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HomeMy WebLinkAboutWPO202000036 Study 2020-06-29SCALE ENGINEERING HYDRAULIC AND HYDROLOGICAL REPORT FOR AFTON STABLES TMP 70-37C1 ALBEMARLE COUNTY, VIRGINIA J U N E 29, 2020 OWNER: PETER AND ANGELA DOOLAN 7451 DICK WOODS ROAD AFTON, VA 22920 ENGINEER• 30 SCALE, LLC MICHAEL MYERS, PE, CFM 434-242-2866 MIKE@30CALE.COM LT 0 M I L F. S Lic. No. 33028 �0 06/29/2020 �sSIONAL ��� TABLE OF CONTENTS 1. PROJECT NARRATIVE 3 2. HYDROGRAPH KEY 4 3. HYDROGRAPH RECAP (1, 2, 10 AND 100-YEAR PEAK FLOWS) 5 4. TIME OF CONCENTRATION CALCULATIONS 6 5. NOAA ATLAS 14 PRECIPITATION FOR SITE 9 6. ONE-YEAR (100% AEP) 24-HOUR STORM HYDROGRAPHS 10 7. TWO-YEAR (50% AEP) 24-HOUR STORM HYDROGRAPHS 14 8. TEN-YEAR (10% AEP) 24-HOUR STORM HYDROGRAPHS 26 9. 100-YEAR (1% AEP) 24-HOUR STORM HYDROGRAPHS 38 PROJECT NARRATIVE THIS PURPOSE OF THIS VSMP PLAN SUBMITTAL IS TO OBTAIN GENERAL PERMIT COVERAGE FOR SITE DISTURBANCE THAT HAS ALREADY BEEN COMPLETED ONSITE. THE PLAN COVERS THE DISTURBED AREA THAT WAS THE RESPONSIBILITY OF THE CURRENT OWNERS WHO PURCHASED THE PROPERTY ON SEPTEMBER 20, 2017. THE OWNER WAS NOT AWARE OF THE REQUIREMENT FOR VSMP PERMIT COVERAGE AND IS SUBMITTING THIS PLAN RETROACTIVELY TO ACHIEVE COMPLIANCE. THIS PLAN INDICATES THE APPROXIMATE 3.55 ACRES OF AREA IN TOTAL THAT WILL BE DISTURBED TO INCLUDE THE COMPLETED CONSTRUCTION, AND THE INSTALLATION OF 3 LEVEL SPREADERS. THE PURPOSE OF THE LEVEL SPREADERS IS TO ELIMINATE ANY CONCENTRATED OUTFALLS FROM THE DISTURBED AREA. THIS WILL KEEP THE SITE IN COMPLIANCE WITH THE WATER QUANTITY REQUIREMENTS OF THE VSMP BECAUSE ALL RUNOFF WILL LEAVE THE CONSTRUCTION AREA VIA NON - EROSIVE SHEET FLOW. TO ADDRESS WATER QUALITY REQUIREMENTS, THE OWNERS WILL PURCHASE NUTRIENT CREDITS TO OFFSET THE APPROXIMATE 2.3 LBS/YEAR OF PHOSPHORUS REMOVAL REQUIRED. ALSO, APPROXIMATELY 0.56-AC OF CRITICAL SLOPES WERE INADVERTENTLY DISTURBED. THE OWNER IS SUBMITTING A SPECIAL EXCEPTION REQUEST TO ALLOW FOR MITIGATION OF THIS DISTURBANCE CONCURRENT WITH THE VSMP PLAN SUBMISSION. 00 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Legend Hvd. Origin Description 1 SCS Runoff EAST SIDE LS #1 2 SCS Runoff WEST SIDE LS #2 3 SCS Runoff WEST SIDE LS #3 5 SCS Runoff DITCH 1A - EAST 6 SCS Runoff DITCH 1 B -EAST 7 SCS Runoff DITCH 2A - EAST 8 SCS Runoff DITCH 2B - EAST 9 SCS Runoff DITCH 3 - EAST 10 SCS Runoff OVERLAND TO LS #1 12 Combine TOTAL TO DITCH 1A - EAST 13 Combine TOTAL TO DITCH 2A - EAST Project: AFTON SW M.gpw Monday, 06 / 29 / 2020 Hydrograph Return Period Recce draflow Hydrographs Extension for Autodesk®Civil 3D® by Autodesk, Inc. v2020 Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph No. type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff ------ 3.173 4.812 ------- ------- 10.21 ------- ------- 21.53 EAST SIDE LS #1 2 SCS Runoff ------ 4.242 6.179 ------- ------- 12.47 ------- ------- 25.19 WEST SIDE LS #2 3 SCS Runoff ------ 1.453 1.975 ------- ------- 3.570 ------- ------- 6.579 WEST SIDE LS #3 5 SCS Runoff ------ 0.082 0.210 ------- ------- 0.737 ------- ------- 1.990 DITCH 1A - EAST 6 SCS Runoff ------ 0.805 1.173 ------- ------- 2.367 ------- ------- 4.780 DITCH 1 B - EAST 7 SCS Runoff ------ 0.729 1.038 ------- ------- 2.033 ------- ------- 3.997 DITCH 2A - EAST 8 SCS Runoff ------ 0.260 0.388 ------- ------- 0.810 ------- ------- 1.683 DITCH 2B - EAST 9 SCS Runoff ------ 1.489 1.930 ------- ------- 3.223 ------- ------- 5.601 DITCH 3 - EAST 10 SCS Runoff ------ 0.101 0.282 ------- ------- 1.072 ------- ------- 2.977 OVERLAND TO LS #1 12 Combine 5, 6, 9, 2.346 3.271 ------- ------- 6.296 ------- ------- 12.36 TOTAL TO DITCH 1A - EAST 13 Combine 7, 8, 0.989 1.426 ------- ------- 2.843 ------- ------- 5.680 TOTAL TO DITCH 2A - EAST Proj. file: AFTON SWM.gpw Monday, 06 / 29 / 2020 TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 1 EAST SIDE LS #1 Description A B C Totals Sheet Flow Manning's n-value = 0.150 0.011 0.011 Flow length (ft) = 197.