JMA02P003 262 270 Main Street Development Stormwater Management Report

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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 4S: Proposed 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 9.18 8.94 0.00 1.00 0.12 0.02 0.02 48.00 9.18 8.94 0.00 2.00 0.26 0.11 0.04 49.00 9.18 8.94 0.00 3.00 0.42 0.25 0.05 50.00 9.18 8.94 0.00 4.00 0.60 0.41 0.06 51.00 9.18 8.94 0.00 5.00 0.80 0.60 0.07 52.00 9.18 8.94 0.00 6.00 1.02 0.81 0.08 53.00 9.18 8.94 0.00 7.00 1.26 1.05 0.09 54.00 9.18 8.94 0.00 8.00 1.53 1.31 0.09 55.00 9.18 8.94 0.00 9.00 1.81 1.58 0.11 56.00 9.18 8.94 0.00 10.00 2.20 1.97 0.14 57.00 9.18 8.94 0.00 11.00 2.72 2.49 0.25 58.00 9.18 8.94 0.00 12.00 4.34 4.11 2.29 59.00 9.18 8.94 0.00 13.00 6.46 6.22 0.25 60.00 9.18 8.94 0.00 14.00 6.98 6.74 0.15 61.00 9.18 8.94 0.00 15.00 7.37 7.13 0.13 62.00 9.18 8.94 0.00 16.00 7.65 7.41 0.10 63.00 9.18 8.94 0.00 17.00 7.92 7.68 0.09 64.00 9.18 8.94 0.00 18.00 8.16 7.92 0.08 65.00 9.18 8.94 0.00 19.00 8.38 8.14 0.08 66.00 9.18 8.94 0.00 20.00 8.58 8.34 0.07 67.00

0 18.00 8.16 7.92 0.08 65.00 9.18 8.94 0.00 19.00 8.38 8.14 0.08 66.00 9.18 8.94 0.00 20.00 8.58 8.34 0.07 67.00 9.18 8.94 0.00 21.00 8.76 8.52 0.06 68.00 9.18 8.94 0.00 22.00 8.92 8.68 0.05 69.00 9.18 8.94 0.00 23.00 9.06 8.82 0.05 70.00 9.18 8.94 0.00 24.00 9.18 8.94 0.03 71.00 9.18 8.94 0.00 25.00 9.18 8.94 0.00 72.00 9.18 8.94 0.00 26.00 9.18 8.94 0.00 27.00 9.18 8.94 0.00 28.00 9.18 8.94 0.00 29.00 9.18 8.94 0.00 30.00 9.18 8.94 0.00 31.00 9.18 8.94 0.00 32.00 9.18 8.94 0.00 33.00 9.18 8.94 0.00 34.00 9.18 8.94 0.00 35.00 9.18 8.94 0.00 36.00 9.18 8.94 0.00 37.00 9.18 8.94 0.00 38.00 9.18 8.94 0.00 39.00 9.18 8.94 0.00 40.00 9.18 8.94 0.00 41.00 9.18 8.94 0.00 42.00 9.18 8.94 0.00 43.00 9.18 8.94 0.00 44.00 9.18 8.94 0.00 45.00 9.18 8.94 0.00 46.00 9.18 8.94 0.00

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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 Pond 2P: Basin A Inflow Area = 13,934 sf,100.00% Impervious, Inflow Depth = 8.94" for 100-Year-Current event Inflow = 3.36 cfs @ 12.06 hrs, Volume= 10,380 cf Outflow = 3.07 cfs @ 12.09 hrs, Volume= 10,380 cf, Atten= 9%, Lag= 1.8 min Discarded = 0.02 cfs @ 1.55 hrs, Volume= 3,345 cf Primary = 3.04 cfs @ 12.09 hrs, Volume= 7,035 cf Routed to nonexistent node 6L Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 97.74' @ 12.09 hrs Surf.Area= 2,143 sf Storage= 2,895 cf Plug-Flow detention time= 229.3 min calculated for 10,373 cf (100% of inflow) Center-of-Mass det. time= 229.7 min ( 966.0 - 736.2 ) Volume Invert Avail.Storage Storage Description #1A 95.70' 1,544 cf 29.50'W x 72.63'L x 2.71'H Field A 5,803 cf Overall - 1,943 cf Embedded = 3,859 cf x 40.0% Voids #2A 96.20' 1,943 cf Cultec R-180HD x 88 Inside #1 Effective Size= 33.6"W x 20.0"H => 3.44 sf x 6.33'L = 21.8 cf Overall Size= 36.0"W x 20.5"H x 7.33'L with 1.00' Overlap Row Length Adjustment= +1.00' x 3.44 sf x 8 rows 3,487 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 96.60' 2.5" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 97.35' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir

