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HomeMy WebLinkAboutWPO202100069 Calculations 2022-04-21 (2)ALTII OF SHIMP ENGINEERING, P.C. �r� Design Focused Engineering c , April 21, 2022 UO M. SITIN P y Engineering Review Lie. o. 183 Albemarle County o Department of Community Development 2 f 12ti ewe 401 McIntire Road S/oNAL tiNG` Charlottesville, VA 22902 Regarding: WP02021.00069 Scottsville Tiger Fuel Market Stormwater Management Plan Dear John, The purpose of this project is to construct a 16-pump gas station and convenience store. The total area of disturbance is 3.49 acres. Water Quantity: The stormwater management for this site will be addressed through the use of a bioretention basin that outfalls to a stormwater detention pond. The pond will release runoff at rates compliant with the Energy Balance Equation. Summaries of the pre and post development flow rates at the point of analysis are shown below. Please see drainage area maps located in this packet for more detail. Energy Balance Equation Summary /� Scottsville Tiger Fuel (POA 1) Qdevelopeds I.F. *(Qpreds loped RVpfPDeveloped)/RVd elep d Qdeveloped5 (Qmrenea'RUroreseed)/RVdmeloped Op. -de elpped = 0.52 RVp,e.DeVeloped = 0.052 Max Qdw.d,= 0.07 cfa RVD elowd = 0.332 Achieved Post-Dev Max Runoff Qiyr = 0.03 cfs.Site complies with 9 C2 -8-66-(3)A MaxIMUM Q10yr= 3.37 cfs (predev) Achieved 010yr = 0.40 cfs Water Quality: According to the VRRM Re -Development Spreadsheet, a TP Load Reduction of 3.16 Ib/yr is required. The nutrient treatment requirement will be met through the use of a bioretention basin and the purchase of nutrient credits. The bioretention basin treats 2.46 ac of the site and provides 2.28 Ib/yr of treatment. The remaining 0.88 Ib/yr of treatment will be provided through the purchase of nutrient credits. Best Regards, Chris Marshall, EIT Shimp Engineering, P.C. APPROVED by the Albemarle County Community Development Department Date 12/21/2022 File WP0202100069 Contents: Pre -Development Stormwater Management Calculations: Pre -Development Drainage Area Map Pre -Development HydroCAD Analysis Time of Concentration Calculation Time of Concentration Nomographs Post -Development Stormwater Management Calculations: Post -Development Drainage Area Map Post -Development HydroCAD Analysis Energy Balance Equation Summary LD-204 Stormwater Inlet Computations LD-229 Storm Drain Design Computations Outlet Protection Calculations Stormwater Quality Calculations: VRRM Pre -Development Land Use Map VRRM Post -Development Land Use Map VRRM Re -Development Spreadsheet Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Pre -Development Stormwater Management Calculations: Pre -Development Drainage Area Map Pre -Development HydroCAD Analysis Time of Concentration Calculation Time of Concentration Nomographs SCOTTSVILLE TIGER FUEL MARKET PREDEV DRAINAGE AREA MAP 1 \ DRAINAGE AREA 1: TOTAL AREA = 1.69 AC HSG TYPE B / Zr= �� ✓ \( \\ / / l J / \ \ �� �~ IMPERVIOUS = 0.00 AC f �� a o // MANAGED TURF = 0.61 AC \ ✓ f / \ �� SJ - \ I \ \� _ WOODS = 0.66 AC HSG TYPE D IMPERVIOUS = 0.01 AC MANAGED TURF = 0.13 AC WOODS = 0.28 AC V _ TIME OF CONCENTRATION = 15.6 MINUTES OH \\® l l / 1 T 1 . \ \ \-, ) \ \\ --� /� I����� _ �� N •����� \ � � I'� III(\\\\I° N � -- _�� � •• � ,^ � � r/ r� / 11 ��111 POA 1 J J II I I I II 1100 0 100 200 300 II TOC 15.6 MIN. Scale: 1"=100' 1S DA 1 P edev 2L POA 1 Predev Subcat Reach On Link Drainage Diagram for Predev FpHydrreparedTby�enter your company name here}, Printed 12/3/2021 oCA0 s/n 07054 0 2010 HydroCAD Software Solutions LLC PreDev Predev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 2 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Predev Runoff Area=1.685 ac 0.36% Impervious Runoff Depth=0.37" Tc=15.6 min CN=63 Runoff=0.52 cfs 0.052 of Link 2L: POA 1 Predev Inflow=0.52 cfs 0.052 of Primary=0.52 cfs 0.052 of Total Runoff Area = 1.685 ac Runoff Volume = 0.052 of Average Runoff Depth = 0.37' 99.64% Pervious = 1.679 ac 0.36% Impervious = 0.006 ac PreDev Predev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 1S: DA 1 Predev Runoff = 0.52 cfs @ 12.12 hrs, Volume= 0.052 af, Depth= 0.37" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1 YR Rainfall=2.85 Area (ac) CN Description 0.000 98 Paved parking, HSG B 0.006 98 Paved parking, HSG D 0.607 61 >75% Grass cover, Good, HSG B 0.135 80 >75% Grass cover, Good, HSG D 0.656 55 Woods, Good, HSG B 0.281 77 Woods, Good, HSG D 1.685 63 Weighted Average 1.679 99.64% Pervious Area 0.006 0.