Supporting Documentation · Jul 30, 2024
Revised Stormwater Management Report
69ec9df8b1f4567abd2a92749a074a179a57821dd07f0cd16dd61242156a3c29Indexed text
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 34 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 53S: Basin 9 - Imp Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.80 0.03 0.00 1.60 0.06 0.00 2.40 0.10 0.01 3.20 0.14 0.03 4.00 0.18 0.06 4.80 0.22 0.09 5.60 0.27 0.12 6.40 0.32 0.16 7.20 0.38 0.21 8.00 0.45 0.27 8.80 0.52 0.34 9.60 0.62 0.43 10.40 0.75 0.55 11.20 0.96 0.75 12.00 1.65 1.43 12.80 2.48 2.25 13.60 2.69 2.46 14.40 2.82 2.59 15.20 2.92 2.68 16.00 2.99 2.76 16.80 3.06 2.83 17.60 3.12 2.89 18.40 3.17 2.94 19.20 3.22 2.98 20.00 3.26 3.03 20.80 3.30 3.07 21.60 3.34 3.11 22.40 3.38 3.14 23.20 3.41 3.18 24.00 3.44 3.21 24.80 3.44 3.21 25.60 3.44 3.21 26.40 3.44 3.21 27.20 3.44 3.21 28.00 3.44 3.21 28.80 3.44 3.21 29.60 3.44 3.21 30.40 3.44 3.21 31.20 3.44 3.21 32.00 3.44 3.21 32.80 3.44 3.21 33.60 3.44 3.21 34.40 3.44 3.21 35.20 3.44 3.21 36.00 3.44 3.21 36.80 3.44 3.21 37.60 3.44 3.21 38.40 3.44 3.21 39.20 3.44 3.21 40.00 3.44 3.21 Runoff (cfs) 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.03 0.03 0.05 0.06 0.12 0.60 0.15 0.07 0.05 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Time Precip. Excess (hours) (inches)
05 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Time Precip. Excess (hours) (inches) (inches) 40.80 3.44 3.21 41.60 3.44 3.21 42.40 3.44 3.21 43.20 3.44 3.21 44.00 3.44 3.21 44.80 3.44 3.21 45.60 3.44 3.21 46.40 3.44 3.21 47.20 3.44 3.21 48.00 3.44 3.21 48.80 3.44 3.21 49.60 3.44 3.21 50.40 3.44 3.21 51.20 3.44 3.21 52.00 3.44 3.21 52.80 3.44 3.21 53.60 3.44 3.21 54.40 3.44 3.21 55.20 3.44 3.21 56.00 3.44 3.21 56.80 3.44 3.21 57.60 3.44 3.21 58.40 3.44 3.21 59.20 3.44 3.21 60.00 3.44 3.21 60.80 3.44 3.21 61.60 3.44 3.21 62.40 3.44 3.21 63.20 3.44 3.21 64.00 3.44 3.21 64.80 3.44 3.21 65.60 3.44 3.21 66.40 3.44 3.21 67.20 3.44 3.21 68.00 3.44 3.21 68.80 3.44 3.21 69.60 3.44 3.21 70.40 3.44 3.21 71.20 3.44 3.21 72.00 3.44 3.21 72.80 3.44 3.21 73.60 3.44 3.21 74.40 3.44 3.21 75.20 3.44 3.21 76.00 3.44 3.21 76.80 3.44 3.21 77.60 3.44 3.21 78.40 3.44 3.21 79.20 3.44 3.21 80.00 3.44 3.21 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 35 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 54S: Basin 9 - Perv Runoff = 0.33 cfs @ 12.15 hrs, Volume= Routed to Pond 42P : Basin 9 1,079 cf, Depth= 1.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-80.00 hrs, dt= 0.04 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) 2,537 6,379 8,916 8,916 Tc (min) 7.2 Length (feet) 100 0.2 40 7.4 140 CN 74 80 78 Description >75% Grass cover, Good, HSG C >75% Grass cover, Good, HSG D Weighted Average 100.00% Pervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) 0.1000 0.23 Sheet Flow, Sheet Flow (A-B) Grass: Dense n= 0.240 P2= 3.47" 0.0750 4.41 Shallow Concentrated Flow, SCF (B-C) Unpaved Kv= 16.1 fps Total Subcatchment 54S: Basin 9 - Perv Hydrograph 0.36 0.34 0.32 0.3 0.28 0.26 0.24 Flow (cfs) 0.22 0.2 0.18 0.16 0.14 0.12 0.1 Runoff 0.33 cfs NOAA 24-hr D 2-Year Rainfall=3.44" Runoff Area=8,916 sf Runoff Volume=1,079 cf Runoff Depth=1.45" Flow Length=140' Tc=7.4 min CN=78 0.08 0.06 0.04 0.02 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 Time (hours)
