Drainage Report

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 18S: OL-4 Runoff = 0.70 cfs @ 12.16 hrs, Volume= 0.056 af, Depth= 2.61" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.03 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) CN Description 301 98 Paved roads w/curbs & sewers, HSG C 10,972 74 >75% Grass cover, Good, HSG C 11,273 75 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.7 96 0.0573 0.18 Sheet Flow, Grass: Dense n= 0.240 P2= 3.44" Subcatchment 18S: OL-4 Hydrograph Runoff 0.75 0.70 cfs 0.7 NOAA 24-hr D 0.65 0.6 10-Year Rainfall=5.22" 0.55 Runoff Area=11,273 sf 0.5 Runoff Volume=0.056 af 0.45 Flow (cfs) 0.4 Runoff

Runoff Volume=0.056 af 0.45 Flow (cfs) 0.4 Runoff Depth=2.61" 0.35 Flow Length=96' 0.3 Slope=0.0573 '/' 0.25 0.2 Tc=8.7 min 0.15 CN=74/98 0.1 0.05 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 Time (hours)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 24 Hydrograph for Subcatchment 18S: OL-4 Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.09 0.00 0.01 0.00 3.00 0.20 0.00 0.07 0.00 4.50 0.31 0.00 0.16 0.00 6.00 0.45 0.00 0.27 0.00 7.50 0.61 0.00 0.42 0.00 9.00 0.83 0.00 0.63 0.00 10.50 1.17 0.05 0.96 0.02 12.00 2.50 0.61 2.27 0.30 13.50 4.05 1.63 3.82 0.07 15.00 4.39 1.89 4.16 0.04 16.50 4.61 2.06 4.37 0.03 18.00 4.77 2.19 4.54 0.02 19.50 4.91 2.29 4.67 0.02 21.00 5.02 2.38 4.79 0.02 22.50 5.13 2.47 4.89 0.01 24.00 5.22 2.54 4.98 0.01 25.50 5.22 2.54 4.98 0.00 27.00 5.22 2.54 4.98 0.00 28.50 5.22 2.54 4.98 0.00 30.00 5.22 2.54 4.98 0.00 31.50 5.22 2.54 4.98 0.00 33.00 5.22 2.54 4.98 0.00 34.50 5.22 2.54 4.98 0.00 36.00 5.22 2.54 4.98 0.00 37.50 5.22 2.54 4.98 0.00 39.00 5.22 2.54 4.98 0.00 40.50 5.22 2.54 4.98 0.00 42.00 5.22 2.54 4.98 0.00 43.50 5.22 2.54 4.98 0.00 45.00 5.22 2.54 4.98 0.00 46.50 5.22 2.54 4.98 0.00 48.00 5.22 2.54 4.98 0.00 49.50 5.22 2.54 4.98 0.00 51.00 5.22 2.54 4.98 0.00 52.50 5.22 2.54 4.98 0.00 54.00 5.22 2.54 4.98 0.00 55.50 5.22

2.54 4.98 0.00 51.00 5.22 2.54 4.98 0.00 52.50 5.22 2.54 4.98 0.00 54.00 5.22 2.54 4.98 0.00 55.50 5.22 2.54 4.98 0.00 57.00 5.22 2.54 4.98 0.00 58.50 5.22 2.54 4.98 0.00 60.00 5.22 2.54 4.98 0.00 61.50 5.22 2.54 4.98 0.00 63.00 5.22 2.54 4.98 0.00 64.50 5.22 2.54 4.98 0.00 66.00 5.22 2.54 4.98 0.00 67.50 5.22 2.54 4.98 0.00 69.00 5.22 2.54 4.98 0.00 70.50 5.22 2.54 4.98 0.00 72.00 5.22 2.54 4.98 0.00

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 19S: pre-dev basin 4 Runoff = 4.06 cfs @ 12.25 hrs, Volume= 0.408 af, Depth= 2.20" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.03 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) CN Description 96,981 70 Woods, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.4 100 0.0500 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.44" 1.5 90 0.0400 1.00 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 15.9 190 Total Subcatchment 19S: pre-dev basin 4 Hydrograph Runoff 4.06 cfs 4 NOAA 24-hr D 10-Year Rainfall=5.22" Runoff Area=96,981 sf 3 Runoff Volume=0.408 af Flow (cfs) Runoff Depth=2.20" 2

