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HomeMy WebLinkAboutWPO201600027 Calculations 2016-05-20PROJECT MANAGEMENT SHIMCIVIL ENGINEERING LAND PLANNING ENGIN EEM N May 20, 2016 John Anderson Albemarle County Community Development 401 McIntire Road, North Vying Charlottesville, VA22902 Regarding: Wildrock Day Camp VSNP Plan WPO 2016-00027 Dear M . Anderson, Enclosed is the storn-mter management calculations for the Wdrock Site Plan. The stomvBter management strategy for this site is governed by the VRRM Re -Development spreadsheet. Due to the removal of existing gravel impervious area, the water quality of the site runoff is not required to be improved. To treat runoff quantity, two strategies have been employed that reduce the impact to the site and maintain lower development costs. Site runoff is fairly low due to the A and B soil groups that make up this area. This low runoff can be effectively managed Wth grass ditches and swales. The energy balance equation was applied to the concentrated runoff that exits the site toward the concrete ditch to the east of the property. VVe reduced the drainage area that outlets at this point and were able to meet the energy balance equation without the need for detention methods. The rest of the disturbed area was routed through culverts and grass channels to a level spreader. The total runoff directed to this has a 10 -Year flow rate of 8.52 cfs, so a timber level spreader will safely divert the concentrated runoff to sheet flow where it WWI eventually run to the existing stream that runs under Route 810. The level spreader was designed according to the standards set forth in the Vrginia Erosion and Sediment Control Handbook Section 3.21 and was placed at an existing flat location for best performance. The energy balance equation is not required for sheet flow and was not applied to this runoff. In this handbook are included the both pre- and post -development runoff analyses and standard \/DOT channel calculations for the ditches and culverts on site. If you have any questions please do not hesitate to contact me at: Justin(or73hirrp-engineenng.com or by phone at 434-953-6116. Contents: Pre -Development Stor Tmoter Management Calculations: Pre -Development Drainage Map Time of Concentration Nomographs Energy Balance Equation Pre -Development HydroCAD Analysis Post -Development StonTmrater Management Calculations: Post -Development Drainage Map Post -Development HydroCAD Analysis Ditch Drainage Map Rational Method Calculations Culvert Sizing Nomographs VDOT LD -268 Stormwater (duality Calculations: VRRM Redevelopment Spreadsheet Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Pre-Development StonTmater Management Calculations: Pre-Development Drainage Map Time of Concentration Nomographs Energy Balance Equation Pre-Development HydroCAD Analysis Time of Concentration Nomographs Blue: Pre-Dev Pink: Post-Dev Source: Data Book for Civil Engineers, E.E. Seelye Plate 5-1 35- 530Paved 30— Paved q z 25- 0 .e 300 a: cD 7 Bare LL- o 20— N 200 Soil ep Poor \ Gross w z Surface -Q-.5 a W Avera a .4 z 0.5 w z w 100 Surface �- I.0 o 15 z _ g p O 2'0 J cn/ / a_ Dense a z o cr_ Grass 70 2 N 60 v o: wo 50z 0 n. w _J 40 10 z U 30 9 w z J Z 8 20 7- 10 6 OVERLAND FLOW TIME (Seelye Chart) Source: Data Book for Civil Engineers, E.E. Seelye Plate 5-1 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.09 0.08 0.07 0 0.06 0.05 0.04 0.03 0.02 0.01 0.005 0 c C �lc��Oq�o � La ccL— ��o o 0 0 0 0 0 000 Velocity (ft/s) NEH Figure 15-4 TRAVEL TIME FOR CHANNEL FLOW (Kirpich Chart) H (feetl Gnn T (MPn,j 200 100 50 T14E OF CONCENTRATION OF SMALL DRAINAGE BASINS Pre-Dev: 10 5 1 Overland Flow: 200 feet = 11.4 min (Seelye) Shallow Concentrated: 500 feet / 1.5 ft/s x (1 min/60 sec) x 500 ft = 5.6 min (NEH Figure 15-4) Channel Flow: 740 feet, H difference of 50 feet = 4.5 min Total = 21.5 min Post-Dev: Overland Flow: 200 feet = 14.0 min (Seelye) Channel Flow: 275 feet, H difference of 19 feet = 1.7 (Kirpich) Total = 15.7 min Wildrock Energy Balance Equation 24 Hr 1 year Storm: Qddeveloped!� I.F. *(Qpre-developed*RVPre-Developed)/RVdeveloped Qdeveloped:5 (Qforested* RVforested)RVdeveloped Drainage Area : Qpre-developed = 0.72 RVPre-Developed — 0.125 Qdeveloped = 1.22 cfs RVDeveloped = 0.059 Qdev must be below pre -developed conditions. Qdev effective max = 0.72 cfs DRAINAGE TO POA Subcat Reach on Link PRE-DEV Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 2 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 1.700 HSG A 2S 2.750 HSG B 2S 0.000 HSG C 0.000 HSG D 0.500 Other 2S 4.950 TOTAL AREA PRE -DEV Type //24 -hr 1 -YEAR Rainfall=3.38" Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 2S: DRAINAGE TO POA Runoff = 0.72 cfs @ 12.24 hrs, Volume= 0.125 af, Depth> 0.30" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1 -YEAR Rainfall=3.38" Area (ac) CN Description 2.750 61 >75% Grass cover, Good, HSG B 0.600 39 >75% Grass cover, Good, HSG A 1.100 30 Woods, Good, HSG A 0.500 98 I M P 4.950 55 Weighted Average 4.450 89.90% Pervious Area 0.500 10.10% Impervious Area Tc Length Slope Velocity Capacity Description min) (feet) (ft/ft) (ft/sec) (cfs) 21.5 Direct Entry, PRE -DEV Type 1124 -hr 10 -YEAR Rainfall=6.14" Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 2S: DRAINAGE TO POA Runoff = 7.53 cfs @ 12.17 hrs, Volume= 0.655 af, Depth> 1.59" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24 -hr 10 -YEAR Rainfall=6.14" Area (ac) CN Description 2.750 61 >75% Grass cover, Good, HSG B 0.600 39 >75% Grass cover, Good, HSG A 1.100 30 Woods, Good, HSG A 0.500 98 I M P 4.950 55 Weighted Average 4.450 89.90% Pervious Area 0.500 10.10% Impervious Area Tc Length Slope Velocity Capacity Description min) (feet) (ft/ft) (ft/sec) (cfs) 21.5 Direct Entry, POST -DEV Type // 24 -hr 1 -YEAR Rainfall=3.38" Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 3S: DRAINAGE TO POA Runoff = 0.59 cfs @ 12.14 hrs, Volume= 0.059 af, Depth> 0.48" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1 -YEAR Rainfall=3.38" Area (ac) CN Description 0.990 61 >75% Grass cover, Good, HSG B 0.330 39 >75% Grass cover, Good, HSG A 0.170 98 IMP 1.490 60 Weighted Average 1.320 88.59% Pervious Area 0.170 11.41% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.3 Direct Entry, Subcatchment 3S: DRAINAGE TO POA Hydrograph ——+——++——+——+�—I—+—+- 0.65 ■Runoff 0.6 1 1 0.59 cfs Type�ll 24 hr #+YEAR 0.55 I 1 a I I � I I I I I I I I I I I I I I 0.5 ®alnf#aNr p.� �}I -ff -Ar A9O lacr 1 -1 - I- -f - I- t -1 - 1- -t - 0.45 Rul l 6�l 1 RU11O�fi1TOTume-0.053a� 1 1 1 1 1 1 0.4 0.35 1 FA unoif ���p_ BOO #8i' I I 1 1 ° 0.3 1 Tc. -07.3 Min' 1 1 1 1 1 1 LL �-1-ccT^^-I- 0.25 SJr1JC—V1V_ I I — I— _ 0.2 0.15 -1 1 1 1 L 1 1 1 1 L-1 1 L A I L 1 L 1 0.1 0.05 I I I I I I I I I I I I I I I 0 ------------ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Post -Development Stonmater Management Calculations: Post -Development Drainage Map Post -Development HydroCAD Analysis Ditch Drainage Map Rational Method Calculations Culvert Sizing Nomographs VDOT LD -268 (3S DRAINAGE TO POA Subcat Reach Pon Link (5S TO LEVEL SPREADER POST -DEV Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 2 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 1.230 HSG A 3S, 5S 2.720 HSG B 3S, 5S 0.000 HSG C 0.000 HSG D 0.710 Other 3S, 5S 4.660 TOTAL AREA POST -DEV Type // 24 -hr 1 -YEAR Rainfall=3.38" Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 3S: DRAINAGE TO POA Runoff = 0.63 cfs @ 12.12 hrs, Volume= 0.059 af, Depth> 0.48" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1 -YEAR Rainfall=3.38" Area (ac) CN Description 0.990 61 >75% Grass cover, Good, HSG B 0.330 39 >75% Grass cover, Good, HSG A 0.170 98 IMP 1.490 60 Weighted Average 1.320 88.59% Pervious Area 0.170 11.41% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.7 Direct Entry, Summary for Subcatchment 5S: TO LEVEL SPREADER Runoff = 1.31 cfs @ 12.06 hrs, Volume= 0.107 af, Depth> 0.40" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1 -YEAR Rainfall=3.38" Area (ac) CN Description 1.110 61 >75% Grass cover, Good, HSG B 0.540 98 I M P 0.400 39 >75% Grass cover, Good, HSG A 0.620 55 Woods, Good, HSG B 0.500 30 Woods, Good, HSG A 3.170 58 Weighted Average 2.630 82.97% Pervious Area 0.540 17.03% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.1 Direct Entry, POST -DEV Type 1124 -hr 10 -YEAR Rainfall=6.14" Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 3S: DRAINAGE TO POA Runoff = 3.62 cfs @ 12.09 hrs, Volume= 0.249 at, Depth> 2.00" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24 -hr 10 -YEAR Rainfall=6.14" Area (ac) CN Description 0.990 61 >75% Grass cover, Good, HSG B 0.330 39 >75% Grass cover, Good, HSG A 0.170 98 IMP 1.490 60 Weighted Average 1.320 88.59% Pervious Area 0.170 11.41% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.7 Direct Entry, Summary for Subcatchment 5S: TO LEVEL SPREADER Runoff = 8.52 cfs @ 12.03 hrs, Volume= 0.486 at, Depth> 1.84" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24 -hr 10 -YEAR Rainfall=6.14" Area (ac) CN Description 1.110 61 >75% Grass cover, Good, HSG B 0.540 98 I M P 0.400 39 >75% Grass cover, Good, HSG A 0.620 55 Woods, Good, HSG B 0.500 30 Woods, Good, HSG A 3.170 58 Weighted Average 2.630 82.97% Pervious Area 0.540 17.03% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.1 Direct Entry, POST -DEV Type 1124 -hr 100 -YEAR Rainfall= 10. 00 " Prepared by Shimp Engineering, P.C. Printed 5/20/2016 HydroCAD® 9.10 s/n 07054 @2011 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 3S: DRAINAGE TO POA Runoff = 9.15 cfs @ 12.08 hrs, Volume= 0.606 at, Depth> 4.88" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -YEAR Rainfall=10.00" Area (ac) CN Description 0.990 61 >75% Grass cover, Good, HSG B 0.330 39 >75% Grass cover, Good, HSG A 0.170 98 IMP 1.490 60 Weighted Average 1.320 88.59% Pervious Area 0.170 11.41% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.7 Direct Entry, Summary for Subcatchment 5S: TO LEVEL SPREADER Runoff = 22.14 cfs @ 12.02 hrs, Volume= 1.220 at, Depth> 4.62" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -YEAR Rainfall=10.00" Area (ac) CN Description 1.110 61 >75% Grass cover, Good, HSG B 0.540 98 I M P 0.400 39 >75% Grass cover, Good, HSG A 0.620 55 Woods, Good, HSG B 0.500 30 Woods, Good, HSG A 3.170 58 Weighted Average 2.630 82.97% Pervious Area 0.540 17.03% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.1 Direct Entry, M.: it ((% / m I ; \--------- ; r "------------ - - ------------------------ - -- ------ -- �l ki Typical Ditch Sections Section Area to Q10 Flow Channel Channel Left Right Ditch (max) Depth