Loading...
HomeMy WebLinkAboutWPO201500101 Plan - VSMP 2015-12-10 Albemarle County Engineering Manual For The Church of Jesus Christ of Latter Day Saints LDS Church - Airport Road site Stormwater Management and Water Quality Calcs and Plan SWM Revision: December 1, 2015 SWM Revision: December 7, 2015 �.LTN DA L�. p EDMONI)H. afireL.)- APPROVED ,o 4 Lie.No.023831 ,� by the Albemarle County 21-15" 4wCommunity Development Department SIONAL E0\. Date 17.1 sol File wit>2I`Sco vo Blackwell Engineering PLC 566 East Market Street Harrisonburg, VA 22801 Ph. (540)432-9555 Fax(540)434-7604 Blackwellengineering.com BE# 1460 Table of Contents Description Page Project SWM Narrative and Summary 1 Time of Concentration Calcs Pre-Development—Exisitng 2 Runoff Calculations Predevelopment 3 Site VDOT LD-229 form for proposed Tc 4 Virginia Runoff Reduction Method for New Development 5 Energy Balance Calcs per 9VAC25-870-66.B.3 6 Detention Pond Hydrographs and Flow Routings Hydraflow Table of Contents 7 Flow Summary for all storm events 9 (2) 1 Year Storm 10-14 (3-7) Pond Report for pond with 3 inch orifice 15 (8) 2 Year Storm 16-20 (9-13) 10 Year Storm 21-25 (14-18) 100 Year Storm 26-30 (19-23) ... Rainfall Report 31 (24) SWM Plan End LDS Church—2015 SWM Basin STORM WATER MANAGEMENT NARRITIVE AND SUMMARY WATER QUANTITY: Stormwater management for the LDS Church site is required and is provided in two locations. The front third of the site, 1.33 acres, flows toward Airport Road. An existing storm drain system will conduct the stormwater to a private regional detention pond in the northern side of the Hollymead Town Center. Long term maintenance of this detention facility and outlet systems is the responsibility of the Hollymead Town Center. The rear two thirds of the site, 3.81 acres, flows toward the north into a temporary sediment basin on TM#32, Parcel 17. This temporary sediment basin is to be converted into a permanent detention pond as per the attached SWM Plan. This permanent local detention pond will act as a detention pond until such time as Parcel 17 is developed and a permanent regional detention pond is provided to serve any future development and the LDS Church site. The local detention pond is proposed that will serve the entire 5.68 aces draining to it. This pond will met MS-19 and the energy balance requirements of DEQ. This pond will reduce the post-developed runoff to or below the predeveloped rate. Long term maintenance of this local detention facility and outlet system shall be the responsibility of the LDS Church. This maintenance shall include mowing of the detention basin; cleaning out sediment buildup; and cleaning of outlet pipe system of sedimentation and debris. The energy balance equation yields an allowable flow of 0.277 cfs. The proposed detention basin, in order to meet the energy balance flow, will need an orifice less than 3". This is less than the DEQ recommended minimum of 3", therefore the 3" orifice will be utilized. Hydrograph Summary in CFS Description 1-year 2-year 10-year 100-year Existing (Hydrograph 2) 1.23 2.92 10.49 29.27 Proposed with 3" orf. (Hy. 5) 0.307 1.67 10.42 48.25 WATER QUALITY: Water Quality for the two drainage areas will be as follows. The front 1.33 acres that drains to Hollymeade Town Center will be covered under that projects BMP facility. The LDS Church purchased capacity from Hollymeade Town Center in 2006 during the original site plan approval. The rear 3.81 acres of the site will purchase phosphorus credits via the DEQ Nutrient Credit Exchange Program. A total of 4.62 pounds will be purchased. P1 File:1460-TC-CAL-ALBEMARLE-NEW.xIs Printed:12/112015 Runoff Calculations - Rational Method Existing Drainage Area to SWM Basin 1.) Area = 5.68 ac Project Name: AIRPORT ROAD SITE Project#: 1460 B Soils 2.) C = 0.27 1.61 ac @ 0.30 grass CN=61 0.32 ac @ 0.90 Impervious CN=98 3.75 ac @ 0.20 woods CN=55 3.) Time of Concentration Slope a. Overland: (200' max) L= 200 ft. Height= 15 ft. 7.5% VDOT Drainage Manual Appendix 6D-1: T,= 15.1 min. b. Shallow: (1000' max) L = ft. Height= ft. Average velocity = 0.0 fps (paved) VDOT Drainage Manual Appendix 6D-6: T,= 0.0 min. L= 347 ft. Height= 25 ft. 7.2% Average velocity = 4.3 fps (unpaved) VDOT Drainage Manual Appendix 6D-6: T,= 1.3 min. T,= L/60V Subtotal TO= 1.3 min. c. Channel: L= 0 ft. Height= 0 ft.(paved) VDOT Drainage Manual Appendix 6D-5: T,= 0.0 min. L= 0 ft. Height= 0 ft.