8 af Flow (cfs) Runoff Depth=2.20" 2 Flow Length=190' Tc=15.9 min CN=70/0 1 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 Time (hours)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 26 Hydrograph for Subcatchment 19S: pre-dev basin 4 Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.09 0.00 0.00 0.00 3.00 0.20 0.00 0.00 0.00 4.50 0.31 0.00 0.00 0.00 6.00 0.45 0.00 0.00 0.00 7.50 0.61 0.00 0.00 0.00 9.00 0.83 0.00 0.00 0.00 10.50 1.17 0.02 0.00 0.06 12.00 2.50 0.46 0.00 1.30 13.50 4.05 1.36 0.00 0.56 15.00 4.39 1.60 0.00 0.29 16.50 4.61 1.75 0.00 0.21 18.00 4.77 1.87 0.00 0.16 19.50 4.91 1.97 0.00 0.14 21.00 5.02 2.05 0.00 0.13 22.50 5.13 2.13 0.00 0.11 24.00 5.22 2.20 0.00 0.10 25.50 5.22 2.20 0.00 0.00 27.00 5.22 2.20 0.00 0.00 28.50 5.22 2.20 0.00 0.00 30.00 5.22 2.20 0.00 0.00 31.50 5.22 2.20 0.00 0.00 33.00 5.22 2.20 0.00 0.00 34.50 5.22 2.20 0.00 0.00 36.00 5.22 2.20 0.00 0.00 37.50 5.22 2.20 0.00 0.00 39.00 5.22 2.20 0.00 0.00 40.50 5.22 2.20 0.00 0.00 42.00 5.22 2.20 0.00 0.00 43.50 5.22 2.20 0.00 0.00 45.00 5.22 2.20 0.00 0.00 46.50 5.22 2.20 0.00 0.00 48.00 5.22 2.20 0.00 0.00 49.50 5.22 2.20 0.00 0.00 51.00 5.22 2.20 0.00 0.00 52.50 5.22 2.20 0.00 0.00 54.00 5.22 2.20 0.00 0.00 55.50

2 2.20 0.00 0.00 51.00 5.22 2.20 0.00 0.00 52.50 5.22 2.20 0.00 0.00 54.00 5.22 2.20 0.00 0.00 55.50 5.22 2.20 0.00 0.00 57.00 5.22 2.20 0.00 0.00 58.50 5.22 2.20 0.00 0.00 60.00 5.22 2.20 0.00 0.00 61.50 5.22 2.20 0.00 0.00 63.00 5.22 2.20 0.00 0.00 64.50 5.22 2.20 0.00 0.00 66.00 5.22 2.20 0.00 0.00 67.50 5.22 2.20 0.00 0.00 69.00 5.22 2.20 0.00 0.00 70.50 5.22 2.20 0.00 0.00 72.00 5.22 2.20 0.00 0.00

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 27 Summary for Pond 17P: Porous pavement system 4 Inflow Area = 1.968 ac, Inflow Depth = 4.29" for 10-Year event Inflow = 8.03 cfs @ 12.15 hrs, Volume= 0.703 af Outflow = 0.70 cfs @ 13.35 hrs, Volume= 0.316 af, Atten= 91%, Lag= 72.3 min Primary = 0.70 cfs @ 13.35 hrs, Volume= 0.316 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.03 hrs Peak Elev= 589.75' @ 13.35 hrs Surf.Area= 10,178 sf Storage= 20,113 cf Plug-Flow detention time= 408.7 min calculated for 0.316 af (45% of inflow) Center-of-Mass det. time= 255.7 min ( 1,022.5 - 766.8 ) Volume Invert Avail.Storage Storage Description #1 585.00' 32,044 cf Custom Stage Data (Prismatic) Listed below (Recalc) 81,424 cf Overall - 1,315 cf Embedded = 80,109 cf x 40.0% Voids #2 586.00' 1,315 cf 36.0" Round Pipe Storage Inside #1 L= 186.0' 33,358 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 585.00 10,178 0 0 593.00 10,178 81,424 81,424 Device Routing Invert Outlet Devices #1 Primary 588.95' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 589.90' 24.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.70 cfs @ 13.35 hrs HW=589.75' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.70 cfs @ 3.56 fps) 2=Orifice/Grate ( Controls 0.00 cfs)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 28 Pond 17P: Porous pavement system 4 Hydrograph Inflow 8.03 cfs Primary 8 Inflow Area=1.968 ac 7 Peak Elev=589.75' 6 Storage=20,113 cf Flow (cfs) 5 4 3 2 1 0.70 cfs 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 Time (hours)