Drainage Report

Runoff Volume=0.027 af Flow (cfs) 0.2 Runoff Depth=1.25" 0.18 0.16 Flow Length=96' 0.14 0.12 Slope=0.0573 '/' 0.1 Tc=8.7 min 0.08 0.06 CN=74/98 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)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 12 Hydrograph for Subcatchment 18S: OL-4 Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.06 0.00 0.00 0.00 3.00 0.13 0.00 0.03 0.00 4.50 0.21 0.00 0.07 0.00 6.00 0.29 0.00 0.14 0.00 7.50 0.40 0.00 0.23 0.00 9.00 0.55 0.00 0.36 0.00 10.50 0.77 0.00 0.57 0.00 12.00 1.65 0.20 1.43 0.13 13.50 2.67 0.71 2.44 0.03 15.00 2.89 0.84 2.66 0.02 16.50 3.04 0.93 2.81 0.01 18.00 3.15 1.00 2.91 0.01 19.50 3.23 1.06 3.00 0.01 21.00 3.31 1.11 3.08 0.01 22.50 3.38 1.16 3.15 0.01 24.00 3.44 1.20 3.21 0.01 25.50 3.44 1.20 3.21 0.00 27.00 3.44 1.20 3.21 0.00 28.50 3.44 1.20 3.21 0.00 30.00 3.44 1.20 3.21 0.00 31.50 3.44 1.20 3.21 0.00 33.00 3.44 1.20 3.21 0.00 34.50 3.44 1.20 3.21 0.00 36.00 3.44 1.20 3.21 0.00 37.50 3.44 1.20 3.21 0.00 39.00 3.44 1.20 3.21 0.00 40.50 3.44 1.20 3.21 0.00 42.00 3.44 1.20 3.21 0.00 43.50 3.44 1.20 3.21 0.00 45.00 3.44 1.20 3.21 0.00 46.50 3.44 1.20 3.21 0.00 48.00 3.44 1.20 3.21 0.00 49.50 3.44 1.20 3.21 0.00 51.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 54.00 3.44 1.20 3.21 0.00 55.50 3.44

1.20 3.21 0.00 51.00 3.44 1.20 3.21 0.00 52.50 3.44 1.20 3.21 0.00 54.00 3.44 1.20 3.21 0.00 55.50 3.44 1.20 3.21 0.00 57.00 3.44 1.20 3.21 0.00 58.50 3.44 1.20 3.21 0.00 60.00 3.44 1.20 3.21 0.00 61.50 3.44 1.20 3.21 0.00 63.00 3.44 1.20 3.21 0.00 64.50 3.44 1.20 3.21 0.00 66.00 3.44 1.20 3.21 0.00 67.50 3.44 1.20 3.21 0.00 69.00 3.44 1.20 3.21 0.00 70.50 3.44 1.20 3.21 0.00 72.00 3.44 1.20 3.21 0.00

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment 19S: pre-dev basin 4 Runoff = 1.67 cfs @ 12.26 hrs, Volume= 0.180 af, Depth= 0.97" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.03 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) CN Description 96,981 70 Woods, Good, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.4 100 0.0500 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.44" 1.5 90 0.0400 1.00 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 15.9 190 Total Subcatchment 19S: pre-dev basin 4 Hydrograph Runoff 1.67 cfs NOAA 24-hr D 2-Year Rainfall=3.44" Runoff Area=96,981 sf Runoff Volume=0.180 af Flow (cfs) 1 Runoff Depth=0.97" Flow