(unpaved VDOT Drainage Manual Appendix 6D-5: T,= 0.0 min. Subtotal T,= 0.0 min. d. Total T,: T,= 16.4 min. 4.) Rainfall Intensities: For Te= 16 min. 12= 4.48 iph 125 = 4.41 iph Ito = 3.93 iph 1100 = 5.34 iph 5.) Proposed Flows: Q =ACI Q2= 6.8 cfs Q25 = 6.7 cfs Qio= 6.0 cfs Q100 = 8.1 cfs -*ow ©2005 Jonathan Brumfield, T. Basil Finnegan, Aaron Showalter Blackwell Engineering, PLC 566 East Market Street Harrisonburg, VA 22801 P2 File:1460-TC-CAL-ALBEMARLE-NEW.xls Printed:11/25/2015 '_,,, Runoff Calculations ® Rational Method Proposed Drainage Area to SWM Basin 1.) Area = 5.68 ac Project Name: AIRPORT ROAD SITE Project#: 1460 B Soils 2.) C = 0.57 2.80 ac @ 0.30 grass CN=61 2.60 ac @ 0.90 Impervious CN=98 0.28 ac @ 0.20 woods CN=55 3.) Time of Concentration Slope a. Overland: (200' max) L= ft. Height= ft. VDOT Drainage Manual Appendix 6D-1: T,= 0.0 min. b. Shallow: (1000' max) L= ft. Height= ft. Average velocity = 0.0 fps (paved) VDOT Drainage Manual Appendix 6D-6: To= 0.0 min. L= ft. Height= ft. Average velocity = 0.0 fps (unpaved) VDOT Drainage Manual Appendix 6D-6: To= 0.0 min. r... To= L/60V Subtotal To= 0.0 min. c. Channel: L = 0 ft. Height= 0 ft.(paved) VDOT Drainage Manual Appendix 6D-5: = 0.0 min. L = 0 ft. Height= 0 ft.(unpaved VDOT Drainage Manual Appendix 6D-5: = 0.0 min. Subtotal To= 0.0 min. d. Total To: T�= 12.7 min. (from LD-229) 4.) Rainfall Intensities: For To= 13 min. 12 = 4.94 iph 125 = 4.84 iph lao = 4.31 iph Itoo = 5.83 iph 5.) Proposed Flows: Q =ACI Q2= 16.0 cfs Q25 = 15.7 cfs Q10 = 14.0 cfs Q1oo = 18.9 cfs ©2005 Jonathan Brumfield, T. Basil Finnegan, Aaron Showalter Blackwell Engineering, PLC 566 East Market Street Harrisonburg, VA 22801 P3 • W U LC) c} O f` CO Imo- CO c0 Cb C'7 r 9 r, r O L() 67 Ln 00 O G 00 CO <-2. N N t j co N Ces om") N CD 0 U- ccCOQ J (/) CO d' CO N d" N U) N- 6) N CO Lf) r Nop uJ Q. O N CO N 6) O O CO L() O CO N d- CO CO Lf) > U- N CO d' e1' r N CC) O r- V- O <- r- O CO CO i5 Ce ELCL I- LL co O CD d Ci- 00 41 QD O N ,_ CO CO f- CA Cfl COO -� U U U CO d N N N d 00 c9 CO O N LL 2 C) Q Z u) 46 Co V' 'Nr 46 4) d' 4p 46 4) 4) 4) Co TO 10 4) ® 0 -- r r r N N v- r- N r r v- r r r r r r J W H 07 O U) 0) CO N- N 6) 6) d- O d' CO CO d- N O 0_ W CO - N- Lf) CO 0) CO N CO N CO O CO N r- N 0 O r O r 0 0 Lf) 6 r O r r r (N (N r N CO J F-- O O O O O r r 0 O O O O O O O O r (,) U- O O O O O O O O O O O O O O O O O I-- CVO CO O Cfl Lf) C7) O f- LO CD O r C) O C9 I- O Lf) Cfl OCD CA O Lf) O f)QD 00 Ll_ O O LO I` O 4 d- O CY) r- CO O CO d r O Z O r O .4Lf) CO CO CO N V- CO 0) d' r N d. W r r r r r r J I ( 6 Lf) Lf) CO CO Lf) Lf) 00 0 0 0 0 0 O O O O 0) W Co 0) co U) r U) Ln CO 0) 6) t N 'd' NI- O O O Z r N- 6 d- 'may- CA 6 06 r 6 o6 N 00 CO L() Lf) CO HO O co COo CO coccocLO CO CO LOO CO CO 6) CO CO CO co 41 N- W ~Q , U z > 2' Lf) CO C) Lf) d' O O N 000 O O O O O C`7 J — W W d" cO v- CO Lf) U) O r d' co CO N r Lf) 00 0) Lf) Q, -I O- o6 fes- ti d d t Lf) 4 N r 6) (6 N 6) CO CO N W a_ co co co CO co 0) 6) Co 6) 6) co 6) 6) CO CO CO co O Z 10 Cf) Lf) L() Lf) LC) Lf) U) Ln Cn 1 Lf) Ln LO Lf) U) Ln Z W tL W O (/) CO Lf) I` d- CO CO CO vim- CO r CO CO 6) N- Lf) N N- W O W Cfl ti N4 CO CO O CO N- N f- co d -7.� Z N r C 6 r NCO O r N r N O O 4 C6 1 U r r r CI L C Nene a) LU E (LI J Z -fN- N ` N N- N- N-ILf) N- CO CO 1.1) CO r LC) O r D W Q Q Cr. CO CO CO CO CO CO CO CO CO Lf) r CO U) CO CO O CO W' LJ Z CO CO CO CO 6 CCS CO CO CO 10 Ln CO Ln LCj CO Ln c ID - CO U a) Q n J DO L.] LI -g O O CO r 00 O O CO O Cb N O O O O Ch O O O CO d O O CO O CO O O O O r N- CD J Cl Z F: (5 Lf) Lf) Ln Lf) Lf) Cd Lf) Lf) LO 00 CO 6) CO CO Q L 4- 0 CD : W O r CO t- d- 6) f` O O d' O d- N O N CO 4) CD N U F- CO t N- O CO r CO 6) r N d. r CO CO r CO N U) Ni ¢ 0r O r N N O O N 0 0 0 0 0 O O O r ® Q D U U) WO r Lf) Lf) CO 6) I"- p O CO N- 'I- CO 6) N Lf) CO Z Z CO 'd- O N CO r CO O r r r r r CO r CO Lf) 0 ® Z11 r- 0000 0 00 000 00 0 0 0 0 00) F- — Q c C CI- O W 0 0 0 0 0 O 0 0 Lf) O CA CO Lf) CO 'c- I` ti 2 U r. f` ti CO co co CO O CO ti N- CO Lf) CO r ti r • o � 0 00000 0 00 000 00 0 0 0 0 0 ; UCL Z CV rn Z N o < Z W Q W' CO O) r r N CN O Nr 6r) r N CO CNO CrO d IQ fOCO) Wx 0 0 0 0 O O O O O O O O O O O OQQQ O0 ®, O Z CO CO Lf) d' r r r '-- CA CO CO -I- co Co N N r W O r r r r r r r U) !1 r c 6 2 Z LL o O CO N CO Lf) r "e) N r O 6) CO U) 't N CO 00 N Oa r r r r r r r r r I-L P4 Virginia Runoff Reduction Method New Development Worksheet-v2.8 -June 2014 To be used w/ DRAFT 2013 BMP Standards and Specifications Site Data Project Name: LDS Church -Airport Road Date: December 1, 2015 data input cells calculation cells - constant values 1. Post-Development Project& Land Cover Information Constants Annual Rainfall(inches) 43 - - 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 _ PI _ 0.90 Land Cover (acres) A soils B Soils C Soils D Soils Totals Forest/Open Space(acres)--undisturbed, protected forest/open 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 0.00 1.21 0.00 0.00 1.21 Impervious Cover(acres) 0.00 2.60 0.00 0.00 2.60 Total 3.81 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) 1.21 Weighted Rv(turf) 0.20 - %Managed Turf 32% Impervious Cover(acres) 2.60 Rv(impervious) 0.95 _ %Impervious 68% _ Total Site Area(acres) 3.81 - Site Rv 0.71 _ Post-Development Treatment Volume(acre-ft) 0.23 Post-Development Treatment Volume(cubic feet) 9,845 Post_Development Load(TP)(Ib/yr) 6.19 Post Development Load(TN)(lb/yr 44.25 Total Load(TP)Reduction Required(Ib/yr) 4.62 ,'moo P5 LDS Church-Charlottesville BE# 1460 Now, 9VAC25-870-66.8.3 Natural Stormwater Conveyance Systems 1-year 24-hour storm event Hydrologic soil group = B CN = 55 Forest Q Developed < l•F• x (Q Pre-Developed x RV Pre-Developed)/ RV Developed QDeveloped (Allowable) = 0.277 cfs (maximum allowable) (Q Forest x RV Forest)/ RV Developed= 0.084 cfs (maximum requirable lower limit) I.F. (Improvement Factor)= 0.8 Site Area = 5.68 acres (Disturbed and Offsite Tributary) QDeveloped = 9.169 cfs (Hydrograph 3) RV Developed = 23,491 Cf QPre-Developed = 1.231 cfs (Hydrograph 2) RV pre-Developed = 6,609 cf QForest= 0.460 cfs (Hydrograph 1) RV Forest= 4,291 cf Now Nkorp- P6 Hydraflow Table of'.. 4e a S362-1512)\1460\Engineering Calculations\Storm\1460swmpond-revisedgpw Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 Watershed Model Schematic Hydrograph Return Period Recap 2 1 - Year Summary Report 3 Hydrograph Reports 4 Hydrograph No. 1, SCS Runoff, Forest Flow 4 Hydrograph No. 2, SCS Runoff, PreDev Runoff 5 Hydrograph No. 3, SCS Runoff, PostDev Runoff to Basin 6 Hydrograph No. 4, Reservoir, PostDev Basin Outlet 7 Pond Report- Detention Basin 8 2 - Year Summary Report 9 Hydrograph Reports 10 Hydrograph No. 1, SCS Runoff, Forest Flow 10 Hydrograph No. 2, SCS Runoff, PreDev Runoff 11 Hydrograph No. 3, SCS Runoff, PostDev Runoff to Basin 12 Hydrograph No. 4, Reservoir, PostDev Basin Outlet 13 10 - Year Summary Report 14 Hydrograph Reports 15 Hydrograph No. 1, SCS Runoff, Forest Flow 15 Hydrograph No. 2, SCS Runoff, PreDev Runoff 16 Hydrograph No. 3, SCS Runoff, PostDev Runoff to Basin 17 Hydrograph No. 4, Reservoir, PostDev Basin Outlet 18 100 - Year Summary Report 19 Hydrograph Reports 20 Hydrograph No. 1, SCS Runoff, Forest Flow 20 Hydrograph No. 2, SCS Runoff, PreDev Runoff 21 Hydrograph No. 3, SCS Runoff, PostDev Runoff to Basin 22 Hydrograph No. 4, Reservoir, PostDev Basin Outlet 23 IDF Report 24 P7 1 Watershed ®dSchematicrlow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 1 2 3 V Project: Z:\Civil\Workfile\2004(1362-1512)\1460\Engineering Calculations\Storm\1460Nznplalycl4lb\iigdc2ga% F8 2 Hydrograph Returner'® yra ��yuraraphs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 I d. Hydrograph Inflow Peak Outflow(cfs) Hydrograph '`441111009. type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff 0.460 1.614 8.015 25.39 Forest Flow 2 SCS Runoff 1.231 2.920 10.49 29.27 PreDev Runoff 3 SCS Runoff 9.169 12.91 25.30 49.89 PostDev Runoff to Basin 4 Reservoir 3 0.307 1.667 10.42 48.25 PostDev Basin Outlet Proj. file: Z:\Civil\Workfile\2004(1362-1512)\1460\Engineering Calculations\SkiamtIWID/nAkilidi1-5evised.gpw P9 3 Hydrograph Summary Repyprta low Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 1 Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph Itiviot. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cult) 1 SCS Runoff 0.460 1 729 4,291 Forest Flow 2 SCS Runoff 1.231 1 727 6,609 PreDev Runoff 3 SCS Runoff 9.169 1 722 23,491 PostDev Runoff to Basin 4 Reservoir 0.307 1 936 21,908 3 567.13 13,933 PostDev Basin Outlet Z:\Civil\Workfile\2004(1362-1512)\1460\En l mrim 'Q t:llditl kStorm\146Ni+a 1pc0dl2• qda0gpw P10 4 Hydrograph ort Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 *ftwrlyd. No. I Forest Flow Hydrograph type = SCS Runoff Peak discharge = 0.460 cfs Storm frequency = 1 yrs Time to peak = 12.15 hrs Time interval = 1 min Hyd. volume = 4,291 cuff Drainage area = 5.680 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 3.04 