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.67 0.00 0.00 Land slope (%) = 14.70 0.00 0.00 Travel Time (min) = 7.09 + 0.00 + 0.00 = 7.09 Shallow Concentrated Flow Flow length (ft) = 0.00 0.00 0.00 Watercourse slope (%) = 0.00 0.00 0.00 Surface description = Paved Paved Paved Average velocity (ft/s) =0.00 0.00 0.00 Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00 Channel Flow X sectional flow area (sqft) = 1.50 0.00 0.00 Wetted perimeter (ft) = 3.00 0.00 0.00 Channel slope (%) = 12.30 0.00 0.00 Manning's n-value = 0.030 0.015 0.015 Velocity (ft/s) =10.95 0.00 0.00 Flow length (ft) ({0})252.0 0.0 0.0 Travel Time (min) = 0.38 + 0.00 + 0.00 = 0.38 Total Travel Time, Tc.............................................................................. 7.50 min TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 2 WEST SIDE LS #2 Description A B C Totals Sheet Flow Manning's n-value = 0.060 0.011 0.011 Flow length (ft) = 172.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.67 0.00 0.00 Land slope (%) = 2.60 0.00 0.00 Travel Time (min) = 6.11 + 0.00 + 0.00 = 6.11 Shallow Concentrated Flow Flow length (ft) = 126.00 0.00 0.00 Watercourse slope (%) = 1.20 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) =1.77 0.00 0.00 Travel Time (min) = 1.19 + 0.00 + 0.00 = 1.19 Channel Flow X sectional flow area (sqft) = 1.50 0.00 0.00 Wetted perimeter (ft) = 3.00 0.00 0.00 Channel slope (%) = 8.20 0.00 0.00 Manning's n-value = 0.030 0.015 0.015 Velocity (ft/s) =8.94 0.00 0.00 Flow length (ft) ({0})573.0 0.0 0.0 Travel Time (min) = 1.07 + 0.00 + 0.00 = 1.07 Total Travel Time, Tc.............................................................................. 8.40 min TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 3 WEST SIDE LS #3 Description A B C Totals Sheet Flow Manning's n-value = 0.050 0.011 0.011 Flow length (ft) = 245.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.67 0.00 0.00 Land slope (%) = 5.30 0.00 0.00 Travel Time (min) = 5.27 + 0.00 + 0.00 = 5.27 Shallow Concentrated Flow Flow length (ft) = 0.00 0.00 0.00 Watercourse slope (%) = 0.00 0.00 0.00 Surface description = Paved Paved Paved Average velocity (ft/s) =0.00 0.00 0.00 Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00 Channel Flow X sectional flow area (sqft) = 1.50 0.00 0.00 Wetted perimeter (ft) = 3.00 0.00 0.00 Channel slope (%) = 10.00 0.00 0.00 Manning's n-value = 0.030 0.015 0.015 Velocity (ft/s) =9.87 0.00 0.00 Flow length (ft) ({0})200.0 0.0 0.0 Travel Time (min) = 0.34 + 0.00 + 0.00 = 0.34 Total Travel Time, Tc.............................................................................. 5.60 min i f i, t Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to Peak (min) Hyd. volume (cuft) Inflow hyd(s) Maximum elevation (ft) Total strge used (cuft) Hydrograph Description 1 SCS Runoff 3.173 2 720 7,490 ------ ------ ------ EAST SIDE LS #1 2 SCS Runoff 4.242 2 720 9,817 ------ ------ ------ WEST SIDE LS #2 3 SCS Runoff 1.453 2 718 2,928 ------ ------ ------ WEST SIDE LS #3 5 SCS Runoff 0.082 2 722 344 ------ ------ ------ DITCH 1A - EAST 6 SCS Runoff 0.805 2 720 1,863 ------ ------ ------ DITCH I - EAST 7 SCS Runoff 0.729 2 720 1,675 ------ ------ ------ DITCH 2A - EAST 8 SCS Runoff 0.260 2 720 608 ------ ------ ------ DITCH 2B - EAST 9 SCS Runoff 1.489 2 718 3,432 ------ ------ ------ DITCH 3 - EAST 10 SCS Runoff 0.101 2 722 478 ------ ------ ------ OVERLAND TO LS #1 12 Combine 2.346 2 720 5,639 5, 6, 9, ------ ------ TOTAL TO DITCH 1A - EAST 13 Combine 0.989 2 720 2,284 7, 8, ------ ------ TOTAL TO DITCH 2A - EAST AFTON SWM.gpw Return Period: 1 Year Monday, 06 / 29 / 2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 1 EAST SIDE LS #1 Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 2.480 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.04 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.960 x 98) + (0.070 x 61) + (1.290 x 55)] / 2.480 Q (cfs) 4.00 3.00 2.00 1.00 0.00 0 120 240 Hyd No. 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor EAST SIDE LS #1 Hyd. No. 1 -- 1 Year 360 480 600 720 840 Monday, 06 / 29 / 2020 = 3.173 cfs = 720 min = 7,490 cuft = 72* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 4.00 3.00 2.00 1.00 0.00 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 2 WEST SIDE LS #2 Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 2.740 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.04 in Storm duration = 24 hrs Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #2 Monday, 06 / 29 / 2020 = 4.242 cfs = 720 min = 9,817 cuft = 75 = 0 ft = 8.40 min = Type II = 484 Q (cfs) Hyd. No. 2 -- 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 Hyd No. 2 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 3 WEST SIDE LS #3 Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 0.610 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.04 in Storm duration = 24 hrs Q (cfs) 2.00 1.00 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #3 Hyd. No. 3 -- 1 Year 120 240 360 480 600 720 840 960 Hyd No. 3 Monday, 06 / 29 / 2020 = 1.453 cfs = 718 min = 2,928 cuft = 82 = 0 ft = 5.60 min = Type II = 484 Q (cfs) 2.00 1.00 ' 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to Peak (min) Hyd. volume (cuft) Inflow hyd(s) Maximum elevation (ft) Total strge used (cuft) Hydrograph Description 1 SCS Runoff 4.812 2 720 11,105 ------ ------ ------ EAST SIDE LS #1 2 SCS Runoff 6.179 2 720 14,158 ------ ------ ------ WEST SIDE LS #2 3 SCS Runoff 1.975 2 716 3,994 ------ ------ ------ WEST SIDE LS #3 5 SCS Runoff 0.210 2 720 625 ------ ------ ------ DITCH 1A - EAST 6 SCS Runoff 1.173 2 720 2,687 ------ ------ ------ DITCH 1 B - EAST 7 SCS Runoff 1.038 2 720 2,375 ------ ------ ------ DITCH 2A - EAST 8 SCS Runoff 0.388 2 720 893 ------ ------ ------ DITCH 2B - EAST 9 SCS Runoff 1.930 2 718 4,488 ------ ------ ------ DITCH 3 - EAST 10 SCS Runoff 0.282 2 720 891 ------ ------ ------ OVERLAND TO LS #1 12 Combine 3.271 2 720 7,800 5, 6, 9, ------ ------ TOTAL TO DITCH 1A - EAST 13 Combine 1.426 2 720 3,269 7, 8, ------ ------ TOTAL TO DITCH 2A - EAST AFTON SWM.gpw Return Period: 2 Year Monday, 06 / 29 / 2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 1 EAST SIDE LS #1 Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 2.480 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.67 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.960 x 98) + (0.070 x 61) + (1.290 x 55)] / 2.480 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor EAST SIDE LS #1 Monday, 06 / 29 / 2020 = 4.812 cfs = 720 min = 11,105 cuft = 72* = 0 ft = 7.50 min = Type II = 484 Q (cfs) Hyd. No. 1 -- 2 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 Hyd No. 1 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 2 WEST SIDE LS #2 Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 2.740 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.67 in Storm duration = 24 hrs Q (cfs) 7.00 .IM 5.00 F 3.00 2.00 1.00 0.00 0 120 240 Hyd No. 2 