Depth Width Slope Slope Ditch 1 1.19 1.8 0.45 1.00 6.0 3:1 3:1 Ditch 2 1.89 3.0 0.54 1.00 6.0 3:1 3:1 Ditch 3 3.04 4.9 0.65 1.25 7.5 3:1 3:1 Ditch 4 0.45 0.9 0.37 1.00 6.0 3:1 3:1 Ditch 5 0.74 1.3 0.42 1.00 6.0 3:1 3:1 Ditch 6 3.55 7.3 0.69 1.25 7.5 3:1 3:1 - --- % �>< j 'QA 3 \1.15\Aci o (�\I ��.04 Ap \ C4 c i X DA 2' Di 3 0.70 A,�cres it 1.89 Ac. To ; i ulvert B WAc 2 / i 100 0 100 200 300 Scale: 1"=100' 03 C/ x'51 Acres Spreadl Ditch;% DA 4, 0.45 Acrips -Ditch 6 /Leve preac Ditch/Culvert Drainage Areas For Wildrock Day Camp Ex. Corm Dib to _11DA 5 0.74 Acres t (culvert E � I \ 1 i / r I I h / 1 � 1 Il I l 1 I 1 I / II SHIMPfYGIYf RING, P. C. ENGINEERING-LANDFLA NNING -PROJECT MANAGEMENT 201 E MAIN ST, STE M PHONE: (434) 227-5140 CHARLOTTESVILLE, VA 22902 JUSTIN®SHIMP-ENGINEERING.COM Wildrock Post -Development Time of Concentration Calculations DA1-Blue 200 ft overland flow 18.0% slope 0.35 C -value 11.2 min Seelye Chart 390 ft s. c. flow -field 18.0% slope 2.0 fps velocity 3.3 min. NEH Figure 15-4 14.5 min. DA2-Purple 200 ft overland flow 25.0% slope 0.35 C -value 10.5 min Seelye Chart 150 ft s. c. flow -field 6.0% slope 1.2 fps velocity 2.1 min. NEH Figure 15-4 12.6 min. DA3 -Green 200 ft overland flow 16.0% slope 0.35 C -value 11.5 min Seelye Chart 400 ft s. c. flow -field 6.3% slope 1.3 fps velocity 5.1 min NEH Figure 15-4 60 ft channel flow 5.0% slope H= 3 ft 0.5 min. Kirpich Chart 17.1 min. DA4-Orange (ditch) 100 ft overland flow 5.3% slope 0.35 C -value 6.8 min. Seelye Chart 494 ft channel flow 5.3% slope H= 26 ft 3.0 min. Kirpich Chart 9.8 min. DA5- Pink (ditch) 730 ft channel flow 6.0% slope H= 44 ft 5.0 min. Kirpich Chart 5.0 min. DA6-Light Blue (ditch) 100 ft overland flow 6.0% slope 0.9 C -value 8.6 min. Seelye Chart 200 ft channel flow 5.0% slope H= 10 1.5 min. Kirpich Chart 10.1 min. DA7-Red Gravel Parking surface: Assumed TOC = 5.0 min 5.0 min. Time of Concentration Nomographs RN OVERLAND FLOW TIME (Seelye Chart) 7 D Source: Data Soak for Civil Engineers, E.E. Seelye Plate 5-1 35- 530Paved 30— Paved a C- 300 0 0 7 Bare 0 20— w 0 Soil Poor uJ z Grass - a g t face < z z Aver = .a J 0.5 W w 2 t p 1.4 N 90 So Dense a ::: 'Q z 70 Gross z \ 5.0 z a cn s 0 0 U- 50 20 LU =� 40 k0 a T o LU z W z 2❑ RN OVERLAND FLOW TIME (Seelye Chart) 7 D Source: Data Soak for Civil Engineers, E.E. Seelye Plate 5-1 1.00 0.90 0.80 0.70 JI: i, 0.50 0.40 0.30 0.20 •• 0.10 0.09 0.08 0.07 v 0.06 0.05 0.04 0.03 0.02 0.01 0.005 0 2 z N eq ItU� cQ N m a a N eq un to ti CO rn a �n O O O © C+ O CD Cif Velocity (WS) NEH Figure 15-4 TRAVEL TIME FOR CHANNEL FLOW (Kirpich Chart) H (feetl cnn TIME OF CONCENTRATION OF SMALL DRAINAGE BASII9S (min, 200 100 50 IO Overland Flow: Seelve Formula T,=0.2250"' -o" T,� = OvvrtsM Flow TIM*. minubm L - L*r%gth 4t $trlp. te*t S Slope. (19uhm"t C: = Ra Jinn Al "C.' VAIL.r.'UF firmrtH C`+h¢r.2C.�#f Shallow Concentrated Flow: NEH Figure 15-4 T = (Length/velocity) *60 sec Channel Flow: Kirpich Chart T= function of Height (H) of farthest point above outlet and length (L) of flow Culvert and Ditch Flow Calculations Rational Method: Q=CiA DA 1 DA5 - Tc 14.45 min. Tc 5 min. I (10yr) 4.3 in/hr I (10yr) 3.85 in/hr C 0.5 C 0.5 A 1.19 ac A 0.740 ac Q 2.5585 cfs To Culvert A Q 1.425 cfs To Culvert E DA 2 DA 6 Tc 13 min. Tc 10 I (10yr) 4.7 in/hr I (10yr) 3.85 in/hr C 0.5 C 0.7 A 0.7 ac A 0.51 ac Q 1.645 cfs Q 1.374 cfs Qtotal 4.2035 cfs To Culvert B Note: Drainage to spreader includes DA's 1-3 Total to To Level 7.319 cfs DA 3 Ditch: Spreader DA7 Tc 17 min. I (10yr) 4.3 in/hr Tc 5 min. assumed C 0.5 1 (10yr) 3.85 in/hr A 0.81 ac C 0.5 Q 1.742 cfs A 0.120 ac Qtotal 5.945 cfs To Culvert C & D Q 0.231 cfs To Culvert F DA 4 Tc 10 min. I (10yr) 3.85 in/hr C 0.5 A 0.45 ac To Offsite IQ 0.866 cfs Concrete Ditch Appendix SC -'I Inlet Control, Circular Concrete CHART 10 184 10.000 1s$ 8,000 EXAMPLE [2) {3) 156 B OQO 0:42 imshes 13.5 feel] $ 144 5,000 9• IZfl cts 5. 4,000 s nw 81 5. 138 o hal 3, pee5 ' 4. 111 2.5 8.9 4. 120 2,000 4.—.- 108 [3] 2.2 7.i 3. a0 is hn 3' 96 1,000 3. $00 84 B00 2' 2- 500 72 400 a 2. tl! = 300 LE ; 2 N F,rt� N x 80 U. 200 W 1.5 54 f Q w 100 x W 7 4■ f a: 80 q x U f g c=7 50 w 1.0 1.0 50 HW ENTRANCE a 40 SCALE 0 TYPE Ir IA 36 30 [i] Sgaart ad Ea with W .9 W w � 33 headwall C .9 q � PQ I>:? 6rmn mad 1NTn q 34 hNdrall Z .8 $ 131 Graavt and •8 2.r Rralesl Ind la 84 8 .7 7 r 6 To rn local* 121 or 131 pra}dat 21 5 horizon/ally fo scale ill, them 4 use tlraltht Ineliasa ❑ne through 0 and G sealas. or reverse as $ 3 it lvstroeed, .g 19 E 1R - L L 5 f.6 .5 � 5 L'p HEADWATER DEPTH FOR HEADWATER SCALES 263 CONCRETE PIPE CULVERTS REVISED MAY Isla WITH INLET CONTROL BUREAU 04' PUBLIC NO�pm JAN. HM Source: HSS -5 v 4aa; °aZLS dv-AdLa 05p Source: USDA -SCS Plate 3.18-3 = Ono OHM I ,_, L. _per--� • _� . Source: USDA -SCS Plate 3.18-3 Wildrock Drainage Area Summary Impervious C 0.9 Pervious C 0.3 DA Area Ac Impervious C C*A 1 1.19 0 0.300 0.357 2 1.89 0.1 0.332 0.627 3 3.04 0.3 0.359 1.092 4 0.45 0.1 0.433 0.195 5 0.74 0.1 0.381 0.282 6 3.55 0.51 0.386 1.371 Wildrock Modified LD -268 Roadside and Median Ditch Desiqn Form M• • -SLOPE ProtectiveMAX • PTH Qn DEPTH ��fflv M11 *Velocity calculations performed using average slope for this application Stommoter Quality Calculations: VRRM Redevelopment Spreadsheet Virginia Runoff