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Summary for Link 2L: POA 1 Predev Inflow Area = 1.685 ac, 0.36% Impervious, Inflow Depth = 0.37" for 1 YR event Inflow = 0.52 cfs @ 12.12 hrs, Volume= 0.052 of Primary = 0.52 cfs @ 12.12 hrs, Volume= 0.052 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs PreDev Predev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 4 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Predev Runoff Area=1.685 ac 0.36% Impervious Runoff Depth=1.65" Tc=15.6 min CN=63 Runoff=3.37 cfs 0.232 of Link 2L: POA 1 Predev Inflow=3.37 cfs 0.232 of Primary=3.37 cfs 0.232 of Total Runoff Area = 1.685 ac Runoff Volume = 0.232 of Average Runoff Depth = 1.65' 99.64% Pervious = 1.679 ac 0.36% Impervious = 0.006 ac PreDev Predev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 5 Summary for Subcatchment 1S: DA 1 Predev Runoff = 3.37 cfs @ 12.09 hrs, Volume= 0.232 af, Depth= 1.65" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10 YR Rainfall=5.22" Area (ac) CN Description 0.000 98 Paved parking, HSG B 0.006 98 Paved parking, HSG D 0.607 61 >75% Grass cover, Good, HSG B 0.135 80 >75% Grass cover, Good, HSG D 0.656 55 Woods, Good, HSG B 0.281 77 Woods, Good, HSG D 1.685 63 Weighted Average 1.679 99.64% Pervious Area 0.006 0.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Summary for Link 2L: POA 1 Predev Inflow Area = 1.685 ac, 0.36% Impervious, Inflow Depth = 1.65" for 10 YR event Inflow = 3.37 cfs @ 12.09 hrs, Volume= 0.232 of Primary = 3.37 cfs @ 12.09 hrs, Volume= 0.232 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs PreDev Predev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 6 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Predev Runoff Area=1.685 ac 0.36% Impervious Runoff Depth=4.12" Tc=15.6 min CN=63 Runoff=8.79 cfs 0.579 of Link 2L: POA 1 Predev Inflow=8.79 cfs 0.579 of Primary=8.79 cfs 0.579 of Total Runoff Area = 1.685 ac Runoff Volume = 0.579 of Average Runoff Depth = 4.12" 99.64% Pervious = 1.679 ac 0.36% Impervious = 0.006 ac PreDev Predev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by {enter your company name here} Printed 12/3/2021 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 7 Summary for Subcatchment 1S: DA 1 Predev Runoff = 8.79 cfs @ 12.08 hrs, Volume= 0.579 af, Depth= 4.12" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100 YR Rainfall=8.57" Area (ac) CN Description 0.000 98 Paved parking, HSG B 0.006 98 Paved parking, HSG D 0.607 61 >75% Grass cover, Good, HSG B 0.135 80 >75% Grass cover, Good, HSG D 0.656 55 Woods, Good, HSG B 0.281 77 Woods, Good, HSG D 1.685 63 Weighted Average 1.679 99.64% Pervious Area 0.006 0.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Summary for Link 2L: POA 1 Predev Inflow Area = 1.685 ac, 0.36% Impervious, Inflow Depth = 4.12" for 100 YR event Inflow = 8.79 cfs @ 12.08 hrs, Volume= 0.579 of Primary = 8.79 cfs @ 12.08 hrs, Volume= 0.579 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Scottsville Tiger Fuel Time of Concentration Calculations - Predev 1 100 ft overland flow 3.5% slope 0.35 C-value 11.8 min Seelye Chart 342 ft s. c. flow 9.6% slope 1.5 fps velocity 3.8 min. NEH Figure 15-4 00 ft swale height min. Kirpich Chart 15.6 min. 5 LENGTH "L" OF STRIP IN FEET N W — N tA A Q A V ww O O O O O 0 O 0000 / O O nm cTg 0'a wm m o� u�iw aen rmi u�ig m� ny� _m GHARAGTER OF GROUND C VAIL h' / V a 4 • v O i V VAE" r PI T LINE , NaO O O O O to PERGE SLOPE \ \ N N W W m J 0) lD O I l U O N O (T I I I r r INLET CONCENTRATION TIME IN MINUTES ."low (hlR) 02 wl 0:7 r� 1. O.li � r rgllry, 0.7 _ /riiar„ar /la. O.ii N4, n rM. Qyr /y /:or I/'.Y mx I/xiH dr{,rhrvr �4Y/x. err/�h. /4 air { .ArRr//Ir'/alyt� q�/rrt :glrgr 7 koMrs P 9 10 — Id Height of tbst Remote Point Above Outlet e t' z f w o � '• � 2 tlh%Imm Length of Travel r r n un � v � Time of Concentration b W W v R U �b U tJ Post -Development Stormwater Management Calculations: Post -Development Drainage