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)_[(0.410 x 61)+(0.320 x 98)+(3.500 x 55)]/5.680 Forest Flow Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 0.00 - - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 `" Hyd No. 1 Time (hrs) P11 5 Hydrograph Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 ...riyd. No. 2 PreDev Runoff Hydrograph type = SCS Runoff Peak discharge = 1.231 cfs Storm frequency = 1 yrs Time to peak = 12.12 hrs Time interval = 1 min Hyd. volume = 6,609 cuft Drainage area = 5.680 ac Curve number = 59* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 3.04 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(1.610 x 61)+(0.320 x 98)+(3.750 x 55)]/5.680 PreDev Runoff Q (cfs) Hyd. No. 2 -- 1 Year Q (cfs) 2.00 2.00 1.00 1.00 0.00 - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 2 P12 6 Hydrograph Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 No. 3 PostDev Runoff to Basin Hydrograph type = SCS Runoff Peak discharge = 9.169 cfs Storm frequency = 1 yrs Time to peak = 12.03 hrs Time interval = 1 min Hyd. volume = 23,491 cuft Drainage area = 5.680 ac Curve number = 78* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.04 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(2.800 x 61)+(2.600 x 98)+(0.280 x 55)]/5.680 PostDev Runoff to Basin Q (cfs) Hyd. No. 3-- 1 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 3 Time (hrs) P13 7 Hydrograph Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 .1....1-1yd. No. 4 PostDev Basin Outlet Hydrograph type = Reservoir Peak discharge = 0.307 cfs Storm frequency = 1 yrs Time to peak = 15.60 hrs Time interval = 1 min Hyd. volume = 21,908 cuft Inflow hyd. No. = 3 - PostDev Runoff to Basin Max. Elevation = 567.13 ft Reservoir name = Detention Basin Max. Storage = 13,933 cuft Storage Indication method used. PostDev Basin Outlet Q (cfs) Hyd. No. 4 -- 1 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 1 0.00 - ' 0.00 0 5 10 15 20 25 30 35 40 45 50 Time (hrs) - Hyd No. 4 Hyd No. 3 ILI i_I i t Total storage used = 13,933 cuft P14 Pond Report 8 Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 Pond No. 2 - Detention Basin Pond Data Contours-User-defined contour areas.Conic method used for volume calculation. Begining Elevation=565.00 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 565.00 5,863 0 0 1.00 566.00 6,485 6,171 6,171 2.00 567.00 7,139 6,809 12,979 3.00 568.00 7,824 7,478 20,458 4.00 569.00 8,539 8,178 28,636 5.00 570.00 9,286 8,909 37,545 6.00 571.00 10,068 9,673 47,218 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 18.00 3.00 4.75 0.00 Crest Len(ft) = 9.42 30.00 0.00 0.00 Span(in) = 18.00 3.00 12.00 0.00 Crest El.(ft) = 568.60 568.60 0.00 0.00 No.Barrels = 1 1 5 0 Weir Coeff. = 3.33 2.60 3.33 3.33 Invert El.(ft) = 565.20 565.20 567.20 0.00 Weir Type = 1 Broad Rect --- Length(ft) = 41.60 0.10 0.10 0.00 Multi-Stage = Yes No Yes No Slope(%) = 4.57 1.00 1.00 n/a N-Value = .015 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Contour) Multi-Stage = n/a Yes Yes No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). Stage(ft) Stage/Discharge Elev(ft) 6.00 -- 571.00 5.00 570.00 4.00 569.00 3.00 568.00 2.00 567.00 1.00 566.00 ... 0.00 565.00 0.0 30.0 60.0 90.0 120.0 150.0 180.0 210.0 240.0 270.0 300.0 330.0 Discharge(cfs) Total Q P15 9 Hyd r®graphSummary ycrt Trafilow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 'd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph Ni.p,,.). type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cult) 1 SCS Runoff 1.614 1 727 8,302 Forest Flow 2 SCS Runoff 2.920 1 726 11,579 PreDev Runoff 3 SCS Runoff 12.91 1 721 32,723 PostDev Runoff to Basin 4 Reservoir 1.667 1 750 31,071 3 567.38 15,854 PostDev Basin Outlet 2 VAf Si )p Z:\Civil\Workfile\2004(1362-1512)\1460\Engft erirn 'Q ntl kStorm\1461 x dpyridadvAsteOgpw P16 10 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 .dyd. No. Forest Flow Hydrograph type = SCS Runoff Peak discharge = 1.614 cfs Storm frequency = 2 yrs Time to peak = 12.12 hrs Time interval = 1 min Hyd. volume = 8,302 cult Drainage area = 5.680 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 3.65 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(0.410 x 61)+(0.320 x 98)+(3.500 x 55)]/5.680 Forest Flow Q (cfs) Hyd. No. 1 --2 Year Q (cfs) 2.00 2.00 1.00 1.