250701_42 ERW_Stormwater Report

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 16 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 PR 1A-P: Runoff Area=13,167 sf 0.00% Impervious Runoff Depth=2.90" Flow Length=203' Tc=5.9 min CN=78 Runoff=1.00 cfs 0.073 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=4.98" Flow Length=136' Tc=1.5 min CN=98 Runoff=4.63 cfs 0.352 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=2.99" Flow Length=180' Tc=7.5 min CN=79 Runoff=5.79 cfs 0.442 af Reach 10R: Inflow=9.28 cfs 0.794 af Outflow=9.28 cfs 0.794 af Reach DP1-PR: Inflow=3.96 cfs 0.367 af Outflow=3.96 cfs 0.367 af Pond BASIN: Peak Elev=17.57' Storage=0.194 af Inflow=9.28 cfs 0.794 af Discarded=0.74 cfs 0.500 af Primary=3.33 cfs 0.294 af Outflow=4.07 cfs 0.794 af Total Runoff Area = 2.922 ac Runoff Volume = 0.867 af Average Runoff Depth = 3.56" 71.00% Pervious = 2.074 ac 29.00% Impervious = 0.847 ac

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 17 Summary for Subcatchment PR 1A-P: [49] Hint: Tc<2dt may require smaller dt Runoff = 1.00 cfs @ 12.13 hrs, Volume= Routed to Reach DP1-PR : 0.073 af, Depth= 2.90" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) 9,975 3,192 13,167 13,167 CN 74 89 78 Description >75% Grass cover, Good, HSG C Gravel roads, HSG C Weighted Average 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.6 100 0.0725 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" 0.3 103 0.1090 5.32 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 5.9 203 Total Subcatchment PR 1A-P: Hydrograph Runoff 1.00 cfs Flow (cfs) 1 0 0 NOAA 24-hr D 10-Year Rainfall=5.22" Runoff Area=13,167 sf Runoff Volume=0.073 af Runoff Depth=2.90" Flow Length=203' Tc=5.9 min CN=78 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)

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 18 Summary for Subcatchment PR 1B-I: [49] Hint: Tc<2dt may require smaller dt Runoff = 4.63 cfs @ 12.07 hrs, Volume= Routed to Reach 10R : 0.352 af, Depth= 4.98" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) 21,449 15,457 36,906 36,906 CN 98 98 98 Description Roofs, HSG C Paved parking, HSG C Weighted Average 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.2 100 0.0200 1.43 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.44" 0.3 36 0.0139 2.39 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.5 136 Total Subcatchment PR 1B-I: Hydrograph Runoff 5 4.63 cfs Flow (cfs) 4 3 2 NOAA 24-hr D 10-Year Rainfall=5.22" Runoff Area=36,906 sf Runoff Volume=0.352 af Runoff Depth=4.98" Flow Length=136' Tc=1.5 min CN=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)

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 19 Summary for Subcatchment PR 1B-P: Runoff = 5.79 cfs @ 12.15 hrs, Volume= Routed to Reach 10R : 0.442 af, Depth= 2.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) 53,321 23,874 77,195 77,195 CN 74 89 79 Description >75% Grass cover, Good, HSG C Gravel roads, HSG C Weighted Average 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.2 100 0.0400 0.23 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" 0.3 80 0.0812 4.59 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 7.5 180 Total Subcatchment PR 1B-P: Hydrograph Runoff 5.79 cfs 6 5 Flow (cfs) 4 3 2 NOAA 24-hr D 10-Year Rainfall=5.22" Runoff Area=77,195 sf Runoff Volume=0.442 af Runoff Depth=2.99" Flow Length=180' Tc=7.5 min CN=79 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)

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 20 Summary for Reach 10R: [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 2.619 ac, 32.35% Impervious, Inflow Depth = 3.64" for 10-Year event Inflow = 9.28 cfs @ 12.10 hrs, Volume= 0.794 af Outflow = 9.28 cfs @ 12.10 hrs, Volume= 0.794 af, Atten= 0%, Lag= 0.0 min Routed to Pond BASIN : Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Reach 10R: Hydrograph 10 9 9.28 cfs 9.28 cfs Inflow Outflow Inflow Area=2.619 ac 8 Flow (cfs) 7 6 5 4 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)

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 21 Summary for Reach DP1-PR: [40] Hint: Not Described (Outflow=Inflow) Inflow Area = Inflow = Outflow = 2.922 ac, 29.00% Impervious, Inflow Depth = 1.51" for 10-Year event 3.96 cfs @ 12.17 hrs, Volume= 0.367 af 3.96 cfs @ 12.17 hrs, Volume= 0.367 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Reach DP1-PR: Hydrograph 3.96 cfs 4 3.96 cfs Inflow Outflow Inflow Area=2.922 ac 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)

