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Home My WebLink AboutWPO201900062 Calculations 2022-03-23SCALE ENGINEERING HYDROLOGY AND HYDRAULIC CALCULATIONS BOOKLET FOR SOUTHWOOD - PHASE 1 CLEAN EARTH FILL - NORTH AREA TMP 90A1-1 D ALBEMARLE COUNTY, VIRGINIA DECEMBER 23, 2021 REVISED FEBRUARY 9, 2022 REVISED MARCH 17, 2022 mwb MO. OAV oe a NO 0 .r OWNER: SOUTHWOOD CHARLOTTESVILLE, LLC WILLIAM THIESSEN 609-651-6404 wthiessen(cDcvillehabitat.org o' APPROVED by the Albemarle County Communit Development Department Date 3/X23/22 Amendment 2 ENGINEER: 30 SCALE, LLC MICHAEL MYERS, PE, CFM 434-242-2866 mike(cD30scale.com MI t F. M VERS Lic. No. 33028 0 03/17/2022 TABLE OF CONTENTS STORMWATER MANAGEMENT/BMP NARRATIVE 3 LAND COVER CONDITIONS 5 STORM SEWER PIPE DESIGN AND INLET CALCULATIONS 6 SWM ACCESS ROAD DITCH DESIGN CALCULATIONS 9 OUTLET PROTECTION CALCULATIONS 12 NOAA ATLAS 14 PRECIPITATION VALUES 13 APPENDICES: A. ARMY CORPS APPROVAL LETTER (EMAIL) 17 B. HYDRAFLOW REPORT - SWM DETENTION POND 22 C. VRRM SPREADSHEETS 49 D. NUTRIENT CREDIT AVAILABILITY LETTER 57 E. NRCS SOILS REPORT 59 STORMWATER MANAGEMENT NARRATIVE PROJECT DESCRIPTION THE PURPOSE OF THIS PROJECT IS TO PERFORM CLEAN EARTH FILL OPERATIONS IN AN APPROXIMATE 1-ACRE GULLY LOCATED IN BETWEEN FIN COURT AND IRIS COURT, BOUNDED ON THE SOUTH BY BITTERNUT LANE AND ENDING AT THE WATER PROTECTION ORDINANCE BUFFER ON THE NORTH. BASED ON SITE VISITS AND CORRESPONDENCE WITH THE US ARMY CORPS OF ENGINEERS (ACOE), THE LIMITS OF DISTURBANCE COVERED BY THIS PLAN IS OUTSIDE OF ANY PROTECTED ELEMENTS OF A "WATERS OF THE UNITED STATES', AND THEREFORE NO ACOE PERMITTING OR REPORTING IS REQUIRED. ALSO, NO DISTURBANCE OF THE WATER PROTECTION ORDINANCE BUFFER IS PROPOSED AND THERE IS NO 100-YEAR FLOODPLAIN WITHIN THE LIMITS OF DISTURBANCE. FOLLOWING THE CLEAN EARTH FILL OPERATIONS, RUNOFF FROM THE FILL AREA WILL FLOW OVERLAND TO THE STORMWATER DETENTION POND. THE EXISTING RUNOFF FROM THE STORM SEWER ON BITTERNUT LANE WILL CONTINUE TO FLOW VIA STORM SEWER PIPE, AND WILL BYPASS THE SWM DETENTION FACILITY AND OUTFALL INTO RIP -RAP OUTLET PROTECTION BEFORE ENTERING THE WATER PROTECTION ORDINANCE BUFFER. CHANNEL PROTECTION CHANNEL PROTECTION IS MET BY COMPLYING WITH 9VAC25-870-66(B)1 b. THE PEAK 1-YEAR, 24-HOUR DEVELOPED DISCHARGE RATE IS LESS THAN THE MAXIMUM ALLOWABLE RUNOFF RATE FOR CONCENTRATED DISCHARGE USING THE ENERGY BALANCE CRITERIA. REFER TO ENERGY BALANCE SUMMARY ON THIS SHEET AND HYDRAULIC AND HYDROLOGIC COMPUTATIONS BOOKLET FOR SUPPORTING CALCULATIONS. Q1 MAXIMUM ALLOWABLE RUNOFF = 1.36 CFS Q1 POST -DEVELOPED = 0.67 CFS OK FLOOD PROTECTION FLOOD PROTECTION IS MET BY COMPLIANCE WITH 9VAC25-870-66(C)2B. THE PEAK 10-YEAR, 24-HOUR (10% AEP) COMBINED DEVELOPED DISCHARGE RATE HAS BEEN REDUCED TO BE LESS THAN THE PRE -DEVELOPMENT 10-YEAR, 24- HOUR DISCHARGE RATE FOR THE ENTIRE 6.28-ACRE DRAINAGE AREA TO THE POINT OF ANALYSIS. THE FOLLOWING PEAK RATES ARE TAKEN FROM THE HYDRAFLOW CALCULATIONS REPORT LOCATED IN THE APPENDICES OF THIS BOOKLET: Page 3 of 76 Q10 PRE -DEVELOPED = 25.5 CFS Q10 POST DEVELOPED = 17.8 CFS OK WATER QUALITY COMPLIANCE NARRATIVE WATER QUALITY WILL BE MET BY THE PURCHASING OF NUTRIENT CREDITS. A LETTER OF AVAILABILITY HAS BEEN PROVIDED ON SHEET 9 OF THE SITE PLAN FOR 0.20 LBS/YR OF PHOSPHORUS CREDITS TO COMPLY WITH THE VRRM REQUIREMENTS. THE NUTRIENT CREDITS WILL BE PURCHASED PRIOR TO WPO AMENDMENT APPROVAL. THE SWM DETENTION POND WILL BE SUBJECT TO THE PREVIOUSLY RECORDED STORMWATER MANAGEMENT MAINTENANCE AGREEMENT FOR SOUTHWOOD REDEVELOPMENT - VILLAGE 1. Page 4 of 76 LAND COVER CALCULATIONS NOTE: HAZEL AND ELIOAK SOILS ARE NRCS "B" SOILS PRE -DEVELOPMENT COMPOSITE CN CALCULATIONS LAND COVER (AC) CN CN*A COMPOSITE CN ROADWAY/SIDEWALKS/DRIVEWAYS 0.26 98 ROOFTOP 0.25 98 GRAVEL TRAIL 0.03 98 TOTAL IMPERVIOUS 0.54 98 52.9 WOODS 1.58 55 86.9 LAWN 0.21 61 12.8 TOTAL AREA 2.33 AC 152.6 66 TIME OF CONCENTRATION GEOMETRY - PRE -DEVELOPMENT L (FT) HI ELEV LO ELEV SLOPE SHEET FLOW 100 489.5 481.5 8.0% SHALLOW CONCENTRATED FLOW 89 481.5 472.0 10.7% CHANNEL FLOW 658 472.0 431.0 6.2% TC = 7.2 MIN POST -DEVELOPMENT COMPOSITE CN CALCULATIONS LAND COVER (AC) CN CN*A COMPOSITE CN ROADWAY/SIDEWALKS/DRIVEWAYS 0.26 98 ROOFTOP 0.25 98 SW M ACCESS ROAD 0.09 98 TOTAL IMPERVIOUS 0.60 98 58.8 WOODS 0.60 55 33.0 LAWN 1.13 61 68.9 TOTAL AREA 2.33 AC 160.7 69 TIME OF CONCENTRATION GEOMETRY - POST -DEVELOPMENT L (FT) HI ELEV LO ELEV SLOPE SHEET FLOW 100 489.5 481.5 8.0% SHALLOW CONCENTRATED FLOW 89 481.5 472.0 10.7% CHANNEL FLOW 642 472.0 431.0 6.4% TC = 7.2 MIN NOTE: USE 5-MINUTE TIME OF CONCENTRATION FOR 2.33-ACRE DRAINAGE AREA FLOWING TO POND OFFSITE COMPOSITE CN CALCULATIONS LAND COVER (AC) CN CN*A COMPOSITE CN ROADWAY/SIDEWALKS/DRIVEWAYS ROOFTOP 1.41 0.32 98 98 TOTAL IMPERVIOUS WOODS LAWN 1.73 2.16 0.06 98 55 61 169.5 118.8 3.7 TOTAL AREA 3.95 AC 292.0 74 Page 5 of 76 STORM SEWER DESIGN COMPUTATIONS (10-YEAR DESIGN STORM) FROM TO A (INC) C AC (INC) Q (INC) AC (ACC) Q (ACC) DIA L INV UP INV DN S n Tc V2 Qcap AC AC) (CFS) (AC) (CFS) (IN FT FT F % MIN FPS CFS 5 4 3.16 0.55 1.74 11.47 1.74 11.47 36 31 460.71 459.32 4.00 0.013 7 8.7 133 4 3 0.79 0.70 0.55 3.65 2.29 15.12 36 255 459.22 435.91 9.00 0.013 7 11.5 200 3 2 0.00 2.29 15.12 36 47 435.81 433.26 5.00 0.013 7 11.5 149 2A 2 2.33 SEE SWM ROUTINGS 6.71 (SWM) 15 10 438.00 437.72 2.00 0.013 7 8.1 9 2 1 0.00 SEE SWM ROUTINGS 21.8 (SWM) 36 59 432.26 431.00 2.00 0.013 7 9.1 94 F2 F1 0.36 0.41 0.15 0.97 0.15 0.96 12 12 442.50 442.00 2.02 0.0131 7 4.6 5 NOAA ATLAS 14 PRECIPITATION INTENSITIES: 2-YR = 5.02 IN/HR, 10-YR = 6.61 IN/HR Inlet Report Hydraflow Express Extension for AutodeskO Civil 3DO by Autodesk, Inc. Friday, Feb 11 2022 STRUCTURE F2 Drop Grate Inlet Calculations Location = Sag Compute by: Known Q Curb Length (ft) _ -0- Q (cfs) = 0.98 Throat Height (in) _ -0- Grate Area (sqft) = 2.33 Highlighted Grate Width (ft) = 2.58 Q Total (cfs) = 0.98 Grate Length (ft) = 2.58 Q Capt (cfs) = 0.98 Q Bypass (cfs) _ -0- Gutter Depth at Inlet (in) = 1.20 Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 12.58 Local Depr (in) _ -0- Gutter Vel (ft/s) _ -0- Gutter Width (ft) = 1.00 Bypass Spread (ft) _ -0- Gutter Slope (%) _ -0- Bypass Depth (in) _ -0- Gutter n-value = -0- Page 7 of 76 Inlet Report Hydraflow Express Extension for Autodesk0 Civil 3DO by Autodesk, Inc. CURB INLETS 4 AND 5 Curb Inlet Location Curb Length (ft) Throat Height (in) Grate Area (sqft) Grate Width (ft) Grate Length (ft) Gutter Slope, Sw (ft/ft) Slope, Sx (ft/ft) Local Depr (in) Gutter Width (ft) Gutter Slope (%) Gutter n-value Nl Elmm--In. Friday, Dec 24 2021 Calculations = Sag Compute by: Q vs Depth = 16.00 (2) 8-FT THROATS Max Depth (in) = 6 _ -0- Highlighted _ -0- Q Total (cfs) = 10.50 _ -0- Q Capt (cfs) = 10.50 Q Bypass (cfs) = -0- Depth at Inlet (in) = 5.98 = 0.080 Efficiency (%) = 100 = 0.020 Gutter Spread (ft) = 18.92 _ -0- Gutter Vel (ft/s) = -0- = 2.00 Bypass Spread (ft) = -0- -0- Bypass Depth (in) = -0- -0- NOTE: CURB INLETS 4 AND 5 WERE MODELED TOGETHER SINCE THEY ARE EACH LOCATED IN A SUMP ON OPPOSITE SIDES OF BITTERNUT LANE. COMBINED, THESE INLETS PROVIDE ADEQUATE CAPACITY TO CONVEY THE 2-YEAR DESIGN STORM WITHOUT OVERTOPPING THE CURB. THE ULTIMATE DESIGN OF SOUTHWOOD PHASE 2 WILL HONOR THE LOCATIONS OF INLETS 4 AND 5; AND SUPPLEMENTAL STORM SEWER DESIGN AT THAT TIME WILL REDUCE THE OVERLAND FLOWS ULTIMATELY FLOWING TO INLETS 4 AND 5. Page 8 of 76 Channel Report SWM ACCESS ROAD DITCH DESIGN CALCULATIONS - LEFT SIDE Hydraflow Express Extension for AutodeskO Civil 3DO by Autodesk, Inc. DITCH