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Now Hyd No. 1 P17 11 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 Hyd. No. 2 PreDev Runoff Hydrograph type = SCS Runoff Peak discharge = 2.920 cfs Storm frequency = 2 yrs Time to peak = 12.10 hrs Time interval = 1 min Hyd. volume = 11,579 cuff Drainage area = 5.680 ac Curve number = 59* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 3.65 in Distribution = Type 11 Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(1.610 x 61)+(0.320 x 98)+(3.750 x 55)]/5.680 PreDev Runoff Q (cfs) Hyd. No. 2 --2 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 `w° Hyd No. 2 Time (hrs) P18 12 Hydrograph Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 ..dyd. No. 3 PostDev Runoff to Basin Hydrograph type = SCS Runoff Peak discharge = 12.91 cfs Storm frequency = 2 yrs Time to peak = 12.02 hrs Time interval = 1 min Hyd. volume = 32,723 cuft Drainage area = 5.680 ac Curve number = 78* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.65 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)_[(2.800 x 61)+(2.600 x 98)+(0.280 x 55)]/5.680 PostDev Runoff to Basin Q (cfs) Hyd. No. 3--2 Year Q (cfs) 14.00 14.00 2.00 12.00 *r.. 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 - ` - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) �rw Hyd No. 3 P19 13 Hydrograph p rt Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 'i Hyd. No. 4 PostDev Basin Outlet Hydrograph type = Reservoir Peak discharge = 1.667 cfs Storm frequency = 2 yrs Time to peak = 12.50 hrs Time interval = 1 min Hyd. volume = 31,071 cuft Inflow hyd. No. = 3 - PostDev Runoff to Basin Max. Elevation = 567.38 ft Reservoir name = Detention Basin Max. Storage = 15,854 cuft Storage Indication method used. PostDev Basin Outlet Q (cfs) Hyd. No. 4 --2 Year Q (cfs) '14.00 14.00 2.00 12.00 10.00 10.00 8.00 I 8.00 6.00 6.00 4.00 4.00 2.00 — 2.00 0.00 0.00 0 4 8 12 16 20 24 28 32 36 40 44 48 Time (hrs) 'saw. -- Hyd No. 4 Hyd No. 3 I_Li_LLLI-I Total storage used = 15,854 cuft P20 14 Hyd r®graphSummary rt y railow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 d. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph fro. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 8.015 1 724 26,097 Forest Flow 2 SCS Runoff 10.49 1 724 32,142 PreDev Runoff 3 SCS Runoff 25.30 1 721 64,103 PostDev Runoff to Basin 4 Reservoir 10.42 1 731 62,354 3 568.59 25,261 PostDev Basin Outlet Nor- I0-y qt2.. s-r0ii i Z:\Civil\Workfile\2004(1362-1512)\1460\Englr #erirn 'QarlaLllffidnsteStorm\14611Vi+;ur>id@yridlads'eDOw P21 15 Hydrograph ep Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 eHyd. No. 1 Forest Flow Hydrograph type = SCS Runoff Peak discharge = 8.015 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 26,097 cuft Drainage area = 5.680 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 5.52 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(0.410 x 61)+(0.320 x 98)+(3.500 x 55)]/5.680 Forest Flow Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 - ' 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 1 P22 16 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 ri-lyd. No. 2 PreDev Runoff Hydrograph type = SCS Runoff Peak discharge = 10.49 cfs Storm frequency = 10 yrs Time to peak = 12:07 hrs Time interval = 1 min Hyd. volume = 32,142 cult Drainage area = 5.680 ac Curve number = 59* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 5.52 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.610 x 61)+(0.320 x 98)+(3.750 x 55)]/5.680 PreDev Runoff Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs) 12.00 12.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 — 2.00 0.00 - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) ---� Hyd No. 2 P23 17 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 No. 3 PostDev Runoff to Basin Hydrograph type = SCS Runoff Peak discharge = 25.30 cfs Storm frequency = 10 yrs Time to peak = 12.02 hrs Time interval = 1 min Hyd. volume = 64,103 cuft Drainage area = 5.680 ac Curve number = 78* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 5.52 in Distribution = Type Il Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(2.800 x 61)+(2.600 x 98)+(0.280 x 55)]/5.680 PostDev Runoff to Basin Q (cfs) Hyd. No. 3 -- 10 Year Q (cfs) 28.00 28.00 x.4.00 24.00 20.00 20.00 16.00 16.00 12.00 12.00 8.00 8.00 4.00 4.00 0.00 __® _ 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 3 P24 18 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 'werrlyd. No. 4 PostDev Basin Outlet Hydrograph type = Reservoir Peak discharge = 10.42 cfs Storm frequency = 10 yrs Time to peak = 12.18 hrs Time interval = 1 min Hyd. volume = 62,354 cuft Inflow hyd. No. = 3 - PostDev Runoff to Basin Max. Elevation = 568.59 ft Reservoir name = Detention Basin Max. Storage = 25,261 cuft Storage Indication method used. PostDev Basin Outlet Q (cfs) Hyd. No. 4-- 10 Year Q (cfs) 28.00 28.00 x,1.00 24.00 20.00 20.00 16.00 16.00 12.00 12.00 8.00 8.00 4.00 4.00 0.00 --- 0.00 0 4 8 12 16 20 24 28 32 36 40 Time (hrs) Hyd No. 4 Hyd No. 3 llILLLL Total storage used =25,261 cuft P25 19 Hydrograph Summary Repyortafilow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 d. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph +!K°o. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 25.39 1 724 73,724 Forest Flow 2 SCS Runoff 29.27 1 723 84,010 PreDev Runoff 3 SCS Runoff 49.89 1 721 129,457 PostDev Runoff to Basin 4 Reservoir 48.25 1 722 127,694 3 569.17 30,135 PostDev Basin Outlet 100 /9 Szbadv1 Z:\Civil\Workfile\2004(1362-1512)\1460\Englra#erini f lta6n`atorm\146@ 1p§Om2-6vDg5w P26 20 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7!2015 '`ft-Hyd. No. 1 Forest Flow Hydrograph type = SCS Runoff Peak discharge = 25.39 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 73,724 cuft Drainage area = 5.680 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 9.06 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(0.410 x 61)+(0.320 x 98)+(3.500 x 55)]/5.680 Forest Flow Q (cfs) Q (cfs) Hyd. No. 1 -- 100 Year 28.00 28.00 ,,,,,,,?4.00 ----------------------— 24.00 20.00 20.00 16.00 16.00 12.00 12.00 8.00 - 8.00 4.00 _----- 4.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 ,,0060,- Time (hrs) Hyd No. 1 P27 21 Hydrograph p® Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12 17/2015 �--Hyd. No. 2 PreDev Runoff Hydrograph type = SCS Runoff Peak discharge = 29.27 cfs Storm frequency = 100 yrs Time to peak = 12.05 hrs Time interval = 1 min Hyd. volume = 84,010 cuft Drainage area = 5.680 ac Curve number = 59* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 16.00 min Total precip. = 9.06 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.610 x 61)+(0.320 x 98)+(3.750 x 55)]/5.680 ProDev Runoff o (cfs) Hyd. No. 2 -- 100 Year Q (cfs) 30.00 30.00 N"lr'25.00 25.00 20.00 20.00 15.00 15.00 10.00 10.00 5.00 — 5.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Time (hrs) P28 22 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 ..4-1yd. No. 3 PostDev Runoff to Basin Hydrograph type = SCS Runoff Peak discharge = 49.89 cfs Storm frequency = 100 yrs Time to peak = 12.02 hrs Time interval = 1 min Hyd. volume = 129,457 cuft Drainage area = 5.680 ac Curve number = 78* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 9.06 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)_[(2.800 x 61)+(2.600 x 98)+(0.280 x 55)]/5.680 PostDev Runoff to Basin Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs) 50.00 50.00 40.00 40.00 30.00 30.00 20.00 20.00 10.00 10.00 0.00 - 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) �..� Hyd No. 3 P29 23 Hydrograph Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Monday, 12/7/2015 Hyd. No. 4 PostDev Basin Outlet Hydrograph type = Reservoir Peak discharge = 48.25 cfs Storm frequency = 100 yrs Time to peak = 12.03 hrs Time interval = 1 min Hyd. volume = 127,694 cuft Inflow hyd. No. = 3 - PostDev Runoff to Basin Max. Elevation = 569.17 ft Reservoir name = Detention Basin Max. Storage = 30,135 cuft Storage Indication method used. PostDev Basin Outlet Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs) 50.00 50.00 40.00 40.00 30.00 30.00 20.00 20.00 10.00 10.00 a 0.00 - ° 16,123116510- 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) `"'"' -� Hyd No. 4 Hyd No. 3 II1LLL_I.; Total storage used = 30,135 cuft P30 24 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday, 12/7/2015 :\r.r Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 2 43.0100 11.2500 0.8400 3 0.0000 0.0000 0.0000 5 44.7100 10.5000 0.8000 10 39.7100 9.2500 0.7400 25 32.1700 6.5000 0.6500 50 28.8500 5.2500 0.6000 100 28.3400 4.7500 0.5700 File name:Rockingham.IDF Intensity= B/(Tc + D)^E Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 %,y, 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 2.39 2.11 1.89 1.72 1.58 1.46 1.36 1.27 1.19 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 4.99 3.99 3.35 2.90 2.57 2.31 2.11 1.94 1.80 1.68 1.58 1.49 10 5.56 4.45 3.75 3.27 2.91 2.63 2.40 2.22 2.07 1.94 1.82 1.73 25 6.58 5.20 4.38 3.82 3.42 3.10 2.86 2.65 2.48 2.34 2.21 2.10 50 7.14 5.63 