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HomeMy WebLinkAboutWPO201800001 Calculations 2018-06-11 Albemarle County __ , Virginia Engineering Manual for Rivanna Community Church Drainage Calculations SDP-201300056 Sixth Site Plan Submittal: November 30, 2017 Seventh Site Plan Submittal: June 1, 2018 o��tipLTH OF r G p EDMOND H. , U BLACKWELL Y „o Lic.No.023831 IDNAL ti� APPROVED by the Albemarle County ComDate �l //Department File L2PD ?M WoO) Blackwell Engineering PLC 566 East Market Street Harrisonburg, VA 22801 Ph. (540)432-9555 Fax(540)434-7604 Blackwellengineering.com BE# 2346 Table of Contents Description Page Project Overview 1 Time of Concentration and Runoff Calculations 2-3 VDOT Storm Drain Design Forms 4-6 Hydrograph Tabulation 7 Energy Balance Calculation 8 SWM Hydrographs 9-29 Drainage Area Map 30 PROJECT OVERVIEW PROJECT DESCRIPTION The purpose of this project is the construction of a 250-seat Sanctuary, Fellowship Hall, removal of an existing entrance on Earlysville Road and a portion of the adjacent parking lot, a new moderate-volume two-way commercial entrance on Earlysville Forest Drive, addition to the existing parking lot, landscaping and the modification of the existing dry detention pond that lies on two adjacent parcels,TM 31-32 and TM 31A-A. The site is located in Albemarle County, Virginia at the northwest corner of the intersection of State Route 743 (Earlysville Road) and Earlysville Forest Drive. 1 File:2346 Tc 3.xlsx Printed:5/31/2018 Runoff Calculations - Rational Method Existing Drainage to As-Built Pond at Underground Detention Discharge 1.) Area= 2.43 ac Project Name: Rivanna Community Chruch Project# : 2346 CN for HSG: B 2.) C = 0.45 0.00 ac @ 0.25 Wooded 55 CN = 70 1.81 ac @ 0.30 Open Grass 61 0.62 ac @ 0.90 Impervious 98 3.) Time of Concentration Slope a. Overland: (200' max) L= 125 ft. Height= 7.5 ft. 6.0% VDOT Drainage Manual Appendix 6D-1:Tc= 12.0 min. b. Shallow: (1000' max) L= ft. Height= ft. Average velocity= fps (paved) VDOT Drainage Manual Appendix 6D-6: Tc= min. L= 260 ft. Height= 14 ft. 5.4% Average velocity= 3.7 fps (unpaved) VDOT Drainage Manual Appendix 6D-6: Tc= 1.2 min. Tc = U60V Subtotal T,= 1.2 min. c. Channel: L= ft. Height= ft.(paved) VDOT Drainage Manual Appendix 6D-5: Tc= min. L= 35 ft. Height= 10 ft.(unpaved; 28.6% VDOT Drainage Manual Appendix 6D-5: Tc= 0.2 min. Subtotal Tc= 0.2 min. d. Total Tc: Tc= 13.4 min. 4.) Rainfall Intensities: For Tc= 13 min. 12 = 3.68 iph 125= 5.42 iph 110= 4.84 iph 1100 = 6.34 iph 5.) Proposed Flows: Q =ACI Q2 = 4.03 cfs Q25 = 5.93 cfs Q10= 5.29 cfs Q100= 6.93 cfs Blackwell Engineering, PLC 566 East Market Street Harrisonburg, VA 22801 2 File:2346 Tc 3.xlsx Printed:5/31/2018 Runoff Calculations - Rational Method Proposed Drainage to Underground Detention Inlet 1.) Area= 1.98 ac Project Name: Rivanna Community Chruch Project# : 2346 CN for HSG: B 2.) C = 0.51 0.00 ac @ 0.25 Wooded 55 CN = 74 1.29 ac @ 0.30 Open Grass 61 0.69 ac @ 0.90 Impervious 98 3.) Time of Concentration Slope a. Overland: (200' max) L= 125 ft. Height= 7.5 ft. 6.0% VDOT Drainage Manual Appendix 6D-1: To= 12.0 min. b. Shallow: (1000' max) L= ft. Height= ft. Average velocity= fps (paved) VDOT Drainage Manual Appendix 6D-6:To= min. L= 180 ft. Height= 5 ft. 2.8% Average velocity= 2.7 fps (unpaved) VDOT Drainage Manual Appendix 6D-6:To= 1.1 min. To= L/60V Subtotal To= 1.1 min. c. Channel: L= ft. Height= ft.(paved) VDOT Drainage Manual Appendix 6D-5: To= min. L= ft. Height= ft.