CALCULATIONS - LEFT SIDE Triangular Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 15.00 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 2.36 Elev (ft) 102.00 � 101.50 101.00 100.50 100.00 99.50 Section 1 1 2 3 4 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) 5 6 Thursday, Feb 10 2022 = 0.37 = 2.360 = 0.41 = 5.75 = 2.34 = 0.53 = 2.22 = 0.88 Depth (ft) 2.00 1.50 1,00 0.50 -0.50 7 8 Page 9 of 76 Channel Re OIt SWM ACCESS ROAD DITCH DESIGN p CALCULATIONS - RIGHT SIDE Hydraflow Express Extension for Autodesk0 Civil 3DO by Autodesk, Inc. DITCH CALCULATIONS - RIGHT SIDE Triangular Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 15.00 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.98 Elev (ft) 101.00 � 100.75 100.50 100.25 100.00 99.75 0 .5 1 1.5 Section 2 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) 2.5 3 Thursday, Feb 10 2022 = 0.27 = 0.980 = 0.22 = 4.48 = 1.71 = 0.37 = 1.62 = 0.58 Depth (ft) 1.00 0.75 0.50 0.25 -0.25 3.5 4 Page 10 of 76 1 MIN L=14' DESIGN OF OUTLET PROTECTION FROM A ROUND PIPE FLOWING FULL MINIMUM TAILWATER CONDITION (Tw - 0.5 DIAMETER) 90 3 ° aD •- �-- �I Outlet M = DO a La Pipe 2 Mi n. Diameter, D° 1 feed _ ... La 0.5D° AQcop 'L' cf s MIN d50=6" Recommended Min. `d d.=6'- � w m CD O J Wm 4 1 i J O 3 5 10 �/20 50 3 100 200 500 1000 / Discharge. Ft./sec. Q10=19 CFS n D np C (n 0�> 30Z0 NInC ;oOm C ;a � CEO mom C f+ -n D0 �Z 'J� 12124/21, 8:53 AM Precipitation Frequency Data Server NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA* Latitude: 38.00080, Longitude: -78.52350' 11A ~ Elevation: 455.13 ft** * source: ESRI Maps ** source: USGS 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), Average recurrence Interval (years) °° a"°°'oo0 10 25 50 100 200 5001 1000 0.352 0.410 OA91 0.551 0.621 0.675 0.724 0.]71 0.827 0.8]2 Sarin (0.317 0.391) (0.377-0.465) (0.441-0.544) (D.496-0.610) (0.555-0.685) (0.6 11 .744) (0.6 11 .798) (0.678 0.851) (0.720-0.914) (0.752 0.968) 0.562 0.668 O]86 0.882 0.890 1.07 1.15 1.22 1.31 1.3] 10-min (0.506-0.624) (0.604-0.744) (0]07-0.871) (0]92-0.976) (0.885-1.09) (0.957-1.19) (1.02-1.27) (1.08-1.35) (1.14-1.45) (1.19-1.52) 0.]02 0.841 0.994 1.12 1.25 1.361.54 1.65 1.72 15-min (0.632-0.780) (0]59-0.935) (0.894-1.10) (L0 1.24) (1.12-1.38) (1.21-1.50) (1.29-1.60) (1.36-1.70) (1.43-1.82) 1 (1.49-1.91) 0.962 7.16 1.41 1.62 1.88 2.05 2.23 2.40 262 2,79 30-min (0.867-1.07) (1.05-1.29) Ljl.27-1.57) (1.4L1]9) (1.66-2.05) 1 (1.82-.26) (1.97-2.46) 11 (2.11-2.65) (228-2.90) (2.41-3.10) 1.2a 7.46 1.91 2.10 2.47 2.7e 3.07 3.37 3.76 4.08 80•min (1. 1.33) (1.32-1.62) (1.632.01) (1.89-233) (2.21-2.73) (2.47-3.06) (272-3.38) 11 (2.%3.71) (3.27-4.16) (3.52-4.52) 1.44 1.75 1.18 2.57 ].O6 3.46 3.88 6.32 4.91 2-hr (126-165) (1-1.99) .53 (192-249) (225-2.92) (2.66-3.46) (3.00-393) (3.35339) .88 (3.69-4) ( 4.15-5.56) 6.53-6.14 1.58 1.91 2.39 2.80 3.34 3.79 4.25 4.73 5.39 1 5.95 Yhr (1.38-1.82) 1 (1,67-2.19) 1 (2.09-2.75) 11 (2.44-3.21) 11 (2.90-3.82) 1 (3,27-4.32) 11 (3.64A.85) 1 (4.02-5.40) (4.52E.15) (4.94-6.80) 252 2.66 3.03 3.s7 0.28 4.91 7F 5.57 6.28 7.28 1 8.16 8•hr (1.79-229) 2.15-2.76) 11 (2,67-3.42) 11 (3.13A.03) 11 (3.73-4.83) 4.25-5.53 (4.78-6.27) 1 (5.32-707)_ (6.08-8.20) (6.72-9.20) 2.55 3.07 3.83 4.53 5.51 6.39 7.33 8.37 9.a9 11.3 12hr 2.25-2.92 271-3.51 3.36A.38 3.97-5.17 4.79-0.2] 5.50-7.25 6.23-8.31 (702-947) (8.13-11.2) (9.11-12.8) 3.05 3.69 4.]2 L58 6.86 7.95 9.16 10.5 12.5 14.2 24-hr 2.74-3.42 3.324.14 4.235.28 4.9".23 6.084.62 7.01-8.83 8.00-10.2 (907_116) (10.6-13.8) (11.9-15.7) 3.59 4.36 5.54 6.52 ].94 9.12 10.4 11.8 13.9 15.6 2-day (3.234.01) (3.91A.87 4.96E.19) (5.82-7. 7) Q.03-8.83) (8.03-10.1) (9.09-11.61 (102-13.1) (11.9-15.5) (13.2-17.4) 3.83 4." 5.89 6.93 8.43 9.68 11.0 12.5 14 7 16.5 3-day (3.48-4.24) (4.21-5.13) (5,34-6.52) (6.26-7.65) (7.57-9.29) (8.64-10.7) (9.78-12.2) (11.0-13.8) (12.7-16.2) (14.1-18.3 1 4.06 4.92 6.25 7.33 8.91 10.2 11.7 13.2 15 17.4 47aY (3.73-446) (4.51-5.40) (5.72-6.85) (6.70-8.03) (8.11-9.75) (9.25-11.2) (10.5-12.8) (11.8-145) .5 (13.6-17.0) (15.1-19.1 1 4.72 5.68 7.10 8.26 9.94 11.3 12.8 14.4 16.0 18.7 7day (434-5131 (5.23-8.18) (6.52-7 ]2) (7.58-8.99) (9.06-108) (10.3-12.3) (11.5-13.9) (12.9-15] ) (14.8-18.3) (16.3-20.5 1 5.34 8.41 792 9.14 10.9 12.3 13.8 15.3 17.6 19.4 10day (4.94-577) (5.94-0.93) (7.32-8.55) (8.43-9.86) (9.98-11] ) ( 11.2-13.2 ) ( 12.5-14.9) (13.8-16.8 ) (15.7-19.1 ) ( 17.2-21.1) 7.02 8.37 10.1 11.5 13.3 14.8 16.3 tt.8 19.8 21.5 20dey (6M 7.50) (7.85-8.95) 1 (9.67-10.8) 1 (10.712.3) 1 (12.6-14.2) 1 (13.7 15.8) (15.1-17.4) 11 (16.4-19.1) j (18.2-21.6) 1 (19.5-23.2) 8.61 10.2 12.1 13.5 15.3 18.8 18.1 19.5 21.3 22.6 30day (8.11-9.16) (9.62-10.9) (11.4-12.8) (12.7-14.3) (14.4-16.3) (15.7-17.8) (16.9-19.3) (18.1-20.8) (19.7-22.7) (20.8-24.2) 10.7 12.7 14.a 18.4 18.5 20.0 21.5 22.9 2A.7 26.1 ud.y, (102-11.4) 1 (12.0-13A) 1 (14.0-15.7) 1 (15.5-17.4) 1 (17.6-19.6) 1 (18.8-21.2) 11 (20.2-22.8) 11 (21.4-2A.3) 1 (23.0-26.3) 1 (24.2-27.8) 12.6 14.6 17.1 18.8 21.0 22.6 2A.2 25.6 27.5 28.8 60day 22.2) J1 (21.3-23.9) (22.725.5) 11 (24.1-27.1) 1 (25.729.1) (26930.6) 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 given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bound, are not hecked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical Page 13 of 76 https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=38.0008&Ion=-78.5235&data=depth&units=english&series=pds 1/3 12124/21, 8:53 AM Precipitation Frequency Data Server PDS-based depth -duration -frequency (DDF) curves Latitude: 38.0008'. wngllude:-78.5235' 30 a e 9 15 a i d 0 T T T T q T q Tq WfdtlOn 2 C 2 L O 1 a n1 n Average recurrence interval (years) NOAA Atlas 14. Wlume 2, Version 3 Created (GMT): Fri Dec 2413:53:06 2021 Back to Top Maps & aerials Small scale terrain Large scale terrain Washington, ❑.C�^ Hartisenbmg� :Nnn[d i V[Ai.I NIA Q IA —�— Ric iynciturg 4 a sbu'g. � RomoMe taaKrn 1� Norio AwaBe re mnw aneml (Y.) 2 — 6 10 25 s0 100 — 200 500 1000 nrxaM n — I In — 3Eay . tamin — "" — 60 In — 10-aay — 2tr — 2 ay — 3Ar — A ay — 9Aa — b0-0ay — 1Xla — 80s1ry — 1Mr Page 14 of 76 https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=38.0008&Ion=-78.5235&data=depth&units=english&series=pds 2/3 12124/21, 8:53 AM Precipitation Frequency Data Server Large scale map \ An .;� Washington Hnnsonbup ml-n L�n.A4Wg Ri u+ Bladubmg Rainokz 00km J I Nor4 d ' Omi Back to Top US Qgnertment of Commerce National Oceanic and Atmosoheric Administration National Weather Service National Water Center 1325 Fast West Highway Silver Spring, MD 20910 Questions?: HDSC Quest onsj§noaa.gov Disclaims Page 15 of 76 https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=38.0008&Ion=-78.5235&data=depth&units=english&series=pds 3/3 12124/21, 8:53 AM Precipitation Frequency Data Server NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA* Latitude: 38.00080, Longitude: -78.52350' 11A ~ Elevation: 455.13 ft** * source: ESRI Maps ** source: USGS 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/hour)1 Average recurrence interval (year) Dumtlon 1 11 2 11 5 11 10 11 25 50 O�O�O 100 200 500 1000 4.22 5.02 5.89 6.61 7. 8.- 8.69 9.25 9.92 10.5 ,.In (3.80-4.69) (4.52-5.58) (5.29-6.53) (5.94-7.32) (6.66-8.22) (].21-8.93 ) ( 7.69-9.58) (0.14-10.2 ) (8.64-11.0 ) ( 9.02-11.6) 3.37 4.01 4.72 5.29 5.84 6.d4 6.91 ].34 ].OS 0.24 10-min (3.04-3Jd) (3.82d.48) (4.26-5.23) (d]5-5.88) (5.31 ,.55) (6.11 7.B 1)l (8.45-8.09) (6.83-8.68) 1 (7.11-9.14) 2.81 3.36 3.98 4A6 5.02 1 5.44 5.82 6.17 6.50 6.90 15-min (2.53-3.12) 1 (3.04-3.74) 3,58-4.40) 11 (4.01-4.94) 11 (4.48-5.54) 11 (4.84-6.00) 1 (5.15-0.42) (5.43-0.80) (5.73-7.28) (5.95-7.65) L92 2.32 2.82 3.23 3.72 4.to 4.4fi 4.60 5.24 5.58 30-min (1.73-2.14) (2.10-2.58) (2.54-3.13) (2.90-3.58 ( 3.32-0.10 ) (3.65-4.52 ) ( 3.95-4.91) (4.22-5.30 ) (4.56-5]9 ) ( 4.82-6.20 ) 1.20 tA6 1.81 2.10 2.47 2- 3.m 3.37 3]6 4.08 60•min (1.08-1.33) (1.32-1.62) (1.63-2.01) (1.8&2.33) (2.21-2]3 ) (247-3.06 ) ( 2]2-3.38) (2.