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #2 Hyd. No. 2 -- 2 Year Monday, 06 / 29 / 2020 = 6.179 cfs = 720 min = 14,158 cuft = 75 = 0 ft = 8.40 min = Type II = 484 Q (cfs) 7.00 M 5.00 4.00 3.00 2.00 SK1111 0.00 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 3 WEST SIDE LS #3 Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.610 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 3.67 in Storm duration = 24 hrs Q (cfs) 2.00 1.00 w1 11 ' 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #3 Hyd. No. 3 -- 2 Year Monday, 06 / 29 / 2020 = 1.975 cfs = 716 min = 3,994 cuft = 82 = 0 ft = 5.60 min = Type II = 484 120 240 360 480 600 720 840 960 1080 1200 1320 Hyd No. 3 Q (cfs) 2.00 1.00 --" 0.00 1440 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 5 DITCH 1A - EAST Hydrograph type = SCS Runoff Peak discharge = 0.210 cfs Storm frequency = 2 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 625 cuft Drainage area = 0.330 ac Curve number = 58* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 7.50 min Total precip. = 3.67 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 . Composite (Area/CN) = [(0.020 x 98) + (0.310 x 55)] / 0.330 Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 DITCH 1A - EAST Hyd. No. 5 -- 2 Year Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 5 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 6 DITCH 1 B - EAST Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.520 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.67 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.230 x 98) + (0.210 x 55) + (0.080 x 61)] / 0.520 Q (cfs) 2.00 1.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 1 B - EAST Hyd. No. 6 -- 2 Year 120 240 360 480 600 720 840 960 Hyd No. 6 Monday, 06 / 29 / 2020 = 1.173 cfs = 720 min = 2,687 cuft = 75* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 2.00 1.00 Tom' ' 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 7 DITCH 2A - EAST Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.420 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.67 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.210 x 98) + (0.210 x 55)] / 0.420 Q (cfs) 2.00 1.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 2A - EAST Hyd. No. 7 -- 2 Year 120 240 360 480 600 720 840 960 Hyd No. 7 Monday, 06 / 29 / 2020 = 1.038 cfs = 720 min = 2,375 cuft = 77* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 2.00 1.00 ' 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 8 DITCH 2B - EAST Hydrograph type = SCS Runoff Peak discharge = 0.388 cfs Storm frequency = 2 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 893 cuft Drainage area = 0.190 ac Curve number = 73* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 7.50 min Total precip. = 3.67 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 . Composite (Area/CN) = [(0.080 x 98) + (0.110 x 55)] / 0.190 Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 DITCH 2113 - EAST Hyd. No. 8 -- 2 Year Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 8 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 9 DITCH 3 - EAST Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.510 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.67 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.400 x 98) + (0.110 x 55)] / 0.510 Q (cfs) 2.00 1.00 0.00 ' 1' 0 120 240 Hyd No. 9 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 3 - EAST Hyd. No. 9 -- 2 Year Monday, 06 / 29 / 2020 = 1.930 cfs = 718 min = 4,488 cuft = 88* = 0 ft = 7.50 min = Type II = 484 360 480 600 720 840 960 1080 1200 1320 Q (cfs) 2.00 1.00 — 0.00 1440 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 10 OVERLAND TO LS #1 Hydrograph type = SCS Runoff Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.510 ac Basin Slope = 0.0 % Tc method = User Total precip. = 3.67 in Storm duration = 24 hrs Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor OVERLAND TO LS #1 Hyd. No. 10 -- 2 Year Monday, 06 / 29 / 2020 = 0.282 cfs = 720 min = 891 cuft = 57 = 0 ft = 7.50 min = Type II = 484 Q (cfs) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hyd No. 10 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 12 TOTAL TO DITCH 1A - EAST Hydrograph type = Combine Peak discharge = 3.271 cfs Storm frequency = 2 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 7,800 cuft Inflow hyds. = 5, 6, 9 Contrib. drain. area = 1.360 ac TOTAL TO DITCH 1A - EAST Q (cfs) Hyd. No. 12 -- 2 Year Q (cfs) 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. 12 — Hyd No. 5 Hyd No. 6 Hyd No. 9 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 13 TOTAL TO DITCH 2A - EAST Hydrograph type = Combine Peak discharge = 1.426 cfs Storm frequency = 2 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 3,269 cuft Inflow hyds. = 7, 8 Contrib. drain. area = 0.610 ac TOTAL TO DITCH 2A - EAST Q (cfs) Hyd. No. 13 -- 2 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. 13 Hyd No. 7 Hyd No. 8 Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to Peak (min) Hyd. volume (cuft) Inflow hyd(s) Maximum elevation (ft) Total strge used (cuft) Hydrograph Description 1 SCS Runoff 10.21 2 718 23,384 ------ ------ ------ EAST SIDE LS #1 2 SCS Runoff 12.47 2 718 28,534 ------ ------ ------ WEST SIDE LS #2 3 SCS Runoff 3.570 2 716 7,347 ------ ------ ------ WEST SIDE LS #3 5 SCS Runoff 0.737 2 720 1,748 ------ ------ ------ DITCH 1A - EAST 6 SCS Runoff 2.367 2 718 5,415 ------ ------ ------ DITCH 1 B - EAST 7 SCS Runoff 2.033 2 718 4,658 ------ ------ ------ DITCH 2A - EAST 8 SCS Runoff 0.810 2 718 1,853 ------ ------ ------ DITCH 2B - EAST 9 SCS Runoff 3.223 2 718 7,693 ------ ------ ------ DITCH 3 - EAST 10 SCS Runoff 1.072 2 720 2,567 ------ ------ ------ OVERLAND TO LS #1 12 Combine 6.296 2 718 14,856 5, 6, 9, ------ ------ TOTAL TO DITCH 1A - EAST 13 Combine 2.843 2 718 6,511 7, 8, ------ ------ TOTAL TO DITCH 2A - EAST AFTON SWM.gpw Return Period: 10 Year Monday, 06 / 29 / 2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 1 EAST SIDE LS #1 Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 2.480 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 5.51 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.960 x 98) + (0.070 x 61) + (1.290 x 55)] / 2.480 Q (cfs) 12.00 10.00 4.00 2.00 0.00 ' ' 0 120 240 Hyd No. 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor EAST SIDE LS #1 Hyd. No. 1 -- 10 Year Monday, 06 / 29 / 2020 = 10.21 cfs = 718 min = 23,384 cuft = 72* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 12.00 10.00 4.00 2.00 0.00 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 2 WEST SIDE LS #2 Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 2.740 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 5.51 in Storm duration = 24 hrs Q (cfs) 14.00 12.00 10.00 NIM 4.00 2.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #2 Hyd. No. 2 -- 10 Year Monday, 06 / 29 / 2020 = 12.47 cfs = 718 min = 28,534 cuft = 75 = 0 ft = 8.40 min = Type II = 484 Q (cfs) 14.00 12.00 10.00 • 11 4.00 2.00 0.00 ' — ' ' ' ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 2 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 3 WEST SIDE LS #3 Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 0.610 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 5.51 in Storm duration = 24 hrs Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #3 