5 0.62 1.01 0.00 0.8 0.62 1.01 0.015 0.015 0.08 0.008 0.050 0.050 0.083 0.083 2.85 3.64 0.21 100.0% 0.62 0.00 2.98 100.0% 1.01 0.00 - - - - J3 DI-] 3X3 38850 0.89 0.52 0.46 4.0 6.5 1.85 3.01 0.00 0.8 1.85 3.01 0.015 0.015 0.08 0.008 0.050 0.050 0.083 0.083 - - - - - 0.16 0.22 0.5 0.5 0.31 0.43 4.79 5.99 LD-229 Storm Drain Design Computations Rivers Edge From TO Catch. Runoff Increment Accum. Accum. Total Total Total Up Down Pipe Invert Pipe Pipe Velocity Flowtime Structure Structure Area Coef AC AC with RD TOC Intensity Flow Invert Invert Length Slope Diameter Capacity Increment (ac) (ac ac) ac (min) (iNhr) cis Elev. Elev. (ft) % (in) cfs) MIS) (min) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 J3 J2 0.89 0.52 0.46 0.46 0.46 5.0 6.81 3.15 388.25 387.57 47.49 1.43% 15 8.37 6.34 0.12 J2 J1 0.00 0.00 0.00 0.46 0.46 5.1 6.77 3.13 387.37 386.00 156.94 0.87% 15 7.02 5.26 0.50 'H3 H2 - - - - - - - 5.25 383.00 374.00 130.82 6.88% 15 18.36 12.91 0.17 'H2 H1 5.25 369.80 358.00 102.98 11.46% 15 23.69 15.52 0.11 F7 F6 0.17 0.53 0.09 0.09 0.09 5.0 6.81 0.61 438.75 435.75 118.46 2.53% 15 11.1 4.86 0.41 F6 F5 0.10 0.76 0.07 0.16 0.58 5.4 6.70 3.87 435.55 431.36 149.89 2.80% 15 11.7 8.6 0.29 F5 F4 0.33 0.69 0.22 0.80 1.64 5.7 6.62 10.82 431.16 425.36 151.35 3.83% 15 13.7 12.4 0.20 F4 F3 0.34 0.64 0.22 1.85 2.27 5.9 6.56 14.90 421.00 418.00 38.07 7.88% 15 19.6 17.6 0.04 F3 F2 0.25 0.58 0.15 2.42 2.42 5.9 6.55 15.84 417.80 414.57 37.11 8.70% 15 20.6 18.5 0.03 F2 F1 0.17 0.58 0.10 4.97 4.97 6.0 6.54 32.51 408.08 400.74 89.51 8.20% 18 32.9 20.1 0.07 F2C F2B 0.47 0.66 0.31 0.31 1.56 5.0 6.81 10.63 410.67 409.78 98.6 0.90% 18 10.8 7.0 0.24 F2B F2A 0.00 0.00 0.00 1.56 1.56 5.0 6.81 10.63 409.58 408.86 80.7 0.90% 18 10.8 7.0 0.19 F2A F2 0.08 0.73 0.06 1.62 2.45 5.2 6.75 16.56 408.66 408.28 75.0 0.50% 24 17.3 6.3 0.20 E4 E3 0.34 0.64 0.22 0.22 0.63 5.0 6.81 4.31 399.00 397.75 101.2 1.24% 15 7.8 6.5 0.26 E3 E2 0.00 0.00 0.00 0.63 0.63 5.0 6.81 4.31 397.55 397.00 31.7 1.74% 15 9.2 7.4 0.07 E2 E1 0.34 0.64 0.22 0.85 1.27 5.0 6.81 8.62 396.80 396.40 28.4 1.41% 18 13.5 8.1 0.06 D2 D1 0.19 0.71 0.14 0.14 0.97 5.0 6.81 6.59 400.00 398.00 23.4 8.53% 15 20.4 14.8 0.03 C3 C2 C2 C1 0.30 0.38 0.60 0.61 0.18 0.23 0.18 0.83 0.60 1.66 5.0 5.0 6.81 6.81 4.06 11.29 400.54 399.00 399.20 397.50 112.9 113.3 1.19% 1.32% 15 18 7.7 13.0 6.3 8.3 0.30 0.23 B2 B1 0.25 0.63 0.16 0.16 0.57 5.0 6.81 3.90 400.00 398.00 23.8 8.40% 15 20.3 12.8 0.03 'G1B At - - - - - - - 26.70 393.24 392.00 18.0 6.90% 36 189.8 19.0 - 'Flow rate from detention taken from 10-yr HydroCAD model ROOF DRAIN Computations Roof Drain Catch. Runoff Increment Accum. Total Total Total To Str # Area Coeff. AC AC TOC Intensity Flow Unit # (ac) (ac) (ac) (min) (in/hr) (cfs) 1 2 3 4 5 6 7 8 9 1 F6 0.03 0.90 0.03 0.03 5.00 6.81 0.21 2 F6 0.03 0.90 0.03 0.03 5.00 6.81 0.21 3 F5 0.03 0.90 0.03 0.03 5.00 6.81 0.21 4 F5 0.03 0.90 0.03 0.03 5.00 6.81 0.21 5 F5 0.03 0.90 0.03 0.03 5.00 6.81 0.21 6 F5 0.03 0.90 0.03 0.03 5.00 6.81 0.21 7 F4 0.03 0.90 0.03 0.03 5.00 6.81 0.21 8 F4 0.03 0.90 0.03 0.03 5.00 6.81 0.21 9 F2A 0.03 0.90 0.03 0.03 5.00 6.81 0.21 10 F2A 0.03 0.90 0.03 0.03 5.00 6.81 0.21 11 F213 0.03 0.90 0.03 0.03 5.00 6.81 0.21 12 F213 0.03 0.90 0.03 0.03 5.00 6.81 0.21 13 F2A 0.03 0.90 0.03 0.03 5.00 6.81 0.21 14 F2A 0.03 0.90 0.03 0.03 5.00 6.81 0.21 15 F213 0.03 0.90 0.03 0.03 5.00 6.81 0.21 16 F213 0.03 0.90 0.03 0.03 5.00 6.81 0.21 17 F213 0.03 0.90 0.03 0.03 5.00 6.81 0.21 18 F26 0.03 0.90 0.03 0.03 5.00 6.81 0.21 19 C3 0.03 0.90 0.03 0.03 5.00 6.81 0.21 20 C3 0.03 0.90 0.03 0.03 5.00 6.81 0.21 21 C2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 22 C2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 23 C2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 24 C2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 25 B2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 26 B2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 27 D2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 28 D2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 29 D2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 30 D2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 31 E2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 32 E2 0.03 0.90 0.03 0.03 5.00 6.81 0.21 33 E3 0.03 0.90 0.03 0.03 5.00 6.81 0.21 34 E3 0.03 0.90 0.03 0.03 5.00 6.81 0.21 Energy Balance Equation Summary For POA 1 Rivers Edge POA 1 1Yr.39Hrsmnnr mwrl:on: 1-YEAR STORM ANALYSIS: To mfel Ene gy Me. Requirements, I.F.'(QP__,'RV__,)/RV_, R¢Wce Hiss I PDA by: AchiwOd Total R000if(InclUdln Make O�c(Q 'In/s l/RV� (a .M. Om.) = requlrelrelucLan®POA PREOEV POSTOEV Pre Olcelle Drainage Area = LBB iM - 013 = 0.91 ch lequlred 1-YR pPre= ].9] pest- 2.9f Post Omlle Drainage Area = 488 as ACHIEVEO1jr REOULTIONATPOAI: 3-YR Qpre= 111M O.post= g.9Y Qe..