%3]i ) (3.2]-4.18) (3.52-4.52 ) 0.720 0. 774 -281F1. 33 1.]3 1.94 2.16 2.46 2.71 2-hr IF (0.632-0.824) (0.766-0.998) (0.958-1.24) 1 (1.13-1.46) 1 (1.33-1.73) (1.50-1.96) (1.67-2.20) 11 (l.W2.44) (2.08-2.78) (226-3.07) 0.525 0.933 1.11 1.42 1.58 1.79 3 hr (0.460-0.605) N-O. (0.556-0.731) (0.694-0.915) 91 (0.813-1.W) (0.984-1.27) 9 . (1.09-1.44) (1.21-1.81) (1.34-1.80) (1.51-2.05) 4 2. (1.64-226) 0.337 0.407 0.508 0.596 0.715 0.820 0.930 1.05 1.22 1.36 8-hr (0.29&0.382) (0.380-0A61) (0.445-O.S7) (0.522-0.673) (0.626-0.80]) (0.710-0.923) (0]97-1.05) (0.889-1.18). (1.02-1.37) (1.12-1.54) 0.211 0.255 TM 0.37fi 0. 556 0.530 0.609 0.894 0,821 0.935 12-hr (0.186-0.242) (0.225-0.292) (0.29-0.363) (0.330-0.429) (0.398-0.520) (0.456-0.602) (0.51]-0.690( (0.582-0.786) (0.675-0.931) (0.756-1AB) 0.154 0.197 0.232 0.286 0.331 0.382 0.438 0.521 0.593 24-hr JF-0.12] (0.114-0.142) (0.138-0.172) (0.176-0220) (0.208-0.259) (0.253-0.318) (0.292-0.368) (0.333-0.423) (0.37&0.484) (0.443-0.576) (0.496-0.655) 0.075 0.091 0.115 0.136 0.165 0.190 0.21] 0.246 0.289 0.325 2dey (0.0670.084) (0.081-0.101) (0.103-0.129) (0.121-0.151) (0.167-0.184) (0.16]-0.211) (0.189-0.241) (0.213 0.274) (0.247-0.322) (0.274 02 2) 0.053 0.084 0.082 0.096 0.117 0.134 0.153 0.174 0.204 0.229 3day (LO48-0.059) (0.059-0.071) (0.074-0.091) (0.087-0.106) (0.105-0.129) (0.120-0.148) (0.136-0.169) (0.153-0.192) (0.177-0.225) (0.196-0.254) 0.042 0.051 0.065 0.07fi 0.093 0.107 0.121 0.138 0.161 0.181 4day (0.03&0.046) (0.047-0.056) (0.06&0.0]1) (0.070-0.084) (0.084-0.102) (0.096-0.117) (0.109-0.133)1(0.123-0.151) (0.142-0.177) (0.15]-0.199) 0.028 0.034 0.042 0.049 0.059 0.067 0.076 O.0a6 0.100 0.111 7dey (0.026-0.031) (0.031-0.037) (0.039-0.046) (0.045-0.053) (0.054-0.064) (0.061-0.073) (0.069-0.083) (0.077-0.094) (0.088-0.109) (0.097-0.122) 0.022 0.02] 0.033 0.038 0.045 0.051 0.057 0.084 0.073 0.081 1Oday (0.021-0.024) (0.025-0.029) (0.031-0.036) (0.035-0.041) (0.042-0.049) (0.047-0.055) (0.052-0.062) (0.058-0.069) (0.065-0.079) (0.072-0.088) 0015 0.01] 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.045 20day (0.016-0.016) (0.016-0.019) (0.02&0.023) (0.022-0.026) (0.026-0.030) (0.029-0.033) (0.031-0.036) (0.034-0.040) (0.038-0.045) (0.041-0.048) 30dq 0.012 (0.011-0.013) 00 07FOO12 0.014 (0.013-0.015) 0.017 (0.016-0.018) F 00 47FOO15 0.019 (0.018-0.020) 0.021 (0.020-0.023) 00 77FOO19 0.023 (0.022-0.025) 0.025 (0.023-0.027) 0.020 0.027 (0.02&0.029) F0021 0.030 (0.027-0.032) 0.023 0.031 (0.029-0.034) 0.024 45 � (0.009-0.011) (0.011-0.012) (0.013-0.015) (0.014-0.016) (0.016-0.018) (0.017-0.020) (0.019-0.021) (0.02&0.023) (0.021-0.026) (0.022-0.026) 00097FOO10 0.012 0.013 00 17FOO18-1F0.017 0.018 0.019 0.020 60dey (0.0o8-0.009) (0.010-0.011) (0.011 o-ol3 (L.012-0.014) (0.o16-0.015) (o.015-0.017) (0.016-0.018) (0.017-0.019) (0.018-0.020) (0.019-0.021) 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 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 hecked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more informabon. Back to Top PF graphical Page 16 of 76 https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=38.0008&Ion=-78.5235&data=intensity&units=english&series=pds 1/3 APPENDIX A APPENDIX B HYDRAFLOW REPORT - SWM DETENTION POND APPENDIX C VRRM SPREADSHEETS APPENDIX D NUTRIENT CREDIT AVAILABILITY LETTER APPENDIX E NRCS SOILS REPORT Page 17 of 76 Mike Myers From: Pero, Vincent D CIV USARMY CENAO (USA) <Vincent.D.Pero@usace.army.mil> Sent: Wednesday, December 8, 2021 6:33 AM To: Mike Myers; William Thiessen; RJ Wright Cc: Frank Pohl; Andrew Vinisky; Bryan Rieckmann Subject: RE: Southwood - Proposed Fill in Northern Gully HI Mike Thanks for showing me around the site. No permit is required from my office to fill the northern gully. The Corps determination for that area only is that it is a drainage channel and not a water of the U.S. Thanks and let me know if you need anything more from my office at this time Vinny Vinny Pero U.S. Army Corps of Engineers Norfolk District Western Virginia Regulatory Section Charlottesville Field Office 920 Gardens Boulevard, Suite 103-B Charlottesville, Virginia 22901 757-297-0011 (temp while teleworking) The Norfolk District is committed to providing the highest level of support to the public. In order for us to better serve you, please complete our Customer Satisfaction Survey at: https://regulatory.ops.usace.army.mil/Ords/f?P=136:4 From: Mike Myers <mike@30scale.com> Sent: Thursday, December 2, 20217:22 PM To: Pero, Vincent D CIV USARMY CENAO (USA)<Vincent.D.Pero@usace.army.mil>; William Thiessen <wthiessen@cvillehabitat.org>; RJ Wright<rjwright@faulconerconstruction.com> Cc: Frank Pohl <fpohl@albemarle.org>; Andrew Vinisky <avinisky@cvillehabitat.org>; Bryan Rieckmann <brieckmann @faulconerconstruction.com> Subject: [Non-DoD Source] Southwood - Proposed Fill in Northern Gully Vinny, Thanks for meeting up with Bill (Habitat for Humanity), RJ Wright (Faulconer Construction) and me this morning at Southwood to walk the site and discuss our plan to fill the northern gully with excess dirt from Village 1 in an effort to reduce costs for trucking off excess dirt. Based on our site meeting this morning, it is our understanding that the proposed fill operations will not require a Corps permit. However, I wanted to make sure you had the various maps so that you could provide Albemarle County and us written confirmation. Page 18 of 76 Our goal is to perform the fill operations in 10 of 2022 so that we can coordinate with the Village 1 construction schedule. I have provided snapshots of the various maps below and here is a E LINK to the full-size pdfs of each of these. Thanks very much, and please let me know if you have any questions or if you need clarification on anything, great to see you this morning, Mike PS to Frank and Matt, Once we hear back from Vinny, we would like to schedule a meeting with you (onsite preferably) so we can review our proposal in the field prior to formal submission of the E&S Plan. I will follow up with you, but wanted you to be aware of our plans and schedule. Feel free to reach out with questions as well, Mike Michael Myers, PE, CFM 30 Scale, LLC C: 434-242-2866 1 Web: 30Scale.com MAPS/EXHIBITS/PHOTOS Marked -Up WSSI WOTUS MAP — NORTHERN GULLY STREAM REACH C — I NORTHERN STUDY AREA 60UNDARY NORTHERN GULLY TO BE FILLED 1ys TMs awnwawn wui p98) tAouaq ark auou OaA.iwnon AAwn,s' Eaa 6 TM Rowns P+-Sb l feW nark was RerM 8 T" WOTUS I.. ah 9 m Vt5Sl1 alungn. Iti 1M mr^a,a abmiwab do a mq w.man CFR S 4ewiaf n u It, CFR Sxno1 322 ] n In NalmEr 1], 19g5i He Earn IRat auto IaXurwa ma COE to cmcw mut u aLle MndeLO^ uWw 9 f0 $Vaam avwauon rtu Depertnronl d>�E+c Yk irvnrmalrn, slmoms IMa iMee rtq¢ip]s we�a uw w fre s'EFI` Gnamt m W SSra teatoN Unol nrtw,a Ev me coE, d mn Ceamawn rnpea Marked -up Albemarle County GIS Map showing approximate location of fill, storm sewer and E&S z Page 19 of 76 Conceptual Fill Plan Page 20 of 76 Photo of "Ski Slope" in Village 1 — Excess dirt to be placed in northern gully Page 21 of 76 APPENDIX A ARMY CORPS APPROVAL LETTER (EMAIL) APPENDIX C VRRM SPREADSHEETS APPENDIX D NUTRIENT CREDIT AVAILABILITY LETTER APPENDIX E NRCS SOILS REPORT Page 22 of 76 Watershed Model Schematic I Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 11 Leaend HHyd. origin Description 1 SCS Runoff PRE -DEVELOPMENT 2 SCS Runoff POST -DEVELOPMENT 4 SCS Runoff PRE-DEV POND 5 SCS Runoff POST-DEV TO POND 7 Reservoir ROUTING 9 SCS Runoff OFFSITE 11 Combine COMBINEDOUTFLOW Project: NG SW M ROUTINGS.gpw Friday, 02 / 1 f8 Mf 76 Hydraflow Table of Contents NG SWIM ROUTINGS.gpw Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 111 / 2022 Watershed Model Schematic...................................................................................... 