Drainage Report

Basin 4 without exfiltration Proposed basin 4 R5 Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 4 Area Listing (all nodes) Area CN Description (acres) (subcatchment-numbers) 0.812 74 >75% Grass cover, Good, HSG C (16S, 18S) 0.007 98 Paved roads w/curbs & sewers, HSG C (18S) 2.226 70 Woods, Good, HSG C (19S) 1.408 98 roof and parking (16S) 4.453 80 TOTAL AREA

Basin 4 without exfiltration Proposed basin 4 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 3.045 HSG C 16S, 18S, 19S 0.000 HSG D 1.408 Other 16S 4.453 TOTAL AREA

Basin 4 without exfiltration Proposed basin 4 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 0.812 0.000 0.000 0.812 >75% Grass cover, Good 16 S, 18 S 0.000 0.000 0.007 0.000 0.000 0.007 Paved roads w/curbs & sewers 18 S 0.000 0.000 2.226 0.000 0.000 2.226 Woods, Good 19 S 0.000 0.000 0.000 0.000 1.408 1.408 roof and parking 16 S 0.000 0.000 3.045 0.000 1.408 4.453 TOTAL AREA

Basin 4 without exfiltration Proposed basin 4 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 16S 0.00 0.00 309.0 0.0261 0.013 0.0 15.0 9.0

Basin 4 without exfiltration Proposed basin 4 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=0.03 hrs, 2401 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 16S: Basin 4 Porous pvmt Runoff Area=85,708 sf Runoff Depth=2.64" Flow Length=509' Tc=8.1 min CN=74/98 Runoff=4.96 cfs 0.432 af Subcatchment 18S: OL-4 Runoff Area=11,273 sf Runoff Depth=1.25" Flow Length=96' Slope=0.0573 '/' Tc=8.7 min CN=74/98 Runoff=0.33 cfs 0.027 af Subcatchment 19S: pre-dev basin 4 Runoff Area=96,981 sf Runoff Depth=0.97" Flow Length=190' Tc=15.9 min CN=70/0 Runoff=1.67 cfs 0.180 af Pond 17P: Porous pavement system 4 Peak Elev=589.11' Storage=17,538 cf Inflow=4.96 cfs 0.432 af Outflow=0.08 cfs 0.045 af Total Runoff Area = 4.453 ac Runoff Volume = 0.639 af Average Runoff Depth = 1.72"

Basin 4 without exfiltration Proposed basin 4 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 16S: Basin 4 Porous pvmt [47] Hint: Peak is 202% of capacity of segment #3 Runoff = 4.96 cfs @ 12.15 hrs, Volume= 0.432 af, Depth= 2.64" Routed to Pond 17P : Porous pavement system 4 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 2-Year Rainfall=3.44" Area (sf) CN Description * 61,324 98 roof and parking 24,384 74 >75% Grass cover, Good, HSG C 85,708 91 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 100 0.0520 0.26 Sheet Flow, grass Grass: Short n= 0.150 P2= 3.44" 0.6 100 0.0300 2.60 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 1.0 309 0.0261 5.35 2.45 Pipe Channel, 15.0" Round w/ 9.0" inside fill Area= 0.5 sf Perim= 2.9' r= 0.16' n= 0.013 Corrugated PE, smooth interior 8.1 509 Total Subcatchment 16S: Basin 4 Porous pvmt Hydrograph Runoff 4.96 cfs

Runoff 4.96 cfs 5 NOAA 24-hr D 2-Year Rainfall=3.44" 4 Runoff Area=85,708 sf Runoff Volume=0.432 af Flow (cfs) 3 Runoff Depth=2.64" Flow Length=509' 2 Tc=8.1 min CN=74/98 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 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 16S: Basin 4 Porous pvmt Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.06 0.00 0.00 0.01 3.00 0.13 0.00 0.03 0.03 4.50 0.21 0.00 0.07 0.05 6.00 0.29 0.00 0.14 0.07 7.50 0.40 0.00 0.23 0.10 9.00 0.55 0.00 0.36 0.14 10.50 0.77 0.00 0.57 0.25 12.00 1.65 0.20 1.43 2.45 13.50 2.67 0.71 2.44 0.39 15.00 2.89 0.84 2.66 0.20 16.50 3.04 0.93 2.81 0.15 18.00 3.15 1.00 2.91 0.11 19.50 3.23 1.06 3.00 0.10 21.00 3.31 1.11 3.08 0.09 22.50 3.38 1.16 3.15 0.08 24.00 3.44 1.20 3.21 0.07 25.50 3.44 1.20 3.21 0.00 27.00 3.44 1.20 3.21 0.00 28.50 3.44 1.20 3.21 0.00 30.00 3.44 1.20 3.21 0.00 31.50 3.44 1.20 3.21 0.00 33.00 3.44 1.20 3.21 0.00 34.50 3.44 1.20 3.21 0.00 36.00 3.44 1.20 3.21 0.00 37.50 3.44 1.20 3.21 0.00 39.00 3.44 1.20 3.21 0.00 40.50 3.44 1.20 3.21 0.00 42.00 3.44 1.20 3.21 0.00 43.50 3.44 1.20 3.21 0.00 45.00 3.44 1.20 3.21 0.00 46.50 3.44 1.20 3.21 0.00 48.00 3.44 1.20 3.21 0.00 49.50 3.44 1.20 3.21 0.00 51.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 54.00 3.44 1.20 3.21 0.00 55.50

4 1.20 3.21 0.00 51.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 54.00 3.44 1.20 3.21 0.00 55.50 3.44 1.20 3.21 0.00 57.00 3.44 1.20 3.21 0.00 58.50 3.44 1.20 3.21 0.00 60.00 3.44 1.20 3.21 0.00 61.50 3.44 1.20 3.21 0.00 63.00 3.44 1.20 3.21 0.00 64.50 3.44 1.20 3.21 0.00 66.00 3.44 1.20 3.21 0.00 67.50 3.44 1.20 3.21 0.00 69.00 3.44 1.20 3.21 0.00 70.50 3.44 1.20 3.21 0.00 72.00 3.44 1.20 3.21 0.00

Basin 4 without exfiltration Proposed basin 4 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 18S: OL-4 Runoff = 0.33 cfs @ 12.16 hrs, Volume= 0.027 af, Depth= 1.25" 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 2-Year Rainfall=3.44" 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 0.36 Runoff 0.34 0.33 cfs 0.32 NOAA 24-hr D 0.3 0.28 2-Year Rainfall=3.44" 0.26 Runoff Area=11,273 sf 0.24 0.22 Runoff Volume=0.027 af Flow (cfs) 0.2 Runoff Depth=1.25" 0.18 0.16