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HomeMy WebLinkAboutWPO201400054 Calculations 2014-12-16 GRACE ESTATE WINERY STORMWATER MANAGEMENT CALCULATION PACKET Date of Calculations NOVEMBER 19, 2014 Revised on DECEMBER 16, 2014 PREPARED BY: COLLINS 200 GARRETT STREET, SUITE K CHARLOTTESVILLE,VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com DEQ Virginia Runoff Reduction Method Water Quality Calculations Virginia Runoff Reduction Method New Development Worksheet -v2.8 -June 2014 To be used w/2011 BMP Standards and Specifications Site Data Project Name:Grace Farm Vineyards Date: 11/17/14 data input cells calculation cells constant values 1. Post-Development Project& Land Cover Information 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 Land Cover (acres) iminewir A soils B Soils C Soils D Soils Totals Forest/Open Space(acres)--undisturbed, protected forest/open space or reforested land Managed Turf(acres)--disturbed,graded for yards or other turf to be mowed/managed 0.00 1.60 0.00 0.00 1.60 Impervious Cover(acres) Q,QQ 0,41) . 0.00 , -QM-,,,r, 0.40 Total 2.00 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 Forest/Open Space Cover(acres) 0.00 Weighted Rv(forest) 0.00 %Forest 0% Managed Turf Cover(acres) 1.60 Weighted Rv(turf) _ 0.20 °%Managed Turf 80% Impervious Cover(acres) 0.40 Rv(impervious) 0.95 Impervious 20% Total Site Area(acres) 2.00 Site Rv 0.35 Post-Development Treatment Volumeacre-ft) 0.06 Post-Development Treatment Volume(cubic feet) 2,541 Post_Development Load(TP)(Ib/yr) 1.63 Post Development Load(TN)(Ib/yr), 11.691 Total Load(TP)Reduction Required(Ib/yr) 0.81 A, Runall RaluNbn Pnctlpw to Rvtlun TnabnwR V � MI �© _nrrwwr._... 111121 000 — — ossa 000 00 a� ®' n�•M=■ �• ■_ es�e 0. 000 000 00 a o� 000 000 om R■■1 � ossa a. a0 s o..o,000° o� S asses a� •PIo0 s o0 PIM esa® 0. 000 P� ® a� 000 aaa o� �Fesa® ooPo. 000 . ® o� 000 0 a 000 N� es ® — — cc. Iom 0� 000 0oa FIgNiiillIMPIPPliISPIPIM eseE!M0.0 000 0 0. I o� 0 OffillIMPINEMP ill 000 IMENEa®III1MIIIIIPP INIMINMEIIIME, t MI �MIa®M���F ®MEQ M� saa®EPII 000 000 NM �ar....P�� � ase® a00 000 .o� PPRIMPFE ase® o.a o00 o0. moi, .�R..�rd �.� ass® 0. 000 a0 e o0. 000 _ � ass® o� li PM 000 a0 EN o. ..—G....� ...wr I�.� sea® om 0 EU 000 a0 MI 000 111 0-----", � see® — : EMsaaEU ®" o00 0000. 000 EM easEM 000 0 00 00 WA, ® o00 000 000 o00 se"�.rs, aaa 0. a00 0. PP ® 000 000 000 GOO •WM aaa r :: 0.0 000 0. e. ��® ass® om �.,o� o� om om , r ® ass® — — EN — 0 o� ,, :w. asses o: o� o� o:. MI e: o: oPo o� EIRggiliPPMERIIasaEM 0. o00 o00 om o� 00 o00 o00 awe® o0 o 0. ®° a00 000 000 000 s •� aae® o o0 ® a� om o0. 0. „ a, IP. ass® . o0 o00 o00 000 o00 •� ase® o0 00 a00 w00 NI 0. 0. 000 000 • P I o0 ass® o� NM o00 a,0.00� 0. 000 000 _MI ese® a00 0. 000 0°--, ■IIIMIMIIPIMPVII- saa® 0. 0. 00 WU ME 000 00 0. EPP IIP=illilgi MIIIIIIIMPIIIIMIIMPINIMIIMI MI IMIIIMEMPIII 000 ,* e��� ��� s ��® asEMa a o00 e�s� WM —o0 PM ossaM e 14.4fadititsta Ataitfiar== imnuwi.A. I&1iA616"iiiiFuw.- .,eu. NEM MEI .a e•Coaelst Main, EiIMEEMINEMI - �sa�� - ®"'EN � NM . 