Area Map Post -Development HydroCAD Analysis Energy Balance Equation Summary LD-204 Stormwater Inlet Computations LD-229 Storm Drain Design Computations Outlet Protection Calculation SCOTTSVILLE TIGER FUEL MARKET POSTDEV DRAINAGE AREA MAP DRAINAGE AREA 1: TOTAL AREA = 3.50 AC HSG TYPE B IMPERVIOUS = 1.77 AC MANAGED TURF = 1.15 AC WOODS = 0.38 AC HSG TYPE D IMPERVIOUS = 0.00 AC MANAGED TURF = 0.14 AC WOODS = 0.06 AC TIME OF CONCENTRATION (ASSUMED) = 5.0 MINUTES 100 0 100 200 300 Scale: 1 "=100' DA 1 ostdev BIORETENTION BASIN Pond POA 1 Postdev S4 Reach Aon 4 Postdev Postdev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by {enter your company name here} Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 2 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Postdev Runoff Area=3.495 ac 50.59% Impervious Runoff Depth=1.14" Tc=5.0 min CN=80 Runoff=7.36 cfs 0.332 of Link 2L: POA 1 Postdev Inflow=0.03 cfs 0.013 of Primary=0.03 cfs 0.013 of Pond 2P: BIORETENTION BASIN Peak EIev=405.42' Storage=13,899 cf Inflow=7.36 cfs 0.332 of Outflow=0.09 cfs 0.013 of Pond 3P: Pond Peak EIev=396.13' Storage=457 cf Inflow=0.09 cfs 0.013 of Outflow=0.03 cfs 0.013 of Total Runoff Area = 3.495 ac Runoff Volume = 0.332 of Average Runoff Depth = 1.14" 49.41% Pervious = 1.727 ac 50.59% Impervious = 1.768 ac Postdev Postdev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 1S: DA 1 Postdev Runoff = 7.36 cfs @ 11.97 hrs, Volume= 0.332 af, Depth= 1.14" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1 YR Rainfall=2.85" Area (ac) CN Description 1.768 98 Paved parking, HSG B 0.000 98 Paved parking, HSG D 1.148 61 >75% Grass cover, Good, HSG B 0.142 80 >75% Grass cover, Good, HSG D 0.375 55 Woods, Good, HSG B 0.062 77 Woods, Good, HSG D 3.495 80 Weighted Average 1.727 49.41 % Pervious Area 1.768 50.59% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Link 2L: POA 1 Postdev Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth > 0.04" for 1 YR event Inflow = 0.03 cfs @ 24.14 hrs, Volume= 0.013 of Primary = 0.03 cfs @ 24.14 hrs, Volume= 0.013 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Summary for Pond 2P: BIORETENTION BASIN Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 1.14" for 1 YR event Inflow = 7.36 cfs @ 11.97 hrs, Volume= 0.332 of Outflow = 0.09 cfs @ 22.57 hrs, Volume= 0.013 af, Atten= 99%, Lag= 636.5 min Primary = 0.09 cfs @ 22.57 hrs, Volume= 0.013 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 405.42' @ 22.57 hrs Surf.Area= 4,662 sf Storage= 13,899 cf Plug -Flow detention time= 714.6 min calculated for 0.013 of (4% of inflow) Center -of -Mass det. time= 547.0 min ( 1,391.6 - 844.6 ) Volume Invert #1 399.99' Avail. Descri 16,740 cf Bioretention Basin (Prismatic)Listed below (Recalc) Postdev Postdev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 4 Elevation (feet) Surf.Area (sq-ft) Voids (%) Inc.Store (cubic -feet) Cum.Store (cubic -feet) 399.99 3,800 0.0 0 0 400.00 3,800 40.0 15 15 402.50 3,800 25.0 2,375 2,390 404.50 3,800 100.0 7,600 9,990 406.00 5,200 100.0 6,750 16,740 Device Routing Invert Outlet Devices #1 Primary 405.42' 40.0' long (Profile 4) Broad -Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 2.77 2.97 3.21 Primary OutFlow Max=0.03 cfs @ 22.57 hrs HW=405.42' (Free Discharge) L1=13road-Crested Rectangular Weir(Weir Controls 0.03 cfs @ 0.17 fps) Summary for Pond 3P: Pond Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 0.04" for 1 YR event Inflow = 0.09 cfs @ 22.57 hrs, Volume= 0.013 of Outflow = 0.03 cfs @ 24.14 hrs, Volume= 0.013 af, Atten= 61 %, Lag= 94.0 min Primary = 0.03 cfs @ 24.14 hrs, Volume= 0.013 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 396.13' @ 24.14 hrs Surf.Area= 3,477 sf Storage= 457 cf Plug -Flow detention time= 308.9 min calculated for 0.013 of (97% of inflow) Center -of -Mass det. time= 307.3 min ( 1,698.9 - 1,391.6 ) Volume Invert Avail.Storage Storage Description #1 396.00' 31,898 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 396.00 3,400 0 0 398.00 4,564 7,964 7,964 400.00 5,800 10,364 18,328 402.00 7,770 13,570 31,898 Device Routing Invert Outlet Devices #1 Primary 393.00' 12.0" Round 12" HDPE L= 50.0' CUP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 393.00' / 391.00' S= 0.0400 T Cc= 0.900 n= 0.010 #2 Device 1 400.00' 36.0" Horiz. 36" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 396.00' 3.0" Vert. 1 yr control orifice C= 0.600 #4 Primary 401.00' 10.0' long x 22.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Postdev Postdev Type 11 24-hr 1 YR Rainfall=2.85" Prepared by (enter your company name here) Printed 4/21/2022 Primary OutFlow Max=0.03 cfs @ 24.14 hrs HW=396.13' (Free Discharge) 1=12" HDPE (Passes 0.03 cfs of 4.84 cfs potential flow) 2=36" Standpipe ( Controls 0.00 cfs) 3=1 yr control orifice (Orifice Controls 0.03 cfs @ 1.24 fps) = Broad-C rested Rectangular Weir( Controls 0.00 cfs) Postdev Postdev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by {enter your company name here} Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 6 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Postdev Runoff Area=3.495 ac 50.59% Impervious Runoff Depth=3.09" Tc=5.0 min CN=80 Runoff=19.54 cfs 0.899 of Link 2L: POA 1 Postdev Inflow=0.40 cfs 0.578 of Primary=0.40 cfs 0.578 of Pond 2P: BIORETENTION BASIN Peak EIev=405.72' Storage=15,305 cf Inflow=19.54 cfs 0.899 of Outflow=17.83 cfs 0.580 of Pond 3P: Pond Peak EIev=398.98' Storage=12,756 cf Inflow=17.83 cfs 0.580 of Outflow=0.40 cfs 0.578 of Total Runoff Area = 3.495 ac Runoff Volume = 0.899 of Average Runoff Depth = 3.09" 49.41% Pervious = 1.727 ac 50.59% Impervious = 1.768 ac Postdev Postdev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 7 Summary for Subcatchment 1S: DA 1 Postdev Runoff = 19.54 cfs @ 11.96 hrs, Volume= 0.899 af, Depth= 3.09" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10 YR Rainfall=5.22" Area (ac) CN Description 1.768 98 Paved parking, HSG B 0.000 98 Paved parking, HSG D 1.148 61 >75% Grass cover, Good, HSG B 0.142 80 >75% Grass cover, Good, HSG D 0.375 55 Woods, Good, HSG B 0.062 77 Woods, Good, HSG D 3.495 80 Weighted Average 1.727 49.41 % Pervious Area 1.768 50.59% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Link 2L: POA 1 Postdev Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth > 1.99" for 10 YR event Inflow = 0.40 cfs @ 15.79 hrs, Volume= 0.578 of Primary = 0.40 cfs @ 15.79 hrs, Volume= 0.578 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Summary for Pond 2P: BIORETENTION BASIN Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 3.09" for 10 YR event Inflow = 19.54 cfs @ 11.96 hrs, Volume= 0.899 of Outflow = 17.83 cfs @ 12.01 hrs, Volume= 0.580 af, Atten= 9%, Lag= 2.9 min Primary = 17.83 cfs @ 12.01 hrs, Volume= 0.580 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 405.72' @ 12.01 hrs Surf.Area= 4,936 sf Storage= 15,305 cf Plug -Flow detention time= 178.1 min calculated for 0.580 of (65% of inflow) Center -of -Mass det. time= 71.4 min (887.3 - 815.9) Volume Invert #1 399.99' Avail. Descri 16,740 cf Bioretention Basin (Prismatic)Listed below (Recalc) Postdev Postdev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 8 Elevation (feet) Surf.Area (sq-ft) Voids (%) Inc.Store (cubic -feet) Cum.Store (cubic -feet) 399.99 3,800 0.0 0 0 400.00 3,800 40.0 15 15 402.50 3,800 25.0 2,375 2,390 404.50 3,800 100.0 7,600 9,990 406.00 5,200 100.0 6,750 16,740 Device Routing Invert Outlet Devices #1 Primary 405.42' 40.0' long (Profile 4) Broad -Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 2.77 2.97 3.21 Primary OutFlow Max=16.44 cfs @ 12.01 hrs HW=405.70' (Free Discharge) L1=13road-Crested Rectangular Weir (Weir Controls 16.44 cfs @ 1.47 fps) Summary for Pond 3P: Pond Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 1.99" for 10 YR event Inflow = 17.83 cfs @ 12.01 hrs, Volume= 0.580 of Outflow = 0.40 cfs @ 15.79 hrs, Volume= 0.578 af, Atten= 98%, Lag= 226.8 min Primary = 0.40 cfs @ 15.79 hrs, Volume= 0.578 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 398.98' @ 15.79 hrs Surf.Area= 5,172 sf Storage= 12,756 cf Plug -Flow detention time= 424.9 min calculated for 0.578 of (100% of inflow) Center -of -Mass det. time= 423.9 min ( 1,311.2 - 887.3 ) Volume Invert Avail.Storage Storage Description #1 396.00' 31,898 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 396.00 3,400 0 0 398.00 4,564 7,964 7,964 400.00 5,800 10,364 18,328 402.00 7,770 13,570 31,898 Device Routing Invert Outlet Devices #1 Primary 393.00' 12.0" Round 12" HDPE L= 50.0' CUP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 393.00' / 391.00' S= 0.0400 T Cc= 0.900 n= 0.010 #2 Device 1 400.00' 36.0" Horiz. 36" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 396.00' 3.0" Vert. 1 yr control orifice C= 0.600 #4 Primary 401.00' 10.0' long x 22.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Postdev Postdev Type 11 24-hr 10 YR Rainfall=5.22" Prepared by (enter your company name here) Printed 4/21/2022 Primary OutFlow Max=0.40 cfs @ 15.79 hrs HW=398.98' (Free Discharge) 1=12" HDPE (Passes 0.40 cfs of 6.99 cfs potential flow) 2=36" Standpipe ( Controls 0.00 cfs) 3=1 yr control orifice (Orifice Controls 0.40 cfs @ 8.14 fps) = Broad-C rested Rectangular Weir( Controls 0.00 cfs) Postdev Postdev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by {enter your company name here} Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 10 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 Postdev Runoff Area=3.495 ac 50.59% Impervious Runoff Depth=6.16" Tc=5.0 min CN=80 Runoff=37.62 cfs 1.794 of Link 2L: POA 1 Postdev Inflow=10.05 cfs 1.472 of Primary=10.05 cfs 1.472 of Pond 2P: BIORETENTION BASIN Peak EIev=405.90' Storage=16,231 cf Inflow=37.62 cfs 1.794 of Outflow=37.10 cfs 1.476 of Pond 3P: Pond Peak EIev=401.16' Storage=25,751 cf Inflow=37.10 cfs 1.476 of Outflow=10.05 cfs 1.472 of Total Runoff Area = 3.495 ac Runoff Volume = 1.794 of Average Runoff Depth = 6.16" 49.41% Pervious = 1.727 ac 50.59% Impervious = 1.768 ac Postdev Postdev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCADO 9.10 s/n 07054 © 2010 HvdroCAD Software Solutions LLC Paae 11 Summary for Subcatchment 1S: DA 1 Postdev Runoff = 37.62 cfs @ 11.96 hrs, Volume= 1.794 af, Depth= 6.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100 YR Rainfall=8.57" Area (ac) CN Description 1.768 98 Paved parking, HSG B 0.000 98 Paved parking, HSG D 1.148 61 >75% Grass cover, Good, HSG B 0.142 80 >75% Grass cover, Good, HSG D 0.375 55 Woods, Good, HSG B 0.062 77 Woods, Good, HSG D 3.495 80 Weighted Average 1.727 49.41 % Pervious Area 1.768 50.59% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Link 2L: POA 1 Postdev Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth > 5.05" for 100 YR event Inflow = 10.05 cfs @ 12.11 hrs, Volume= 1.472 of Primary = 10.05 cfs @ 12.11 hrs, Volume= 1.472 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Summary for Pond 2P: BIORETENTION BASIN Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 6.16" for 100 YR event Inflow = 37.62 cfs @ 11.96 hrs, Volume= 1.794 of Outflow = 37.10 cfs @ 11.97 hrs, Volume= 1.476 af, Atten= 1 %, Lag= 0.7 min Primary = 37.10 cfs @ 11.97 hrs, Volume= 1.476 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 405.90' @ 11.97 hrs Surf.Area= 5,108 sf Storage= 16,231 cf Plug -Flow detention time= 114.0 min calculated for 1.476 of (82% of inflow) Center -of -Mass det. time= 38.5 min (834.8 - 796.3) Volume Invert #1 399.99' Avail. Descri 16,740 cf Bioretention Basin (Prismatic)Listed below (Recalc) Postdev Postdev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by (enter your company name here) Printed 4/21/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 12 Elevation (feet) Surf.Area (sq-ft) Voids (%) Inc.Store (cubic -feet) Cum.Store (cubic -feet) 399.99 3,800 0.0 0 0 400.00 3,800 40.0 15 15 402.50 3,800 25.0 2,375 2,390 404.50 3,800 100.0 7,600 9,990 406.00 5,200 100.0 6,750 16,740 Device Routing Invert Outlet Devices #1 Primary 405.42' 40.0' long (Profile 4) Broad -Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 2.77 2.97 3.21 Primary OutFlow Max=36.91 cfs @ 11.97 hrs HW=405.90' (Free Discharge) L1=13road-Crested Rectangular Weir(Weir Controls 36.91 cfs @ 1.92 fps) Summary for Pond 3P: Pond Inflow Area = 3.495 ac, 50.59% Impervious, Inflow Depth = 5.07" for 100 YR event Inflow = 37.10 cfs @ 11.97 hrs, Volume= 1.476 of Outflow = 10.05 cfs @ 12.11 hrs, Volume= 1.472 af, Atten= 73%, Lag= 8.2 min Primary = 10.05 cfs @ 12.11 hrs, Volume= 1.472 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 401.16' @ 12.11 hrs Surf.Area= 6,947 sf Storage= 25,751 cf Plug -Flow detention time= 311.7 min calculated for 1.472 of (100% of inflow) Center -of -Mass det. time= 310.3 min ( 1,145.1 - 834.8 ) Volume Invert Avail.Storage Storage Description #1 396.00' 31,898 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 396.00 3,400 0 0 398.00 4,564 7,964 7,964 400.00 5,800 10,364 18,328 402.00 7,770 13,570 31,898 Device Routing Invert Outlet Devices #1 Primary 393.00' 12.0" Round 12" HDPE L= 50.0' CUP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 393.00' / 391.00' S= 0.0400 T Cc= 0.900 n= 0.010 #2 Device 1 400.00' 36.0" Horiz. 36" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 396.00' 3.0" Vert. 1 yr control orifice C= 0.600 #4 Primary 401.00' 10.0' long x 22.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Postdev Postdev Type 11 24-hr 100 YR Rainfall=8.57" Prepared by (enter your company name here) Printed 4/21/2022 Primary OutFlow Max=9.98 cfs @ 12.11 hrs HW=401.16' (Free Discharge) 1=12" HDPE (Inlet Controls 8.26 cfs @ 10.52 fps) 2=36" Standpipe (Passes < 36.66 cfs potential flow) 3=1 yr control orifice (Passes < 0.53 cfs potential flow) = Broad-C rested Rectangular Weir(Weir Controls 1.71 cfs @ 1.07 fps) Energy Balance Equation Summary Scottsville Tiger Fuel (POA 1) Qdeveloped� I.F. *(Qpre-developed*RVPre-Developed)/Redeveloped Qdeveloped!5 (Qforestedx RVforested) Redeveloped Qpre-developed = 0.52 RVPre-Developed = 0.052 MaxQdevek= 0.07cfs RVDeveloped Achieved Post-Dev Max Runoff Q1yr = 0.03 cfs. Site complies with 9VAC25-870-66-(3)A Maximum Q1oyr= 3.37 cfs (predev) Achieved Q10yr= 0.40 cfs Scottsville Tiger Fuel Market LD•204 Stormwater Inlet Computations Inlets on Grade Only Sag Inlets Only 0 0 8i o 6 z 0 U a $ O E g as a yN+ X Ka+ n _ n m 0 q `v u 8 ` 2 w E m p n s m s _ < 5 m 5 S a F m z 0 U rc c� o (I O (7 a c1 r y a" a O 2 1 2 3 4 5 6 8 9 1 10 1 11 1 12 1 13 1 14 1 15 16 17 18 1 19 20 21 22 23 24 (5) (s0 (ac) 0�+0 (cts) (cfs) (cfs) (r) (f) V) (8) (5) (cts) (cfa) (In (0) (ft) A6 DI-3C 8 9,828 0.23 0.90 0.20 5.2 1.05 1.05 0.015 0.02 0.06 0.02 3.34 2.41 100.0% 1.06 0.00 0.124 0.5 0.248 2.069 6.2 1.25 1.25 0.015 0.02 0.06 0.02 3.57 2.57 100.0% 1.18 0.07 0.139 0.5 0.278 2.324 A5 DI-3C 8 2,880 0.07 0.90 0.06 5.2 0.31 0.31 0.015 0.02 0.05 0.02 2.37 1.42 100.0% 0.31 0.00 0.055 0.5 0.11 1.101 6.2 0.37 0.37 0.015 0.02 0.05 0.02 2.53 1.52 100.0% 0.37 0.00 0.062 0.5 0.124 1.239 A4 DI-3C 10 15,032 0.35 0.90 0.31 5.2 1.61 1.61 0.015 0.02 0.04 0.02 4.40 2.64 100.0% 1.61 0.00 0.142 0.5 0.284 3.557 6.2 1.92 1.92 0.015 0.02 0.04 0.02 4.70 2.82 100.0% 1.92 0.00 0.16 0.5 0.32 4 A2 DI-3C 8 22,212 0.51 0.90 0.46 5.2 2.37 2.37 0.015 0.02 0.03 0.02 7.00 2.52 100.0% 2.37 0.00 0.214 0.5 0.428 7.121 6.2 2.94 2.84 0.015 0.02 0.03 0.02 7.49 2.70 100.0% 2.84 0.00 0.241 0.5 0.482 8.034 A2A DI-38 8 13,555 0.31 0.90 0.28 5.2 1.45 1.45 0.015 0.02 0.03 0.02 5.82 2.09 100.0% 1.45 0.00 0.154 0.5 0.308 5.132 6.2 1.73 1.73 0.015 0.02 0.03 0.02 6.22 2.24 100.0% 1.73 0.00 0.173 0.5 0.346 5.773 Scottsville Tiger Fuel Market LD-229 Storm Drain Design Computations From To Catch. Runoff Increment Arum. Total 10-yr 10-yr Up Dawn Pipe Invert Pipe Pipe Velocity Fl.time Stmctum Stmclure Area Coef AC AC TOG Intensity Flow Invert Invert Length Slope Diameter Capadty Increment I.) (min) (inlh0 (cfs) Elev. Elea (0) % (in) (cis) (Ns) (min) 1 2 3 4 5 6 T 8 9 10 11 12 13 14 15 16 17 A6 A5 0.19 0.90 0.17 0.17 5.00 6.18 1.06 416.75 415.60 108.50 1.06% 15 1.3 3.6 0.50 A5 A4 0.15 0.90 0.14 031 5.00 6.19 1.89 41540 413.98 141.00 1.01% 15 2.2 4A 0.57 Trench Drain A4 0.13 0.90 0.12 0.12 6.00 6.18 0.72 419.72 415.00 97.00 4.87% 12 1.6 5.2 0.31 A4 A3 0.33 0.90 030 0.32 500 6.19 4.45 41378 413.04 71.50 1.03% 15 4.6 5A 0.23 A3 A2 0.13 0.90 0.12 0.84 5.00 6.18 5.17 412.84 410.60 220.00 1.02% 15 5.3 54 0.67 A2A A2 0.37 0.90 0.33 033 500 6.18 2.06 414.00 411.00 214.00 140% 15 2.8 4.8 0.75 A2 Al 0.49 0.90 0." 1.61 5.00 6.18 9.96 410.40 408.00 68.00 3.53% 18 Me 10.9 0.10 Outlet Protection Calculations - Reference Nomograph 3.18-3 a0a�avaaa®aoa©ate©_©_�_ C N a Stormwater Quality Calculations: VRRM Pre -Development Land Use Map VRRM Post -Development Land Use Map VRRM Re -Development Spreadsheet SCOTTSVILLE TIGER FUEL MARKET PREDEV LAND USE MAP ell :`' ::::::::::::::::::::::::::•:.. .:.:.:.:.::::.:.:.:.:.:.:.::: .. �� _ )II1 fIII100 PROPERTY AREA & LIMITS OF DISTURBANCE = 3.49 AC USG TYPE B SOILS IMPERVIOUS = 0.06 AC MANAGED TURF = 0.70 AC WOODS = 0.97 AC USG TYPE D SOILS IMPERVIOUS = 0.20 AC MANAGED TURF = 0.97 AC WOODS = 0.59 AC IMPERVIOUS AREA MANAGED TURF WOODS 0 100 200 N 300 SCOTTSVILLE TIGER FUEL MARKET POSTDEV LAND USE MAP � I � �/ / ':• a°o�°a° as°aa° a°cnn°a�°at°.