JMA02P003 262 270 Main Street Development Stormwater Management Report

Existing Flows NOAA10 24-hr D 10-Year-Future Rainfall=6.31" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Hydrograph for Subcatchment 2S: Existing Pervious Time Precip. Excess Runoff Time Precip. Excess Runoff (hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 47.00 6.31 3.45 0.00 1.00 0.08 0.00 0.00 48.00 6.31 3.45 0.00 2.00 0.18 0.00 0.00 49.00 6.31 3.45 0.00 3.00 0.29 0.00 0.00 50.00 6.31 3.45 0.00 4.00 0.41 0.00 0.00 51.00 6.31 3.45 0.00 5.00 0.55 0.00 0.00 52.00 6.31 3.45 0.00 6.00 0.70 0.00 0.00 53.00 6.31 3.45 0.00 7.00 0.87 0.01 0.00 54.00 6.31 3.45 0.00 8.00 1.05 0.03 0.00 55.00 6.31 3.45 0.00 9.00 1.24 0.07 0.00 56.00 6.31 3.45 0.00 10.00 1.51 0.15 0.00 57.00 6.31 3.45 0.00 11.00 1.87 0.29 0.00 58.00 6.31 3.45 0.00 12.00 2.99 0.90 0.02 59.00 6.31 3.45 0.00 13.00 4.44 1.93 0.00 60.00 6.31 3.45 0.00 14.00 4.80 2.20 0.00 61.00 6.31 3.45 0.00 15.00 5.07 2.42 0.00 62.00 6.31 3.45 0.00 16.00 5.26 2.57 0.00 63.00 6.31 3.45 0.00 17.00 5.44 2.72 0.00 64.00 6.31 3.45 0.00 18.00 5.61 2.86 0.00 65.00 6.31 3.45 0.00 19.00 5.76 2.98 0.00 66.00 6.31 3.45 0.00

0.00 64.00 6.31 3.45 0.00 18.00 5.61 2.86 0.00 65.00 6.31 3.45 0.00 19.00 5.76 2.98 0.00 66.00 6.31 3.45 0.00 20.00 5.90 3.10 0.00 67.00 6.31 3.45 0.00 21.00 6.02 3.20 0.00 68.00 6.31 3.45 0.00 22.00 6.13 3.30 0.00 69.00 6.31 3.45 0.00 23.00 6.23 3.38 0.00 70.00 6.31 3.45 0.00 24.00 6.31 3.45 0.00 71.00 6.31 3.45 0.00 25.00 6.31 3.45 0.00 72.00 6.31 3.45 0.00 26.00 6.31 3.45 0.00 27.00 6.31 3.45 0.00 28.00 6.31 3.45 0.00 29.00 6.31 3.45 0.00 30.00 6.31 3.45 0.00 31.00 6.31 3.45 0.00 32.00 6.31 3.45 0.00 33.00 6.31 3.45 0.00 34.00 6.31 3.45 0.00 35.00 6.31 3.45 0.00 36.00 6.31 3.45 0.00 37.00 6.31 3.45 0.00 38.00 6.31 3.45 0.00 39.00 6.31 3.45 0.00 40.00 6.31 3.45 0.00 41.00 6.31 3.45 0.00 42.00 6.31 3.45 0.00 43.00 6.31 3.45 0.00 44.00 6.31 3.45 0.00 45.00 6.31 3.45 0.00 46.00 6.31 3.45 0.00

Existing Flows NOAA10 24-hr D 10-Year-Future Rainfall=6.31" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Link 3L: Total Site Flows Inflow Area = 30,218 sf, 99.00% Impervious, Inflow Depth = 6.05" for 10-Year-Future event Inflow = 4.98 cfs @ 12.06 hrs, Volume= 15,223 cf Primary = 4.98 cfs @ 12.06 hrs, Volume= 15,223 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Link 3L: Total Site Flows Hydrograph Inflow 4.98 cfs Primary 4.98 cfs 5 Inflow Area=30,218 sf 4 Flow (cfs) 3 2 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)

