1240815StormWaterManagementReport

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 = 8.60" for 100-Year-2020 event Inflow = 1.58 cfs @ 12.06 hrs, Volume= 0.120 af Outflow = 0.74 cfs @ 12.15 hrs, Volume= 0.120 af, Atten= 53%, Lag= 5.6 min Discarded = 0.11 cfs @ 10.90 hrs, Volume= 0.094 af Primary = 0.64 cfs @ 12.15 hrs, Volume= 0.027 af Routed to Pond 5 : Pipes Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 415.25' @ 12.15 hrs Surf.Area= 1,620 sf Storage= 1,132 cf Plug-Flow detention time= 32.8 min calculated for 0.120 af (100% of inflow) Center-of-Mass det. time= 32.7 min ( 774.5 - 741.8 ) 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 @ 10.90 hrs HW=413.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.11 cfs) Primary OutFlow Max=0.64 cfs @ 12.15 hrs HW=415.24' (Free Discharge) 2=Culvert (Barrel Controls 0.64 cfs @ 3.23 fps) 40

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 1.58 cfs Inflow Outflow Discarded Inflow Area=0.168 ac Primary Peak Elev=415.25' Storage=1,132 cf 1 Flow (cfs) 0.74 cfs 0.64 cfs 0.11 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) 41

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 = 1.68 cfs @ 12.06 hrs, Volume= 0.122 af, Depth= 7.67" 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 100-Year-2020 Rainfall=9.18", 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 42

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 1.68 cfs Runoff NOAA 24-hr D 100-Year-2020 Rainfall=9.18" P2=3.47" Runoff Area=8,332 sf Runoff Volume=0.122 af Flow (cfs) 1 Runoff Depth=7.67" 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) 43

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 = 4.98" for 100-Year-2020 event Inflow = 2.19 cfs @ 12.07 hrs, Volume= 0.149 af Outflow = 1.83 cfs @ 12.15 hrs, Volume= 0.149 af, Atten= 16%, Lag= 4.6 min Discarded = 0.03 cfs @ 7.50 hrs, Volume= 0.045 af Primary = 1.80 cfs @ 12.15 hrs, Volume= 0.104 af Routed to Link 7 : Proposed Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 414.08' @ 12.14 hrs Surf.Area= 400 sf Storage= 640 cf Plug-Flow detention time= 14.9 min calculated for 0.149 af (100% of inflow) Center-of-Mass det. time= 14.9 min ( 773.4 - 758.5 ) 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 @ 7.50 hrs HW=411.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=1.77 cfs @ 12.15 hrs HW=414.07' (Free Discharge) 2=Culvert (Passes 1.77 cfs of 5.52 cfs potential flow) 3=Orifice (Orifice

1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=1.77 cfs @ 12.15 hrs HW=414.07' (Free Discharge) 2=Culvert (Passes 1.77 cfs of 5.52 cfs potential flow) 3=Orifice (Orifice Controls 1.28 cfs @ 6.50 fps) 4=Grate (Weir Controls 0.49 cfs @ 0.87 fps) 44

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 5: Pipes Hydrograph 2.19 cfs Inflow Outflow Discarded 2 1.83 Inflow Area=0.359 ac Primary 1.80 cfs cfs Peak Elev=414.08' Storage=640 cf Flow (cfs) 1 0.03 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) 45

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 6: Bypass Runoff = 0.09 cfs @ 12.13 hrs, Volume= 0.007 af, Depth= 5.99" Routed to Link 7 : Proposed 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 100-Year-2020 Rainfall=9.18", P2=3.47" Area (sf) CN Description 605 74 >75% Grass cover, Good, HSG C 605 74 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.9 100 0.0650 0.28 Sheet Flow, 1 Grass: Short n= 0.150 P2= 3.47" 0.1 28 0.0900 4.50 Shallow Concentrated Flow, 2 Grassed Waterway Kv= 15.0 fps 6.0 128 Total Subcatchment 6: Bypass Hydrograph 0.1 0.095 0.09 cfs Runoff 0.09 0.085 NOAA 24-hr D 0.08 100-Year-2020 Rainfall=9.18" 0.075 0.07 P2=3.47" 0.065 Runoff Area=605 sf

P2=3.47" 0.065 Runoff Area=605 sf 0.06 Runoff Volume=0.007 af Flow (cfs) 0.055 0.05 Runoff Depth=5.99" 0.045 0.04 Flow Length=128' 0.035 Tc=6.0 min 0.03 0.025 CN=74/0 0.02 0.015 0.01 0.005 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) 46

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 Link 7: Proposed Inflow Area = 0.373 ac, 69.07% Impervious, Inflow Depth = 3.57" for 100-Year-2020 event Inflow = 1.89 cfs @ 12.15 hrs, Volume= 0.111 af Primary = 1.89 cfs @ 12.15 hrs, Volume= 0.111 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Link 7: Proposed Hydrograph 2 1.89 cfs Inflow Primary Inflow Area=0.373 ac Flow (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) 47