Drainage Report

Basin 3 without exfiltration proposed basin 3 R5 Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 5 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.000 HSG A 0.000 HSG B 5.234 HSG C 34S, 36S, 37S 0.000 HSG D 0.000 Other 5.234 TOTAL AREA

Basin 3 without exfiltration proposed basin 3 R5 Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 6 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 0.000 1.718 0.000 0.000 1.718 >75% Grass cover, Good 34 S, 36 S 0.000 0.000 0.744 0.000 0.000 0.744 Paved parking 34 S 0.000 0.000 0.155 0.000 0.000 0.155 Paved roads w/curbs & sewers 36 S 0.000 0.000 2.617 0.000 0.000 2.617 Woods, Good 37 S 0.000 0.000 5.234 0.000 0.000 5.234 TOTAL AREA

Basin 3 without exfiltration proposed basin 3 R5 Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 7 Pipe Listing (all nodes) Line# Node In-Invert Out-Invert Length Slope n Width Diam/Height Inside-Fill Node Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) Name 1 34S 0.00 0.00 450.0 0.0600 0.013 0.0 15.0 8.0

Basin 3 without exfiltration proposed basin 3 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 8 Time span=0.00-72.00 hrs, dt=0.05 hrs, 1441 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 34S: Basin 3 Runoff Area=95,425 sf Runoff Depth=1.88" Flow Length=670' Tc=10.0 min CN=74/98 Runoff=3.73 cfs 0.343 af Subcatchment 36S: Basin 3 undetained Runoff Area=18,573 sf Runoff Depth=1.93" Flow Length=45' Slope=0.1000 '/' Tc=10.0 min CN=74/98 Runoff=0.74 cfs 0.068 af Subcatchment 37S: Basin 3 pre-development Runoff Area=113,998 sf Runoff Depth=0.97" Flow Length=304' Tc=19.4 min CN=70/0 Runoff=1.79 cfs 0.212 af Pond 35P: Basin 3 Peak Elev=530.38' Storage=12,717 cf Inflow=3.73 cfs 0.343 af Outflow=0.09 cfs 0.080 af Total Runoff Area = 5.234 ac Runoff Volume = 0.624 af Average Runoff Depth = 1.43"

Basin 3 without exfiltration proposed basin 3 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 34S: Basin 3 Runoff = 3.73 cfs @ 12.17 hrs, Volume= 0.343 af, Depth= 1.88" Routed to Pond 35P : Basin 3 Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) CN Description 32,412 98 Paved parking, HSG C 63,013 74 >75% Grass cover, Good, HSG C 95,425 82 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 100 0.0800 0.21 Sheet Flow, Grass: Dense n= 0.240 P2= 3.44" 0.1 20 0.0800 4.24 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 0.4 100 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.8 450 0.0600 8.91 5.00 Pipe Channel, 15.0" Round w/ 8.0" inside fill Area= 0.6 sf Perim= 3.1' r= 0.18' n= 0.013 Concrete sewer w/manholes & inlets 9.2 670 Total, Increased to minimum Tc = 10.0 min Subcatchment 34S: Basin 3 Hydrograph

Subcatchment 34S: Basin 3 Hydrograph Runoff 4 3.73 cfs NOAA 24-hr D 2-Year Rainfall=3.44" 3 Runoff Area=95,425 sf Runoff Volume=0.343 af Flow (cfs) Runoff Depth=1.88" 2 Flow Length=670' Tc=10.0 min 1 CN=74/98 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 3 without exfiltration proposed basin 3 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 10 Hydrograph for Subcatchment 34S: Basin 3 Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 2.50 0.11 0.00 0.02 0.01 5.00 0.24 0.00 0.09 0.03 7.50 0.40 0.00 0.23 0.05 10.00 0.68 0.00 0.49 0.11 12.50 2.35 0.53 2.12 1.10 15.00 2.89 0.84 2.66 0.19 17.50 3.11 0.98 2.88 0.12 20.00 3.26 1.08 3.03 0.09 22.50 3.38 1.16 3.15 0.08 25.00 3.44 1.20 3.21 0.00 27.50 3.44 1.20 3.21 0.00 30.00 3.44 1.20 3.21 0.00 32.50 3.44 1.20 3.21 0.00 35.00 3.44 1.20 3.21 0.00 37.50 3.44 1.20 3.21 0.00 40.00 3.44 1.20 3.21 0.00 42.50 3.44 1.20 3.21 0.00 45.00 3.44 1.20 3.21 0.00 47.50 3.44 1.20 3.21 0.00 50.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 55.00 3.44 1.20 3.21 0.00 57.50 3.44 1.20 3.21 0.00 60.00 3.44 1.20 3.21 0.00 62.50 3.44 1.20 3.21 0.00 65.00 3.44 1.20 3.21 0.00 67.50 3.44 1.20 3.21 0.00 70.00 3.44 1.20 3.21 0.00

Basin 3 without exfiltration proposed basin 3 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 36S: Basin 3 undetained Runoff = 0.74 cfs @ 12.17 hrs, Volume= 0.068 af, Depth= 1.93" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) CN Description 11,836 74 >75% Grass cover, Good, HSG C 6,737 98 Paved roads w/curbs & sewers, HSG C 18,573 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.8 45 0.1000 0.20 Sheet Flow, Grass: Dense n= 0.240 P2= 3.44" 3.8 45 Total, Increased to minimum Tc = 10.0 min Subcatchment 36S: Basin 3 undetained Hydrograph Runoff 0.8 0.74 cfs 0.75 0.7 NOAA 24-hr D 0.65 2-Year Rainfall=3.44" 0.6 Runoff Area=18,573 sf 0.55 0.5 Runoff Volume=0.068 af Flow (cfs) 0.45

ea=18,573 sf 0.55 0.5 Runoff Volume=0.068 af Flow (cfs) 0.45 Runoff Depth=1.93" 0.4 0.35 Flow Length=45' 0.3 Slope=0.1000 '/' 0.25 0.2 Tc=10.0 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 3 without exfiltration proposed basin 3 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 12 Hydrograph for Subcatchment 36S: Basin 3 undetained Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 2.50 0.11 0.00 0.02 0.00 5.00 0.24 0.00 0.09 0.01 7.50 0.40 0.00 0.23 0.01 10.00 0.68 0.00 0.49 0.02 12.50 2.35 0.53 2.12 0.22 15.00 2.89 0.84 2.66 0.04 17.50 3.11 0.98 2.88 0.02 20.00 3.26 1.08 3.03 0.02 22.50 3.38 1.16 3.15 0.01 25.00 3.44 1.20 3.21 0.00 27.50 3.44 1.20 3.21 0.00 30.00 3.44 1.20 3.21 0.00 32.50 3.44 1.20 3.21 0.00 35.00 3.44 1.20 3.21 0.00 37.50 3.44 1.20 3.21 0.00 40.00 3.44 1.20 3.21 0.00 42.50 3.44 1.20 3.21 0.00 45.00 3.44 1.20 3.21 0.00 47.50 3.44 1.20 3.21 0.00 50.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 55.00 3.44 1.20 3.21 0.00 57.50 3.44 1.20 3.21 0.00 60.00 3.44 1.20 3.21 0.00 62.50 3.44 1.20 3.21 0.00 65.00 3.44 1.20 3.21 0.00 67.50 3.44 1.20 3.21 0.00 70.00 3.44 1.20 3.21 0.00