Reduction Method ReDevelopment Worksheet - v2.8 - June 2014 To be used w/ 2011 BMP Standards and Specific tions Site Data Project Name: Wildrock Date: April 26, 2016 data input cells calculation cells constant values Post-ReDevelopment Project & Land Cover Information Total Disturbed Acreage Constants Annual Rainfall (inches) Target Rainfall Event (inches) 1.00 Phosphorus EMC (mg/L) 0.26 Nitrogen EMC (mg/L) 1.86 Target Phosphorus Target Load (Ib/acre/yr) 0.41 Pj 0.90 Pre-ReDevelo ment Land Cover acres A soils B Soils C Soils D Soils Totals Forest/Open Space (acres) -- undisturbed, protected forestlopen space or reforested land .00 .00 I 1W.00 .00 0.00 Managed Turf (acres) -- disturbed, graded for yards or other turf to be mowed/managed 1.08 3.51 0.00 0.00 4.59 Impervious Cover (acres) 0.60 0.61 0.00 0.00 1.21 Post-ReDevelo ment Land Cover acres Total 5.80 A soils B Soils C Soils D Soils Totals Forest/Open Space (acres) -- undisturbed, protected forestlopen space or reforested land 0.00 0.00 0.00 0.00 0.00 Managed Turf (acres) -- disturbed, graded for yards or other turf to be mowed/managed 1.68 3.41 0.00 0.00 5.09 Impervious Cover (acres) 0.00 0.71 0.00 0.00 0.71 Total 5.80 Area Check Okay Okay Okay Okay Rv Coefficients A soils B Soils C Soils D Soils Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 Land Cover Summary Listed Adjusted' Land Cover Summary Land Cover Summary Pre-ReDevelopment Post-ReDevelopment Post-ReDevelopment New Impervious Forest/Open Space Cover acres 0.00 0.00 Forest/Open Space Cover acres 0.00 Composite Rv forest 0.00 0.00 Composite Rv forest 0.00 Forest 0% 0% %Forest 0% Managed Turf Cover acres 4.59 4.49 Managed Turf Cover acres 5.09 Composite Rv turf0.19 0.19 Composite Rv(turf) 0.18 %Managed Turf 79% 79% % Managed Turf 88% teryCo1.21 veracresous 1.21 ReDev. Impervious Cover (acres) 0.71 New Impervious Cover (acres) 0.00 (,m 0.95 0.95 Rv(impervious) 0.95 Rv(impervious) 0.95 %Impervious 21% 21 % % Impervious 12% % Impervious 0% Total Site Area acres 5.80 5.70 Total ReDev. Site Area (acres) 5.80 Total New Dev. Site Area (acres) 0.00 Site Rv 0.35 0.35 ReDev. Site Rv 0.28 New Dev. Site Rv 0.00 Pre -Development Treatment Volume (acre -ft) 0.1678 0.1662 Post- ReDevelopment Treatment Volume (acre -ft) 0.1340 Post -Development Treatment Volume (acre -ft) 0.0000 Pre -Development Treatment Volume (cubic feet) 7,309 7,241 Post- ReDevelopment Treatment Volume (cubic feet) 5,839 Post -Development Treatment Volume (cubic feet) 0 Pre -Development Load (TP) (lb/yr) 4.59 4Load Posl- ReDevelopment (TP) (Ib/yr) 3.67 Post -Development Load (TP) (Ib/yr) 0.00 'Adjusted Land Cover Summary reflects the pre redevelopment land cover minus the pervious land cover (forest/open space or managed turf) acreage proposed for new impervious cover. The adjusted total acreage is consistent with the Post Redevelopment acreage (minus the acreage of new impervious cover). The load reduction requriement for the new impervious cover to meet the new development load limit is computed in Column I. Mabmum % Reduction Required Below Pre-ReDevelopment Load TP Load Reduction Required for Redeveloped Area (lb/yr) Total Load Reduction Required (Ibtyr) 20% 0.00 0.00 TP Load Reduction Required for New Impervious Area (lb r) Yre-uevelopmern Load (Irv) (irvyr) I Post -Development Loatl (TN) (Ib/yr)j- Zb.[41 Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report 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 January 15, 2016 704400 38° 1337" N g M M N a 38° 12'57" N 704400 704600 704800 705000 705200 3 Map Scale: 1:8,530 if printed on A landscape (11" x 8.5") sheet. Meters N 0 100 200 400 600 Feet 0 400 800 1600 2400 Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 17N WGS84 8 Custom Soil Resource Report Soil Map 704600 704800 705000 705200 705400 705600 705800 706000 706200 38° 1337 N 705400 705600 705800 706000 S N M N a 38° 12'57" N 706200 3 m Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest (AOI) Spoil Area The soil surveys that comprise your AOI were mapped at 1:15,800. 0 Area of Interest (AOI) Stony Spot Soils Very Stony Spot Warning: Soil Map may not be valid at this scale. 0 Soil Map Unit Polygons Wet Spot Enlargement of maps beyond the scale of mapping can cause rtir Soil Map Unit Lines � Other misunderstanding of the detail of mapping and accuracy of soil line Soil Map Unit Points placement. The maps do not show the small areas of contrasting .; special Line Features soils that could have been shown at a more detailed scale. Special Point Features Blowout Water Features Streams and Canals Please rely on the bar scale on each map sheet for map Borrow Pit measurements. Transportation Clay Spot Rails Source of Map: Natural Resources Conservation Service Closed Depression Interstate Highways Web Soil Survey URL: http://websoilsurvey.nres.usda.gov Gravel Pit Coordinate System: Web Mercator (EPSG:3857) „ US Routes .14 Gravelly Spot Y Major Roads Maps from the Web Soil Survey are based on the Web Mercator 0 Landfill Local Roads projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Lava Flow Background Albers equal-area conic projection, should be used if more accurate Marsh or swamp . Aerial Photography calculations of distance or area are required. Mine or Quarry This product is generated from the USDA-NRCS certified data as of Miscellaneous Water the version date(s) listed below. Perennial Water Soil Survey Area: Albemarle County, Virginia Rock Outcrop Survey Area Data: Version 10, Dec 11, 2013 Saline Spot Soil map units are labeled (as space allows) for map scales 1:50,000 Sandy Spot or larger. 