Monday, 06 / 29 / 2020 = 3.570 cfs = 716 min = 7,347 cuft = 82 = 0 ft = 5.60 min = Type II = 484 Q (cfs) Hyd. No. 3 -- 10 Year Q (cfs) 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 Hyd No. 3 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 5 DITCH 1A - EAST Hydrograph type = SCS Runoff Peak discharge = 0.737 cfs Storm frequency = 10 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 1,748 cuft Drainage area = 0.330 ac Curve number = 58* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 7.50 min Total precip. = 5.51 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 . Composite (Area/CN) = [(0.020 x 98) + (0.310 x 55)] / 0.330 Q (cfs) 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 DITCH 1A - EAST Hyd. No. 5 -- 10 Year Q (cfs) 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 5 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 6 DITCH 1 B - EAST Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 0.520 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.51 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.230 x 98) + (0.210 x 55) + (0.080 x 61)] / 0.520 Q (cfs) 3.00 2.00 1.00 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 1 B - EAST Hyd. No. 6 -- 10 Year 120 240 360 480 600 720 840 960 Hyd No. 6 Monday, 06 / 29 / 2020 = 2.367 cfs = 718 min = 5,415 cuft = 75* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 3.00 2.00 1.00 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 7 DITCH 2A - EAST Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 0.420 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.51 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.210 x 98) + (0.210 x 55)] / 0.420 Q (cfs) 3.00 2.00 1.00 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 2A - EAST Hyd. No. 7 -- 10 Year 120 240 360 480 600 720 840 960 Hyd No. 7 Monday, 06 / 29 / 2020 = 2.033 cfs = 718 min = 4,658 cuft = 77* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 3.00 2.00 1.00 ' 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 8 DITCH 2B - EAST Hydrograph type = SCS Runoff Peak discharge = 0.810 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 1,853 cuft Drainage area = 0.190 ac Curve number = 73* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 7.50 min Total precip. = 5.51 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 . Composite (Area/CN) = [(0.080 x 98) + (0.110 x 55)] / 0.190 Q (cfs 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 DITCH 2113 - EAST Hyd. No. 8 -- 10 Year Q (cfs) 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.10 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 8 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 9 DITCH 3 - EAST Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 0.510 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.51 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.400 x 98) + (0.110 x 55)] / 0.510 Q (cfs) 4.00 3.00 2.00 1.00 0.00 ' 1' 0 120 240 Hyd No. 9 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor DITCH 3 - EAST Hyd. No. 9 -- 10 Year 360 480 600 720 840 960 Monday, 06 / 29 / 2020 = 3.223 cfs = 718 min = 7,693 cuft = 88* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 4.00 3.00 2.00 1.00 0.00 1080 1200 1320 1440 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 10 OVERLAND TO LS #1 Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 0.510 ac Basin Slope = 0.0 % Tc method = User Total precip. = 5.51 in Storm duration = 24 hrs Q (cfs) 2.00 1.00 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor OVERLAND TO LS #1 Hyd. No. 10 -- 10 Year 120 240 360 480 600 720 840 960 Hyd No. 10 Monday, 06 / 29 / 2020 = 1.072 cfs = 720 min = 2,567 cuft = 57 = 0 ft = 7.50 min = Type II = 484 Q (cfs) 2.00 1.00 0.00 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 12 TOTAL TO DITCH 1A - EAST Hydrograph type = Combine Peak discharge = 6.296 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 14,856 cuft Inflow hyds. = 5, 6, 9 Contrib. drain. area = 1.360 ac TOTAL TO DITCH 1A -EAST Q (cfs) Hyd. No. 12 -- 10 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. 