(unpaved; VDOT Drainage Manual Appendix 6D-5: To= 0.0 min. Subtotal To= 0.0 min. d. Total To: To= 13.1 min. 4.) Rainfall Intensities: For To= 13 min. 12 = 3.68 iph 125 = 5.42 iph Ito = 4.84 iph I1oo= 6.34 iph 5.) Proposed Flows: Q =ACI Q2 = 3.72 cfs Q25 = 5.47 cfs Q10 = 4.88 cfs Q100= 6.40 cfs Blackwell Engineering, PLC 566 East Market Street Harrisonburg,VA 22801 3 File:2347 VDOT LD-229 05-2018.xIs Printed:6/1/2018 STORM SEWER DESIGN COMPUTATIONS LD-229 Rivanna Community Church AREA RUNOFF CA INLET RAIN RUNOFF INVERT CAPA- FLOW FROM TO DRAIN COEF INCRE ACCUM TIME FALL Q ELEVATIONS LENGTH SLOPE DIAM CITY VEL TIME POINT POINT ACRES C MENT ULATED Tc,min IN/HR CFS UPPER LOWER FT FT/FT IN CFS FPS SEC 3 2 0.25 0.61 0.15 0.15 5.00 6.67 1.02 629.00 626.07 173.71 0.0169 12" 4.64 1.29 134.1 2 1 0 0 0.00 0.15 7.24 6.07 0.93 626.07 624.95 66.24 0.0169 12" 4.64 1.18 56.2 Note: Mannings"n" adjusted for pipe type and diameter. File:2347 VDOT LD-229 05-2018.xls Printed:6/1/2018 HYDRAULIC GRADE LINE LD-347 Rivanna Community Church JUNCTION LOSS INLET Outlet Sfo Viz Angle 1.3 0.5 Final Inlet Rim # WSE Do R. Lo % Hf Vo Ho Q, V, Q;V, 2g H, K HD Ht Ht HL H WSE Elev. 3 626.87 12" 1.0 174' 0.08 0.14 1.29 0.01 - - - - - - - 0.01 0.01 - 0.15 627.02 631.66 2 627.02 12" 0.9 66' 0.07 0.05 1.18 0.01 1.0 1.29 1.32 0.03 0.01 0.43 0.01 0.03 0.03 - 0.08 627.10 630.00 Mannings"n"= 0.013 90° K=0.70 70° K=0.61 50° K=0.47 30° K=0.28 20° K=0.16 80° K=0.66 60° K=0.55 40° K=0.38 25° K=0.22 15° K=0.10 U, File:2347 VDOT LD-229 05-2018.xls Printed:6/1/2018 STORMWATER INLET COMPUTATIONS LD-204 Rivanna Community Church INLET DA Q QT S Sx P SAG INLETS ONLY DRAIN E Q CARRY GUTTER GUTTER CROSS T S'W Se EFFEC Q (lb T No. TYPE LENGTH AREA C CA CA I INCR OVER FLOW SLOPE SLOPE SPREAD W WIT SW SWISx EO a =a/(12W) =Sx+S'wE0 LT LENGTH LILT E INTERCEPT CARRYOVER d h dlh SPREAD (FT) (AC) (INIHR) (CFS) (CFS) (CFS) (FT/FT) (FT/FT) (FT) (FT) (FT/FT) (FT/FT) (FT/FT) (FT) (FT) (CFS) (CFS) (FT) (FT) (FT) 3 Yard Inlet YI-1 0.25 0.61 0.15 0.15— 4.00 0.61 0.00 0.61 Weir 0.06 rn RIVANNA COMMUNITY CHURCH BE#2346 Hydrograph Summary of SCS Analysis of Existing As-Built Dry Detention Pond on TMP 31A-A and TMP 31-32 Flow to As-Built Pond at Point of Analysis:Toe of Slope in Pond at Discharge of Underground Detention 1-Yr 2-Yr 10-Yr 100-Yr Condition Hydrograph (cfs) (cfs) (cfs) (cfs) Pre-Developed 1 4.972 6.761 12.22 22.60 Post-Developed 3 1.412 2.299 5.692 13.46 Pristine Forest 4 0.198 — — — Increase (+)/ Decrease (-) -4.462 -6.528 -9.14 7 9VAC25-870-66.B.3 Natural Stormwater Conveyance Systems PROJECT NAME: RIVANNA COMMUNITY CHURCH BE#2346 1-year 24-hour storm event Hydrologic soil group= B CN = 55 Forest Q Developed< I.F. X (Q Pre-Developed x RV Pre-Developed)/RV Developed QDeveloped (Allowable)= 13.40 cfs (maximum allowable) Oa Forest X RV Forest)/RV Developed= 0.09 cfs (maximum requirable lower limit) I.F. (Improvement Factor)= 0.8 Site Area = 1.98 acres (Disturbed and Offsite Tributary) CI Developed= 1.412 cfs (Hydrograph 3 ) RV Developed= 3,729 cf CI Pre-Developed= 4.972 cfs (Hydrograph 1 ) RV pre-Developed= 12,561 cf CI Forest= 0.198 cfs (Hydrograph 4) RV Forest= 1,691 cf 8 Watershed Model Schematic Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 1 -Ex.Drainage to As-Built Pond 2-Prop.Drainage to UG Detention V 4-Pristine Forest 3-Pipe Detention Legend I L ri i Description 1 SCS Runoff Ex.Drainage to As-Built Pond 2 SCS Runoff Prop.Drainage to UG Detention 3 Reservoir Pipe Detention 4 SCS Runoff Pristine Forest Project: 2346 As Built Pond w Pipe Detention.gpw Tuesday, 05/22/2018 9 Hydraflow Rainfall Report 'iydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 2 49.0200 10.5000 0.8200 3 0.0000 0.0000 0.0000 5 55.7100 11.5000 0.8000 10 46.9500 9.5000 0.7300 ------- 25 40.1100 7.7500 0.6600 50 35.6800 6.5000 0.6100 100 31.0900 5.0000 0.5500 File name:Albemarle.