96.60' 2.5" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 97.35' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #3 Discarded 95.70' 0.500 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.02 cfs @ 1.55 hrs HW=95.73' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=2.93 cfs @ 12.09 hrs HW=97.73' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.17 cfs @ 4.88 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 2.76 cfs @ 1.80 fps)

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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. Pond 2P: Basin A - Chamber Wizard Field A Chamber Model = Cultec R-180HD (For residential use only) Effective Size= 33.6"W x 20.0"H => 3.44 sf x 6.33'L = 21.8 cf Overall Size= 36.0"W x 20.5"H x 7.33'L with 1.00' Overlap Row Length Adjustment= +1.00' x 3.44 sf x 8 rows 36.0" Wide + 6.0" Spacing = 42.0" C-C Row Spacing 11 Chambers/Row x 6.33' Long +1.00' Row Adjustment = 70.63' Row Length +12.0" End Stone x 2 = 72.63' Base Length 8 Rows x 36.0" Wide + 6.0" Spacing x 7 + 12.0" Side Stone x 2 = 29.50' Base Width 6.0" Stone Base + 20.5" Chamber Height + 6.0" Stone Cover = 2.71' Field Height 88 Chambers x 21.8 cf +1.00' Row Adjustment x 3.44 sf x 8 Rows = 1,943.5 cf Chamber Storage 5,802.8 cf Field - 1,943.5 cf Chambers = 3,859.4 cf Stone x 40.0% Voids = 1,543.8 cf Stone Storage Chamber Storage + Stone Storage = 3,487.2 cf = 0.080 af Overall Storage Efficiency = 60.1% Overall System Size = 72.63' x 29.50' x 2.71' 88 Chambers 214.9 cy Field 142.9 cy Stone

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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. Pond 2P: Basin A Hydrograph 3.36 cfs Inflow Outflow 3.07 cfs Inflow Area=13,934 sf Discarded Primary 3.04 cfs Peak Elev=97.74' 3 Storage=2,895 cf Flow (cfs) 2 1 0.02 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)

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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. Pond 2P: Basin A Stage-Discharge Total Discarded Primary 98 Broad-Crested Rectangular Weir Elevation (feet) 97 Orifice/Grate 96 Exfiltration 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Discharge (cfs)

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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. Pond 2P: Basin A Stage-Area-Storage Surface/Horizontal/Wetted Area (sq-ft) 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 Surface Storage 98 Elevation (feet) 97 Cultec R-180HD 96 Field A 0 500 1,000 1,500 2,000 2,500 3,000 Storage (cubic-feet)

Proposed Flows NOAA10 24-hr D 100-Year-Current Rainfall=9.18" 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 Pond 2P: Basin A Time Inflow Storage Elevation Outflow Discarded Primary (hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs) 0.00 0.00 0 95.70 0.00 0.00 0.00 2.50 0.04 66 95.78 0.02 0.02 0.00 5.00 0.06 335 96.09 0.02 0.02 0.00 7.50 0.08 777 96.40 0.02 0.02 0.00 10.00 0.13 1,421 96.77 0.06 0.02 0.04 12.50 0.33 2,479 97.42 0.39 0.02 0.36 15.00 0.12 2,258 97.28 0.15 0.02 0.12 17.50 0.08 1,842 97.02 0.12 0.02 0.09 20.00 0.06 1,557 96.85 0.09 0.02 0.06 22.50 0.05 1,389 96.75 0.06 0.02 0.03 25.00 0.00 1,203 96.64 0.03 0.02 0.00 27.50 0.00 977 96.51 0.02 0.02 0.00 30.00 0.00 754 96.38 0.02 0.02 0.00 32.50 0.00 531 96.26 0.02 0.02 0.00 35.00 0.00 308 96.06 0.02 0.02 0.00 37.50 0.00 84 95.80 0.02 0.02 0.00 40.00 0.00 0 95.70 0.00 0.00 0.00 42.50 0.00 0 95.70 0.00 0.00 0.00 45.00 0.00 0 95.70 0.00

0 95.70 0.00 0.00 0.00 42.50 0.00 0 95.70 0.00 0.00 0.00 45.00 0.00 0 95.70 0.00 0.00 0.00 47.50 0.00 0 95.70 0.00 0.00 0.00 50.00 0.00 0 95.70 0.00 0.00 0.00 52.50 0.00 0 95.70 0.00 0.00 0.00 55.00 0.00 0 95.70 0.00 0.00 0.00 57.50 0.00 0 95.70 0.00 0.00 0.00 60.00 0.00 0 95.70 0.00 0.00 0.00 62.50 0.00 0 95.70 0.00 0.00 0.00 65.00 0.00 0 95.70 0.00 0.00 0.00 67.50 0.00 0 95.70 0.00 0.00 0.00 70.00 0.00 0 95.70 0.00 0.00 0.00