�u 1.W IF. = 0.8 9.93 cfa 1(1 Qpre= Q,N O"Past= III RVe-n--t= 0.035 Nat ci•— • 0.13 eft RVo..a.Qe 0.612 ACHIEVED 1.YR Reduction I(i Reduction o.w eares NMe: Since the 1-yr reJuctlonM quIdol m un atthi Po0511earea)I5greatersEnIMre]uctlon by the Enegy Ealance Equation, Runo%al this POA Is compliant vAIM1 Ne Ereryy Balanre E uallon. RuroXlo Nlsypoim an iscomment asevAtM19VAC2S8]ILBCeme by use ea Idallame to IM1Is paint Is rMure!Uyanamount AG2M 7IM2udlonreq t Uymee km eis equdlm. Slle mmplleS vnIM1 9VACl58]I188f(2)G Mrause lM lDyr peak mno%Is 2]ucel. Energy Balance Equation Summary Rivers Edge POA 2 Qdeveloped� I.F. *(Q,reA.lopM*RVP,e-Developed)/Rvdeeeloped QdeveloWed (Qrorened*RVf0M ed)/RvdeMoW Pre-Dev DA= 7.79 ac Post-Dev DA= 7.18 ac QpredevelopM = 3.22 RVPre Develold = 0.227 Max Qd k= 2.16 cis RVce.10,d = 0.268 Achieved Post-Dev Max Runoff Q1yr = 2.08cfs. Site complies with 9VAC25-870-66-(3)A Maximum Q1Qyr = 20.95cfs (predev) Achieved Q10yr = 16.13cfs Flow Rates Flow Rates Predev cfs Postdev cfe 1- r 3.22 1- r 2.08 2-yr 6.87 2-yr 4.56 10-yr 20.95 10-yr 16.13 100- 54.28 1 00-W 48.01 E38723 Post Development HydroCAD Report Rivers Edge 2S 18 6S 5S DA1 Unma aged :711, ipe Detention DA2 Unm aged Dev o Dry Pond 3P 7P DET TION SYSTEM ry Pond 4L 8L POA1 POA2 Sub4 Reach Aon Llnk Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here} Printed 6/30/2022 Time span=1.00-60.00 hrs, dt=0.05 hrs, 1181 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Dev to Pipe Detention Runoff Area=4.880 ac 65.78% Impervious Runoff Depth=1.55" Tc=5.0 min CN=85 Runoff=13.61 cfs 0.632 of Subcatchment2S: DA1 Unmanaged Runoff Area=16.140 ac 0.06% Impervious Runoff Depth=0.18" Tc=7.0 min CN=55 Runoff=1.57 cfs 0.248 of Subcatchment5S: Dev to Dry Pond Runoff Area=1.510 ac 42.38% Impervious Runoff Depth=1.04" Tc=5.0 min CN=77 Runoff=2.82 cfs 0.131 of Subcatchment6S: DA2 Unmanaged Runoff Area=5.670 ac 14.64% Impervious Runoff Depth=0.29" Tc=7.0 min UI Adjusted CN=59 Runoff=1.64 cfs 0.137 of Pond 3P: DETENTION SYSTEM Peak Elev=398.33' Storage=0.340 of Inflow=13.61 cfs 0.632 of Outflow=0.53 cfs 0.632 of Pond 7P: Dry Pond Peak Elev=385.46' Storage=1,935 cf Inflow=2.82 cfs 0.131 of Outflow=0.48 cfs 0.131 of Link 4L: POA1 Inflow=2.04 cfs 0.880 of Primary=2.04 cfs 0.880 of Link 8L: POA2 Inflow=2.08 cfs 0.268 of Primary=2.08 cfs 0.268 of Total Runoff Area = 28.200 ac Runoff Volume = 1.148 of Average Runoff Depth = 0.49" 83.37% Pervious = 23.510 ac 16.63% Impervious = 4.690 ac Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here} Printed 6/30/2022 Runoff = Summary for Subcatchment 1S: Dev to Pipe Detention 13.61 cfs @ 11.96 hrs, Volume= 0.632 af, Depth= 1.55" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Rainfall=2.96" Area (ac) CN Description 3.210 98 Impervious 1.670 61 >75% Grass cover, Good, HSG B 4.880 85 Weighted Average 1.670 34.22% Pervious Area 3.210 65.78% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 2S: DA1 Unmanaged Runoff = 1.57 cfs @ 12.05 hrs, Volume= 0.248 af, Depth= 0.18" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Rainfall=2.96" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG B 2.130 58 Meadow, non -grazed, HSG B 14.000 55 Woods. Good. HSG B 16.140 55 Weighted Average 16.130 99.94% Pervious Area 0.010 0.06% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: Dev to Dry Pond Runoff = 2.82 cfs @ 11.96 hrs, Volume= 0.131 af, Depth= 1.04" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 1-yr Rainfall=2.96" Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here) Printed 6/30/2022 Area (ac) CN Description 0.640 98 Impervious 0.870 61 >75% Grass cover. Good. HSG B 1.510 77 Weighted Average 0.870 57.62% Pervious Area 0.640 42.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA2 Unmanaged Runoff = 1.64 cfs @ 12.02 hrs, Volume= 0.137 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Rainfall=2.96" Area (ac) CN Description 0.830 98 Unconnected pavement, HSG B 1.160 61 >75% Grass cover, Good, HSG B 3.680 55 Woods, Good, HSG B 5.670 63 Weighted Average, UI Adjusted CN = 59 4.840 85.36% Pervious Area 0.830 14.64% Impervious Area 0.830 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Pond 3P: DETENTION SYSTEM Inflow Area = 4.880 ac, 65.78% Impervious, Inflow Depth = 1.55" for 1-yr event Inflow = 13.61 cfs @ 11.96 hrs, Volume= 0.632 of Outflow = 0.53 cfs @ 13.62 hrs, Volume= 0.632 af, Atten= 96%, Lag= 99.7 min Primary = 0.53 cfs @ 13.62 hrs, Volume= 0.632 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 398.33' @ 13.62 hrs Surf.Area= 0.082 ac Storage= 0.340 of Plug -Flow detention time= 337.1 min calculated for 0.632 of (100% of inflow) Center -of -Mass det. time= 337.3 min ( 1,162.8 - 825.5 ) Volume Invert Avail.Storage Storage Description #1 393.24' 0.584 of 108.0" D x 400.01 Pipe Storage Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 1-yr Rainfall=2.96" Prepared by {enter your company name here) Printed 6/30/2022 Device Routing Invert Outlet Devices #1 Primary 393.24' 36.0" Round Culvert L= 18.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 393.24' / 392.00' S= 0.0689 T Cc= 0.900 n= 0.012 #2 Device 1 393.24' 3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 399.44' 12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 400.74' 6.7' long x 1.