1 1 -Year HydrographReports................................................................................................................... 2 Hydrograph No. 1, SCS Runoff, PRE-DEVELOPMENT.......................................................... 2 TR-55 Tc Worksheet........................................................................................................... 3 Hydrograph No. 2, SCS Runoff, POST-DEVELOPMENT........................................................ 4 Hydrograph No. 4, SCS Runoff, PRE-DEV POND................................................................... 5 Hydrograph No. 5, SCS Runoff, POST-DEV TO POND........................................................... 6 Hydrograph No. 7, Reservoir, ROUTING................................................................................. 7 PondReport - POND........................................................................................................... 8 Hydrograph No. 9, SCS Runoff, OFFSITE............................................................................... 9 Hydrograph No. 11, Combine, COMBINED OUTFLOW........................................................ 10 10 -Year HydrographReports................................................................................................................. 11 Hydrograph No. 1, SCS Runoff, PRE-DEVELOPMENT........................................................ 11 Hydrograph No. 2, SCS Runoff, POST-DEVELOPMENT...................................................... 12 Hydrograph No. 4, SCS Runoff, PRE-DEV POND................................................................. 13 Hydrograph No. 5, SCS Runoff, POST-DEV TO POND ......................................................... 14 Hydrograph No. 7, Reservoir, ROUTING............................................................................... 15 Hydrograph No. 9, SCS Runoff, OFFSITE............................................................................. 16 Hydrograph No. 11, Combine, COMBINED OUTFLOW........................................................ 17 100 -Year HydrographReports................................................................................................................. 18 Hydrograph No. 1 SCS Runoff PRE-DEVELOPMENT........................................................ 18 Hydrograph No. 2, SCS Runoff, POST-DEVELOPMENT...................................................... 19 Hydrograph No. 4, SCS Runoff, PRE-DEV POND................................................................. 20 Hydrograph No. 5, SCS Runoff, POST-DEV TO POND ......................................................... 21 Hydrograph No. 7, Reservoir, ROUTING............................................................................... 22 Hydrograph No. 9, SCS Runoff, OFFSITE............................................................................. 23 Hydrograph No. 11, Combine, COMBINED OUTFLOW........................................................ 24 OFReport.................................................................................................................. 25 Page 24 of 76 Hydrograph Report 2 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 1 PRE -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.05 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 66)] / 6.280 Q (cis) 8.00 .m 4.00 2.00 0.00 0 120 240 Hyd No. 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE -DEVELOPMENT Hyd. No. 1 -- 1 Year 360 480 600 720 840 Friday, 02 / 1112022 = 7.554 cfs = 720 min = 17,994 cuft = 71* = 0 ft = 7.20 min = Type II = 484 Q (Cfs) 8.00 4.00 2.00 'I I' 1 0.00 960 1080 1200 1320 1440 1560 Time (min) Page 25 of 76 3 TR55 Tc Worksheet Hydraflow Hydrograp his Extension for Autodesk� Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 1 PRE -DEVELOPMENT Description A B C Totals Sheet Flow Manning's n-value = 0.150 0.011 0.011 Flow length (ft) = 100.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.36 0.00 0.00 Land slope (%) = 8.00 0.00 0.00 Travel Time (min) = 5.49 + 0.00 + 0.00 = 5.49 Shallow Concentrated Flow Flow length (ft) = 89.00 0.00 0.00 Watercourse slope (%) = 3.30 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) =2.93 0.00 0.00 Travel Time (min) = 0.51 + 0.00 + 0.00 = 0.51 Channel Flow X sectional flow area (sqft) = 1.00 0.00 0.00 Wetted perimeter (ft) = 2.00 0.00 0.00 Channel slope (%) = 6.20 0.00 0.00 Manning's n-value = 0.025 0.015 0.015 Velocity (ft/s) =9.33 0.00 0.00 Flow length (ft) ({0))658.0 0.0 0.0 Travel Time (min) = 1.18 + 0.00 + 0.00 = 1.18 Total Travel Time, Tc.............................................................................. 7.20 min Page 26 of 76 Hydrograph Report 4 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 2 POST -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.05 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 69)] / 6.280 Q (cis) 10.00 1.181011 .M 4.00 Nut Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor POST -DEVELOPMENT Hyd. No. 2 -- 1 Year Friday, 02 / 1112022 = 8.098 cfs = 720 min = 19,103 cuft = 72* = 0 ft = 7.20 min = Type II = 484 Q (Cfs) 10.00 9.18111 4-00 2.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time (min) Page 27 of 76 Hydrograph Report 5 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 4 PRE-DEV POND Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 2.330 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.05 in Storm duration = 24 hrs Q (cis) 2.00 1.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE-DEV POND Hyd. No. 4 -- 1 Year 120 240 360 480 600 720 840 960 Hyd No. 4 Friday, 02 / 1112022 = 1.853 cfs = 720 min = 4,811 tuft = 66 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 2.00 1.00 'I 10.00 1080 1200 1320 1440 1560 Time (min) Page 28 of 76 Hydrograph Report I Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 5 POST-DEV TO POND Hydrograph type = SCS Runoff Peak discharge Storm frequency = 1 yrs Time to peak Time interval = 2 min Hyd. volume Drainage area = 2.330 ac Curve number Basin Slope = 0.0 % Hydraulic length Tc method = User Time of conc. (Tc) Total precip. = 3.05 in Distribution Storm duration = 24 hrs Shape factor Q (cis) 3.00 2.00 1.00 0.00 0 120 240 Hyd No. 5 POST-DEV TO POND Hyd. No. 5 -- 1 Year 360 480 600 720 840 Friday, 02 / 1112022 = 2.412 cfs = 720 min = 5,892 cuft = 69 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 3.00 2.00 ' 0.00 960 1080 1200 1320 1440 1560 Time (min) Page 29 of 76 Hydrograph Report 7 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 / 1112022 Hyd. No. 7 ROUTING Hydrograph type = Reservoir Peak discharge = 0.670 cfs Storm frequency = 1 yrs Time to peak = 730 min Time interval = 2 min Hyd. volume = 5,892 cuft Inflow hyd. No. = 5 - POST-DEV TO POND Max. Elevation = 440.84 ft Reservoir name = POND Max. Storage = 1,323 cuft Storage Indication method used Q (cis) 3.00 2.00 1.00 0.00 0 120 240 Hyd No. 7 360 480 600 — Hyd No. 5 ROUTING Hyd. No. 7 -- 1 Year 720 Q (Cfs) 3.00 2.00 ' 0.00 840 960 1080 1200 1320 1440 1560 ® Total storage used = 1,323 cult Time (min) Page 30 of 76 Pond Report $ Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 / 1112022 Pond No. 3 - POND Pond Data Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 438.00 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cuft) Total storage (cult) 0.00 438.00 55 0 0 2.00 440.00 537 509 509 4.00 442.00 1,488 1,946 2,455 6.00 444.00 2,884 4,295 6,750 7.00 445.00 3,617 3,243 9,993 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in) = 36.00 4.00 0.00 0.00 Crest Len (ft) = 12.57 2.00 Inactive 0.00 Span (in) = 36.00 4.00 0.00 0.00 Crest El. (ft) = 444.00 442.00 0.00 0.00 No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El. (ft) = 438.00 438.00 0.00 0.00 Weir Type = 1 Real Rect --- Length (ft) = 40.00 1.00 0.00 0.00 Multi -Stage = Yes No No No Slope I%) = 1.00 1.