Existing Flows NOAA10 24-hr D 10-Year-Future Rainfall=6.31" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Hydrograph for Link 3L: Total Site Flows Time Inflow Elevation Primary Time Inflow Elevation Primary (hours) (cfs) (feet) (cfs) (hours) (cfs) (feet) (cfs) 0.00 0.00 0.00 0.00 47.00 0.00 0.00 0.00 1.00 0.02 0.00 0.02 48.00 0.00 0.00 0.00 2.00 0.05 0.00 0.05 49.00 0.00 0.00 0.00 3.00 0.06 0.00 0.06 50.00 0.00 0.00 0.00 4.00 0.08 0.00 0.08 51.00 0.00 0.00 0.00 5.00 0.09 0.00 0.09 52.00 0.00 0.00 0.00 6.00 0.10 0.00 0.10 53.00 0.00 0.00 0.00 7.00 0.11 0.00 0.11 54.00 0.00 0.00 0.00 8.00 0.13 0.00 0.13 55.00 0.00 0.00 0.00 9.00 0.14 0.00 0.14 56.00 0.00 0.00 0.00 10.00 0.19 0.00 0.19 57.00 0.00 0.00 0.00 11.00 0.33 0.00 0.33 58.00 0.00 0.00 0.00 12.00 3.13 0.00 3.13 59.00 0.00 0.00 0.00 13.00 0.34 0.00 0.34 60.00 0.00 0.00 0.00 14.00 0.20 0.00 0.20 61.00 0.00 0.00 0.00 15.00 0.17 0.00 0.17 62.00 0.00 0.00 0.00 16.00 0.13 0.00 0.13 63.00 0.00 0.00 0.00 17.00

0.00 0.00 15.00 0.17 0.00 0.17 62.00 0.00 0.00 0.00 16.00 0.13 0.00 0.13 63.00 0.00 0.00 0.00 17.00 0.12 0.00 0.12 64.00 0.00 0.00 0.00 18.00 0.11 0.00 0.11 65.00 0.00 0.00 0.00 19.00 0.10 0.00 0.10 66.00 0.00 0.00 0.00 20.00 0.09 0.00 0.09 67.00 0.00 0.00 0.00 21.00 0.08 0.00 0.08 68.00 0.00 0.00 0.00 22.00 0.07 0.00 0.07 69.00 0.00 0.00 0.00 23.00 0.06 0.00 0.06 70.00 0.00 0.00 0.00 24.00 0.04 0.00 0.04 71.00 0.00 0.00 0.00 25.00 0.00 0.00 0.00 72.00 0.00 0.00 0.00 26.00 0.00 0.00 0.00 27.00 0.00 0.00 0.00 28.00 0.00 0.00 0.00 29.00 0.00 0.00 0.00 30.00 0.00 0.00 0.00 31.00 0.00 0.00 0.00 32.00 0.00 0.00 0.00 33.00 0.00 0.00 0.00 34.00 0.00 0.00 0.00 35.00 0.00 0.00 0.00 36.00 0.00 0.00 0.00 37.00 0.00 0.00 0.00 38.00 0.00 0.00 0.00 39.00 0.00 0.00 0.00 40.00 0.00 0.00 0.00 41.00 0.00 0.00 0.00 42.00 0.00 0.00 0.00 43.00 0.00 0.00 0.00 44.00 0.00 0.00 0.00 45.00 0.00 0.00 0.00 46.00 0.00 0.00 0.00

Existing Flows NOAA10 24-hr D 100-Year-Future Rainfall=11.52" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Time span=0.00-72.00 hrs, dt=0.05 hrs, 1441 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Existing Impervious Runoff Area=29,916 sf 100.00% Impervious Runoff Depth=11.28" Flow Length=166' Tc=0.9 min CN=98 Runoff=9.05 cfs 28,118 cf Subcatchment 2S: Existing Pervious Runoff Area=302 sf 0.00% Impervious Runoff Depth=8.17" Tc=1.0 min CN=74 Runoff=0.08 cfs 205 cf Link 3L: Total Site Flows Inflow=9.13 cfs 28,323 cf Primary=9.13 cfs 28,323 cf Total Runoff Area = 30,218 sf Runoff Volume = 28,323 cf Average Runoff Depth = 11.25" 1.00% Pervious = 302 sf 99.00% Impervious = 29,916 sf

