1240815StormWaterManagementReport

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 = 3.01" for 2-Year-2020 event Inflow = 0.57 cfs @ 12.06 hrs, Volume= 0.042 af Outflow = 0.11 cfs @ 11.75 hrs, Volume= 0.042 af, Atten= 81%, Lag= 0.0 min Discarded = 0.11 cfs @ 11.75 hrs, Volume= 0.042 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= 414.04' @ 12.36 hrs Surf.Area= 1,620 sf Storage= 347 cf Plug-Flow detention time= 16.5 min calculated for 0.042 af (100% of inflow) Center-of-Mass det. time= 16.5 min ( 773.5 - 757.0 ) 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 @ 11.75 hrs HW=413.53' (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) 14

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 0.6 0.57 cfs Inflow Outflow 0.55 Discarded 0.5 Inflow Area=0.168 ac Primary 0.45 Peak Elev=414.04' 0.4 Storage=347 cf Flow (cfs) 0.35 0.3 0.25 0.2 0.15 0.11 cfs 0.1 0.05 0.00 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) 15

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 = 0.52 cfs @ 12.06 hrs, Volume= 0.038 af, Depth= 2.37" 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 2-Year-2020 Rainfall=3.47", 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 16

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 0.55 0.52 cfs Runoff 0.5 NOAA 24-hr D 0.45 2-Year-2020 Rainfall=3.47" 0.4 P2=3.47" 0.35 Runoff Area=8,332 sf Flow (cfs) 0.3 Runoff Volume=0.038 af 0.25 Runoff Depth=2.37" Flow Length=92' 0.2 Tc=0.9 min 0.15 CN=74/98 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) 17

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 = 1.26" for 2-Year-2020 event Inflow = 0.52 cfs @ 12.06 hrs, Volume= 0.038 af Outflow = 0.44 cfs @ 12.10 hrs, Volume= 0.038 af, Atten= 16%, Lag= 2.3 min Discarded = 0.03 cfs @ 10.80 hrs, Volume= 0.024 af Primary = 0.41 cfs @ 12.10 hrs, Volume= 0.014 af Routed to Link 7 : Proposed Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 412.44' @ 12.10 hrs Surf.Area= 400 sf Storage= 183 cf Plug-Flow detention time= 15.6 min calculated for 0.038 af (100% of inflow) Center-of-Mass det. time= 15.6 min ( 792.5 - 776.9 ) 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 @ 10.80 hrs HW=411.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.41 cfs @ 12.10 hrs HW=412.44' (Free Discharge) 2=Culvert (Passes 0.41 cfs of 0.58 cfs potential flow) 3=Orifice (Orifice

1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.41 cfs @ 12.10 hrs HW=412.44' (Free Discharge) 2=Culvert (Passes 0.41 cfs of 0.58 cfs potential flow) 3=Orifice (Orifice Controls 0.41 cfs @ 2.26 fps) 4=Grate ( Controls 0.00 cfs) 18

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 0.55 0.52 cfs Inflow Outflow Discarded 0.5 0.44 cfs Inflow Area=0.359 ac Primary 0.45 0.41 cfs Peak Elev=412.44' 0.4 Storage=183 cf 0.35 Flow (cfs) 0.3 0.25 0.2 0.15 0.1 0.05 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) 19

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 = 0.02 cfs @ 12.14 hrs, Volume= 0.001 af, Depth= 1.22" 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 2-Year-2020 Rainfall=3.47", 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 0.021 0.02 0.02 cfs Runoff 0.019 0.018 NOAA 24-hr D 0.017 0.016 2-Year-2020 Rainfall=3.47" 0.015 0.014 P2=3.47" 0.013 Runoff Area=605

P2=3.47" 0.013 Runoff Area=605 sf 0.012 Flow (cfs) 0.011 Runoff Volume=0.001 af 0.01 0.009 Runoff Depth=1.22" 0.008 Flow Length=128' 0.007 0.006 Tc=6.0 min 0.005 CN=74/0 0.004 0.003 0.002 0.001 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) 20

PLEASANT VALLEY WAY 1240815-pipes NOAA 24-hr D 2-Year-2020 Rainfall=3.47", 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 = 0.49" for 2-Year-2020 event Inflow = 0.43 cfs @ 12.10 hrs, Volume= 0.015 af Primary = 0.43 cfs @ 12.10 hrs, Volume= 0.015 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 0.48 0.46 0.44 0.43 cfs Inflow Primary 0.42 0.4 0.38 Inflow Area=0.373 ac 0.36 0.34 0.32 0.3 0.28 Flow (cfs) 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 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) 21