49, Severely Eroded Spot Date(s) aerial images were photographed: May 9, 2011—Jun 4, Sinkhole 2011 Jp Slide or Slip The orthophoto or other base map on which the soil lines were o, Sodic Spot compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting 7 Custom Soil Resource Report Map Unit Legend Albemarle County, Virginia (VA003) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 913 Braddock very stony loam, 2 to 7 0.6 0.2% percent slopes Braddock very stony loam, 7 to 5.4 9C 1.5% 15 percent slopes Chester very stony loam, 7 to 15 9.9 15C 2.8% percent slopes 15D Chester very stony loam, 15 to 7.8 2.2% 25 percent slopes 15E Chester very stony loam, 25 to 3.8 1.1% 45 percent slopes 17 Craigsville loam 12.4 3.5% 38C Hayesville very stony loam, 7 to 5.5 1.6% 15 percent slopes 60E Myersville-Catoctin very stony 0.5 0.1% silt loams, 25 to 60 percent slopes 66D Parker very stony loam, 15 to 25 6.1 1.7% percent slopes 66E Parker very stony loam, 25 to 45 69.7 19.9% percent slopes 67D Parker extremely stony loam, 15 18.7 5.3% to 25 percent slopes 67E Parker extremely stony loam, 25 118.8 33.9% to 60 percent slopes 82C Thurmont very stony loam, 7 to 16.6 4.7% 15 percent slopes 82D Thurmont very stony loam, 15 to 18.2 5.2% 25 percent slopes 87C Tusquitee stony loam, 7 to 15 32.0 9.1% percent slopes 87D Tusquitee stony loam, 15 to 25 24.6 7.0% percent slopes 350.7 100.0% Totals for Area of Interest 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 10 Custom Soil Resource Report 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 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 11 Custom Soil Resource Report 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 Custom Soil Resource Report Albemarle County, Virginia 913-13raddock very stony loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: kbgg 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 Braddock and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Braddock Setting Landform: Fans Landform position (three-dimensional): Tread Down-slope shape: Convex Across -slope shape: Linear Parent material: Alluvium and colluvium derived from acid crystalline rocks Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 79 inches: clay Properties and qualities Slope: 2 to 7 percent Percent of area covered with surface fragments: 7.5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 9C—Braddock very stony loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kbgh Mean annual precipitation: 25 to 65 inches 13 Custom Soil Resource Report Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Not prime farmland Map Unit Composition Braddock and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Braddock Setting Landform: Fans Landform position (three-dimensional): Tread Down-slope shape: Convex Across -slope shape: Linear Parent material: Alluvium and colluvium derived from acid crystalline rocks Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 79 inches: clay Properties and qualities Slope: 7 to 15 percent Percent of area covered with surface fragments: 7.5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 15C—Chester very stony loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kb84 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 Chester and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. 14 Custom Soil Resource Report Description of Chester 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 granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam H3 - 41 to 79 inches: loam Properties and qualities Slope: 7 to 15 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 15D—Chester very stony loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kb85 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 Chester and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Chester Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve 15 Custom Soil Resource Report Down-slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam H3 - 41 to 79 inches: loam Properties and qualities Slope: 15 to 25 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 15E—Chester very stony loam, 25 to 45 percent slopes Map Unit Setting National map unit symbol: kb86 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 Chester and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Chester 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 granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam 16 Custom Soil Resource Report H3 - 41 to 79 inches: loam Properties and qualities Slope: 25 to 45 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: B 17—Craigsville loam Map Unit Setting National map unit symbol: kb88 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 Craigsville and similar soils: 70 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Craigsville Setting Landform: Flood plains Down-slope shape: Linear Across -slope shape: Linear Parent material: Alluvium derived from sandstone Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 23 inches: very cobbly sandy loam H3 - 23 to 79 inches: extremely cobbly sandy loam Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Very low 17 Custom Soil Resource Report Capacity of the most limiting layer to transmit water (Ksat): High to very high (1.98 to 19.