°°°°rg°°a°�'aa�a a o°m°oa°� .. �a \ \� C��� \ \ \ o000 0 0000 o00000 oaooa�yo°o � � I \ � ) / � o •. aoaao ° o a�o aoaao o a ao�o° °aa°°°aoao°ao �, ' \\�� � 1 � � / •: o 0 0 o°a°oo 0 0 / °dsQd'Qa°Qd' a o a °000°aa°aa°' PROPERTY AREA &LIMITS OF DISTURBANCE = 3.49 AC USG TYPE B SOILS IMPERVIOUS = 0.63 AC MANAGED TURF = 1.06 AC WOODS = 0.04 AC USG TYPE D SOILS IMPERVIOUS = 1.21 AC MANAGED TURF = 0.52 AC WOODS = 0.03 AC °"a a ° �'°° !j • `-� \ \ \\�\� \ 1 \\ 11 \ ro--o IMPERVIOUS AREA MANAGED TURF WOODS � J :��•• \� � � � `- �' � J/(( �f Jl ill 100 0 100 Scale: V=100' PA1111 N 300 ... lmaesumaraxamem speaxers —0k..u...Psunaano.dasl,a.w�en auam�mnm+wn e'. .1. 3 liar nod Me�bt P Limo, Der omeoP-jem nn lite Information lost -Development Project (Treatment Volume and Loads) Ent.rtotal Dirturbetl Am.(or—) j 369 Treatment Volume and Nutrient Load Check: muPDesign5pen'fi,utiun. fist: 2013 Dmtt stex&So... on romt eDrvmee omo emereer ✓ ,eundon- -alunal— va TP Load Pedudmn Reguiree ll&/y,l 3.36 Nitrogen Wtls(IMarmational Purposes Only) mwedarmmrmmmt1�4Y1 vrzr pms�irt.mpm1, n..... rv�otal 3o zr VWO EBEEME o�a0o a�000 a0000 00000 00000 00000 00000 00000 00000 00000 a0000 a�000 00000 00000 00000 00000 00000 om000 a0000 ®0000 00000 00000 a0000 00000 00000 00000 0 Site Results (Water Quality Compliance) Area Checks O.A.A O.A.B O.A.0 D.A.D D.A.E AREAMECK FOREST/OVEN SPACE (a[) 0.07 O.W 0.00 0.00 0.W OK. IMPERVIOUS DOVER IMPERVIOUS COVERTREATED (a[I 1.77 1JJ 0.00 O.W OLD 0.00 0.00 0.00 O.W OIL OK. MANAGED TURF AREA (aa) 0.62 0.00 0.00 0.00 O.N OK. MANAGED TURF AREA TREATED (a[) 0.62 0.00 0.00 0.00 0.N OK. AREAMECK OK OR. OK. OK. OR. Site Treatment Volume (ffa) 7,591 Runoff Reduction Volume and TP By Drainage Area O.A. A O.A. B O.A. C D.A. D D.A. E TOTAL RUNOFF REDUCTION VOLUME ACHIEVED (N3) 2,695 0 0 0 0 2,635 TV LOAD AVAILABLE FOR REMOVAL(Ib/yi 4.30 O.N 0.00 0.00 O.N 0.10 TV LOAD REOUCTIONAOUEVED(Ib/yr) 2.2J O.N 0.On 0.w O.00 2.27 TP LOAD REMAINING (lb/yr) 1.BJ O.W 0.00 0.00 LOU 1.BJ NITROGEN LOAD REDUCTION AofiEVED (Ib/yr)jj 18.93 O.00 0.00 0.00 0.W 18.93 Total Phosphorus FINAL POST -DEVELOPMENT TP LOAD (Ib/yQ 9JJ TP LOAD REDUCTION REQUIRED (Ib/yr) 3.16 TP LOAD REDUCTIONACHIEVED(Ib/yr) 2.27 TV LOAD REMAINING (Ib/yr): 2.50 REMAINING TP LOAD REDUCTION REQUIRED (Ib/yr): On Total Nitrogen (For Information Purposes) POST -DEVELOPMENT LOAD (Ib/yr) 30.30 NITROGEN LOAD REDUCTION ACHIEVED (Ib/y0 18 .93 REMAINING POST -DEVELOPMENT NITRW EN LOAD (Ib/yrl 15.21 m,_n �... [m�Plunu Summed ___ __. ___ __. __. __. __ °1Y' ._ ._ wP1 �.._�. mFl PM � rePna -00000 �000000 �000000 �000000 0 �. � ���m �0®® m� o�ooaoa ��00000 �00000 ®©ooa0 m00000 �0000m ®®0000 m00000 �0o00m m0000® Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Hydrologic Soil Group —Albemarle County, Virginia 3 (Scottsville Tiger Fuel Market) n I 37 48'24•N T7— •^ I , — 7 sW 71M10 719w 72MIO 72MM 3 m MapSde: 1:2,110VprhWm A pp4ait(8.5'x11")sheet N Melea 0 30 EO 120 180 /V 0 100 ZOD 400 600 Map pry: Web M uator Co coudi atm: WGS84 Edgetm UIM Zme 17N WU.S84 l5m Natural Resources Web Soil Survey -01111111111111 Conservation Service National Cooperative Soil Survey W10 11/5/2021 Page 1 of 4 3A 4938'N MAPLEGEND Area of Interest (AOI) Area of Interest (AOI) Solis Soil Rating Polygons 0 A Q AID Q B Q BID o D 0 CID 0 D O Not rated or not available Soil Rating Lines ~ A ~ AID N B �y B/D .ems C sV CID y D 0 Not rated or not available Soil Rating Points ■ A e AID ❑ B ❑ B/D Hydrologic Soil Group —Albemarle County, Virginia (Scottsville Tiger Fuel Market) ® C ■ CID ■ D 13 Not rated or not available Water Features Streams and Canals Transportation H Rails N Interstate Highways �y US Routes Major Roads Local Roads Background . Aerial Photography MAP INFORMATION The soil surveys that comprise your AOI 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 15, Sep 13, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Oct 