000 as - . -w SERIMEINEMEI - e® - 0EU - - - 0 li � e%a�aEE � 0 0 - © 000 "o N . . - aa�EE - - .. - MI - ... El "" ems--•® ". --n— ". .. - MI - EU - MI - ase - ®� om �- . - ,.aa„o Site Results Ii- DAA • D.A.B DAC DAD ' D.A.E AREA CHECK IMPERVIOUS COVER • 0.00 0.00' 0.00 OK. IMPERVIOUS COVER TREATED 0.00 0.00 0.00 OK. TURF AREA 0.00 OK. TURF AREA TREATED 0.00 OK. AREA CHECK OK. OK K. OK Phosphorus •• TOTALTREATMENTREQUIRED LB/EAR TOTAL PHOSPHORUS LOAD REDUCTION REQUIRED LB/YEAR RUNOFF REDUCTION Cf F PHOSPHORUS LOAD REDUCTION ACHIEVED LB/YR i ADJUSTED POST-DEVELOPMENT PHOSPHORUS LOAD(TP)(Ib/Yr) REMAINING PHOSPHORUS LOAD REDUCTION(LB/YR)NEEDED)CONGRATULATIONSII YOU EXCEEDED THE TARGET REDUCTION BY 0.4 LBIYEARI Nitrogen(for Information purposos) } TOTAL TREATMENT VOLUME(41)1=•=1. RUNOFF REDUCTION(Cf) NITROGEN LOAD REDUCTION ACHIEVED LB/YR } • ADJUSTED POST-DEVELOPMENT NITROGEN LOAD(TN)(1b/r).111 SCS TR-55 Calculations Soils Mapping (Source: NRCS Web Soil Survey Online Database) _f A :�:r' a!�i; .k l " jam , , f i: 'air.o.*,:".•, IX i ' 'R4 • ry 1 , N.„„..... ,' ,-, . - ,3,..e ,6 - . . ,.....- f . Soils Table (Source: NRCS Web Soil Survey Online Database) Albemarle County,Virginia(VA003) Map Map Unit Name Percent Unit of AOI Symbol 4D Ashe loam, 15 to 25 percent 9.5°%o slopes 58 Belvoir loam,2 to 7 percent 9.5% slopes 78 Braddock loam,2 to 7 percent 23.9% slopes 7C Braddock loam,7 to 15 7.7% percent slopes 25B Dyke silt loam,2 to 7 percent 4.9% slopes 26C3 Dyke clay loam,7 to 15 0.6% percent slopes,severely eroded 368 Hayesville loam,2 to 7 2.2% percent slopes 37C3 Hayesville clay loam,7 to 15 25.8% percent slopes,severely eroded 568 Meadowville loam,2 to 7 1.0% percent slopes 818 Thurmont loam,2 to 7 percent 14.8% slopes Totals for Area of Interest 100.00/o Note: Soils' properties witin proposed disturbances are predominantly composed of hydrologic type B soils. U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 2:Runoff Curve Number and Runoff Project: Grace Estate Winery Designed By: FGM,PE Date: 12/15/2014 Location: Route 810&Mount Juliet Farm Checked By:FGM,PE Date: 12/15/2014 Check One: Present X Developed X 1.Runoff curve Number(CN) Cover description Drainage Soil name and CN(weighted)= (Cover type,treatment,and hydrologic condition; Area Product of CN Calculated Area hydrologic group CN total product/ percent impervious;unconnected/connected (Acres) x Area 'S'Value Description (Appendix A) total area impervious area ratio) DA A Impervious Areas 98 0.00 0.0 (Present) B Woods in Good Condition 55 0.55 30.3 59 6.85 Lawns in Good Condition(75%+Groundcover) 61 1.45 88.5 DA A Impervious Areas 98 0.40 39.4 (Developed) B Woods in Good Condition 55 0.53 29.2 67 4.96 Lawns in Good Condition(75%+Groundcover) 61 1.07 65.1 2.Runoff 2-Year Storm _ 10-Year Storm Drainage Area Description Frequency-years 2 10 n/a Rainfall,P(24 hour)-inches 3.7 5.6 n/a Runoff,Q-inches 0.59 1.62 DA A(Present) Runoff,Q-inches 0.96 2.22 DA A(Developed) • U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 3:Time of Concentration(T,)or Travel Time(T,) Project: Grace Estate Winery Designed By:FGM,PE Date: 12/15/2014 Location: Route 810&Mount Juliet Farm Checked By:FGM,PE Date: 12/15/2014 Check One: Present X Developed X Check One: T, X T, Through subarea n/a DAA DAA Segment ID: (Present) (Developed) Sheet Flow:(Applicable to T,only) 1 Surface description(Table 3-1) Dense Grass Dense Grass 2 Manning's roughness coeff.,n(Table 3-1 0.24 0.24 3 Flow length,L(total L<100)(ft) 100 100 4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 5 Land slope,s(ft/ft) 0.05 0.05 6 Compute T,=[0.007(n*L)0e]/P255 s 4 0.15 0.15 Shallow Concentrated Flow: Unpaved-Gravel 