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 22 Summary for Pond BASIN: Inflow Area = 2.619 ac, 32.35% Impervious, Inflow Depth = 3.64" for 10-Year event Inflow = 9.28 cfs @ 12.10 hrs, Volume= 0.794 af Outflow = 4.07 cfs @ 12.28 hrs, Volume= 0.794 af, Atten= 56%, Lag= 10.9 min Discarded = 0.74 cfs @ 12.28 hrs, Volume= 0.500 af Primary = 3.33 cfs @ 12.28 hrs, Volume= 0.294 af Routed to Reach DP1-PR : Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 17.57' @ 12.28 hrs Surf.Area= 0.108 ac Storage= 0.194 af Plug-Flow detention time= 38.8 min calculated for 0.793 af (100% of inflow) Center-of-Mass det. time= 38.8 min ( 832.5 - 793.8 ) Volume #1A Invert 15.00' Avail.Storage 0.129 af #2A 15.75' 0.216 af 0.345 af Storage Description 44.25'W x 106.08'L x 5.00'H Field A 0.539 af Overall - 0.216 af Embedded = 0.323 af x 40.0% Voids ADS_StormTech MC-3500 d +Cap x 84 Inside #1 Effective Size= 70.4"W x 45.0"H => 15.33 sf x 7.17'L = 110.0 cf Overall Size= 77.0"W x 45.0"H x 7.50'L with 0.33' Overlap 84 Chambers in 6 Rows Cap Storage= 14.9 cf x 2 x 6 rows = 178.8 cf Total Available Storage Storage Group A created with Chamber Wizard Device #1 Routing Primary Invert 15.96' #2 Primary 16.55' #3 Primary 18.90' #4 Discarded 15.00' Outlet Devices 3.5" Vert. Orifice/Grate X 4.00 C= 0.600 Limited to weir flow at low heads 5.0" Vert. Orifice/Grate X 3.00 C= 0.600 Limited to weir flow at low heads 1.0' 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 3.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 13.00' Discarded OutFlow Max=0.74 cfs @ 12.28 hrs HW=17.56' (Free Discharge) 4=Exfiltration ( Controls 0.74 cfs) Primary OutFlow Max=3.32 cfs @ 12.28 hrs HW=17.56' (Free Discharge) 1=Orifice/Grate (Orifice Controls 1.55 cfs @ 5.81 fps) 2=Orifice/Grate (Orifice Controls 1.77 cfs @ 4.32 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)

250624_42 ERW Waymaker NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 23 Pond BASIN: - Chamber Wizard Field A Chamber Model = ADS_StormTech MC-3500 d +Cap (ADS StormTech® MC-3500 d rev 03/14 with Cap volume) Effective Size= 70.4"W x 45.0"H => 15.33 sf x 7.17'L = 110.0 cf Overall Size= 77.0"W x 45.0"H x 7.50'L with 0.33' Overlap Cap Storage= 14.9 cf x 2 x 6 rows = 178.8 cf 77.0" Wide + 9.0" Spacing = 86.0" C-C Row Spacing 14 Chambers/Row x 7.17' Long +1.85' Cap Length x 2 = 104.08' Row Length +12.0" End Stone x 2 = 106.08' Base Length 6 Rows x 77.0" Wide + 9.0" Spacing x 5 + 12.0" Side Stone x 2 = 44.25' Base Width 9.0" Stone Base + 45.0" Chamber Height + 6.0" Stone Cover = 5.00' Field Height 84 Chambers x 110.0 cf + 14.9 cf Cap Volume x 2 x 6 Rows = 9,414.8 cf Chamber Storage 23,470.2 cf Field - 9,414.8 cf Chambers = 14,055.4 cf Stone x 40.0% Voids = 5,622.2 cf Stone Storage Chamber Storage + Stone Storage = 15,036.9 cf = 0.345 af Overall Storage Efficiency = 64.1% Overall System Size = 106.08' x 44.25' x 5.00' 84 Chambers 869.3 cy Field 520.6 cy Stone

NOAA 24-hr D 10-Year Rainfall=5.22" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 24 Pond BASIN: Hydrograph 9.28 cfs 10 9 8 Inflow Area=2.619 ac Peak Elev=17.57' Storage=0.194 af Flow (cfs) 7 6 4.07 cfs 5 4 3.33 cfs 3 2 0.74 cfs 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) Inflow Outflow Discarded Primary

NOAA 24-hr D 25-Year Rainfall=6.44" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 25 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 PR 1A-P: Runoff Area=13,167 sf 0.00% Impervious Runoff Depth=3.97" Flow Length=203' Tc=5.9 min CN=78 Runoff=1.36 cfs 0.100 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=6.20" Flow Length=136' Tc=1.5 min CN=98 Runoff=5.73 cfs 0.438 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=4.07" Flow Length=180' Tc=7.5 min CN=79 Runoff=7.82 cfs 0.602 af Reach 10R: Inflow=12.08 cfs 1.040 af Outflow=12.08 cfs 1.040 af Reach DP1-PR: Inflow=5.28 cfs 0.551 af Outflow=5.28 cfs 0.551 af Pond BASIN: Peak Elev=18.32' Storage=0.253 af Inflow=12.08 cfs 1.040 af Discarded=0.87 cfs 0.589 af Primary=4.37 cfs 0.451 af Outflow=5.24 cfs 1.040 af Total Runoff Area = 2.922 ac Runoff Volume = 1.140 af Average Runoff Depth = 4.68" 71.00% Pervious = 2.074 ac 29.00% Impervious = 0.847 ac