Drainage Report

Basin 2-3 without exfiltration Proposed Basin 2-3 R5 Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 3 Rainfall Events Listing (selected events) Event# Event Storm Type Curve Mode Duration B/B Depth AMC Name (hours) (inches) 1 2-Year NOAA 24-hr D Default 24.00 1 3.44 2 2 10-Year NOAA 24-hr D Default 24.00 1 5.22 2 3 100-Year NOAA 24-hr D Default 24.00 1 8.66 2

Basin 2-3 without exfiltration Proposed Basin 2-3 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) 0.959 74 >75% Grass cover, Good, HSG C (40S) 1.060 98 Roofs, HSG C (40S) 0.239 98 Water Surface, 0% imp, HSG C (40S) 2.282 70 Woods, Good, HSG C (45S) 4.541 79 TOTAL AREA

Basin 2-3 without exfiltration Proposed Basin 2-3 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 4.541 HSG C 40S, 45S 0.000 HSG D 0.000 Other 4.541 TOTAL AREA

Basin 2-3 without exfiltration Proposed Basin 2-3 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 0.959 0.000 0.000 0.959 >75% Grass cover, Good 40S 0.000 0.000 1.060 0.000 0.000 1.060 Roofs 40S 0.000 0.000 0.239 0.000 0.000 0.239 Water Surface, 0% imp 40S 0.000 0.000 2.282 0.000 0.000 2.282 Woods, Good 45S 0.000 0.000 4.541 0.000 0.000 4.541 TOTAL AREA

Basin 2-3 without exfiltration Proposed Basin 2-3 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 40S 0.00 0.00 1,326.0 0.0300 0.010 0.0 15.0 0.0

Basin 2-3 without exfiltration Proposed Basin 2-3 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 40S: Basin 2-3 Runoff Area=98,395 sf Runoff Depth=2.30" Flow Length=1,558' Tc=10.5 min CN=79/98 Runoff=4.65 cfs 0.434 af Subcatchment 45S: basin 2-3 pre-development Runoff Area=99,393 sf Runoff Depth=0.97" Flow Length=280' Tc=12.2 min CN=70/0 Runoff=1.92 cfs 0.185 af Pond 44P: pond 2-3 Peak Elev=543.43' Storage=14,908 cf Inflow=4.65 cfs 0.434 af Outflow=0.15 cfs 0.144 af Total Runoff Area = 4.541 ac Runoff Volume = 0.618 af Average Runoff Depth = 1.63"

Basin 2-3 without exfiltration Proposed Basin 2-3 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 40S: Basin 2-3 Runoff = 4.65 cfs @ 12.18 hrs, Volume= 0.434 af, Depth= 2.30" Routed to Pond 44P : pond 2-3 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 41,793 74 >75% Grass cover, Good, HSG C 46,190 98 Roofs, HSG C 10,412 98 Water Surface, 0% imp, HSG C 98,395 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.0 100 0.0300 0.21 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" 0.4 60 0.0330 2.72 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 0.2 72 0.0800 5.74 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.9 1,326 0.0300 11.85 14.55 Pipe Channel, 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.010 10.5 1,558 Total

Basin 2-3 without exfiltration Proposed Basin 2-3 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 Subcatchment 40S: Basin 2-3 Hydrograph Runoff 5 4.65 cfs NOAA 24-hr D 4 2-Year Rainfall=3.44" Runoff Area=98,395 sf Runoff Volume=0.434 af 3 Flow (cfs) Runoff Depth=2.30" Flow Length=1,558' 2 Tc=10.5 min CN=79/98 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 2-3 without exfiltration Proposed Basin 2-3 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 Hydrograph for Subcatchment 40S: Basin 2-3 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 0.02 5.00 0.24 0.00 0.09 0.04 7.50 0.40 0.00 0.23 0.08 10.00 0.68 0.01 0.49 0.17 12.50 2.35 0.73 2.12 1.37 15.00 2.89 1.10 2.66 0.23 17.50 3.11 1.26 2.88 0.14 20.00 3.26 1.37 3.03 0.11 22.50 3.38 1.46 3.15 0.09 25.00 3.44 1.50 3.21 0.00 27.50 3.44 1.50 3.21 0.00 30.00 3.44 1.50 3.21 0.00 32.50 3.44 1.50 3.21 0.00 35.00 3.44 1.50 3.21 0.00 37.50 3.44 1.50 3.21 0.00 40.00 3.44 1.50 3.21 0.00 42.50 3.44 1.50 3.21 0.00 45.00 3.44 1.50 3.21 0.00 47.50 3.44 1.50 3.21 0.00 50.00 3.44 1.50 3.21 0.00 52.50 3.44 1.50 3.21 0.00 55.00 3.44 1.50 3.21 0.00 57.50 3.44 1.50 3.21 0.00 60.00 3.44 1.50 3.21 0.00 62.50 3.44 1.50 3.21 0.00 65.00 3.44 1.50 3.21 0.00 67.50 3.44 1.50 3.21 0.00 70.00 3.44 1.50 3.21 0.00

Basin 2-3 without exfiltration Proposed Basin 2-3 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 Summary for Subcatchment 45S: basin 2-3 pre-development Runoff = 1.92 cfs @ 12.21 hrs, Volume= 0.185 af, Depth= 0.97" 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 99,393 70 Woods, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.1 100 0.1200 0.16 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.44" 2.1 180 0.0830 1.44 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 12.2 280 Total Subcatchment 45S: basin 2-3 pre-development Hydrograph Runoff 2 1.92 cfs NOAA 24-hr D 2-Year Rainfall=3.44" Runoff Area=99,393 sf Runoff Volume=0.185 af Flow (cfs) Runoff Depth=0.97" 1