14, 2019--Oct 15, 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. tlSDA Natural Resources Web Soil Survey 111512021 011111111111 Conservation Service National Cooperative Soil Survey Page 2 of 4 Hydrologic Soil Group —Albemarle County, Virginia Scottsville Tiger Fuel Market Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 49B Manassas silt loam, 2 to 7 percent slopes, occasionally flooded B 0.1 0.8% 51E Bugley channery silt loam, 25 to 45 percent slopes D 3.5 32.5% 62B Butfstat silt loam, 2 to 7 percent slopes B 4.0 36.8% 68C Penn silt loam, 7 to 15 percent slopes B 0.0 0.0% 91 Urban land 3.2 29.9% Totals for Area of Interest 10.8 100.0% Natural Resources Web Soil Survey 11/52021 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group —Albemarle County, Virginia Scottsville Tiger Fuel Market 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 neady 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 11/52021 Conservation Service National Cooperative Soil Survey Page 4 of 4 NOAA Atlas 14, Volume 2, Version 3 Location name: Scottsville, Virginia USA' Latitude: 37, Longitude:-78.5007° Elevation: 421.91 ft"' € 'source: ESRIUMaps "source: SGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, 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)1 Average recurrence interval (years) Duration 1 2 5 10 25 50 1100 100 200 ��� 500 1000 5-min (0.305-0 377) (0.357--0.440) (0.411 � 09) (04 772-0 582) (0.529-0 653) (05 74 0 711) (0.6113-0..764) (0.648-0 812) (0.684-0.67) (0- 115-0 916) 17 10-min541 (0.48 0601) (0-5771--0..704) 2- 16) (0.68 7 54 (00930) (0.843-1.04) (0.914-L13) (0.975-11.21) (1.03-1.29) (1.08-� 37) (1.13-1..44) 0.(0.610-0752) 15-min (0.7118-0885) (0.393003) (0.954-11.18) (1.07132) (116--31043) (1.23--31953) (1.30-1.63) (1.36-11..73)1 (1.41-6i381) F-049 30-min (0. 36---11.03) (0.992-11.2) (1.19-3i47) (1.38-1..71) (1.58-�95) (17 42.16) (1.89 2335) (2.022953) (2.?�75) (22 922..93) 1.16 1.38 1.69 2.00 2.35 2.65 2.93 3.21 3.56 3.85 60-min (1.04-1.29) 1 (1.25-1.53) 1 (1.53-1.88) 1 (1.80-222) 1 (2.11-2.60) 1 (2.36-2.93) 1 (2.60-3.24) 1 (2.83-3.55) (3.11-3.94) 1 (3.344.28) 1.39 1.65 2.03 2.42 2.88 3.28 3.67 4.07 Z 5.02 2-hr I (1.24-1.6) 1 (IA7-1.86) (1.81-2.29) (2.16-272) (2.54-3.22) (2.88-3.67) (3.20-4.10) (3.34.54) (3.93-5.12) (4.27-5.64) 3-12 3-hr (1.34---11.71) (1.59 2903) (1.96 2.50) (2.32 2397) (2.753.52) (3.1314.00) (3.46448) (3.814'96) (4.2495.60) (4.616.15) 6-hr (1.70 2.17) (2.01 2?58) (2.463815) (2.92 376) (3. 5 4.49) (398-5.16) (4.53.84) (4.966.6) (5.61-67854) (6: 8-8.43) 2.38 2.83 3.47 4.17 5.06 5.89 6.74 7.68 8.99 10.2 1r 2-h (2.12-2.72) (2.52-3.23) (3.08-3.96) (3.684.75) (4.42-5.73) (5.106.6) (5.77-7.61) (6.48-8.65) (7.45-10.1) (8.33-11.5) 24-hr (2.57 3520) (3.131 3 87) (3.87 4.95) (4.675?84) 1 (5. 1-7.16) (6.58-8.29) (7.52 9753) (8.52-810.9) (9.97-12.9) (11.2-14.7) 2�ey (3.023573) (3. 64b 1) (4.655573) (54 56.73) (6.608717) (7.3-9.37) (8. 3-610.7) )(9.5912.1) 1 (111-14.2) 1 (123- 6.0) 5. 3-0ay (3.2436.95) (3.92478) (4.97 6807) (583--7.12) (7.04 8364) (8.049.91) (9.10-121.3) (10 2- 2.8) (11 8-15.0) (13.1--16.8) 4day (3. 54817) (4-1 �05) (5.29$40) (6.20-7.51) (74 9-911) (8.56-10.4) 1 (9.67-111.9) (10.913.5) (12.6-15.8) (13.9187.7) 7tley (4.01 4777) (4.845674) (6. 3---7717) (7.00-8.34) (8-37 10-0) (9.49-151.4) (10 7- 2.9) (11.9-14.5) (13. -1.8) (15.0-18.8) 10.1ay (4.575536) (5. 96.44) (6. 63394) (77 8-9.16) 1 (9.21- 0.9) (10.3 2.3) (11 5-13.8) (12.8-15.3) 1 (14.4-127.6) (15.8-19.4) -IF 118-51F 20riay21.6) (6. 2-�04) (7.30 8.39) (8.81- 0.1) (9.98- 1.5) (11.6- 3.3) (12.8-14.8) (14?0- 6.3) (152-167.8) (16.9- 9.9) (18� 8.06 9.55 77.3 12.6 14.3 157 16.9 78.2 19.8 21.0 30tlay (7.57-8.59) (8.98-10.2) (10.6-12.0) (11.8-13.4) (13.4-15.3) (14.6-16.7) (15.8-18.0) (16.9-19-4) (18.3-21.2) (19.3-2.6) 454ey (9.51810.7) (112' 2.6) (137314.8) (14.5- 6.3) (16.3- 8.4) (176-19.9) (18?9- 1.4) (200- 2.8) (215324.7) 1 (22s- 6.0) 6011ay (11.3-12.6) (132-14.8) (15.3-127.1) (16.818.8) (187--20.9) (20212.5) (214-24.0) (22625.5) (2421--27.4) (25-2 8.7) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estmates and may be higher than currently valid PMP values. Please refer to NOAA Allas 14 document for more information. Back to Top