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 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 5.18 4.12 3.44 2.97 2.63 2.36 2.14 1.97 1.82 1.70 1.59 1.50 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 5.91 4.79 4.05 3.53 3.13 2.83 2.58 2.38 2.21 2.06 1.94 1.83 10 6.67 5.37 4.55 3.97 3.54 3.21 2.94 2.72 2.54 2.38 2.24 2.12 25 7.48 6.01 5.10 4.47 4.01 3.65 3.36 3.13 2.93 2.76 2.61 2.48 50 8.04 6.45 5.49 4.83 4.35 3.98 3.68 3.43 3.22 3.05 2.89 2.76 100 8.76 7.01 5.98 5.29 4.79 4.40 4.09 3.83 3.62 3.43 3.27 3.13 Tc=time in minutes.Values may exceed 60. Precip.file name:Z:\Civil\Library\Civil Software Data\Hydraflow\2008 IDF&PCP Files\Albemarle Zone 2.pcp Rainfall Precipitation Table(in) Storm 1 Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 3.00 3.63 0.00 4.63 5.48 6.72 7.79 8.96 SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1-luff-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 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10 Hydrograph Return Period Recap y ow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 rd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph .... type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff 4.972 6.761 ------ 12.22 ----- 22.60 Ex.Drainage to As-Built Pond 2 SCS Runoff 1.260 2.235 ------ 5.690 13.46 Prop.Drainage to UG Detention 3 Reservoir 2 1.412 2.299 ------ 5.692 13.46 Pipe Detention 4 SCS Runoff ----- 0.198 0.776 ----- ---- 3.787 ----- 11.74 Pristine Forest Proj.file: 2346 As Built Pond w Pipe Detention.gpw Tuesday, 05/22/2018 11 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 rd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph ..�. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 6.761 1 721 17,092 Ex.Drainage to As-Built Pond 2 SCS Runoff 2.235 1 722 6,169 Prop.Drainage to UG Detention 3 Reservoir 2.299 1 722 6,043 2 622.57 133 Pipe Detention 4 SCS Runoff 0.776 1 724 3,392 ----- ----- Pristine Forest 2346 As Built Pond w Pipe Detention.gpw Return Period: 2 Year Tuesday, 05/22/2018 12 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Friday,06/1 /2018 Hyd. No. 1 Ex. Drainage to As-Built Pond Hydrograph type = SCS Runoff Peak discharge = 4.972 cfs Storm frequency = 1 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 12,561 cuft Drainage area = 2.430 ac Curve number = 83* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.00 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.810 x 61)+(0.620 x 98)]/2.430 Ex. Drainage to As-Built Pond Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs) 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 — - • - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 1 13 Hydrograph Report -lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Friday,06/1 /2018 Hyd. No. 2 Prop. Drainage to UG Detention Hydrograph type = SCS Runoff Peak discharge = 1.260 cfs Storm frequency = 1 yrs Time to peak = 723 min Time interval = 1 min Hyd. volume = 3,855 cuft Drainage area = 1.980 ac Curve number = 66* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.00 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.290 x 61)+(0.690 x 98)]/1.980 Prop. Drainage to UG Detention Q (cfs) Hyd. No. 2-- 1 Year Q (cfs) 2.00 2.00 1.00 1.00 1 0.00 L - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 2 14 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Friday,06/1 /2018 Hyd. No. 3 Pipe Detention Hydrograph type = Reservoir Peak discharge = 1.412 cfs Storm frequency = 1 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 3,729 cuft Inflow hyd. No. = 2 - Prop. Drainage to UG DeteMisct Elevation = 622.60 ft Reservoir name = 48 inch Pipe Detention Max. Storage = 131 cuft Storage Indication method