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 ExFI.(in/hr) = 0.000 (by Wet area) Multi -Stage = n/a Yes No No TW Elev. (ft) = 0.00 Stage (ft) 8.00 6.00 4.00 r�trn� 0.00 0.00 8.00 Total Q Note: Culvert/Orifice ouHlow are analyzed under inlet(ic) and outlet(oc) control. Weir risers checked for orifice conditions (to) and submergence(s). Stage / Discharge 16.00 24.00 32.00 40.00 48.00 56.00 64.00 72.00 Elev (ft) 446.00 442.00 440.00 1 438.00 80.00 Discharge (cfs) Page 31 of 76 Hydrograph Report I Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 9 OFFSITE Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 3.950 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.05 in Storm duration = 24 hrs Q (cis) 6.00 5.00 4.00 3.00 2.00 1.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor OFFSITE Hyd. No. 9 -- 1 Year Friday, 02 / 1112022 = 5.797 cfs = 720 min = 13,480 cuft = 74 = 0 ft = 8.30 min = Type II = 484 Q (cfs) 6.00 5.00 4.00 3.00 2.00 1.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 9 Time (min) Page 32 of 76 10 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 / 1112022 Hyd. No. 11 COMBINED OUTFLOW Hydrograph type = Combine Peak discharge = 5.797 cfs Storm frequency = 1 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 13,480 cuft Inflow hyds. = 9 Contrib. drain. area = 3.950 ac Q (cis) 6.00 5.00 4.00 3.00 2.00 1.00 COMBINED OUTFLOW Hyd. No. 11 -- 1 Year Q (Cfs) 6.00 5.00 4.00 3.00 2.00 1.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 — Hyd No. 11 —Hyd No. 9 Time (min) Page 33 of 76 Hydrograph Report 11 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 1 PRE -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 5.58 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 66)] / 6.280 Q (cis) 28.00 24.00 20.00 fi[:1(1III 12.00 :m m Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE -DEVELOPMENT Hyd. No. 1 -- 10 Year Friday, 02 / 1112022 = 25.51 cfs = 720 min = 58,455 cuft = 71* = 0 ft = 7.20 min = Type II = 484 Q (Cfs) 28.00 24.00 20.00 f[:1[111% 12.00 4.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) Page 34 of 76 Hydrograph Report 12 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 2 POST -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.58 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 69)] / 6.280 Q (cfs 28.00 24.00 20.00 fi[:1(�Bl 12.00 MM M Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor POST -DEVELOPMENT Hyd. No. 2 -- 10 Year Friday, 02 / 1112022 = 26.42 cfs = 718 min = 60,489 cuft = 72* = 0 ft = 7.20 min = Type II = 484 Q (Cfs) 28.00 24.00 20.00 f[:1[111% 12.00 4.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time (min) Page 35 of 76 Hydrograph Report 13 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 4 PRE-DEV POND Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 2.330 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.58 in Storm duration = 24 hrs Q (cis) 8.00 .M 4.00 2.00 0.00 0 120 240 Hyd No. 4 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE-DEV POND Hyd. No. 4 -- 10 Year 360 480 600 720 840 Friday, 02 / 1112022 = 7.873 cfs = 720 min = 18,047 tuft = 66 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 8.00 M 4.00 2.00 ' 0.00 960 1080 1200 1320 1440 1560 Time (min) Page 36 of 76 Hydrograph Report 14 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 5 POST-DEV TO POND Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 2.330 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.58 in Storm duration = 24 hrs Q (cis) 10.00 1.11I011 .M 4.00 M rl Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor POST-DEV TO POND Hyd. No. 5 -- 10 Year Friday, 02 / 1112022 = 8.828 cfs = 720 min = 20,205 cuft = 69 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 10.00 9.18I11 M 4-00 2.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 5 Time (min) Page 37 of 76 Hydrograph Report 15 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 7 ROUTING Hydrograph type = Reservoir Peak discharge Storm frequency = 10 yrs Time to peak Time interval = 2 min Hyd. volume Inflow hyd. No. = 5 - POST-DEV TO POND Max. Elevation Reservoir name = POND Max. Storage Storage Indication method used. Q (cis) 10.00 1.181011 .M 4.00 Nut ROUTING Hyd. No. 7 -- 10 Year Friday, 02 / 1112022 = 6.710 cfs = 724 min = 20,204 cuft = 442.91 ft = 4,410 cuft Q (cfs) 10.00 9.18111 4-00 2.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 — Hyd No. 7 —Hyd No. 5 ®Total storage used = 4,410 cult Time (min) Page 38 of 76 Hydrograph Report 16 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 9 OFFSITE Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 3.950 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.58 in Storm duration = 24 hrs Q (cis) 18.00 15.00 12.00 •M .M 3.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor OFFSITE Hyd. No. 9 -- 10 Year Friday, 02 / 1112022 = 17.77 cfs = 718 min = 40,650 cuft = 74 = 0 ft = 8.30 min = Type II = 484 Q (cfs) 18.00 15.00 12.00 M M 3.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 9 Time (min) Page 39 of 76 17 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 / 1112022 Hyd. No. 11 COMBINED OUTFLOW Hydrograph type = Combine Peak discharge = 17.77 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 40,650 cuft Inflow hyds. = 9 Contrib. drain. area = 3.950 ac Q (cis) 18.00 15.00 12.00 •M .M 3.00 COMBINED OUTFLOW Hyd. No. 11 -- 10 Year Q (Cfs) 18.00 15.00 12.00 • �e M 3.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 — Hyd No. 11 —Hyd No. 9 Time (min) Page 40 of 76 Hydrograph Report 18 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 1 PRE -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 9.16 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 66)] / 6.280 Q (cis) 60.00 50.00 40.00 30.00 20.00 10.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE -DEVELOPMENT Hyd. No. 1 -- 100 Year Friday, 02 / 1112022 = 55.38 cfs = 718 min = 127,683 cuft = 71* = 0 ft = 7.20 min = Type II = 484 Q (cfs) 60.00 50.00 40.00 30.00 20.00 10.00 0.00 - -1 1 1-' . 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) Page 41 of 76 Hydrograph Report 19 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 2 POST -DEVELOPMENT Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 6.280 ac Basin Slope = 0.0 % Tc method = User Total precip. = 9.16 in Storm duration = 24 hrs * Composite (Area/CN) _ [(3.950 x 74) + (2.330 x 69)] / 6.280 Q (cis) 60.00 50.00 40.00 30.00 20.00 10.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor POST -DEVELOPMENT Hyd. No. 2 -- 100 Year Friday, 02 / 1112022 = 56.50 cfs = 718 min = 130,527 cuft = 72* = 0 ft = 7.20 min = Type II = 484 Q (cfs) 60.00 50.00 40.00 30.00 20.00 10.00 0.00 -1 1 1-' . 