1240815StormWaterManagementReport

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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=4.37" Flow Length=141' Tc=5.9 min CN=74/98 Runoff=1.63 cfs 0.136 af Subcatchment 2: Parking Lot Runoff Area=7,305 sf 88.61% Impervious Runoff Depth=4.86" Flow Length=92' Tc=0.9 min CN=74/98 Runoff=0.91 cfs 0.068 af Pond 3: Pervious Pavers Peak Elev=414.62' Storage=727 cf Inflow=0.91 cfs 0.068 af Discarded=0.11 cfs 0.066 af Primary=0.04 cfs 0.002 af Outflow=0.15 cfs 0.068 af Subcatchment 4: Proposed Runoff Area=8,332 sf 56.96% Impervious Runoff Depth=4.08" Flow Length=92' Tc=0.9 min CN=74/98 Runoff=0.90 cfs 0.065 af Pond 5: Pipes Peak Elev=412.73' Storage=267 cf Inflow=0.90 cfs 0.067 af Discarded=0.03 cfs 0.033 af Primary=0.66 cfs 0.034 af Outflow=0.68 cfs 0.067 af Subcatchment 6: Bypass Runoff Area=605 sf 0.00% Impervious Runoff Depth=2.67" Flow Length=128' Tc=6.0 min CN=74/0 Runoff=0.04 cfs 0.003 af Link 7: Proposed Inflow=0.70 cfs 0.037 af Primary=0.70 cfs 0.037 af 22

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 = 1.63 cfs @ 12.13 hrs, Volume= 0.136 af, Depth= 4.37" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. UI as Pervious, Time Span= 0.00-72.00 hrs, dt= 0.05 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 23

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 1.63 cfs Runoff NOAA 24-hr D 10-Year-2020 Rainfall=5.38" P2=3.47" Runoff Area=16,242 sf Flow (cfs) 1 Runoff Volume=0.136 af Runoff Depth=4.37" Flow Length=141' Tc=5.9 min CN=74/98 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) 24

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 = 0.91 cfs @ 12.06 hrs, Volume= 0.068 af, Depth= 4.86" 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 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 25

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 1 0.91 cfs Runoff NOAA 24-hr D 10-Year-2020 Rainfall=5.38" P2=3.47" Runoff Area=7,305 sf Flow (cfs) Runoff Volume=0.068 af Runoff Depth=4.86" Flow Length=92' Tc=0.9 min CN=74/98 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) 26

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 = 4.86" for 10-Year-2020 event Inflow = 0.91 cfs @ 12.06 hrs, Volume= 0.068 af Outflow = 0.15 cfs @ 12.49 hrs, Volume= 0.068 af, Atten= 83%, Lag= 25.6 min Discarded = 0.11 cfs @ 11.50 hrs, Volume= 0.066 af Primary = 0.04 cfs @ 12.49 hrs, Volume= 0.002 af Routed to Pond 5 : Pipes Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 414.62' @ 12.49 hrs Surf.Area= 1,620 sf Storage= 727 cf Plug-Flow detention time= 36.4 min calculated for 0.068 af (100% of inflow) Center-of-Mass det. time= 36.4 min ( 785.7 - 749.3 ) 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 @ 11.50 hrs HW=413.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.11 cfs) Primary OutFlow Max=0.04 cfs @ 12.49 hrs HW=414.62' (Free Discharge) 2=Culvert (Barrel Controls 0.04 cfs @ 1.69 fps) 27

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 1 0.91 cfs Inflow Outflow Discarded Inflow Area=0.168 ac Primary Peak Elev=414.62' Storage=727 cf Flow (cfs) 0.15 cfs 0.11 cfs 0.04 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) 28

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 = 0.90 cfs @ 12.06 hrs, Volume= 0.065 af, Depth= 4.08" 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 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 29

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 1 0.90 cfs Runoff NOAA 24-hr D 10-Year-2020 Rainfall=5.38" P2=3.47" Runoff Area=8,332 sf Flow (cfs) Runoff Volume=0.065 af Runoff Depth=4.08" Flow Length=92' Tc=0.9 min CN=74/98 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) 30

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 = 2.23" for 10-Year-2020 event Inflow = 0.90 cfs @ 12.06 hrs, Volume= 0.067 af Outflow = 0.68 cfs @ 12.11 hrs, Volume= 0.067 af, Atten= 24%, Lag= 2.8 min Discarded = 0.03 cfs @ 9.75 hrs, Volume= 0.033 af Primary = 0.66 cfs @ 12.11 hrs, Volume= 0.034 af Routed to Link 7 : Proposed Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 412.73' @ 12.11 hrs Surf.Area= 400 sf Storage= 267 cf Plug-Flow detention time= 15.4 min calculated for 0.067 af (100% of inflow) Center-of-Mass det. time= 15.4 min ( 785.3 - 770.0 ) 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 @ 9.75 hrs HW=411.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.65 cfs @ 12.11 hrs HW=412.72' (Free Discharge) 2=Culvert (Passes 0.65 cfs of 1.42 cfs potential flow) 3=Orifice (Orifice