4.75 4.16 3.73 3.40 3.14 2.93 2.75 2.60 2.47 2.35 100 7.74 6.11 5.18 4.55 4.10 3.75 3.47 3.25 3.06 2.89 2.75 2.63 Tc=time in minutes.Values may exceed 60. Precip.file name:Z:\Civil\Library\Civil Software Data\Hydraflow\2008 IDF&PCP Files\Rockingham Zone 1.pcp 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 3.04 3.65 0.00 3.43 5.52 4.91 5.66 9.06 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 0.00 0.00 0.00 0.00 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 `r✓ 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 0.00 0.00 0.00 0.00 0.00 P31 C�# / rii , 11/,� /®i /•;� t � , ,1 t / iii ,; lri /�✓ ! � \ I I ) `� \ ► / �®��' � a �,� /// iii /�, I - � \ I i � � ♦ /' l� / �,' •.., _ j` � � / (� I \ 1 'Ori, \ / ?o RETURN LOPE 'ORIGINAL GRADE D ION OVAL OF , / / 98.6 ,. �� .� 98•e8.3 = 1FlI i "'''' / 1 TC -+ 1. ! .m '•'�Cp� 1. f !' /�' J /+/ 'ZI / f / TOP NEWT'f IN- 583.88 r// ��.�; /':.. - `ri♦ �` - r� L--------- --J I I I I 1 \ \ \1 11 --------1---- I:-- yLn N 0704.50' E 572.99 \ I► = - EXISTING SHEET v i e e /i / <� (a / , / / / / // / r/ / / /i I 1 FLOW 200' / \r / r � , A� i � � � � h •�. �� � i - I- - i � / CON�ISNTRATEDH OW 34T ' \ � / / / / / �'�y J/�,/j/ Z .,,�A51 N /TO B E \ \ / \ \ \ \\ < �WM BOND - 570- XY, 00 l ` ✓ / rl 1. ♦l 97.8 C X98 9 Tc7 OS GR� :'s ' \ \ 93.8 6-zilc L., ... is ..+' .' \ \ � \ \ \ � .97 / 1 11 I �' r;, \ .. , ..:" �. \ �,/1' \ \ \ \ \ - _ S�90 DRAINAGE EA TO I \ / IT l/ l I� !l i [ s / ✓ / \ \ \ \ \ \ \ \ \ \ \ BASIN = 5.R68 ACRES \ \ \ II 15•R / / / / L , ° , \ u' \ 1 `\ �.(e� • / t.ox 95 tc 9g tc ?4.4 sQg \ \ \ \ \ \ \ \ \ \ \ \ \ \ r?fes(. ( -.j, --- 9 \ \ \ \ \ \ \ \ \ \ \ r ' \ \ \ /®/ l l - ,o "�O •\ - \ � -� \ \ ` \ \ \ \ \ \ 535 - \ \ \ \ \ - - //fir � /• , � 1 1 \ _\� /� rl { \ f �'` 14+00 i - - - - -,S+oo \ t5+00 _ ,foo \ \ too \ \ \ _ \ 194-00� \I \ / s % IXISITNG DI -38, Lt -8 \ S 0711'58' W 413.38' /////J // ra! / � � :% , /' IXP 24901N� 584.56 \ l _ I I ) - \ \ \ r \ 80) `'�B \ \ \ \ ♦ \ \ \ \ \ \ I 1 \ I ► ( / I I 1 TIMBERWOOD BOULEVARD / 50' Row am 1; CONs aio0 BNL Y urrED AND f 0tpopOF AMERICA �.,,. \ \ \ n I 111 1 1 wu\ U� I I I / / \ GRAPHIC \,S6ALE \ \ \ \ 56 I 0" 50'\ \ oo' \ \ SCALE. '1"=56, \ \ Virginia Runoff Reduction Method New Development Worksheet - v2.8 - June 2014 To be used w/ DRAFT 2013 BMP Standards and Specifications BMP Maintenance and Inspections (by Property Owner Association) Site Data 1. Embankment: The embankment should be mowed regularly. All bare areas should be seeded and mulched to prevent erosion. DRAINAGE INFO FOR SWM BASIN Project Name: LDS Church -Airport Road TOTAL DRAINAGE AREA = 5.68 ac. Date: December 1, 2015 2. Embankment: All animal borrows should be backfilled and compacted and SITE AREA TO POND= 3.81 ac. EXISTING Tc = 16.4 min. borrowing animals removed from the area. data input cells PROPOSED Tc = 12.6 min. calculation cells 3. Embankment: No trees, wooding vegetation, or other deep-rooted growth constant values should be removed from the embankment and extending 25 feet from the toe of embankment. 1. Post -Development Project & Land Cover Information, 4. Principal Spillway: Spillway structure should be cleared of debris on a Constants regular basis and after any significant rainfall event where inspection reveals - a significant blockage. Annual Rainfall (inches) Target Rainfall Event (inches) Phosphorus EMC (mg/L) Target Phosphorus Target Load (Ib/acre/yr) Pj Removal of sediment should be removed on an annual basis or more often as Land Cover (acres) needed. A soils B Soils C Soils D Soils Forest/Open Space (acres) - undisturbed, protected forest/open space or reforested land 0.00 0.00 0.00 0.00 Managed Turf (acres) - disturbed, graded for yards or other turf to be mowed/managed 0.00 1.21 0.00 0.00 Impervious Cover (acres) 0.00 2.60 0.00 1 0.00 Tota I Rv Coefficients _ 5. Debris and litter will accumulate near and in the standpipe orifices, weir, and crest (flow points). All structure flow points and trash racks should be Nitrogen EMC (mg/L)l 1.86 inspected and cleared of debris on a regular basis and after any significant rainfall event. 6. Sediment deposition should be continually monitored in the BMP facility. 