used. Pipe Detention Q (cfs) Hyd. No. 3-- 1 Year Q(cfs) 2.00 2.00 1.00 1.00 0.00 - - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 3 Hyd No. 2 11 1 1 1 1 1 0 Total storage used = 131 cuft 15 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Hyd. No. 4 Pristine Forest Hydrograph type = SCS Runoff Peak discharge = 0.198 cfs Storm frequency = 1 yrs Time to peak = 726 min Time interval = 1 min Hyd. volume = 1,691 cuft Drainage area = 2.430 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.00 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Pristine Forest Q (cfs) Hyd. No. 4-- 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 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 4 16 Pond Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Pond No. 6- 48 inch Pipe Detention Pond Data UG Chambers-Invert elev.=620.40 ft, Rise x Span=4.00 x 4.00 ft, Barrel Len=20.00 ft, No.Barrels=1, Slope=0.00%, Headers=No Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 620.40 n/a 0 0 0.40 620.80 n/a 13 13 0.80 621.20 n/a 23 36 1.20 621.60 n/a 28 63 1.60 622.00 n/a 30 94 2.00 622.40 n/a 32 126 2.40 622.80 n/a 32 158 2.80 623.20 n/a 30 188 3.20 623.60 n/a 28 216 3.60 624.00 n/a 23 238 4.00 624.40 n/a 13 251 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 12.00 4.00 0.00 0.00 Crest Len(ft) = 3.93 0.00 0.00 0.00 Span(in) = 12.00 4.00 0.00 0.00 Crest El.(ft) = 623.40 0.00 0.00 0.00 No.Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 619.40 621.40 0.00 0.00 Weir Type = 1 --- --- --- Length(ft) = 111.00 0.00 0.00 0.00 Multi-Stage = Yes No No No Slope(%) = 46.80 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Wet area) Multi-Stage = n/a No No 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) 5.00 625.40 4.00 624.40 3.00 623.40 2.00 622.40 1.00 621.40 0.00 620.40 0.00 7.00 14.00 21.00 28.00 35.00 42.00 49.00 56.00 63.00 70.00 77.00 Discharge(cfs) Total Q 17 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 .-Iyd. No. 1 Ex. Drainage to As-Built Pond Hydrograph type = SCS Runoff Peak discharge = 6.761 cfs Storm frequency = 2 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 17,092 cuft Drainage area = 2.430 ac Curve number = 83* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.63 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.810 x 61)+(0.620 x 98)]/2.430 Ex. Drainage to As-Built Pond Q (cfs) Hyd. No. 1 --2 Year Q (cfs) 7.00 7.00 6.00 6.00 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 — 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 1 18 Hydrograph Report 'lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 dyd. No. 2 Prop. Drainage to UG Detention Hydrograph type = SCS Runoff Peak discharge = 2.235 cfs Storm frequency = 2 yrs Time to peak = 722 min Time interval = 1 min Hyd. volume = 6,169 cuft Drainage area = 1.980 ac Curve number = 66* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 3.63 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.290 x 61)+(0.690 x 98)]/1.980 Prop. Drainage to UG Detention 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 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 2 19 Hydrograph Report 'lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 rlyd. No. 3 Pipe Detention Hydrograph type = Reservoir Peak discharge = 2.299 cfs Storm frequency = 2 yrs Time to peak = 722 min Time interval = 1 min Hyd. volume = 6,043 cuft Inflow hyd. No. = 2 - Prop. Drainage to UG DeteMise Elevation = 622.57 ft Reservoir name = 48 inch Pipe Detention Max. Storage = 133 cuft Storage Indication method used. Pipe Detention Q (cfs) Hyd. No. 3--2 Year Q (cfs) 3.00 3.00 2.00 2.00 _ _ l 1.00 1.00 0.00 — 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 3 Hyd No. 2 II 1 1 1 1 1 V Total storage used = 133 cult 20 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 d. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph rlu. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 12.22 1 721 31,359 ----- ---- Ex.Drainage to As-Built Pond 2 SCS Runoff 5.690 1 722 14,590 ---- ----- Prop.Drainage to UG Detention 3 Reservoir 5.692 1 722 14,465 2 622.56 138 Pipe Detention 4 SCS Runoff 3.787 1 722 10,667 ----- Pristine Forest 2346 As Built Pond w Pipe Detention.gpw Return Period: 10 Year Tuesday, 05/22/2018 21 Hydrograph Report 'lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 rlyd. No. 1 Ex. Drainage to As-Built Pond Hydrograph type = SCS Runoff Peak discharge = 12.22 cfs Storm frequency = 10 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 31,359 cuft Drainage area = 2.430 ac Curve number = 83* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 5.48 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 "Composite(Area/CN)=[(1.810 x 61)+(0.620 x 98)]/2.430 Ex. Drainage to As-Built Pond Q (cfs) Hyd. No. 1 -- 10 Year Q(cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 , 2.00 \ ---------.' ' 0.00 — - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 1 22 Hydrograph Report .iydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 dyd. No. 2 Prop. Drainage to UG Detention Hydrograph type = SCS Runoff Peak discharge = 5.690 cfs Storm frequency = 10 yrs Time to peak = 722 min Time interval = 1 min Hyd. volume = 14,590 cuft Drainage area = 1.980 ac Curve number = 66* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 5.48 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.290 x 61)+(0.690 x 98)]/1.980 Prop. Drainage to UG Detention Q (cfs) Hyd. No. 2-- 10 Year Q (cfs) 6.00 6.00 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 — - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time(min) 23 Hydrograph Report 'iydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Hyd. No. 3 Pipe Detention Hydrograph type = Reservoir Peak discharge = 5.692 cfs Storm frequency = 10 yrs Time to peak = 722 min Time interval = 1 min Hyd. volume = 14,465 cuft Inflow hyd. No. = 2 - Prop. Drainage to UG DeteMian Elevation = 622.56 ft Reservoir name = 48 inch Pipe Detention Max. Storage = 138 cuft Storage Indication method used. Pipe Detention Q (cfs) Hyd. No. 3-- 10 Year Q (cfs) 6.00 6.00 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 3 Hyd No. 2 I 1 1 1 1 1 Total storage used = 138 cuft 24 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 d. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph NO. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 22.60 1 721 59,896 ----- Ex.Drainage to As-Built Pond 2 SCS Runoff 13.46 1 721 34,009 ----- Prop.Drainage to UG Detention 3 Reservoir 13.46 1 721 33,884 2 622.68 148 Pipe Detention 4 SCS Runoff 11.74 1 721 30,036 ---- Pristine Forest 2346 As Built Pond w Pipe Detention.gpw Return Period: 100 Year Tuesday, 05/22/2018 25 Hydrograph Report 'iydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Hyd. No. 1 Ex. Drainage to As-Built Pond Hydrograph type = SCS Runoff Peak discharge = 22.60 cfs Storm frequency = 100 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 59,896 cuft Drainage area = 2.430 ac Curve number = 83* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 8.96 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.810 x 61)+(0.620 x 98)]/2.430 Ex. Drainage to As-Built Pond Q (cfs) Hyd. No. 1 -- 100 Year Q(cfs) 24.00 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 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 1 26 Hydrograph Report '-lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Hyd. No. 