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 7.5' Crest Height #5 Primary 402.24' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.53 cfs @ 13.62 hrs HW=398.33' (Free Discharge) 1=Culvert (Passes 0.53 cfs of 56.87 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.53 cfs @ 10.72 fps) 3=Orifice/Grate ( Controls 0.00 cfs) =Sharp -Crested Rectangular Weir( Controls 0.00 cfs) S=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 7P: Dry Pond Inflow Area = 1.510 ac, 42.38% Impervious, Inflow Depth = 1.04" for 1-yr event Inflow = 2.82 cfs @ 11.96 hrs, Volume= 0.131 of Outflow = 0.48 cfs @ 12.17 hrs, Volume= 0.131 af, Atten= 83%, Lag= 12.5 min Primary = 0.48 cfs @ 12.17 hrs, Volume= 0.131 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Peak Elev= 385.46' @ 12.17 hrs Surf.Area= 1,627 sf Storage= 1,935 cf Plug -Flow detention time= 53.8 min calculated for 0.131 of (100% of inflow) Center -of -Mass det. time= 53.2 min ( 905.8 - 852.6 ) Volume Invert #1 384.00' Avail. Descri 10,553 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 384.00 1,018 0 0 386.00 1,851 2,869 2,869 388.00 2,899 4,750 7,619 388.90 3,620 2,934 10,553 Device Routing Invert Outlet Devices #1 Primary 383.00' 18.0" Round Culvert L= 130.8' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 383.00' / 370.00' S= 0.0994 T Cc= 0.900 n= 0.012 #2 Device 1 384.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 387.00' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Post Development - Rivers Edge Prepared by {enter your company name here) Post-Dev Hydrocad Analysis Type 11 24-hr 1-yr Rainfall=2.96" Printed 6/30/2022 Primary OutFlow Max=0.48 cfs @ 12.17 hrs HW=385.46' (Free Discharge) tTCulvert (Passes 0.48 cfs of 9.82 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.48 cfs @ 5.48 fps) 3=Orifice/Grate ( Controls 0.00 cfs) Summary for Link 4L: POA1 Inflow Area = 21.020 ac, 15.32% Impervious, Inflow Depth = 0.50" for 1-yr event Inflow = 2.04 cfs @ 12.05 hrs, Volume= 0.880 of Primary = 2.04 cfs @ 12.05 hrs, Volume= 0.880 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Summary for Link 8L: POA2 Inflow Area = 7.180 ac, 20.47% Impervious, Inflow Depth = 0.45" for 1-yr event Inflow = 2.08 cfs @ 12.02 hrs, Volume= 0.268 of Primary = 2.08 cfs @ 12.02 hrs, Volume= 0.268 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type/1 24-hr 2-yr Rainfall=3.58" Prepared by {enter your company name here} Printed 6/30/2022 Time span=1.00-60.00 hrs, dt=0.05 hrs, 1181 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Dev to Pipe Detention Runoff Area=4.880 ac 65.78% Impervious Runoff Depth=2.09" Tc=5.0 min CN=85 Runoff=18.11 cfs 0.848 of Subcatchment2S: DA1 Unmanaged Runoff Area=16.140 ac 0.06% Impervious Runoff Depth=0.37" Tc=7.0 min CN=55 Runoff=6.40 cfs 0.502 of Subcatchment5S: Dev to Dry Pond Runoff Area=1.510 ac 42.38% Impervious Runoff Depth=1.49" Tc=5.0 min CN=77 Runoff=4.06 cfs 0.188 of Subcatchment6S: DA2 Unmanaged Runoff Area=5.670 ac 14.64% Impervious Runoff Depth=0.52" Tc=7.0 min UI Adjusted CN=59 Runoff=4.03 cfs 0.248 of Pond 3P: DETENTION SYSTEM Peak Elev=399.72' Storage=0.450 of Inflow=18.11 cfs 0.848 of Outflow=1.06 cfs 0.848 of Pond 7P: Dry Pond Peak Elev=386.08' Storage=3,011 cf Inflow=4.06 cfs 0.188 of Outflow=0.58 cfs 0.188 of Link 4L: POA1 Inflow=6.92 cfs 1.350 of Primary=6.92 cfs 1.350 of Link 8L: POA2 Inflow=4.56 cfs 0.436 of Primary=4.56 cfs 0.436 of Total Runoff Area = 28.200 ac Runoff Volume = 1.786 of Average Runoff Depth = 0.76" 83.37% Pervious = 23.510 ac 16.63% Impervious = 4.690 ac Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type/1 24-hr 2-yr Rainfall=3.58" Prepared by {enter your company name here} Printed 6/30/2022 Runoff = Summary for Subcatchment 1S: Dev to Pipe Detention 18.11 cfs @ 11.96 hrs, Volume= 0.848 af, Depth= 2.09" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Rainfall=3.58" Area (ac) CN Description 3.210 98 Impervious 1.670 61 >75% Grass cover, Good, HSG B 4.880 85 Weighted Average 1.670 34.22% Pervious Area 3.210 65.78% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 2S: DA1 Unmanaged Runoff = 6.40 cfs @ 12.02 hrs, Volume= 0.502 af, Depth= 0.37" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Rainfall=3.58" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG B 2.130 58 Meadow, non -grazed, HSG B 14.000 55 Woods. Good. HSG B 16.140 55 Weighted Average 16.130 99.94% Pervious Area 0.010 0.06% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: Dev to Dry Pond Runoff = 4.06 cfs @ 11.96 hrs, Volume= 0.188 af, Depth= 1.49" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 2-yr Rainfall=3.58" Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type/1 24-hr 2-yr Rainfall=3.58" Prepared by {enter your company name here) Printed 6/30/2022 Area (ac) CN Description 0.640 98 Impervious 0.870 61 >75% Grass cover. Good. HSG B 1.510 77 Weighted Average 0.870 57.62% Pervious Area 0.640 42.