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 36 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 54S: Basin 9 - Perv Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.80 0.03 0.00 1.60 0.06 0.00 2.40 0.10 0.00 3.20 0.14 0.00 4.00 0.18 0.00 4.80 0.22 0.00 5.60 0.27 0.00 6.40 0.32 0.00 7.20 0.38 0.00 8.00 0.45 0.00 8.80 0.52 0.00 9.60 0.62 0.00 10.40 0.75 0.01 11.20 0.96 0.05 12.00 1.65 0.30 12.80 2.48 0.77 13.60 2.69 0.91 14.40 2.82 1.00 15.20 2.92 1.07 16.00 2.99 1.12 16.80 3.06 1.17 17.60 3.12 1.22 18.40 3.17 1.25 19.20 3.22 1.29 20.00 3.26 1.32 20.80 3.30 1.35 21.60 3.34 1.38 22.40 3.38 1.40 23.20 3.41 1.43 24.00 3.44 1.45 24.80 3.44 1.45 25.60 3.44 1.45 26.40 3.44 1.45 27.20 3.44 1.45 28.00 3.44 1.45 28.80 3.44 1.45 29.60 3.44 1.45 30.40 3.44 1.45 31.20 3.44 1.45 32.00 3.44 1.45 32.80 3.44 1.45 33.60 3.44 1.45 34.40 3.44 1.45 35.20 3.44 1.45 36.00 3.44 1.45 36.80 3.44 1.45 37.60 3.44 1.45 38.40 3.44 1.45 39.20 3.44 1.45 40.00 3.44 1.45 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.14 0.05 0.03 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Time Precip. Excess (hours) (inches)
02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Time Precip. Excess (hours) (inches) (inches) 40.80 3.44 1.45 41.60 3.44 1.45 42.40 3.44 1.45 43.20 3.44 1.45 44.00 3.44 1.45 44.80 3.44 1.45 45.60 3.44 1.45 46.40 3.44 1.45 47.20 3.44 1.45 48.00 3.44 1.45 48.80 3.44 1.45 49.60 3.44 1.45 50.40 3.44 1.45 51.20 3.44 1.45 52.00 3.44 1.45 52.80 3.44 1.45 53.60 3.44 1.45 54.40 3.44 1.45 55.20 3.44 1.45 56.00 3.44 1.45 56.80 3.44 1.45 57.60 3.44 1.45 58.40 3.44 1.45 59.20 3.44 1.45 60.00 3.44 1.45 60.80 3.44 1.45 61.60 3.44 1.45 62.40 3.44 1.45 63.20 3.44 1.45 64.00 3.44 1.45 64.80 3.44 1.45 65.60 3.44 1.45 66.40 3.44 1.45 67.20 3.44 1.45 68.00 3.44 1.45 68.80 3.44 1.45 69.60 3.44 1.45 70.40 3.44 1.45 71.20 3.44 1.45 72.00 3.44 1.45 72.80 3.44 1.45 73.60 3.44 1.45 74.40 3.44 1.45 75.20 3.44 1.45 76.00 3.44 1.45 76.80 3.44 1.45 77.60 3.44 1.45 78.40 3.44 1.45 79.20 3.44 1.45 80.00 3.44 1.45 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 37 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Summary for Pond 21P: Basin 3 Inflow Area = 51,670 sf, 62.76% Impervious, Inflow Depth = 2.46" for 2-Year event Inflow = 2.77 cfs @ 12.15 hrs, Volume= 10,588 cf Outflow = 1.87 cfs @ 12.25 hrs, Volume= 10,588 cf, Atten= 32%, Lag= 5.5 min Discarded = 1.21 cfs @ 12.00 hrs, Volume= 10,212 cf Primary = 0.66 cfs @ 12.25 hrs, Volume= 376 cf Routed to Pond 27P : Basin 2 Routing by Stor-Ind method, Time Span= 0.00-80.00 hrs, dt= 0.04 hrs Peak Elev= 559.36' @ 12.25 hrs Surf.Area= 5,227 sf Storage= 748 cf Plug-Flow detention time= 2.0 min calculated for 10,582 cf (100% of inflow) Center-of-Mass det. time= 2.0 min ( 781.5 - 779.5 ) Volume #1 Invert 559.00' Elevation (feet) 559.00 560.00 561.00 561.17 Device #1 #2 Avail.Storage 4,537 cf Surf.Area (sq-ft) 5,227 5,227 5,227 5,227 Routing Primary Discarded Invert 559.22' 559.00' Storage Description Custom Stage Data (Prismatic) Listed below 11,343 cf Overall x 40.0% Voids Inc.Store (cubic-feet) 0 5,227 5,227 889 Cum.Store (cubic-feet) 0 5,227 10,454 11,343 Outlet Devices 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 10.000 in/hr Exfiltration over Surface area Discarded OutFlow Max=1.21 cfs @ 12.00 hrs HW=559.02' (Free Discharge) 2=Exfiltration (Exfiltration Controls 1.21 cfs) Primary OutFlow Max=0.65 cfs @ 12.25 hrs HW=559.36' (Free Discharge) 1=Sharp-Crested Rectangular Weir (Weir Controls 0.65 cfs @ 1.20 fps)