2 Prop. Drainage to UG Detention Hydrograph type = SCS Runoff Peak discharge = 13.46 cfs Storm frequency = 100 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 34,009 cuft Drainage area = 1.980 ac Curve number = 66* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 13.00 min Total precip. = 8.96 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 *Composite(Area/CN)=[(1.290 x 61)+(0.690 x 98)]/1.980 Prop. Drainage to UG Detention Q (cfs) Hyd. No. 2-- 100 Year Q (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 { 6.00 4.00 4.00 2.00 - 2.00 J. ...,_ 0.00 — ` - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time(min) 27 Hydrograph Report 'iydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 rlyd. No. 3 Pipe Detention Hydrograph type = Reservoir Peak discharge = 13.46 cfs Storm frequency = 100 yrs Time to peak = 721 min Time interval = 1 min Hyd. volume = 33,884 cuft Inflow hyd. No. = 2 - Prop. Drainage to UG DeteC4von Elevation = 622.68 ft Reservoir name = 48 inch Pipe Detention Max. Storage = 148 cuft Storage Indication method used. Pipe Detention Q (cfs) Hyd. No. 3-- 100 Year Q (cfs) 14.00 I 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 — — 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 3 Hyd No. 2 II I I I I I I Total storage used = 148 cult 28 Hydraflow Rainfall Report 'lydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v12 Tuesday,05/22/2018 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 2 49.0200 10.5000 0.8200 3 0.0000 0.0000 0.0000 5 55.7100 11.5000 0.8000 10 46.9500 9.5000 0.7300 ------ 25 40.1100 7.7500 0.6600 50 35.6800 6.5000 0.6100 ------- 100 31.0900 5.0000 0.5500 ------- File name:Albemarle.IDF Intensity= B/(Tc + D)AE Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 5.18 4.12 3.44 2.97 2.63 2.36 2.14 1.97 1.82 1.70 1.59 1.50 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 5.91 4.79 4.05 3.53 3.13 2.83 2.58 2.38 2.21 2.06 1.94 1.83 10 6.67 5.37 4.55 3.97 3.54 3.21 2.94 2.72 2.54 2.38 2.24 2.12 25 7.48 6.01 5.10 4.47 4.01 3.65 3.36 3.13 2.93 2.76 2.61 2.48 50 8.04 6.45 5.49 4.83 4.35 3.98 3.68 3.43 3.22 3.05 2.89 2.76 100 8.76 7.01 5.98 5.29 4.79 4.40 4.09 3.83 3.62 3.43 3.27 3.13 Tc=time in minutes.Values may exceed 60. Precip.file name:Z:\Civil\Library\Civil Software Data\Hydraflow\2008 IDF&PCP Files\Albemarle Zone 2.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 3.00 3.63 0.00 4.63 5.48 6.72 7.79 8.96 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 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 29 \ \ ZTDA 59,4C 7_— _ 9 EcTt/NG /r.a act X/RY OfF/N A TEASL /Y�/S 60 4 Ect Dt7ZWT�QNP©NO sus Ecf r I I I I \ RIVANNA COMMUNITY i I I CHURCH I I I ri TMP 31-32 � �-•„•-..__— � ��`_ —== /_ / /yam < i" I I I I I ( ( PRO DA 1 I I I I I I f I q 1,98 AC � � _rill / ——___—� II `� •moo d.� I Ii II �/ OS 11!_ I III j I \ �\/ , � �I I ff lI� PRO DA 2 6� I I �0 � � �' o.00 AC '' 0 rr ,, PATH OF TRAVEL i i I l s 'U �J 14 32 � I I ROGER W. PERKINS F! �! / TMP 31A—A I DRAINAGE DIVIDE lllif 11 1 J % I ` �4F / fr:; ;s::5::::^.. 633.1 I o ::.:::; " -. _:>;::. III I •� TT - Jill I PRO DA 3! ��— — — — — — EARLYSVILLE ROAD \ _ CLASSIFICATION: URBAN COLLECTOR f MOP/ � BLACKWELL ENGINEERING, 566 East Market Street PLC Harrisonburg, Virginia 22801 Phone: (540) 432-9555 BE®BlackwellEngineering.com Fax: (540) 434-7604 Date: OCT 2013 Revision Date DEC 2014, JUL 2015 SEP 2017 MAY 2018 Designed by: Scale: TBF ' Drawn by: 1 "=50 TBF Job No. 2346 p���ALTH Op t L p EDMOND H. CU BLACKWELL Y ,d Lic. No.023831 w NAL GRAPHIC SCALE 50' 0 50' 100' SCALE: 1 "=50' DRAINAGE AREA MAP RIVANNA COMMUNITY CHURCH 601 EARLYSVILLE GREEN EARLYSVILLE, VA 22936 Drawing No. of 1 Sheets