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time (min) Page 42 of 76 Hydrograph Report 20 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 4 PRE-DEV POND Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 2.330 ac Basin Slope = 0.0 % Tc method = User Total precip. = 9.16 in Storm duration = 24 hrs Q (cis) 21.00 15.00 12.00 • "@ am 3.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor PRE-DEV POND Hyd. No. 4 -- 100 Year Friday, 02 / 1112022 = 18.38 cfs = 718 min = 42,090 cuft = 66 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 21.00 15.00 EPA4I1 • 11 M 3.00 0.00 —' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 4 Time (min) Page 43 of 76 Hydrograph Report 21 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 5 POST-DEV TO POND Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 2.330 ac Basin Slope = 0.0 % Tc method = User Total precip. = 9.16 in Storm duration = 24 hrs Q (cis) 21.00 15.00 12.00 • "@ am 3.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor POST-DEV TO POND Hyd. No. 5 -- 100 Year Friday, 02 / 1112022 = 19.70 cfs = 718 min = 45,261 cuft = 69 = 0 ft = 7.20 min = Type II = 484 Q (cfs) 21.00 15.00 EPA4I1 • 11 M 3.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 5 Time (min) Page 44 of 76 Hydrograph Report 22 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 7 ROUTING Hydrograph type = Reservoir Peak discharge Storm frequency = 100 yrs Time to peak Time interval = 2 min Hyd. volume Inflow hyd. No. = 5 - POST-DEV TO POND Max. Elevation Reservoir name = POND Max. Storage Storage Indication method used. Q (cis) 21.00 15.00 f VAIIIIrl • M§ .M 3.00 ROUTING Hyd. No. 7 -- 100 Year Friday, 02 / 1112022 = 18.01 cfs = 722 min = 45,260 cuft = 443.87 ft = 6,466 cuft Q (cfs) 21.00 15.00 iPA4I1 • IN 3.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 — Hyd No. 7 —Hyd No. 5 ®Total storage used = 6,466 cult Time (min) Page 45 of 76 Hydrograph Report 23 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Hyd. No. 9 OFFSITE Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 3.950 ac Basin Slope = 0.0 % Tc method = User Total precip. = 9.16 in Storm duration = 24 hrs Q (cis) 40.00 30.00 20.00 10.00 0.00 0 120 240 Hyd No. 9 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conic. (Tc) Distribution Shape factor OFFSITE Hyd. No. 9 -- 100 Year 360 480 600 720 840 960 Friday, 02 / 1112022 = 36.90 cfs = 718 min = 85,673 cuft = 74 = 0 ft = 8.30 min = Type II = 484 Q (cfs) 40.00 30.00 20.00 10.00 0.00 1080 1200 1320 1440 Time (min) Page 46 of 76 Hydrograph Report 24 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Friday, 02 / 1112022 Hyd. No. 11 COMBINED OUTFLOW Hydrograph type = Combine Peak discharge = 36.90 cfs Storm frequency = 100 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 85,673 cuft Inflow hyds. = 9 Contrib. drain. area = 3.950 ac Q (cis) 40.00 30.00 20.00 10.00 0.00 0 120 240 Hyd No. 11 COMBINED OUTFLOW Hyd. No. 11 -- 100 Year 360 480 600 — Hyd No. 9 720 840 960 Q (Cfs) 40.00 30.00 20.00 10.00 0.00 1080 1200 1320 1440 Time (min) Page 47 of 76 Hydraflow Rainfall Report 25 Hydraflow Hydrogmphs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Return Period Intensity -Duration -Frequency Equation Coefficients (FHA) (Yrs) B D E (NIA) 1 0.0000 0.0000 0.0000 -------- 2 53.4281 12.5000 0.8941 -------- 3 0.0000 0.0000 0.0000 -------- 5 75.7517 14.2000 0.8271 -------- 10 50.0721 10.7000 0.7889 -------- 25 103.3028 16.6000 0.8227 -------- 50 116.5747 17.3000 0.8234 -------- 100 124.5731 17.6000 0.8144 -------- File name: SampleFHA.idf Intensity = B / (Tc + D)AE Friday, 02 / 1112022 Return Period Intensity Values (in/hr) (Yrs) 5 min 10. 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 4.13 3.30 2.76 2.38 2.09 1.87 1.69 1.55 1.43 1.32 1.24 1.16 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 6.58 5.43 4.65 4.08 3.64 3.30 3.02 2.79 2.59 2.42 2.28 2.15 10 5.70 4.59 3.87 3.36 2.98 2.69 2.46 2.26 2.10 1.96 1.84 1.74 25 8.25 6.95 6.03 5.34 4.81 4.38 4.03 3.73 3.48 3.26 3.08 2.91 50 9.05 7.66 6.67 5.92 5.34 4.87 4.48 4.16 3.88 3.64 3.43 3.25 100 9.83 8.35 7.30 6.49 5.87 5.36 4.94 4.59 4.29 4.03 3.80 3.60 Tc = time in minutes. Values may exceed 60. Preci . file name: Sam le. c Rainfall Precipitation Table (in) storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 3.05 3.69 0.00 3.30 5.58 5.77 6.80 9.16 SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff -1st 0.00 0.00 0.00 2.75 0.00 0.00 6.50 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 2.80 0.00 0.00 6.00 0.00 Page 48 of 76 APPENDIX A ARMY CORPS APPROVAL LETTER (EMAIL) APPENDIX B HYDRAFLOW REPORT - SWM DETENTION POND APPENDIX D NUTRIENT CREDIT AVAILABILITY LETTER APPENDIX E NRCS SOILS REPORT Page 49 of 76 DEO Virginia Runoff Reduction Method Re -Development Compliance Spreadsheet - Version 3.0 D 20136Mp Standards and Spedficadom 02013 Draft BMP Standards and 5patfsations Project Name: SOUTHWOOD - FILL IN NORTHERN AREA WEDGE datamprtmis Date: 3/17/2022 constaotvalues Linear Development Project?. No colaulatlanceds Site Information Post -Development Project (Treatment Volume and Loads) Enter Total Disturbed Pre-ReDevelopment Land Cover (acres) Area (acres) --> • 1.01 Check: BMP Design Specifications List: 2013 Drag Stds & S ec$ Linearproject? No Land cover areas entered correctly? ✓ Total disturbed area entered? ✓ A Soils Bsoils CSoils DSails Totals forest/Open Spare lxon-un rmarree forest/opens ace 0.98 0.99 Managed Turtacral - plea bed, graded for ores or othertunmhe mowea/mans ee 0.00 0.00 Impervious Coverlacra) 0.03 0.03 1.01 Post -Development Land Cover (acres) Asians Bsoils CSoils DSoils Totals Forest/Open Sparelxresl-'undisturbed, roracred forest/o s n rreforested land OW Managed Turflaual di:tamed, graded Far ores orothertuntobe mowed/maned 0.92 0.92 Impervious cover (arrest 009 0.09 Area Check OK. OIL OIL Ch. 1.01 Constants Runoff Coefficients Rv Annual prong(inches) 43 ASolls B$Otis C$a65 DSoils Target Rainfall Event (inches) 1.00 Forest/open Sparc Onn! 0.03 0.04 0.05 Total Pnoapnorus(TP) EMC(mg/L) 0.26 Managed Turf 0.15 0,20 0.22 0.25 Total Nitrogen"I EMC(mg/L) 1.86 Impervious Cover Os5 0.95 0.95 0.95 TargM iP Wad(IE/acre/ur) 0. Pj(unid- correction factort 0.90 LAND COVER SUMMARY PRE -REDEVELOPMENT LAND COVER SUMMARY POST over Summary t-F�rte-lopment DEVELOPMENT -Post Lond Cover Summmr-Post Post- Development New Impervious 0,00 0,00 0% 9E 0.20 Land Coversummarv-Pre LarMCaver Summary-POst(Amal) Pre'Reoevelapment Listed Adjualr& Post aspen. impervious Sir -Cover lacres1 0.98 092 Forest/Open Space Cover acres 0'0 SpaceForest/Open res Weighted Rmforen) LIM 0.03 Weighted Rvforem 0.00 FFoma/O�n (foren) %Forest 97% 97% %Forest 0% Managed Turf CoWr(acres) 0.00 SIM Managed Tun Cover 092 f Covet Weighted Pucual) 0.08 O.W Welgned Rv(tun) 0.20 turn Page 50 of 76 A, Managed Turf 0% 0% %Managetl Turf 91% %Managetl Turf 97% Reoev. impervious 003 New imperic-Cover 0.06 Impervious Cover (acres) 0.03 0.03 Impervious ower(acres) 0.0 Cover(area (acres] Rdimpervious) 0.95 0.95 Rvtimperviousl 0.95 Rvlimpervious) 0.95 Rvpmpervmasl 0.95 %Impervious 3% 3% %Impervious 9% %Impervious 3% Tuul Site Area label 1.01 0.95 Final She Area fears) 1.01 Tool ReDev. She Are. i rand 0.95 0.32 Si. RV 0.06 0.06 Final post Dar, she RV 0.27 beget/ She Rv Treatment Volume and Nutrient Load Treatment Volume and Nutrient Load prat -Development PmArrovelopment Treatment Volume Final Pao -Development 1 SF=Develapment (aaei 0.0048 0.004] Tremment Volume 0.0225 Treatment Volume 0.0177 Tmmmml Volume 0.0048 (acre-ft) (.