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 38 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Pond 21P: Basin 3 Hydrograph 2.77 cfs Inflow Area=51,670 sf Peak Elev=559.36' Storage=748 cf 3 Inflow Outflow Discarded Primary 1.87 cfs Flow (cfs) 2 1.21 cfs 1 0.66 cfs 0 0 5 10 15 20 25 30 35 40 45 Time (hours) 50 55 60 65 70 75 80 Pond 21P: Basin 3 Stage-Discharge Total Discarded Primary Elevation (feet) 561 560 Sharp-Crested Rectangular Weir Exfiltration 559 0 5 10 15 20 Discharge (cfs) 25 30
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 39 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 21P: Basin 3 Time (hours) 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00 30.00 32.00 34.00 36.00 38.00 40.00 42.00 44.00 46.00 48.00 50.00 52.00 54.00 56.00 58.00 60.00 62.00 64.00 66.00 68.00 70.00 72.00 74.00 76.00 78.00 80.00 Inflow (cfs) 0.00 0.01 0.02 0.04 0.06 0.11 1.34 0.17 0.10 0.07 0.06 0.05 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Storage (cubic-feet) 0 0 1 1 2 4 52 6 4 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Elevation (feet) 559.00 559.00 559.00 559.00 559.00 559.00 559.02 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 559.00 Outflow (cfs) 0.00 0.01 0.02 0.04 0.06 0.11 1.21 0.17 0.10 0.07 0.06 0.05 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Discarded (cfs) 0.00 0.01 0.02 0.04 0.06 0.11 1.21 0.17 0.10 0.07 0.06 0.05 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Primary (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 40 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Stage-Discharge for Pond 21P: Basin 3 Elevation (feet) 559.00 559.05 559.10 559.15 559.20 559.25 559.30 559.35 559.40 559.45 559.50 559.55 559.60 559.65 559.70 559.75 559.80 559.85 559.90 559.95 560.00 560.05 560.10 560.15 560.20 560.25 560.30 560.35 560.40 560.45 560.50 560.55 560.60 560.65 560.70 560.75 560.80 560.85 560.90 560.95 561.00 561.05 561.10 561.15 Discharge (cfs) 0.00 1.21 1.21 1.21 1.21 1.28 1.50 1.82 2.20 2.64 3.12 3.65 4.22 4.82 5.46 6.12 6.82 7.54 8.30 9.07 9.87 10.69 11.53 12.40 13.28 14.18 15.10 16.03 16.99 17.96 18.94 19.94 20.95 21.98 23.02 24.07 25.14 26.21 27.30 28.40 29.51 30.63 31.76 32.90 Discarded (cfs) 0.00 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 Primary (cfs) 0.00 0.00 0.00 0.00 0.00 0.07 0.29 0.61 0.99 1.43 1.91 2.44 3.01 3.61 4.25 4.91 5.61 6.33 7.09 7.86 8.66 9.48 10.32 11.19 12.07 12.97 13.89 14.82 15.78 16.75 17.73 18.73 19.74 20.77 21.81 22.86 23.93 25.00 26.09 27.19 28.30 29.42 30.55 31.69
POA 2 proposed 2024-05-12 HydroCad - Proposed POA 2 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 6/29/2024 Page 41 HydroCAD® 10.20-5a s/n 06666 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 21P: Basin 3 Elevation (feet) 559.00 559.05 559.10 559.15 559.20 559.25 559.30 559.35 559.40 559.45 559.50 559.55 559.60 559.65 559.70 559.75 559.80 559.85 559.90 559.95 560.00 560.05 560.10 560.15 560.20 560.25 560.30 560.35 560.40 560.45 560.50 560.55 560.60 560.65 560.70 560.75 560.80 560.85 560.90 560.95 561.00 561.05 561.10 561.15 Surface (sq-ft) 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 5,227 Storage (cubic-feet) 0 105 209 314 418 523 627 732 836 941 1,045 1,150 1,254 1,359 1,464 1,568 1,673 1,777 1,882 1,986 2,091 2,195 2,300 2,404 2,509 2,614 2,718 2,823 2,927 3,032 3,136 3,241 3,345 3,450 3,554 3,659 3,763 3,868 3,973 4,077 4,182 4,286 4,391 4,495
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- Sep 29, 2026
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