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA2 Unmanaged Runoff = 4.03 cfs @ 12.01 hrs, Volume= 0.248 af, Depth= 0.52" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Rainfall=3.58" Area (ac) CN Description 0.830 98 Unconnected pavement, HSG B 1.160 61 >75% Grass cover, Good, HSG B 3.680 55 Woods, Good, HSG B 5.670 63 Weighted Average, UI Adjusted CN = 59 4.840 85.36% Pervious Area 0.830 14.64% Impervious Area 0.830 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Pond 3P: DETENTION SYSTEM Inflow Area = 4.880 ac, 65.78% Impervious, Inflow Depth = 2.09" for 2-yr event Inflow = 18.11 cfs @ 11.96 hrs, Volume= 0.848 of Outflow = 1.06 cfs @ 12.83 hrs, Volume= 0.848 af, Atten= 94%, Lag= 52.3 min Primary = 1.06 cfs @ 12.83 hrs, Volume= 0.848 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 399.72' @ 12.83 hrs Surf.Area= 0.074 ac Storage= 0.450 of Plug -Flow detention time= 371.4 min calculated for 0.848 of (100% of inflow) Center -of -Mass det. time= 371.7 min ( 1,188.8 - 817.2 ) Volume Invert Avail.Storage Storage Description #1 393.24' 0.584 of 108.0" D x 400.01 Pipe Storage Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type/1 24-hr 2-yr Rainfall=3.58" Prepared by {enter your company name here) Printed 6/30/2022 Device Routing Invert Outlet Devices #1 Primary 393.24' 36.0" Round Culvert L= 18.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 393.24' / 392.00' S= 0.0689 T Cc= 0.900 n= 0.012 #2 Device 1 393.24' 3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 399.44' 12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 400.74' 6.7' long x 1.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 7.5' Crest Height #5 Primary 402.24' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.06 cfs @ 12.83 hrs HW=399.72' (Free Discharge) 1=Culvert (Passes 1.06 cfs of 66.99 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.60 cfs @ 12.13 fps) 3=Orifice/Grate (Orifice Controls 0.47 cfs @ 1.69 fps) =Sharp -Crested Rectangular Weir( Controls 0.00 cfs) S=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 7P: Dry Pond Inflow Area = 1.510 ac, 42.38% Impervious, Inflow Depth = 1.49" for 2-yr event Inflow = 4.06 cfs @ 11.96 hrs, Volume= 0.188 of Outflow = 0.58 cfs @ 12.22 hrs, Volume= 0.188 af, Atten= 86%, Lag= 15.6 min Primary = 0.58 cfs @ 12.22 hrs, Volume= 0.188 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Peak Elev= 386.08' @ 12.22 hrs Surf.Area= 1,891 sf Storage= 3,011 cf Plug -Flow detention time= 60.2 min calculated for 0.187 of (100% of inflow) Center -of -Mass det. time= 60.6 min ( 902.6 - 842.0 ) Volume Invert #1 384.00' Avail. Descri 10,553 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 384.00 1,018 0 0 386.00 1,851 2,869 2,869 388.00 2,899 4,750 7,619 388.90 3,620 2,934 10,553 Device Routing Invert Outlet Devices #1 Primary 383.00' 18.0" Round Culvert L= 130.8' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 383.00' / 370.00' S= 0.0994 T Cc= 0.900 n= 0.012 #2 Device 1 384.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 387.00' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Post Development - Rivers Edge Prepared by {enter your company name here) Post-Dev Hydrocad Analysis Type/1 24-hr 2-yr Rainfall=3.58" Printed 6/30/2022 Primary OutFlow Max=0.58 cfs @ 12.22 hrs HW=386.07' (Free Discharge) tTCulvert (Passes 0.58 cfs of 11.45 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.58 cfs @ 6.65 fps) 3=Orifice/Grate ( Controls 0.00 cfs) Summary for Link 4L: POM Inflow Area = 21.020 ac, 15.32% Impervious, Inflow Depth = 0.77" for 2-yr event Inflow = 6.92 cfs @ 12.02 hrs, Volume= 1.350 of Primary = 6.92 cfs @ 12.02 hrs, Volume= 1.350 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Summary for Link 8L: POA2 Inflow Area = 7.180 ac, 20.47% Impervious, Inflow Depth = 0.73" for 2-yr event Inflow = 4.56 cfs @ 12.01 hrs, Volume= 0.436 of Primary = 4.56 cfs @ 12.01 hrs, Volume= 0.436 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here} Printed 6/30/2022 Time span=1.00-60.00 hrs, dt=0.05 hrs, 1181 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Dev to Pipe Detention Runoff Area=4.880 ac 65.78% Impervious Runoff Depth=3.75" Tc=5.0 min CN=85 Runoff=31.69 cfs 1.525 of Subcatchment2S: DA1 Unmanaged Runoff Area=16.140 ac 0.06% Impervious Runoff Depth=1.19" Tc=7.0 min CN=55 Runoff=30.21 cfs 1.602 of Subcatchment5S: Dev to Dry Pond Runoff Area=1.510 ac 42.38% Impervious Runoff Depth=2.97" Tc=5.0 min CN=77 Runoff=8.02 cfs 0.374 of Subcatchment6S: DA2 Unmanaged Runoff Area=5.670 ac 14.64% Impervious Runoff Depth=1.47" Tc=7.0 min UI Adjusted CN=59 Runoff=13.68 cfs 0.696 of Pond 3P: DETENTION SYSTEM Peak EIev=401.81' Storage=0.574 of Inflow=31.69 cfs 1.525 of Outflow=26.70 cfs 1.522 of Pond 7P: Dry Pond Peak EIev=387.23' Storage=5,541 cf Inflow=8.02 cfs 0.374 of Outflow=5.25 cfs 0.374 of Link 4L: POA1 Inflow=56.52 cfs 3.124 of Primary=56.52 cfs 3.124 of Link 8L: POA2 Inflow=16.13 cfs 1.070 of Primary=16.13 cfs 1.070 of Total Runoff Area = 28.200 ac Runoff Volume = 4.196 of Average Runoff Depth = 1.79" 83.37% Pervious = 23.510 ac 16.63% Impervious = 4.690 ac Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here} Printed 6/30/2022 Runoff = Summary for Subcatchment 1S: Dev to Pipe Detention 31.69 cfs @ 11.95 hrs, Volume= 1.525 af, Depth= 3.75" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Rainfall=5.41" Area (ac) CN Description 3.210 98 Impervious 1.670 61 >75% Grass cover, Good, HSG B 4.880 85 Weighted Average 1.670 34.22% Pervious Area 3.210 65.78% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 2S: DA1 Unmanaged Runoff = 30.21 cfs @ 12.00 hrs, Volume= 1.602 af, Depth= 1.19" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Rainfall=5.41" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG B 2.130 58 Meadow, non -grazed, HSG B 14.000 55 Woods. Good. HSG B 16.140 55 Weighted Average 16.130 99.94% Pervious Area 0.010 0.06% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: Dev to Dry Pond Runoff = 8.02 cfs @ 11.96 hrs, Volume= 0.374 af, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 10-yr Rainfall=5.41" Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here) Printed 6/30/2022 Area (ac) CN Description 0.640 98 Impervious 0.870 61 >75% Grass cover. Good. HSG B 1.510 77 Weighted Average 0.870 57.62% Pervious Area 0.640 42.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA2 Unmanaged Runoff = 13.68 cfs @ 11.99 hrs, Volume= 0.696 af, Depth= 1.47" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Rainfall=5.41" Area (ac) CN Description 0.830 98 Unconnected pavement, HSG B 1.160 61 >75% Grass cover, Good, HSG B 3.680 55 Woods, Good, HSG B 5.670 63 Weighted Average, UI Adjusted CN = 59 4.840 85.36% Pervious Area 0.830 14.64% Impervious Area 0.830 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Pond 3P: DETENTION SYSTEM Inflow Area = 4.880 ac, 65.78% Impervious, Inflow Depth = 3.75" for 10-yr event Inflow = 31.69 cfs @ 11.95 hrs, Volume= 1.525 of Outflow = 26.70 cfs @ 12.01 hrs, Volume= 1.522 af, Atten= 16%, Lag= 3.6 min Primary = 26.70 cfs @ 12.01 hrs, Volume= 1.522 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 401.81' @ 12.02 hrs Surf.Area= 0.035 ac Storage= 0.574 of Plug -Flow detention time= 263.3 min calculated for 1.521 of (100% of inflow) Center -of -Mass det. time= 262.6 min ( 1,063.0 - 800.5 ) Volume Invert Avail.Storage Storage Description #1 393.24' 0.584 of 108.0" D x 400.01 Pipe Storage Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 10-yr Rainfall= 5.41 " Prepared by {enter your company name here) Printed 6/30/2022 Device Routing Invert Outlet Devices #1 Primary 393.24' 36.0" Round Culvert L= 18.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 393.24' / 392.00' S= 0.0689 T Cc= 0.900 n= 0.012 #2 Device 1 393.24' 3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 399.44' 12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 400.74' 6.7' long x 1.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 7.5' Crest Height #5 Primary 402.24' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=23.73 cfs @ 12.01 hrs HW=401.68' (Free Discharge) 1=Culvert (Passes 23.73 cfs of 79.10 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.68 cfs @ 13.88 fps) 3=Orifice/Grate (Orifice Controls 3.39 cfs @ 6.78 fps) =Sharp -Crested Rectangular Weir(Weir Controls 19.65 cfs @ 3.22 fps) S=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 7P: Dry Pond Inflow Area = 1.510 ac, 42.38% Impervious, Inflow Depth = 2.97" for 10-yr event Inflow = 8.02 cfs @ 11.96 hrs, Volume= 0.374 of Outflow = 5.25 cfs @ 12.05 hrs, Volume= 0.374 af, Atten= 35%, Lag= 5.8 min Primary = 5.25 cfs @ 12.05 hrs, Volume= 0.374 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Peak Elev= 387.23' @ 12.05 hrs Surf.Area= 2,495 sf Storage= 5,541 cf Plug -Flow detention time= 67.7 min calculated for 0.374 of (100% of inflow) Center -of -Mass det. time= 67.1 min ( 889.2 - 822.1 ) Volume Invert #1 384.00' Avail. Descri 10,553 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 384.00 1,018 0 0 386.00 1,851 2,869 2,869 388.00 2,899 4,750 7,619 388.90 3,620 2,934 10,553 Device Routing Invert Outlet Devices #1 Primary 383.00' 18.0" Round Culvert L= 130.8' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 383.00' / 370.00' S= 0.0994 T Cc= 0.900 n= 0.012 #2 Device 1 384.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 387.00' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Post Development - Rivers Edge Prepared by {enter your company name here) Post-Dev Hydrocad Analysis Type 11 24-hr 10-yr Rainfall=5.41 " Printed 6/30/2022 Primary OutFlow Max=5.04 cfs @ 12.05 hrs HW=387.22' (Free Discharge) tTCulvert (Passes 5.04 cfs of 13.99 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.73 cfs @ 8.42 fps) 3=Orifice/Grate (Weir Controls 4.30 cfs @ 1.54 fps) Summary for Link 4L: POA1 Inflow Area = 21.020 ac, 15.32% Impervious, Inflow Depth = 1.78" for 10-yr event Inflow = 56.52 cfs @ 12.01 hrs, Volume= 3.124 of Primary = 56.52 cfs @ 12.01 hrs, Volume= 3.124 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Summary for Link 8L: POA2 Inflow Area = 7.180 ac, 20.47% Impervious, Inflow Depth = 1.79" for 10-yr event Inflow = 16.13 cfs @ 12.02 hrs, Volume= 1.070 of Primary = 16.13 cfs @ 12.02 hrs, Volume= 1.070 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here} Printed 6/30/2022 Time span=1.00-60.00 hrs, dt=0.05 hrs, 1181 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Dev to Pipe