[Taft) (abrwft) Pre-ReDevelopmem Treatment Volume Final in t-Development past-ReOevelopment pasbDevelopmwl ([ubi[fM) 210 204 1re.man, Volume 978 Trealmad Vdume M Paramount Volume (cubic 207 (cubicfem) (cubic felt) feet) Pre-R¢Develo py,) TP Load Final Post- past-ReDevelopmem PowDevelopment TP (16/ 0.13 0.13 Development to Load 0.61 isLgad (TP) aA8 Leatl (Ib/P) 0.13 (lb/yr) Ilb/yrl' Pre Renevelopmem TP la el per a[re Final Poet-Dweloarni TP Post-wrovelopment To (Ib/a[re/yd 0.13 0.13 laatlpera[re D.6 t Loadpera[re h. ObfacreM) 111"wr /rd Raseline TP Wad(m/yr) Maa. Red... 0.e,.imd (0.411Mhemi applied to prprtdevelopmentama warding pervious 0.39 retie.Ism, z0% land pmposed bar new Impervious cover) Rmwelopmem Ls d) Adjusted Land Cover Summary: Pre ReDevelopmem land cover minus pervious land cover(foresaiii spate or TP Load Reduatgn Required for 0.10 d Reduction retl for New F,m�.. 0.11 managed tad) Cvamep.,bsadf.r new Inherits. over. Redeveloped Area us Area Ob/i b/ l Adjusted total aaeoge is[onsilest with Poire,revelopment sai(minus a[reage of new impmi0us cover). # RedrMbn barbw, new development land IlmhatWn Fiat required Column l shows load reduction rearmament for new impervious cover (based on new development load limit 0.41 dc,scie/yeor). Post-Development Load Reduction Required (lb/yr) 0.20 Nitrogen Loads (Informational Purposes Only) Final Pos4Development TN Land Pra-.celopment TNbad(Ib/yQ 0.94 (,V,woevelapment& New Impervious) 4.40 b/ ) Page 51 of 76 Site Results (Water Quality Compliance) Area Checks D.A. A D.A. a D.A. C D.A. D D.A. E AREA CHECK FOREST/OPEN SPACE In) 0.00 0.00 0.00 0.00 0.00 OK. IMPERVIOUS COVER(ac) 0.00 0.00 0.00 0.00 0.00 OK. IMPERVIOUS COVER TREATED(ac) 0.00 0.00 0.00 0.00 0.00 OK. MANAGED TURF AREA (ac) 0.00 0.00 0.00 0.00 0.00 OK. MANAGED TURF AREA TREATED(ac) 0.00 0.00 0.00 0.00 0.00 OK. AREA CHECK OK. OK. OK. OK. OK. Site Treatment Volume (ft3) 978 Runoff Reduction Volume and TP By Drainage Area D.A. A D.A. B D.A. C D.A. D D.A. E TOTAL RUNOFF REDUCTION VOLUME ACHIE4po 0 0 0 0 0 0 TP LOAD AVAILABLE FOR REMOVA00 0.00 0.00 0.00 0.00 0.00 TP LOAD REDUCTION ACHIEVED00 0.00 0.00 0.00 0.00 0.00 TP LOAD REMAINING (Ib/yr) 0.00 0.00 0.00 0.00 0.00 0.00 NITROGEN LOAD REDUCTION ACHIEVED (Ib/yr) 0.00 0.00 0.00 0.00 0.00 0.00 Total Phosphorus FINAL POST-DEVELOPMENTTP LOAD(Ib/yr) 0.61 TP LOAD REDUCTION REQUIRED (Ib/yr) 0.20 TP LOAD REDUCTION ACHIEVED (Ib/yr) 0.00 TP LOAD REMAINING (Ib/yr): 0.61 REMAINING TP LOAD REDUCTION REQUIRED (Ib/yr): 0.20 Total Nitrogen (For Information Purposes) POST -DEVELOPMENT LOAD (Ib/yr) 4.40 NITROGEN LOAD REDUCTION ACHIEVED (Ib/yr) 0.00 REMAINING POST -DEVELOPMENT NITROGEN LOAD Ib/ r) 4.40 Page 52 of 76 Virginia Runoff Reduction Method Worksheet DEQ Virginia Runoff Reduction Method Re -Development Compliance Spreadsheet - Version 3.0 BMP Design Specifications List: 2013 Draft Stds & Specs Site Summary Project Title: SOUTHWOOD - FILL IN NORTHERN AREA WEDGE Date: 44637 Total Rainfall (in): 43 Total Disturbed Acreage: 1.01 Site Land Cover Summary Pre-ReDevelopment Land Cover (acres) Asoils !.Soils CSoils DSoils Totals %of Total Forest/Open (acres) 0.00 0.98 0.00 0.00 0.98 97 Managed Turf(acres) 0.00 0.00 0.00 0.00 0.00 0 Impervious Cover (acres) 0.00 0.03 0.00 0.00 0.03 3 1.01 100 Post-ReDevelopment Land Cover (acres Asoils Soils CSoils DSoils Totals %of Total Forest/Open(acres) 0.00 0.00 0.00 0.00 0.00 0 Managed Turf(acres) 0.00 0.92 0.00 0.00 0.92 91 Impervious Cover (acres) 0.00 0.09 0.00 0.00 0.09 9 1.01 100 Site Tv and Land Cover Nutrient Loads Final Post -Development Post- Post Adjusted Pre- (Post-ReDevelopment ReDevelopment Development ReDevelopment &New Impervious) (New Impervious) Site Rv 0.27 0.22 0.95 0.06 Treatment Volume(ft) 978 771 207 204 TP Load(lb/yr) 0.61 0.48 0.13 0.13 Baseline TP Load(lb/yr): 0.3895' "Reduction below new development loodlimitation not required Total TP Load Reduction Required (Ib/yr) 0.20 0.10 0.11 Final Post -Development Wad (Post-ReDevelopment & New Impervious) Pre- ReDevelopmem TN Load (lb/yr) 4.40 0.94 Pre- ReDevelopment Final Post -Development Post-ReDevelopment TP TPWadpe TP Load per acre Load per acre (Ib/acre/yr) (lb/acre/yr) (lb/acre/yr) 0.13 0.61 0.51 Summary Print Page 53 Of 76 Virginia Runoff Reduction Method Worksheet Site Compliance Summary Maximum% Reduction Required Belo 20% "Note: % Reduction will reduce post -development TP load to less than or equal to baseline load of0.39 lb/yr(0.41 lb/ac/yr) Pre-ReDaelopmem laad (Required reductionfor Post-ReDev.- Post-RCDev TP load- baseline load of0.38951b/yrf, baseline load= site area x 0.41 lb/ac/yr Total Runoff Volume Reduction (ff) 0 Total TP Load Reduction Achieved (Ili 0.00 Total TN Load Reduction Achieved (Ib/yr) 0.00 Remaining Post Development TP Load 0.61 (lb/yr) Remaining TP Load Reduction (Ib/yr) Required D 20 "Reduction below new development load limitation not required Summary Print Page 54 of 76 Virginia Runoff Reduction Method Worksheet ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Drainage Area Summary DA. A Forest/Open (acres) 0.00 D.A. B 0.00 D.A. C 0.00 D.A. D 0.00 D.A. E 0.00 Total 0.00 Managed Turf (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Impervious Cover(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Total Area (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Drainage Area Compliance Summary D.A. A D.A. B D.A. C D.A. D DA. E Total TP Load Reduced (Ils/yr) 1 0.00 0.00 1 0.00 1 0.00 0.00 0.00 TN Load Reduced Ills/yr) 1 0.00 0.00 1 0.00 1 0.00 0.00 0.00 Summary Print Page 55 Of 76 Virginia Runoff Reduction Method Worksheet ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Runoff Volume and CN Calculations 1-yearstorm 2-yearstorm 10-yearstorm Target Rainfall Event (in) 1 0.00 0.00 0.00 Drainage Areas RV&CN Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area CN 0 0 0 0 0 RR (Ra) 0 0 0 0 0 1-year return period RV wa RR(ws-in) 0.00 0.00 0.00 0.00 0.00 RV w RR (wHn) 0.00 0.00 0.00 0.00 0.00 M adjuned 0 0 0 0 0 2-year return period RV wo RR(ws-in) 0.00 0.00 0.00 0.00 0.00 RVw RR(wsan) 0.00 0.00 0.00 0.00 0.00 CN adjust 0 0 0 0 0 10-year return period RV wo RR (.id) 0.00 0.00 0.00 0.00 0.00 RVw RR (ws-inj 0.00 0.00 0.00 0.00 0.00 CN atljunetl 0 0 0 0 0 Summary Print Page 56 of 76 APPENDIX A ARMY CORPS APPROVAL LETTER (EMAIL) APPENDIX B HYDRAFLOW REPORT - SWM DETENTION POND APPENDIX C VRRM SPREADSHEETS NUTRIENT CREDIT AVAILABILITY LETTER APPENDIX E NRCS SOILS REPORT Page 57 of 76 ECOSYSTEM SERVICES, LLC 1739 Allied Street, Suite A Charlottesville, VA 22903 540.578.4296 www. ecosystemservices.us jon&ecospstemservices.us March 11, 2022 Michael Myers, PE, CFM 30 Scale, LLC 871 Justin Drive Palmyra, VA 22963 RE: Nutrient Offset Credit —Credit Availability Letter Southwood Redevelopment Village 1— Northern Wedge Fill Hickory Street, Charlottesville, VA 22902 Project Tax Map Parcel ID: 09A1-00-00-003E0, 09000-00-00-OOIA0 Project HUC: 020802040402 Bank HUC: 020802040202 Bank Address: 1705 Lambs Road, Charlottesville, VA 22901 Dear Mr. Myers, We appreciate the opportunity to provide a credit availability letter for 0.20 pounds of phosphorus for the above referenced project. This letter is to certify that as of today, March 11, 2022, Ivy Creek Nutrient Bank has 173.20 pounds of phosphorus (TP), 266.53 pounds of nitrogen (TN), and 54,615.39 pounds of TSS available for transfer to those entities requiring offsets in accordance with the Chesapeake Bay Watershed Nutrient Credit Exchange Program (VA Code § 62.1-44.19:14 et seq.). Those offsets are also transferable in accordance with the Virginia stormwater offset program (VA Code § 62.1-44.15:35) and the Virginia Soil and Water Conservation