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: Frequent Frequency of ponding: None Available water storage in profile: Low (about 5.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3w Hydrologic Soil Group: A Minor Components Worsham Percent of map unit: 5 percent Landform: Drainageways Landform position (two-dimensional): Footslope Landform position (three-dimensional): Head slope, tread Down-slope shape: Concave Across -slope shape: Convex 38C—Hayesville very stony loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kb9z 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 Hayesville and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hayesville 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 granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 58 inches: clay H3 - 58 to 67 inches: sandy clay loam H4 - 67 to 83 inches: fine sandy loam 18 Custom Soil Resource Report Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 10.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 60E—Myersville-Catoctin very stony silt loams, 25 to 60 percent slopes Map Unit Setting National map unit symbol: kbcz 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 Myersville and similar soils: 60 percent Catoctin and similar soils: 30 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Myersville Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from greenstone Typical profile H1 - 0 to 7 inches: silt loam H2 - 7 to 28 inches: silty clay loam H3 - 28 to 44 inches: silt loam H4 - 44 to 79 inches: bedrock Properties and qualities Slope: 25 to 60 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: 40 to 60 inches to paralithic bedrock Natural drainage class: Well drained 19 Custom Soil Resource Report Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Very low to high (0.00 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: B Description of Catoctin Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from greenstone Typical profile H1 - 0 to 5 inches: silt loam H2 - 5 to 18 inches: very channery silt loam H3 - 18 to 28 inches: extremely channery silt loam H4 - 28 to 79 inches: bedrock Properties and qualities Slope: 25 to 60 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: 20 to 40 inches to lithic bedrock Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low to high (0.00 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 3.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: B 66D—Parker very stony loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kbdb 20 Custom Soil Resource Report 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 Parker and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Parker Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 14 inches: extremely stony loam H2 - 14 to 38 inches: extremely cobbly loam H3 - 38 to 67 inches: very stony sandy loam H4 - 67 to 79 inches: bedrock Properties and qualities Slope: 15 to 25 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: 48 to 80 inches to lithic bedrock Natural drainage class: Somewhat excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low (0.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: A 66E—Parker very stony loam, 25 to 45 percent slopes Map Unit Setting National map unit symbol: kbdc 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 21 Custom Soil Resource Report Map Unit Composition Parker and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Parker Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 14 inches: extremely stony loam H2 - 14 to 38 inches: extremely cobbly loam H3 - 38 to 67 inches: very stony sandy loam H4 - 67 to 79 inches: bedrock Properties and qualities Slope: 25 to 45 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: 48 to 80 inches to lithic bedrock Natural drainage class: Somewhat excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low (0.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: A 67D—Parker extremely stony loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kbdd 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 Parker and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. 22 Custom Soil Resource Report Description of Parker Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 14 inches: extremely stony loam H2 - 14 to 38 inches: extremely cobbly loam H3 - 38 to 67 inches: very stony sandy loam H4 - 67 to 79 inches: bedrock Properties and qualities Slope: 15 to 25 percent Percent of area covered with surface fragments: 35.0 percent Depth to restrictive feature: 48 to 80 inches to lithic bedrock Natural drainage class: Excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low (0.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: A 67E—Parker extremely stony loam, 25 to 60 percent slopes Map Unit Setting National map unit symbol: kbdf 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 Parker and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Parker Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope 23 Custom Soil Resource Report Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 14 inches: extremely stony loam H2 - 14 to 38 inches: extremely cobbly loam H3 - 38 to 67 inches: very stony sandy loam H4 - 67 to 79 inches: bedrock Properties and qualities Slope: 25 to 60 percent Percent of area covered with surface fragments: 35.0 percent Depth to restrictive feature: 48 to 80 inches to lithic bedrock Natural drainage class: Excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low (0.