Detention Runoff Area=4.880 ac 65.78% Impervious Runoff Depth=7.05" Tc=5.0 min CN=85 Runoff=57.29 cfs 2.865 of Subcatchment2S: DA1 Unmanaged Runoff Area=16.140 ac 0.06% Impervious Runoff Depth=3.39" Tc=7.0 min CN=55 Runoff=92.40 cfs 4.556 of Subcatchment5S: Dev to Dry Pond Runoff Area=1.510 ac 42.38% Impervious Runoff Depth=6.07" Tc=5.0 min CN=77 Runoff=15.91 cfs 0.764 of Subcatchment6S: DA2 Unmanaged Runoff Area=5.670 ac 14.64% Impervious Runoff Depth=3.87" Tc=7.0 min UI Adjusted CN=59 Runoff=37.19 cfs 1.829 of Pond 3P: DETENTION SYSTEM Peak EIev=402.49' Storage=0.584 of Inflow=57.29 cfs 2.865 of Outflow=56.92 cfs 2.881 of Pond 7P: Dry Pond Peak EIev=387.53' Storage=6,313 cf Inflow=15.91 cfs 0.764 of Outflow=15.05 cfs 0.764 of Link4L: POA1 Inflow=145.21 cfs 7.436 of Primary=145.21 cfs 7.436 of Link 8L: POA2 Inflow=52.16 cfs 2.592 of Primary=52.16 cfs 2.592 of Total Runoff Area = 28.200 ac Runoff Volume = 10.013 of Average Runoff Depth = 4.26" 83.37% Pervious = 23.510 ac 16.63% Impervious = 4.690 ac Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here} Printed 6/30/2022 Runoff = Summary for Subcatchment 1S: Dev to Pipe Detention 57.29 cfs @ 11.95 hrs, Volume= 2.865 af, Depth= 7.05" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Rainfall=8.86" Area (ac) CN Description 3.210 98 Impervious 1.670 61 >75% Grass cover, Good, HSG B 4.880 85 Weighted Average 1.670 34.22% Pervious Area 3.210 65.78% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 2S: DA1 Unmanaged Runoff = 92.40 cfs @ 11.99 hrs, Volume= 4.556 af, Depth= 3.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Rainfall=8.86" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG B 2.130 58 Meadow, non -grazed, HSG B 14.000 55 Woods. Good. HSG B 16.140 55 Weighted Average 16.130 99.94% Pervious Area 0.010 0.06% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 5S: Dev to Dry Pond Runoff = 15.91 cfs @ 11.95 hrs, Volume= 0.764 af, Depth= 6.07" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type 11 24-hr 100-yr Rainfall=8.86" Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here) Printed 6/30/2022 Area (ac) CN Description 0.640 98 Impervious 0.870 61 >75% Grass cover. Good. HSG B 1.510 77 Weighted Average 0.870 57.62% Pervious Area 0.640 42.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 6S: DA2 Unmanaged Runoff = 37.19 cfs @ 11.99 hrs, Volume= 1.829 af, Depth= 3.87" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Rainfall=8.86" Area (ac) CN Description 0.830 98 Unconnected pavement, HSG B 1.160 61 >75% Grass cover, Good, HSG B 3.680 55 Woods, Good, HSG B 5.670 63 Weighted Average, UI Adjusted CN = 59 4.840 85.36% Pervious Area 0.830 14.64% Impervious Area 0.830 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Pond 3P: DETENTION SYSTEM Inflow Area = 4.880 ac, 65.78% Impervious, Inflow Depth = 7.05" for 100-yr event Inflow = 57.29 cfs @ 11.95 hrs, Volume= 2.865 of Outflow = 56.92 cfs @ 11.95 hrs, Volume= 2.881 af, Atten= 1 %, Lag= 0.0 min Primary = 56.92 cfs @ 11.95 hrs, Volume= 2.881 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 402.49' @ 11.95 hrs Surf.Area= 0.000 ac Storage= 0.584 of Plug -Flow detention time= 166.8 min calculated for 2.864 of (100% of inflow) Center -of -Mass det. time= 174.0 min ( 956.9 - 782.9 ) Volume Invert Avail.Storage Storage Description #1 393.24' 0.584 of 108.0" D x 400.01 Pipe Storage Post-Dev Hydrocad Analysis Post Development - Rivers Edge Type 11 24-hr 100-yr Rainfall=8.86" Prepared by {enter your company name here) Printed 6/30/2022 Device Routing Invert Outlet Devices #1 Primary 393.24' 36.0" Round Culvert L= 18.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 393.24' / 392.00' S= 0.0689 T Cc= 0.900 n= 0.012 #2 Device 1 393.24' 3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 399.44' 12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 400.74' 6.7' long x 1.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 7.5' Crest Height #5 Primary 402.24' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=56.54 cfs @ 11.95 hrs HW=402.48' (Free Discharge) 1=Culvert (Passes 51.65 cfs of 83.56 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.71 cfs @ 14.54 fps) 3=Orifice/Grate (Orifice Controls 4.02 cfs @ 8.04 fps) =Sharp -Crested Rectangular Weir (Orifice Controls 46.92 cfs @ 4.89 fps) S=Orifice/Grate (Weir Controls 4.89 cfs @ 1.61 fps) Summary for Pond 7P: Dry Pond Inflow Area = 1.510 ac, 42.38% Impervious, Inflow Depth = 6.07" for 100-yr event Inflow = 15.91 cfs @ 11.95 hrs, Volume= 0.764 of Outflow = 15.05 cfs @ 11.98 hrs, Volume= 0.764 af, Atten= 5%, Lag= 1.3 min Primary = 15.05 cfs @ 11.98 hrs, Volume= 0.764 of Routing by Stor-Ind method, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Peak Elev= 387.53' @ 11.98 hrs Surf.Area= 2,652 sf Storage= 6,313 cf Plug -Flow detention time= 51.7 min calculated for 0.764 of (100% of inflow) Center -of -Mass det. time= 51.1 min ( 852.8 - 801.7 ) Volume Invert #1 384.00' Avail. Descri 10,553 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 384.00 1,018 0 0 386.00 1,851 2,869 2,869 388.00 2,899 4,750 7,619 388.90 3,620 2,934 10,553 Device Routing Invert Outlet Devices #1 Primary 383.00' 18.0" Round Culvert L= 130.8' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 383.00' / 370.00' S= 0.0994 T Cc= 0.900 n= 0.012 #2 Device 1 384.