Existing Flows NOAA10 24-hr D 100-Year-Future Rainfall=11.52" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment 1S: Existing Impervious Runoff = 9.05 cfs @ 12.06 hrs, Volume= 28,118 cf, Depth=11.28" Routed to Link 3L : Total Site Flows Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA10 24-hr D 100-Year-Future Rainfall=11.52" Area (sf) CN Description 11,049 98 Roofs, HSG C 18,867 98 Paved parking, HSG C 29,916 98 Weighted Average 29,916 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.7 100 0.0750 2.42 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.43" 0.2 66 0.0530 4.67 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.9 166 Total

Existing Flows NOAA10 24-hr D 100-Year-Future Rainfall=11.52" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Subcatchment 1S: Existing Impervious Hydrograph 10 Runoff 9.05 cfs 9 NOAA10 24-hr D 8 100-Year-Future Rainfall=11.52" Runoff Area=29,916 sf 7 Runoff Volume=28,118 cf 6 Runoff Depth=11.28" Flow (cfs) Flow Length=166' 5 Tc=0.9 min 4 CN=98 3 2 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)

Existing Flows NOAA10 24-hr D 100-Year-Future Rainfall=11.52" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Hydrograph for Subcatchment 1S: Existing Impervious Time Precip. Excess Runoff Time Precip. Excess Runoff (hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 47.00 11.52 11.28 0.00 1.00 0.15 0.04 0.06 48.00 11.52 11.28 0.00 2.00 0.33 0.17 0.11 49.00 11.52 11.28 0.00 3.00 0.53 0.34 0.13 50.00 11.52 11.28 0.00 4.00 0.76 0.56 0.16 51.00 11.52 11.28 0.00 5.00 1.01 0.80 0.18 52.00 11.52 11.28 0.00 6.00 1.28 1.07 0.20 53.00 11.52 11.28 0.00 7.00 1.59 1.37 0.21 54.00 11.52 11.28 0.00 8.00 1.92 1.69 0.23 55.00 11.52 11.28 0.00 9.00 2.27 2.04 0.27 56.00 11.52 11.28 0.00 10.00 2.76 2.53 0.35 57.00 11.52 11.28 0.00 11.00 3.41 3.18 0.60 58.00 11.52 11.28 0.00 12.00 5.45 5.21 5.69 59.00 11.52 11.28 0.00 13.00 8.11 7.87 0.62 60.00 11.52 11.28 0.00 14.00 8.76 8.52 0.36 61.00 11.52 11.28 0.00 15.00 9.25 9.01 0.31 62.00 11.52 11.28 0.00 16.00 9.60 9.36 0.24 63.00 11.52 11.28 0.00 17.00 9.93 9.69 0.22 64.00 11.52 11.28 0.00 18.00 10.24 9.99 0.20 65.00 11.52 11.28 0.00 19.00 10.51 10.27 0.18 66.00 11.52

9.93 9.69 0.22 64.00 11.52 11.28 0.00 18.00 10.24 9.99 0.20 65.00 11.52 11.28 0.00 19.00 10.51 10.27 0.18 66.00 11.52 11.28 0.00 20.00 10.76 10.52 0.17 67.00 11.52 11.28 0.00 21.00 10.99 10.75 0.15 68.00 11.52 11.28 0.00 22.00 11.19 10.95 0.13 69.00 11.52 11.28 0.00 23.00 11.37 11.13 0.11 70.00 11.52 11.28 0.00 24.00 11.52 11.28 0.07 71.00 11.52 11.28 0.00 25.00 11.52 11.28 0.00 72.00 11.52 11.28 0.00 26.00 11.52 11.28 0.00 27.00 11.52 11.28 0.00 28.00 11.52 11.28 0.00 29.00 11.52 11.28 0.00 30.00 11.52 11.28 0.00 31.00 11.52 11.28 0.00 32.00 11.52 11.28 0.00 33.00 11.52 11.28 0.00 34.00 11.52 11.28 0.00 35.00 11.52 11.28 0.00 36.00 11.52 11.28 0.00 37.00 11.52 11.28 0.00 38.00 11.52 11.28 0.00 39.00 11.52 11.28 0.00 40.00 11.52 11.28 0.00 41.00 11.52 11.28 0.00 42.00 11.52 11.28 0.00 43.00 11.52 11.28 0.00 44.00 11.52 11.28 0.00 45.00 11.52 11.28 0.00 46.00 11.52 11.28 0.00