Board's Guidance Document on Stormwater Nonpoint Nutrient Offsets approved on July 23, 2009, to those regulated entities qualifying for nutrient credits. We can certainly accommodate your needs and could offer to fulfil the order of 0.20 pounds of phosphorus. Please feel free to contact us with any questions. I hope we have the opportunity to work together on this project. Sincerely, Ecosystem Services, LLC By: Jonathan R. Roller, AOSE PSS CNMP Manager —Authorized Representative APPENDIX A ARMY CORPS APPROVAL LETTER (EMAIL) APPENDIX B HYDRAFLOW REPORT - SWM DETENTION POND APPENDIX C VRRM SPREADSHEETS APPENDIX D NUTRIENT CREDIT AVAILABILITY LETTER APPENDIX E NRCS SOILS REPORT Page 59 of 76 USDA United States Department of Agriculture N RCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Albemarle County, Virginia Oatffl M21, 2021 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nres.usda.gov/wps/ portal/nres/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/? cid=nres142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 Page 61 of 76 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Page 62 of 76 Contents Preface.................................................................................................................... 2 How Soil Surveys Are Made..................................................................................5 SoilMap.................................................................................................................. 8 SoilMap................................................................................................................9 Legend................................................................................................................10 MapUnit Legend................................................................................................ 11 MapUnit Descriptions.........................................................................................11 Albemarle County, Virginia..............................................................................13 27B—Elioak loam, 2 to 7 percent slopes .................................................... 13 27C—Elioak loam, 7 to 15 percent slopes .................................................. 14 39D—Hazel loam, 15 to 25 percent slopes.................................................15 References............................................................................................................16 4 Page 63 of 76 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil -vegetation -landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 Page 64 of 76 Custom Soil Resource Report scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many Feld observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil -landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil -landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field -observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and 6 Page 65 of 76 Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. 7 Page 66 of 76 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. Page 67 of 76 Custom Soil Resource Report N Soil Map 3 VSN 3A 95TN �T HYPO n1310 71T.141 71T M7 3 Map Smia: 1:1,710 NpriNEed w A kidsmpe (11" x 8.51 Meet N Meets 0 25 50 100 750 A` o so 100 zu �10 Map projation: Web W=N Ga cm dirahs: WGS84 Edge bm: UFM Zeta 17N WGS84 9 n74M n7510 nnm 717'.60 3 0 1 3U° N 37 %Y 'N 7176 3 Page 68 of 76 MAP LEGEND Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons w Soil Map Unit Lines 0 Soil Map Unit Points Special Point Features V Blowout Borrow Pit Clay Spot (? Closed Depression Gravel Pit Gravelly Spot 0 Landfill A. Lava Flow Marshorswamp r� Mine or Quarry 0 Miscellaneous Water C Perennial Water V Rock Outcrop + Saline Spot Sandy Spot Qy Severely Eroded Spot ,© Sinkhole Jb Slide or Slip of Sodic Spot Custom Soil Resource Report Ig Spoil Area to Stony Spot Very Stony Spot ¢� Wet Spot O Other Special Line Features Water Features Streams and Canals Transportation rit-t Rails ti Interstate Highways A/ 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, 2019Oct 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. 10 Page 69 of 76 Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 27B Elioak loam, 2 to 7 percent slopes 3.4 46.5% 27C Elioak loam, 7 to 15 percent slopes 2.3 31.1 % 39D Hazel loam, 15 to 25 percent slopes 1.7 22.5% Totals for Area of Interest 7.4 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or 11 Page 70 of 76 Custom Soil Resource Report landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 12 Page 71 of 76 Custom Soil Resource Report Albemarle County, Virginia 27B—Elioak loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol., kb8y Elevation: 360 to 790 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Elioak and similar soils: 80 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Elioak Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from mica schist Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 39 inches: silty clay H3 - 39 to 79 inches: silt loam Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Kset): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: Moderate (about 6.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Hydric soil rating: No 13 Page 72 of 76 Custom Soil Resource Report 27C—Elioak loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol. kb8z Elevation: 340 to 820 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Elioak and similar soils: 80 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Elioak Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material. Residuum weathered from mica schist Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 39 inches: silty clay H3 - 39 to 79 inches: silt loam Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of Flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: Moderate (about 6.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No 14 Page 73 of 76 Custom Soil Resource Report 3913—Hazel loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol. kbb3 Elevation: 310 to 1,300 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Not prime farmland Map Unit Composition Hazel and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mepunit. Description of Hazel Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material. Residuum weathered from graywacke sandstone and mica schist Typical profile H1 - 0 to 10 inches: loam H2 - 10 to 20 inches: loam H3 - 20 to 30 inches: channery loam H4 - 30 to 79 inches: bedrock Properties and qualities Slope: 15 to 25 percent Depth to restrictive feature: 20 to 40 inches to lithic bedrock Drainage class: Excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: Low (about 4.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No 15 Page 74 of 76 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/ n res/d etai I/natio nal/so i Is/?cid=n res 142 p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres l42p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres l42p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/ h ome/?cid=n res 142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/ detail/national/land use/rangepasture/?cid=stelprdb l043084 16 Page 75 of 76 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 43041. http://www.nres.usda.gov/wps/portal/ n res/d eta i I/so i Is/sci enti sts/?cid=n res 142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/? cid=n res 142 p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/lnternet/FSE—DOCUMENTS/nrcsl42p2_052290.pdf 17 Page 76 of 76