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 387.00' 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Post Development - Rivers Edge Prepared by {enter your company name here) Post-Dev Hydrocad Analysis Type 11 24-hr 100-yr Rainfall=8.86" Printed 6/30/2022 Primary OutFlow Max=14.56 cfs @ 11.98 hrs HW=387.51' (Free Discharge) tCulvert (Inlet Controls 14.56 cfs @ 8.24 fps) 2=Orifice/Grate (Passes < 0.77 cfs potential flow) 3=Orifice/Grate (Passes < 14.96 cfs potential flow) Summary for Link 4L: POA1 Inflow Area = 21.020 ac, 15.32% Impervious, Inflow Depth = 4.25" for 100-yr event Inflow = 145.21 cfs @ 11.98 hrs, Volume= 7.436 of Primary = 145.21 cfs @ 11.98 hrs, Volume= 7.436 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Summary for Link 8L: POA2 Inflow Area = 7.180 ac, 20.47% Impervious, Inflow Depth = 4.33" for 100-yr event Inflow = 52.16 cfs @ 11.98 hrs, Volume= 2.592 of Primary = 52.16 cfs @ 11.98 hrs, Volume= 2.592 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-60.00 hrs, dt= 0.05 hrs Runoff Quality Calculations: VRRM Map Pre-Dev VRRM Map Post-Dev VRRM Re -Development Spreadsheet Summary Pre-ReDevelopment Land Cover (acres) I \ I I \ \ j \ •I A soils B Soils C Soils D Soils Totals % of Total Forest/Open (acres) 0.20 5.20 0.00 0.00 5.39 58 Managed Turf (acres) 0.10 2.11 0.00 0.00 2.21 24 Impervious Cover (acres) 0.21 1.42 0.00 0.00 1.63 18 9.23 100 C I I 1 \ I \ I \ \ I 1 \ \ I L 1 \ \ I \ LIMITS OF DISTURBANCE T ----- "- ;' ----- 9.21 AC ---- 1 .. \ Vt i RIVER'S EDGE PREDEVELOPMENT ON\ \ - VRRM MAP Post -Re Development Land Cover (acres) A soils B Soils C Soils D Soils Totals % of Total Forest/Open (acres) 0.00 0.00 0.00 0.00 0.00 0 Managed Turf (acres) 0.38 4.91 0.00 0.00 5.29 57 Impervious Cover (acres) 0.12 3.82 0.00 0.00 3.94 43 9.23 100 I 1 1 1 I LIMITS OF DISTURBANCE 9.21 AC RIVER'S EDGE POSTDEVELOPMENT VRRM MAP \ \ r _ LID Ell Total Runoff Volume Reduction (ft') 0 Total TP Load Reduction Achieved 0.00 (lb/yr) Total TN Load Reduction Achieved 0.00 (lb/yr) Remaining Post Development TP Load 10.90 (lb/yr) Remaining TP Load Reduction (lb/yr) Required 6.17 MIj . 00 Ngno Runoff Reauchn MCNM WORaMeI DCQ Virginia Runoff Reduction Method Re -Development Compliance spreadsheet - Version 3.0 BMP Design Sperifimtions List 20B Draft Stds&Spans Site Summary ProierL Tide: River's pulp Dare: 44]4] Total Ralnfan(in): 43 Food Disturbed Aureate: 9.21 Site Land Cover Summary Pre-ReDevelopment Land Cover (acres) A soils BSoiB CSails DSMIs Too6 %oi Tonal Forest/open (acres) a2D 1.20 Doo o.oa s.39 58 Managed Turf(arxs) 0.10 2.11 0.00 0.00 2.21 24 Impervious Comr(acreu 0.21 1 1.42 0.00 0.00 1.63 1B 9.23 300 Post-ReDevelopment land Cover (acres) A sous BbIB CSoila DSMIe Toss, %of Total Forest/open (acres) ann 0.00 0.00 0.00 ORD 0 Managed Turf(aurea) 0.38 4.91 0.00 0.00 529 57 Impervious Couer(acrea) 0.12 3.82 0.00 0.00 394 43 923 180 Site Tv and Land Cover Nutrient Loads Final Post -Development Post. Pest Adjusted Pra, ost#e (&Nee ReDesebPment I[eDeuebixnent lBm�ous) (Nee Impervious) Site Rv 0.52 0.37 0.95 0.30 TreMment Volume(Re) 17,349 9,393 7y56 7,530 TP Load (Ib/yr) 10.90 5.90 5.00 4.73 Food TP Load Reduction Required(Ib/yr) 1 6.17 1 2.12 1 4AS Final Post-DeveI ouentWad (Post-ReOerelopmem&Nee Impervious) PFo- Repevelopnem IN Wad (Ib/yr) ]].98 34.59 Site Compliance Summary Matlmun% RMuabn Required Bekov are hcReoevebpmem Wad Total Runoff Volume Reducim (fl) 0 Food To Wad Reduction A Meaed(lb/yr) 0.00 Total TN Wad Reduction Achieved(lb/yr) MOD Remaining Port Development TP Wad 10.90 (lb/W) Remainin, TP Wad Reduction(lb/yr) 6_17 Required Drainage Area Summary prc- ReOevelopment Final Post -Development Oeml Port-Reopmar, rp TP toad per xre TPWad per ac re bad par acre Ib ac r (lb/xre/Wl IIb/xre/yr) 0.0 1.28 a.. D.A.A DA.B D.A.0 D.A.0 DA.F Total Forest/open(acres) 0.00 O.w 0.00 DOE, Dan 0.00 Managed Turf(aures) 0.00 O.w 0.00 DOE, ano 0.00 Impervious Cover(acres) 0.00 1 00o OnD DOE, ano 0.00 Tool Area(aats) DAB Iam 0.00 am (WO am Drainage Area Compliance Summary D.A.A D.A.B D.A.0 D.A.D DA.F Tool TP Load Reduced (lb/yr) 0.00 O.W O.W O.w 0.00 0 00 TN Wad Reduced (lb/yr) 0.00 0.00 0.00 0.00 0.00 000 Summary F1nt Ngnia Runoff Rududm MCNM MftN A Runoff Volume and CN Calculations r"arsmnn byearatann 1 16yea;T—Ron Target Rainlall Ewen[ (in) 303 3.67 5.50 Drainage Areas RV&CN Drainage AreaA MNoge A.B Drainage AreaC Drainage A.D Dninage AreaE CN 0 0 0 0 0 RR ha 0 0 0 0 0 ]-year Murn period waRJ--) O.BD O.RD 0m om 0.. w RRl�aal o.BD o.BD om om o.Bo w.r..m3 0 0 0 a 0 2-year return period ERR( eiy o.OD o.BD o.BD om R. RR laraal o.ao o.OD o.BD om o.ao w.r..m3 0 0 0 a 0 Mum period . —RR( —in) R.R.0.0 o.ao om oR.16year RR RR o.a0 0.00 00 .00 0m R.w.Ar 0 0 0 a 0 Summary R Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report 76 //34E , 34D � 39 E- MAPLEGEND Area of Interest (A01) 0 Area of Interest A01) Solis Soil Rating Polygons 0 A Q AID o B Q BID o C 0 CID 0 D 0 Not rated or not available Soil Rating Lines . r A ,y AID rV B ram/ B/D N C N CID i D . . Not rated or not available Soil Rating Points A Q AID O B 0 BID Hydrologic Soil Group —Albemarle County, Virginia 0 C CID D 13 Not rated or not available Water Features Streams and Canals Transportation µ� Rails N Interstate Highways �y US Routes Major Roads Local Roads Background . Aerial Photography MAP INFORMATION The soil surveys that comprise your AC I were mapped at 1:15,800. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. 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: Albemarle County, Virginia Survey Area Data: Version 13, Sep 17, 2019 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: May 20, 2019—Aug 1, 2019 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 Web Soil Survey 121512019 Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group —Albemarle County, Virginia Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 10 Ronda loamy sand, 0 to A 9.7 19.8% 2 percent slopes, frequently flooded 14D Chester loam, 15 to 25 B 0.2 0.4% percent slopes 16 Codorus silt loam, 0 to 2 B/D 0.2 0.3% percent slopes, occasionally flooded 34C Glenelg loam, 7 to 15 B 5.0 10.2% percent slopes 34D Glenelg loam, 15 to 25 B 8.4 17.0% percent slopes 34E Glenelg loam, 25 to 45 B 6.8 13.8% percent slopes 39E Hazel loam, 25 to 45 B 0.9 1.8% percent slopes 42133 Yadkin Gay loam, 15 to B 3.2 6.6% 25 percent slopes, severely eroded 47E Philomont sandy loam, A 0.1 0.2% 25 to 45 percent slopes 50E Manor loam, 25 to 45 B 0.2 0.5% percent slopes 76 Dan River loam, 0 to 2 B 3.3 6.7% percent slopes, occasionally flooded 83 Colvard fine sandy A 4.1 8.3% loam, 0 to 2 percent slopes, occasionally flooded W Water 7.1 14.4% Totals for Area of Interest 49.3 100.0% Natural Resources Web Soil Survey 12/52019 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group —Albemarle County, Virginia Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie -break Rule: Higher Natural Resources Web Soil Survey 12/5/2019 Conservation Service National Cooperative Soil Survey Page 4 of 4 NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA*`r Latitude: 38.1528°, Longitude:-78.4168° Elevation: 433.69 ft** 'source: ESRI Maps iA -" source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonin, D. Martin, B. Lin, T. Parzybok, M.Yekta. and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)t Average recurrence interval (years) Duretion 7 ������1 2 6 70 25 60 100 700 200 500 7000 s In (0.314 0 985) (0.307 0.459) (0.44 539) (04 960 607) (0.555-0 683) (0.02-0.0744) (0.645-0 801) (0.6840 857) (0.730-0 928) (07 66-0.987) 70-min (0.5020615) (0.6 0.736) (0.705-0.64) (07 9 -0971) (0.85-1.09) (0.958-1.18) (1.02127) (1.8-LO) (1. 5-31347) (1.21-4.55) 75-min (0.627--0.769) (0.766--0924) (0892--109) (1.00-1.23) (1. 2-21538) (1.21-31650) (1.3�61) 1 (1.37--11671) (1. 5-6L85) 1 (1.511695) 30-min (0. 60-1205) (1.04-1.28) (1.27�'55) (1.45-178) (1.62605) (1.832.26) (1.98-� 7) (2: 32.67) (2.31 2694) (24 5-3.16) 60-min (1.071931) (1.314.60) (1.63--61.99) 8 9 (1-2.32) (2.212772) (2.48-3.06) (2. 338 40) (2.99-3.74) (3.324.2) (3.58461) 2-hr (1.27�61) (1.541395) (1.93-2.44) (22 6-2.87) (2. 8342) (3.03-3.89) (3. 94936) (37 5487) (42 595.59) (4.666.22) 6 IF 6.07 S-hr40) (1.38--61..78) (1.67 2916) (2.08 2770) (2.44-3.16) (2. 0 3?77) (32 84.28) (3.67 4682) (4.0756 (4.61�20) (5.076.90) 6-hr (17 6 2825) (2. 2 2072) (2.62 3838) (3.8-3.98) (3. 8 4.78) (41 �47) (4. 2--r�6.2) (5.27-27A3) (6.05 8 20) (6.781 9.25) 7.16 72-hr (2. 02884) (2.653A2) (3. 9-4.26) (3.8-5.04) (4.68-6.11) (5.37-2738) (6. 08.13) (6.8-9.29) (8. 0111.0) (8.W12.6) 24-hr (F2.63.34) (3. 23104) (4. 0�15) (4.82608) (5. 8-7.44) (6.778061) (7.39689) (8.75- 1.3) (102-13.4) (115--15.3) 2-day (3.14 3990) (3.814372) (4.835799) (5.66-7 03) (6.84 8753) (7.80-9.79) (8.82-1.2) (9.93- 2.7) (11 5314.9) (127---16.8) F-3.711 IF 3-day (3.37-4.12) (4.8-44..99) (5. 86.33) (6.o6-743) (7.339.01) (8.36-10.3) (9.46-1.8) (10.6-13.4) (12.3-15.7) (137--197.7) 4-day (3. 0�35) (4.35-5.26) (5.52$68) (6.47-782) (7.82-99..50) (8.9310.9) (10.1-12.4) (114-14.1) (131- 6.5) (14.68.6) 7-day (4. 9�03) (5.05605) (6. 0-67956) (7.31 8?80) (8. 5-610.6) (9.92- 2.1) (111z 3.6) (12.4-15.4) (142617.9) (157a-20.0) IF 6.0 10dey (4.8-565) (5.746.78) (7.088.37) (8.ir9965) (9.64-11.5) (10.8 2.9) (12314.5) 1 (13.4-16.2) 1 (15.1-8.6) 1 (16.6 0.6) 8.15 1 20aay (6. 8-674.35) (7.61 8.76) (9. 8--1150.6) (10.4- 2.0) (120- 3.9) (13.3-5.4) (14.6-19.0) (15.9-18.6) (176- 0.9) (18.99)2.6) 30-0ay (7.878996) (9.34- 0.6) (11.0- 2.6) (12.314.0) (140415.9) (152-137.4) (16?4- 8.8) (176- 0.3) (19?0-22.2) (202� 3.6) 2.4 454ey (9.87---11.1) (117z 3.1) (13.6-15.3) (15.1--107.0) (16.9- 9.1) (18.3- 0.7) (196022.2) (20.8- 3.7) (22.3-25.7) (23.4-27.1) -24 60-0ay (11.6-13.0) (137 15.3) (15'8-17.6) (17 3 9.4) (1923--21.6) (2027z 3.3) T-1324.9) (23 326.4) (24?9-3.3) (26 P 9.7) t 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 NOAA AOas 14 document for more information. Back to Top