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 1 0.95 1 0.05 Land Cover Summary Forest/Oben Space Cover 6 % Forest _ Managed Turf Cover (acn Weighted Rv(turf) % Managed Turf Impervious Cover (acres) Rv(impervious) % Impervious Total Site Area (acres) Site Rv Post -Development Treatment Volume (acn Post -Development Treatment Volume (cut feet) Post -Development Load (TP) (Ib/yr) Total Load (TP) Reduction Required (Ib/yr) r1liIh 0% 1.21 0.20 32% 2.60 [ Si 68% iii: 0.71 9,845 6.19 Post -Development Load 4.62 44.251 otals 0.00 1.21 2.60 3.81 Proiect Name: LDS Church - Airport Road Note: Table required for all projects with a stormwater management plan. O / 131 SKIN OUT \ F' /STRUCTURE ST 0 R M,WAT.E R VANAUL,mEN/l , / Z_ / w f BASIN ♦ \\ `�\_ -`` \ _.EC -3 LINED SPILLWAY 6 70 - GRAPHIC SCALE ---- 20' 0 �\ 20' 40' \ \\ SCALE: 1"=20' SEE VESCH PLATES: 3.14-2, 3.14-10, STORM OUTLET STRUCTURE 3.14-13, 3.14-14, 3.14.15 FOR 30" DIA. MANHOLE BASE ADDITIONAL DETAILS EXISTNG RISER CREST= 568.1' NEW RISER CREST= 568.6' NEW 4.75"x12" ORIFICE= 567.2' EXISTING DAM TOP= 570.1 EX 4"0 ORIFICE= 566.2' PLUG NEW 3"0 ORIFICE= 565.2' 18" INV OUT= 565.2' 100 YEAR FLOW ELEV.= 569.17' 42"Dx24"H TRASH RACK - - - - - EMERGENCY SPILLWAY ELEV.= 568.6' RAISE TO NEW CREST NEW ORIFICES (5) I►�, V77 4.75"Hx12"W I I (I ( 1 1 I I I 11 _PINV.=567.2' PLUG { { { { F NEW 3" ORIFICE INV= 565.2' ��`3"� { 41.6± LF OF 18" CMP OUT, PIPE INV.= I lil -'I--��i-�� =r T- - - - - 563.5' - I I _� �. �' - �-,-�T' � � III I 11- ►�► � - -_ �h- � --- C IM 54 5.0±'- 54" CONCRETE BASE ANCHOR STAND PIPE TO PREVENT FLOATING STORMWATER MANAGEMENT BASIN NTS GRASS SPILWAY 100 YEAR FLOW ELEV.= 569.17' -) TOP OF BERM=570.1 171 I . EC -3C I�ER�) I! + ( (CREST i LEV=S (8I6I - I _ COMPACTED SOIL EMER GENCY SPILL WA Y NTS APPROVED by the Albemarle County Community Development Department Date 1-1/1, (2 j ►S File w ro?,-otS60j0 BMP TABLE Date: 11-24-15 Type (see below) Design Level (1 or 2) Acres HUC Treated 16. Other- Purchase Credits n/a 3.81 JR11- Flat Branch Trib. J C.- , 4¢04 Z Designed by: EHB 0 0 Z Drawn by: EHB Pollutant Removal Achieved (lb/yr.) P 4.62 Pollutant Removal Required (Ib/yr.) P 4.62 - N/A - Excess Pollutant Removal (if any) (lb/yr.) 0 P 0.00 - N/A - Types (per Virginia BMP Clearinghouse): w W 1. Rooftop Disconnection Z 2. Sheetflowto Veg. Filter/ Open Space 3. Grass Channel Hydrological Unit Codes (HUC): 4. Soil Amendments JR11- Flat Branch Tri b. 5. Vegetated Roof PS23 - Cooks Creek 6. Rainwater Harvesting LL. Q Q PS26- Congers Creek 7. Permeable Pavement PS33 - Cub Run 8. Infiltration .PS56- Linville Creek 9. BioRetention 'PS59- Dry Fork 10. Urban BioRetention p (r) 11. Dry Swale a =Z' 12. Wet Swale 13. Constructed Wetland 14. Wet Pond <W (� > O 15. Extended Detention Pond O :DW m n 16.Other- Purchase Credits Lv Note: Table required for all projects with a stormwater management plan. O / 131 SKIN OUT \ F' /STRUCTURE ST 0 R M,WAT.E R VANAUL,mEN/l , / Z_ / w f BASIN ♦ \\ `�\_ -`` \ _.EC -3 LINED SPILLWAY 6 70 - GRAPHIC SCALE ---- 20' 0 �\ 20' 40' \ \\ SCALE: 1"=20' SEE VESCH PLATES: 3.14-2, 3.14-10, STORM OUTLET STRUCTURE 3.14-13, 3.14-14, 3.14.15 FOR 30" DIA. MANHOLE BASE ADDITIONAL DETAILS EXISTNG RISER CREST= 568.1' NEW RISER CREST= 568.6' NEW 4.75"x12" ORIFICE= 567.2' EXISTING DAM TOP= 570.1 EX 4"0 ORIFICE= 566.2' PLUG NEW 3"0 ORIFICE= 565.2' 18" INV OUT= 565.2' 100 YEAR FLOW ELEV.= 569.17' 42"Dx24"H TRASH RACK - - - - - EMERGENCY SPILLWAY ELEV.= 568.6' RAISE TO NEW CREST NEW ORIFICES (5) I►�, V77 4.75"Hx12"W I I (I ( 1 1 I I I 11 _PINV.=567.2' PLUG { { { { F NEW 3" ORIFICE INV= 565.2' ��`3"� { 41.6± LF OF 18" CMP OUT, PIPE INV.= I lil -'I--��i-�� =r T- - - - - 563.5' - I I _� �. �' - �-,-�T' � � III I 11- ►�► � - -_ �h- � --- C IM 54 5.0±'- 54" CONCRETE BASE ANCHOR STAND PIPE TO PREVENT FLOATING STORMWATER MANAGEMENT BASIN NTS GRASS SPILWAY 100 YEAR FLOW ELEV.= 569.17' -) TOP OF BERM=570.1 171 I . EC -3C I�ER�) I! + ( (CREST i LEV=S (8I6I - I _ COMPACTED SOIL EMER GENCY SPILL WA Y NTS APPROVED by the Albemarle County Community Development Department Date 1-1/1, (2 j ►S File w ro?,-otS60j0 - o C0M U Yui Q) N V) //s�• °� rn a w __ •L w �� U 3 rn o W� LLJ Cm 11.4 n (4 T O --- c; .0 � w O 2 a i Date: 11-24-15 O x aW Q a Scale: AS NOTED J C.- , 4¢04 Z Designed by: EHB 0 0 Z Drawn by: EHB O >_ a Checked by: EHB CL 0 - o C0M U Yui Q) N V) //s�• °� rn a w __ •L w �� U 3 rn o W� LLJ Cm 11.4 n (4 T O --- c; .0 � w O 2 a i Revision Dates O x aW Q a W 0� �Nvo 3 J C.- , 4¢04 Revision Dates Drawing No. SWM 1 of Sheets IJob No.!I H Z 0 0 Z O >_ a CL 0 I.. w W Z LLJ W M V-) LLJ LL. Q Q OWE Q Q I- 3 0 W Z p (r) a =Z' 0 O <W (� > O O :DW m n Lv to to W W I-' - z O 0 O V) U W 2 I -- Drawing No. SWM 1 of Sheets IJob No.!I