1240815StormWaterManagementReport

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.05 hrs, 1441 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. UI as Pervious Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: Exisiting Runoff Area=16,242 sf 68.64% Impervious Runoff Depth=0.73" Flow Length=141' Tc=5.9 min CN=74/98 Runoff=0.73 cfs 0.023 af Subcatchment 2: Parking Lot Runoff Area=7,305 sf 88.61% Impervious Runoff Depth=0.93" Flow Length=92' Tc=0.9 min CN=74/98 Runoff=0.45 cfs 0.013 af Pond 3: Pervious Pavers Peak Elev=413.88' Storage=245 cf Inflow=0.45 cfs 0.013 af Discarded=0.11 cfs 0.013 af Primary=0.00 cfs 0.000 af Outflow=0.11 cfs 0.013 af Subcatchment 4: Proposed Runoff Area=8,332 sf 56.96% Impervious Runoff Depth=0.62" Flow Length=92' Tc=0.9 min CN=74/98 Runoff=0.33 cfs 0.010 af Pond 5: Pipes Peak Elev=412.30' Storage=146 cf Inflow=0.33 cfs 0.010 af Discarded=0.03 cfs 0.005 af Primary=0.23 cfs 0.005 af Outflow=0.26 cfs 0.010 af Subcatchment 6: Bypass Runoff Area=605 sf 0.00% Impervious Runoff Depth=0.07" Flow Length=128' Tc=6.0 min CN=74/0 Runoff=0.00 cfs 0.000 af Link 7: Proposed Inflow=0.23 cfs 0.005 af Primary=0.23 cfs 0.005 af 48

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 1: Exisiting Runoff = 0.73 cfs @ 1.14 hrs, Volume= 0.023 af, Depth= 0.73" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. UI as Pervious, Time Span= 0.00-72.00 hrs, dt= 0.05 Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Area (sf) CN Description * 2,676 98 Buildings * 794 98 Walks/Steps & Patio 7,679 98 Paved parking, HSG C 5,093 74 >75% Grass cover, Good, HSG C 16,242 90 Weighted Average 5,093 74 31.36% Pervious Area 11,149 98 68.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.1 66 0.0680 0.27 Sheet Flow, 1 Grass: Short n= 0.150 P2= 3.47" 1.4 21 0.0950 0.24 Sheet Flow, 2 Grass: Short n= 0.150 P2= 3.47" 0.2 13 0.0390 1.24 Sheet Flow, 3 Smooth surfaces n= 0.011 P2= 3.47" 0.1 13 0.0390 4.01 Shallow Concentrated Flow, 4 Paved Kv= 20.3 fps 0.1 28 0.0360 3.85 Shallow Concentrated Flow, 5 Paved Kv= 20.3 fps 5.9 141 Total 49

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Subcatchment 1: Exisiting Hydrograph 0.8 0.73 cfs 0.75 Runoff 0.7 Water Quality Storm 0.65 Water Quality Rainfall=1.25" 0.6 0.55 P2=3.47" 0.5 Runoff Area=16,242 sf Runoff Volume=0.023 af Flow (cfs) 0.45 0.4 Runoff Depth=0.73" 0.35 Flow Length=141' 0.3 0.25 Tc=5.9 min 0.2 CN=74/98 0.15 0.1 0.05 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) 50

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 2: Parking Lot Runoff = 0.45 cfs @ 1.07 hrs, Volume= 0.013 af, Depth= 0.93" Routed to Pond 3 : Pervious Pavers Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. UI as Pervious, Time Span= 0.00-72.00 hrs, dt= 0.05 Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Area (sf) CN Description 6,473 98 Paved parking, HSG C 832 74 >75% Grass cover, Good, HSG C 7,305 95 Weighted Average 832 74 11.39% Pervious Area 6,473 98 88.61% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.1 8 0.0650 1.38 Sheet Flow, 1 Smooth surfaces n= 0.011 P2= 3.47" 0.1 15 0.6700 3.99 Sheet Flow, 2 Smooth surfaces n= 0.011 P2= 3.47" 0.5 59 0.0500 1.86 Sheet Flow, 3 Smooth surfaces n= 0.011 P2= 3.47" 0.2 10 0.0250 0.99 Sheet Flow, 4 Smooth surfaces n= 0.011 P2= 3.47" 0.9 92 Total 51

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Subcatchment 2: Parking Lot Hydrograph 0.5 0.45 cfs 0.48 Runoff 0.46 0.44 0.42 Water Quality Storm 0.4 0.38 Water Quality Rainfall=1.25" 0.36 0.34 P2=3.47" 0.32 0.3 Runoff Area=7,305 sf Runoff Volume=0.013 af Flow (cfs) 0.28 0.26 0.24 Runoff Depth=0.93" 0.22 0.2 Flow Length=92' 0.18 0.16 Tc=0.9 min 0.14 0.12 CN=74/98 0.1 0.08 0.06 0.04 0.02 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) 52