7 Surface description(paved or unpaved) Unpaved &Grass 8 Flow Length,L(ft) 210 175 9 Watercourse slope,s(ft/ft) 0.11 0.11 10 Average velocity,V(Figure 3-1)(ft/s) 5.4 5.4 11 T,=L/3600*V 0.01 I 0+/- Channel Flow: 12 Cross sectional flow area,a(ftp) 13 Wetted perimeter,P*,(ft) 14 Hydraulic radius,r=a/P*,(ft) 15 Channel Slope,s(ft/ft) 16 Manning's Roughness Coeff,n 17V=[1.49?"s05]/n 18 Flow length,L(ft) 19T,=L/3600*V I I 20 Watershed or subarea T,or T, (Add T,in steps 6,11 and 19) I 0.16 I 0.15 I I I I U.S.Department of Agriculture FL-ENG-21C Natural Resources Conservation Service 06/04 TR 55 Worksheet 4:Graphical Peak Discharge Method Project: Grace Estate Winery Designed By:FGM,PE Date: 12/15/2014 Location: Route 810&Mount Juliet Farm Checked By:FGM,PE Date: 12/15/2014 Check One: Present X Developed X Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area 1.Data Description Description Description Description Description Description Description Description DAA DAA (Present) (Developed) Drainage Area(Am)in miles'= 0.0031 0.0031 Runoff curve number CN= 59 67 Time of concentration(Tc)= 0.16 0.15 Rainfall distribution type= II II Pond and swamp areas spread 0 0 throughout the watershed= 2.Frequency-years 2 10 2 10 3.Rainfall,P(24 hour)-inches 3.7 5.6 3.7 5.6 4.Initial Abstraction,la-inches 1.370 1.370 0.992 0.992 5.Compute Ia/P 0.37 0.24 0.27 0.18 6.Unit peak discharge,Qu-csm/in 675 825 825 850 7.Runoff,Qfrom Worksheet 2-inches 0.59 1.62 0.96 2.22 8.Pond and Swamp adjustment factor,Fp 1 1 1 1 9.Peak Discharge,Op-cfs Routed Thru where Qp=Qu Am Q Fp 1.25 4.16 SWM Facility Post-Development Routed Flows Grace Estate Winery Routing Calculations- REVISED BasinFlow printout INPUT: Basin: Grace Estate Winery 4 Contour Areas Elevation(ft) Area(sf) Computed vol . (cy) 699.50 2418.00 0.0 700.00 2633.00 46.8 701.00 3083.00 152.5 702.00 3558.00 275.4 Start_Elevation(ft) 699. 50 vol . (cy) 0.00 2 Outlet Structures Outlet structure 0 Culvert name: Yard Drain Oulet multiple 1 discharge through dam D (in) 6.000 h (in) 0.000 Length (ft) 48.000 Slope 0.010 Manning's n 0.013 Inlet coeff. Ke 0.500 Equation constant set 3 Invert (ft) 699.500 Outlet structure 1 Weir name: Riser: Elevated Yard Drain Inlet diameter (in) 12.000 side angle 0.000 coefficient 3.300 invert (ft) 700.500 multiple 1 discharge through dam Page 1 Grace Estate Winery Routing Calculations- REVISED 2 Inflow Hydrographs Hydrograph 0 SCS name: 2- Year SCS Peak 24-hour Storm Event Area (acres) 2.000 CN 67.000 Type 2 rainfall , P (in) 3.700 time of conc. (hrs) 0.1500 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 2.247 peak time (hrs) 11.930 volume (cy) 259.215 Hydrograph 1 SCS name: 10- Year SCS Peak 24-hour Storm Event Area (acres) 2.000 CN 67.000 Type 2 rainfall , P (in) 5.600 time of conc. (hrs) 0.1500 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 5.199 peak time (hrs) 11.930 volume (cy) 599.816 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 2- Year SCS Peak 24-hour Storm Event inflow (cfs) 2.245 at 11.94 (hrs) discharge (cfs) 0.696 at 12.12 (hrs) water level (ft) 700.417 at 12.14 (hrs) storage (cy) 88.829 Hydrograph 1 Routing Summary of Peaks: 10- Year SCS Peak 24-hour Storm Event inflow (cfs) 5.194 at 11.94 (hrs) discharge (cfs) 4.060 at 12.04 (hrs) water level (ft) 700.959 at 12.04 (hrs) storage (cy) 147.807 Mon Dec 15 14:56:53 EST 2014 Page 2