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: A 82C—Thurmont very stony loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kbfl 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 Thurmont and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Thurmont Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across -slope shape: Convex Parent material: Colluvium derived from granite, granodiorite, and granite gneiss Typical profile H1 - 0 to 10 inches: loam H2 - 10 to 46 inches: clay loam 24 Custom Soil Resource Report H3 - 46 to 56 inches: loam H4 - 56 to 79 inches: cobbly sandy loam Properties and qualities Slope: 7 to 15 percent Percent of area covered with surface fragments: 7.0 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 48 to 79 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 8.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 82D—Thurmont very stony loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kbfm 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 Thurmont and similar soils: 75 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Thurmont Setting Landform: I nterfluves Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across -slope shape: Convex Parent material: Colluvium derived from granite, granodiorite, and granite gneiss Typical profile H1 - 0 to 10 inches: loam H2 - 10 to 46 inches: clay loam H3 - 46 to 56 inches: loam H4 - 56 to 79 inches: cobbly sandy loam Properties and qualities Slope: 15 to 25 percent Percent of area covered with surface fragments: 7.0 percent 25 Custom Soil Resource Report Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 48 to 79 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 8.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B 87C—Tusquitee stony loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kbfw 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 Tusquitee and similar soils: 85 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Tusquitee Setting Landform: Benches Landform position (two-dimensional): Footslope Landform position (three-dimensional): Base slope Down-slope shape: Concave Across -slope shape: Convex Parent material: Colluvium derived from granite, grandiorite, and granite gneiss Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 45 inches: gravelly clay loam H3 - 45 to 79 inches: very gravelly sandy loam Properties and qualities Slope: 7 to 15 percent Percent of area covered with surface fragments: 1.5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): High (1.98 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None 26 Custom Soil Resource Report Frequency of ponding: None Available water storage in profile: Moderate (about 8.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: A 87D—Tusquitee stony loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kbfx 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 Tusquitee and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Tusquitee Setting Landform: Benches Landform position (two-dimensional): Footslope Landform position (three-dimensional): Base slope Down-slope shape: Concave Across -slope shape: Convex Parent material: Colluvium derived from granite, grandiorite, and granite gneiss Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 45 inches: gravelly clay loam H3 - 45 to 79 inches: very gravelly sandy loam Properties and qualities Slope: 15 to 25 percent Percent of area covered with surface fragments: 1.5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): High (1.98 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 8.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: A 27 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/nres/ detail/national/soils/?cid=nres142p2_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=nres142p2_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=nres142p2_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/ home/?cid=nres142p2_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/landuse/rangepasture/?cid=stelprdb1043084 29 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430 -VI. http://www.nres.usda.gov/wps/portal/ nres/detail/soils/scientists/?cid=nres142p2_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=nres142p2_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/nrcsl 42p2_052290.pdf 30 Precipitation Frequency Data Server http://hdsc. nws.noaa. gov/hdsc/pfds/pfds_printpage.html?lat=3 8.2109&1... NOAA Atlas 14, Volume 2, Version 3 Location name: Crozet, Virginia, US*,, �" Latitude: 38.21091, Longitude: -78.6540° e : Elevation: 1101 ft* source: Google Maps k'^r, r.•� POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAH, 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 (years) 1 2 5 10 25 50 100 200 500 1000 5 -min 4.10 4.93 5.83 6.58 7.45 8.14 8.80 9.43 10.3 11.0 (3.72-4.52) (4.48-5.44) 1 (5.29-6.42) (5.94-7.24) (6.68-8.18) 1 (7.25-8.94) (7.79-9.68) (8.28-10.4) 1 (8.90-11.4) (9.37-12.2) 10 -min 15 -min IF IF IF 30 -min 1 1.87 2.28 2.79 3.21 3.71 4.11 4.50 ) ( 4.88 ) ( 5.39 ) ( 5.80 ) (1.69-2.06) (2.07-2.51) (2.53-3.07) (2.89-3.53) (3.33-4.07) (3.66-4.51) (3.98-4.95 4.28-5.39 4.67-5.98 4.96-6.47 60 -min 1.16 1.43 1.79 2.08 2.46 2.78 3.09 3.42 3.86 4.23 (1.05-1.28) (1.30-1.57) (1.62-1.97) (1.88-2.29) (2.21-2.71) (2.48-3.05) (2.74-3.40) (3.00-3.77) (3.34-4.29) (3.62-4.72) 2 -hr IF IF 3 -hr IF IF IF 6 -hr 0.336 0.409 0.508 0.597 0.718 0.824 0.938 1.06 ) ( 1.25 ) ( 1.41 ) (0.302-0.377) (0.367-0.459) (0.454-0.569) (0.531-0.669) (0.634-0.805) (0.721-0.924) (0.811-1.05) (0.908-1.20 1.04-1.41 1.16-1.60 12 -hr IF IF IF 24 -hr IF IF IF 2 -day 0.082 0.099 0.126 0.148 0.179 0.206 0.235 0.267 0.315 0.357 (0.074-0.091) (0.090-0.110) (0.114-0.140) (0.133-0.164) (0.160-0.199) (0.182-0.228) (0.206-0.261) (0.232-0.298) (0.268-0.354) (0.299-0.402) 3 -day 0.058 0.071 0.090 0.105 0.127 0.146 0.167 0.189 0.223 0.252 (0.053 0.064) (0.064-0.078) (0.081-0.099) (0.095-0.116) (0.115-0.141) (0.130-0.161) (0.148-0.184) (0.166-0.210) (0.192-0.248) (0.214-0.282) 4 -day IF IF IF 7 -day IF IF IF 10 -day 0.025 0.029 0.036 0.042 0.050 0.056 0.062 0.069 0.080 0.088 (0.023-0.027) (0.027-0.032) (0.033-0.039) (0.038-0.045) (0.045-0.054) (0.051-0.061) (0.056-0.068) (0.062-0.076) (0.070-0.087) (0.077-0.097) 20 -day IF IF IF 30 -day IF IF IF 45 -day 0.011 0.013 0.015 0.017 0.019 0.020 0.022 0.023 0.025 0.026 (0.010-0.012) (0.012-0.014) (0.014-0.016) (0.016-0.018) (0.017-0.020) (0.019-0.021) (0.020-0.023) (0.021-0.025) (0.023-0.027) (0.024-0.028) 60 -day 0.009 0.011 0.013 0.014 0.016 0.017 0.018 0.019 0.020 0.021 (0.009 0.010) (0.011-0.012) (0.012-0.014) (0.013 0.015) (0.015 0.017) (0.016 0.018) (0.017-0.019) (0.018 0.020) (0.019 0.022) (0.020-0.023) 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) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. 3.27 3.94 4.67 5.25 5.93 6.47 6.98 7.46 8.09 8.58 (2.97-3.61) (3.58-4.34) (4.23-5.14) (4.74-5.78) (5.32-6.52) (5.77-7.10) (6.17-7.68) (6.55-8.24) (7.00-8.98) (7.34-9.57) 2.72 3.30 3.93 4.43 5.01 5.46 5.89 6.29 6.80 7.19 (2.47-3.00) (3.00-3.64) (3.56-4.33) (4.00-4.87) (4.50-5.50) (4.86-6.00) (5.21-6.48) (5.52-6.94) (5.88-7.54) (6.15-8.02 ) 0.694 0.848 1.07 1.25 1.50 1.70 1.91 2.14 2.46 2.74 1(0.626-0.774)1(0.764-0.944)1(0.960-1.19) (0.231-0.292) (1.13-1.39) (1.33-1.66) (1.51-1.89) (1.68-2.13) (1.87-2.39) (2.12-2.76) (2.33-3.08) 0.510 0.624 0.781 0.917 1.10 1.25 1.41 1.58 1.83 2.04 1(0.459-0.573)1(0.558-0.698)1(0.699-0.875)1(0.818-1.02) (0.152-0.188) (0.972-1.23) (1.10-1.40) (1.23-1.58) (1.37-1.77) (1.56-2.06) (1.72-2.31) 0.213 0.258 0.321 0.379 0.461 0.534 0.615 0.706 0.842 0.967 (0.190-0.241) (0.231-0.292) (0.286-0.364) (0.336-0.429) (0.404-0.521) (0.463-0.604) (0.526-0.697) (0.594-0.802) (0.693-0.962) (0.780-1.11) 0.139 0.169 0.215 0.253 0.309 0.358 0.412 0.472 0.564 0.644 (0.126-0.155) (0.152-0.188) (0.193-0.239) (0.227-0.282) (0.275-0.344) (0.315-0.398) (0.359-0.458) (0.406-0.526) (0.475-0.630) (0.534-0.722) 0.046 0.056 0.071 0.084 0.101 0.116 0.133 0.150 0.177 0.200 (0.043-0.051) (0.051-0.062) (0.065-0.078) (0.076-0.092) (0.092-0.111) (0.105-0.128) (0.118-0.146) (0.133-0.166) (0.154-0.195) (0.172-0.222) 0.031 0.037 0.047 0.054 0.065 0.074 0.084 0.094 0.110 0.123 (0.028-0.034) (0.034-0.041) (0.043-0.051) (0.049-0.059) (0.059-0.071) (0.067-0.081) (0.075-0.092) (0.084-0.104) (0.096-0.121) (0.106-0.136) 0.016 0.019 0.023 0.026 0.030 0.033 0.037 0.040 0.045 0.049 (0.015-0.017) (0.018-0.020) (0.021-0.025) (0.024-0.028) (0.028-0.032) (0.031-0.036) (0.034-0.040) (0.037-0.043) (0.041-0.049) (0.044-0.053) 0.013 0.015 0.018 0.020 0.023 0.025 0.027 0.029 0.032 0.034 (0.012-0.014) (0.015-0.016) (0.017-0.019) (0.019-0.022) (0.022-0.025) (0.024-0.027) (0.025-0.029) (0.027-0.032) (0.030-0.035) (0.031-0.037) Back to Top PF graphical 1 of 4 4/14/2016 6:15 PM Precipitation Frequency Data Server 100.000 10.000 c 41 1.000 c c 0.100 a 0.010 http://hdsc. nws.noaa. gov/hdsc/pfds/pfds—printpage.html?lat=3 8.2109&1... PDS -based intensity -duration -frequency (IDF) curves Latitude: 38.21091, Longitude: -78.65401 0.001 E E rry A Lb r� -0 -U -U '0 -0 -U -0 -0 -U U7 o in o o -q N ry rh 4 r: o 0 o L i o ,1 m w � N m v Lc Duration 100.000 10.000 L C ZI �+ 1.000 c C 0.100 9- 12 0.010 0 001 1 2 5 10 25 50 100 200 500 1000 Average recurrence interval (years) NOAA Atlas 14, Volume 2, Version 3 Created {GMT}: Thu Apr 14 22:15:412016 Average recurrence interval (years) — 1 2 — 5 — 14 25 54 144 240 540 1400 Duration 5 -min — 2 -day — 10 -min — 3 -day 15 -min — 4 -day 30 -min — 7 -day — 60 -min — 10 -day — 2 -hr — 20 -day — 3 -hr — 30 -day — 6 -hr — 45 -day — 12 -hr — 60 -day 24 -hr Back to Top Maps & aerials Small scale terrain York --.:.-Y IVI;ARYLAND. I Wayne v 1 M1Ja[ianaJ'Fares[ � q�� r Baltimore Nashington'D Ell- ' 1 Mononaahels/'�' WEST NatronelForEj.st �Herrisonbu g l :stonoVIRGINIAY'� 1 `1 4 , The,6eorge q r Weshrngton/ Attesville and Jefferson -�- a a _ Go gle National! �. Q 50 km Map datp6W;@kCsiS9mgle 2 of 4 4/14/2016 6:15 PM Precipitation Frequency Data Server http://hdsc. nws.noaa. gov/hdsc/pfds/pfds_printpage.html?lat=3 8.2109&1... Large scale terrain 2 km Map Report a map error Large scale map Boonesville eot F7 eio ' 76S Go-gle 2 km Map Report a map error 3 of 4 4/14/2016 6:15 PM