12 Hyd No. 5 Hyd No. 6 Hyd No. 9 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Monday, 06 / 29 / 2020 Hyd. No. 13 TOTAL TO DITCH 2A - EAST Hydrograph type = Combine Peak discharge = 2.843 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 6,511 cuft Inflow hyds. = 7, 8 Contrib. drain. area = 0.610 ac TOTAL TO DITCH 2A - EAST Q (cfs) Hyd. No. 13 -- 10 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. 13 Hyd No. 7 Hyd No. 8 Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to Peak (min) Hyd. volume (cuft) Inflow hyd(s) Maximum elevation (ft) Total strge used (cuft) Hydrograph Description 1 SCS Runoff 21.53 2 718 49,687 ------ ------ ------ EAST SIDE LS #1 2 SCS Runoff 25.19 2 718 58,565 ------ ------ ------ WEST SIDE LS #2 3 SCS Runoff 6.579 2 716 14,006 ------ ------ ------ WEST SIDE LS #3 5 SCS Runoff 1.990 2 720 4,554 ------ ------ ------ DITCH 1A - EAST 6 SCS Runoff 4.780 2 718 11,114 ------ ------ ------ DITCH I - EAST 7 SCS Runoff 3.997 2 718 9,352 ------ ------ ------ DITCH 2A - EAST 8 SCS Runoff 1.683 2 718 3,891 ------ ------ ------ DITCH 2B - EAST 9 SCS Runoff 5.601 2 718 13,846 ------ ------ ------ DITCH 3 - EAST 10 SCS Runoff 2.977 2 720 6,813 ------ ------ ------ OVERLAND TO LS #1 12 Combine 12.36 2 718 29,515 5, 6, 9, ------ ------ TOTAL TO DITCH 1A - EAST 13 Combine 5.680 2 718 13,243 7, 8, ------ ------ TOTAL TO DITCH 2A - EAST AFTON SWM.gpw Return Period: 100 Year Monday, 06 / 29 / 2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 1 EAST SIDE LS #1 Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 2.480 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 8.93 in Storm duration = 24 hrs . Composite (Area/CN) = [(0.960 x 98) + (0.070 x 61) + (1.290 x 55)] / 2.480 Q (cfs) 24.00 16.00 12.00 :IM 4.00 0.00 0 120 240 Hyd No. 1 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor EAST SIDE LS #1 Hyd. No. 1 -- 100 Year Monday, 06 / 29 / 2020 = 21.53 cfs = 718 min = 49,687 cuft = 72* = 0 ft = 7.50 min = Type II = 484 Q (cfs) 24.00 20.00 16.00 12.00 4.00 r ' ' ' 0.00 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 2 WEST SIDE LS #2 Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 2.740 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 8.93 in Storm duration = 24 hrs Q (cfs) 28.00 24.00 20.00 16.00 12.00 ON 4.00 Peak discharge Time to peak Hyd. volume Curve number Hydraulic length Time of conc. (Tc) Distribution Shape factor WEST SIDE LS #2 Hyd. No. 2 -- 100 Year Monday, 06 / 29 / 2020 = 25.19 cfs = 718 min = 58,565 cuft = 75 = 0 ft = 8.40 min = Type II = 484 Q (cfs) 28.00 24.00 20.00 16.00 12.00 4.00 0.00 ' T ' ' ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Hyd No. 2 Time (min) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Hyd. No. 3 WEST SIDE LS #3 Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 0.610 ac Basin Slope = 0.0 % Tc method = TR55 Total precip. = 8.93 in Storm duration = 24 hrs Monday, 06 / 29 / 2020 Peak discharge = 6.579 cfs Time to peak = 716 min Hyd. volume = 14,006 cuft Curve number = 82 Hydraulic length = 0 ft Time of conc. (Tc) = 5.60 min Distribution = Type II Shape factor = 484 WEST SIDE LS #3 Q (cfs) Hyd. No. 3 -- 100 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 Hyd No. 3 Time (min)