250701_42 ERW_Stormwater Report

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 26 Summary for Subcatchment PR 1A-P: [49] Hint: Tc<2dt may require smaller dt Runoff = 1.36 cfs @ 12.13 hrs, Volume= Routed to Reach DP1-PR : 0.100 af, Depth= 3.97" 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 25-Year Rainfall=6.44" 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 1.36 cfs Flow (cfs) 1 0 0 NOAA 24-hr D 25-Year Rainfall=6.44" Runoff Area=13,167 sf Runoff Volume=0.100 af Runoff Depth=3.97" 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 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 27 Summary for Subcatchment PR 1B-I: [49] Hint: Tc<2dt may require smaller dt Runoff = 5.73 cfs @ 12.07 hrs, Volume= Routed to Reach 10R : 0.438 af, Depth= 6.20" 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 25-Year Rainfall=6.44" 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 6 5.73 cfs 5 Flow (cfs) 4 3 2 NOAA 24-hr D 25-Year Rainfall=6.44" Runoff Area=36,906 sf Runoff Volume=0.438 af Runoff Depth=6.20" 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 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 28 Summary for Subcatchment PR 1B-P: Runoff = 7.82 cfs @ 12.15 hrs, Volume= Routed to Reach 10R : 0.602 af, Depth= 4.07" 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 25-Year Rainfall=6.44" 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 7.82 cfs 8 7 Flow (cfs) 6 5 4 3 2 NOAA 24-hr D 25-Year Rainfall=6.44" Runoff Area=77,195 sf Runoff Volume=0.602 af Runoff Depth=4.07" 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 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 29 Summary for Reach 10R: [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 2.619 ac, 32.35% Impervious, Inflow Depth = 4.76" for 25-Year event Inflow = 12.08 cfs @ 12.10 hrs, Volume= 1.040 af Outflow = 12.08 cfs @ 12.10 hrs, Volume= 1.040 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 13 12 12.08 cfs 12.08 cfs Inflow Outflow Inflow Area=2.619 ac 11 10 Flow (cfs) 9 8 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 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 30 Summary for Reach DP1-PR: [40] Hint: Not Described (Outflow=Inflow) Inflow Area = Inflow = Outflow = 2.922 ac, 29.00% Impervious, Inflow Depth = 2.26" for 25-Year event 5.28 cfs @ 12.17 hrs, Volume= 0.551 af 5.28 cfs @ 12.17 hrs, Volume= 0.551 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 5.28 cfs 5.28 cfs Inflow Outflow Inflow Area=2.922 ac 5 Flow (cfs) 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 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 31 Summary for Pond BASIN: Inflow Area = 2.619 ac, 32.35% Impervious, Inflow Depth = 4.76" for 25-Year event Inflow = 12.08 cfs @ 12.10 hrs, Volume= 1.040 af Outflow = 5.24 cfs @ 12.28 hrs, Volume= 1.040 af, Atten= 57%, Lag= 11.1 min Discarded = 0.87 cfs @ 12.28 hrs, Volume= 0.589 af Primary = 4.37 cfs @ 12.28 hrs, Volume= 0.451 af Routed to Reach DP1-PR : Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 18.32' @ 12.28 hrs Surf.Area= 0.108 ac Storage= 0.253 af Plug-Flow detention time= 39.6 min calculated for 1.039 af (100% of inflow) Center-of-Mass det. time= 39.6 min ( 828.2 - 788.6 ) 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=0.87 cfs @ 12.28 hrs HW=18.31' (Free Discharge) 4=Exfiltration ( Controls 0.87 cfs) Primary OutFlow Max=4.37 cfs @ 12.28 hrs HW=18.31' (Free Discharge) 1=Orifice/Grate (Orifice Controls 1.91 cfs @ 7.15 fps) 2=Orifice/Grate (Orifice Controls 2.45 cfs @ 6.00 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)

250624_42 ERW Waymaker NOAA 24-hr D 25-Year Rainfall=6.44" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 32 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 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 33 Pond BASIN: Hydrograph 12.08 cfs 13 12 11 Inflow Area=2.619 ac Peak Elev=18.32' Storage=0.253 af 10 Flow (cfs) 9 8 5.24 cfs 7 6 5 4.37 cfs 4 3 2 0.87 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 100-Year Rainfall=8.66" 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 34 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=6.00" Flow Length=203' Tc=5.9 min CN=78 Runoff=2.01 cfs 0.151 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=8.42" Flow Length=136' Tc=1.5 min CN=98 Runoff=7.71 cfs 0.594 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=6.13" Flow Length=180' Tc=7.5 min CN=79 Runoff=11.55 cfs 0.905 af Reach 10R: Inflow=17.23 cfs 1.499 af Outflow=17.23 cfs 1.499 af Reach DP1-PR: Inflow=10.10 cfs 0.921 af Outflow=10.10 cfs 0.921 af Pond BASIN: Peak Elev=19.83' Storage=0.338 af Inflow=17.23 cfs 1.499 af Discarded=1.11 cfs 0.729 af Primary=8.90 cfs 0.770 af Outflow=10.01 cfs 1.499 af Total Runoff Area = 2.922 ac Runoff Volume = 1.650 af Average Runoff Depth = 6.78" 71.00% Pervious = 2.074 ac 29.00% Impervious = 0.847 ac

NOAA 24-hr D 100-Year Rainfall=8.66" 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 35 Summary for Subcatchment PR 1A-P: [49] Hint: Tc<2dt may require smaller dt Runoff = 2.01 cfs @ 12.13 hrs, Volume= Routed to Reach DP1-PR : 0.151 af, Depth= 6.00" 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 100-Year Rainfall=8.66" 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 2.01 cfs Flow (cfs) 2 1 0 0 NOAA 24-hr D 100-Year Rainfall=8.66" Runoff Area=13,167 sf Runoff Volume=0.151 af Runoff Depth=6.00" 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)