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Summary for Pond 3: Pervious Pavers Inflow Area = 0.168 ac, 88.61% Impervious, Inflow Depth = 0.93" for Water Quality event Inflow = 0.45 cfs @ 1.07 hrs, Volume= 0.013 af Outflow = 0.11 cfs @ 0.95 hrs, Volume= 0.013 af, Atten= 76%, Lag= 0.0 min Discarded = 0.11 cfs @ 0.95 hrs, Volume= 0.013 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Pond 5 : Pipes Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 413.88' @ 1.27 hrs Surf.Area= 1,620 sf Storage= 245 cf Plug-Flow detention time= 20.6 min calculated for 0.013 af (100% of inflow) Center-of-Mass det. time= 20.6 min ( 88.6 - 68.0 ) Volume Invert Avail.Storage Storage Description #1 413.50' 1,730 cf 60.00'W x 27.00'L x 2.67'H Prismatoid 4,325 cf Overall x 40.0% Voids Device Routing Invert Outlet Devices #1 Discarded 413.50' 2.900 in/hr Exfiltration over Surface area #2 Primary 414.50' 6.0" Round Culvert L= 50.0' Ke= 0.200 Inlet / Outlet Invert= 414.50' / 414.17' S= 0.0066 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf Discarded OutFlow Max=0.11 cfs @ 0.95 hrs HW=413.54' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.11 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=413.50' (Free Discharge) 2=Culvert ( Controls 0.00 cfs) 53

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Pond 3: Pervious Pavers Hydrograph 0.5 0.45 cfs 0.48 Inflow 0.46 Outflow 0.44 Discarded 0.42 0.4 Inflow Area=0.168 ac Primary 0.38 0.36 Peak Elev=413.88' 0.34 0.32 Storage=245 cf 0.3 Flow (cfs) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.11 cfs 0.12 0.1 0.08 0.06 0.04 0.00 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) 54

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 4: Proposed Runoff = 0.33 cfs @ 1.07 hrs, Volume= 0.010 af, Depth= 0.62" Routed to Pond 5 : Pipes Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. UI as Pervious, Time Span= 0.00-72.00 hrs, dt= 0.05 Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Area (sf) CN Description 3,387 98 Roofs, HSG C 1,359 98 Paved parking, HSG C 3,586 74 >75% Grass cover, Good, HSG C 8,332 88 Weighted Average 3,586 74 43.04% Pervious Area 4,746 98 56.96% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.1 8 0.0650 1.38 Sheet Flow, 1 Smooth surfaces n= 0.011 P2= 3.47" 0.1 15 0.6700 3.99 Sheet Flow, 2 Smooth surfaces n= 0.011 P2= 3.47" 0.5 59 0.0500 1.86 Sheet Flow, 3 Smooth surfaces n= 0.011 P2= 3.47" 0.2 10 0.0250 0.99 Sheet Flow, 4 Smooth surfaces n= 0.011 P2= 3.47" 0.9 92 Total 55

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Subcatchment 4: Proposed Hydrograph 0.36 0.33 cfs 0.34 Runoff 0.32 Water Quality Storm 0.3 0.28 Water Quality Rainfall=1.25" 0.26 P2=3.47" 0.24 0.22 Runoff Area=8,332 sf Runoff Volume=0.010 af Flow (cfs) 0.2 0.18 Runoff Depth=0.62" 0.16 0.14 Flow Length=92' 0.12 Tc=0.9 min 0.1 CN=74/98 0.08 0.06 0.04 0.02 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) 56

PLEASANT VALLEY WAY 1240815-pipes Water Quality Storm Water Quality Rainfall=1.25", P2=3.47" Prepared by Casey & Keller, Inc Printed 9/12/2025 HydroCAD® 10.20-7a s/n 03272 © 2025 HydroCAD Software Solutions LLC Summary for Pond 5: Pipes Inflow Area = 0.359 ac, 71.75% Impervious, Inflow Depth = 0.33" for Water Quality event Inflow = 0.33 cfs @ 1.07 hrs, Volume= 0.010 af Outflow = 0.26 cfs @ 1.14 hrs, Volume= 0.010 af, Atten= 22%, Lag= 4.2 min Discarded = 0.03 cfs @ 0.80 hrs, Volume= 0.005 af Primary = 0.23 cfs @ 1.14 hrs, Volume= 0.005 af Routed to Link 7 : Proposed Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 412.30' @ 1.14 hrs Surf.Area= 400 sf Storage= 146 cf Plug-Flow detention time= 19.9 min calculated for 0.010 af (100% of inflow) Center-of-Mass det. time= 19.9 min ( 88.6 - 68.7 ) Volume Invert Avail.Storage Storage Description #1 411.50' 329 cf 10.00'W x 40.00'L x 3.00'H Prismatoid 1,200 cf Overall - 377 cf Embedded = 823 cf x 40.0% Voids #2 412.00' 377 cf 24.0" Round Pipe Storage x 3 Inside #1 L= 40.0' S= 0.0020 '/' 706 cf Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 411.50' 2.900 in/hr Exfiltration over Surface area #2 Primary 412.00' 12.0" Round Culvert L= 14.0' Ke= 0.100 Inlet / Outlet Invert= 412.00' / 411.94' S= 0.0043 '/' Cc= 0.900 n= 0.012 Corrugated PP, smooth interior, Flow Area= 0.79 sf #3 Device 2 412.00' 6.0" Vert. Orifice C= 0.600 Limited to weir flow at low heads #4 Device 2 414.00' 24.0" x 24.0" Horiz. Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.03 cfs @ 0.80 hrs HW=411.54' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.23 cfs @ 1.14 hrs HW=412.30' (Free Discharge) 2=Culvert (Passes 0.23 cfs of 0.27 cfs potential flow) 3=Orifice (Orifice