1 Runoff Depth=0.97" Flow Length=190' Tc=15.9 min CN=70/0 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)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 14 Hydrograph for Subcatchment 19S: pre-dev basin 4 Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.06 0.00 0.00 0.00 3.00 0.13 0.00 0.00 0.00 4.50 0.21 0.00 0.00 0.00 6.00 0.29 0.00 0.00 0.00 7.50 0.40 0.00 0.00 0.00 9.00 0.55 0.00 0.00 0.00 10.50 0.77 0.00 0.00 0.00 12.00 1.65 0.12 0.00 0.42 13.50 2.67 0.54 0.00 0.28 15.00 2.89 0.66 0.00 0.15 16.50 3.04 0.74 0.00 0.11 18.00 3.15 0.80 0.00 0.08 19.50 3.23 0.85 0.00 0.07 21.00 3.31 0.89 0.00 0.07 22.50 3.38 0.93 0.00 0.06 24.00 3.44 0.97 0.00 0.05 25.50 3.44 0.97 0.00 0.00 27.00 3.44 0.97 0.00 0.00 28.50 3.44 0.97 0.00 0.00 30.00 3.44 0.97 0.00 0.00 31.50 3.44 0.97 0.00 0.00 33.00 3.44 0.97 0.00 0.00 34.50 3.44 0.97 0.00 0.00 36.00 3.44 0.97 0.00 0.00 37.50 3.44 0.97 0.00 0.00 39.00 3.44 0.97 0.00 0.00 40.50 3.44 0.97 0.00 0.00 42.00 3.44 0.97 0.00 0.00 43.50 3.44 0.97 0.00 0.00 45.00 3.44 0.97 0.00 0.00 46.50 3.44 0.97 0.00 0.00 48.00 3.44 0.97 0.00 0.00 49.50 3.44 0.97 0.00 0.00 51.00 3.44 0.97 0.00 0.00 52.50 3.44 0.97 0.00 0.00 54.00 3.44 0.97 0.00 0.00 55.50

4 0.97 0.00 0.00 51.00 3.44 0.97 0.00 0.00 52.50 3.44 0.97 0.00 0.00 54.00 3.44 0.97 0.00 0.00 55.50 3.44 0.97 0.00 0.00 57.00 3.44 0.97 0.00 0.00 58.50 3.44 0.97 0.00 0.00 60.00 3.44 0.97 0.00 0.00 61.50 3.44 0.97 0.00 0.00 63.00 3.44 0.97 0.00 0.00 64.50 3.44 0.97 0.00 0.00 66.00 3.44 0.97 0.00 0.00 67.50 3.44 0.97 0.00 0.00 69.00 3.44 0.97 0.00 0.00 70.50 3.44 0.97 0.00 0.00 72.00 3.44 0.97 0.00 0.00

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 15 Summary for Pond 17P: Porous pavement system 4 Inflow Area = 1.968 ac, Inflow Depth = 2.64" for 2-Year event Inflow = 4.96 cfs @ 12.15 hrs, Volume= 0.432 af Outflow = 0.08 cfs @ 22.15 hrs, Volume= 0.045 af, Atten= 98%, Lag= 600.3 min Primary = 0.08 cfs @ 22.15 hrs, Volume= 0.045 af Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.03 hrs Peak Elev= 589.11' @ 22.15 hrs Surf.Area= 10,178 sf Storage= 17,538 cf Plug-Flow detention time= 1,046.9 min calculated for 0.045 af (10% of inflow) Center-of-Mass det. time= 671.5 min ( 1,444.9 - 773.3 ) Volume Invert Avail.Storage Storage Description #1 585.00' 32,044 cf Custom Stage Data (Prismatic) Listed below (Recalc) 81,424 cf Overall - 1,315 cf Embedded = 80,109 cf x 40.0% Voids #2 586.00' 1,315 cf 36.0" Round Pipe Storage Inside #1 L= 186.0' 33,358 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 585.00 10,178 0 0 593.00 10,178 81,424 81,424 Device Routing Invert Outlet Devices #1 Primary 588.95' 6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 589.90' 24.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.08 cfs @ 22.15 hrs HW=589.11' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.08 cfs @ 1.38 fps) 2=Orifice/Grate ( Controls 0.00 cfs)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 16 Pond 17P: Porous pavement system 4 Hydrograph Inflow 4.96 cfs Primary 5 Inflow Area=1.968 ac Peak Elev=589.11' 4 Storage=17,538 cf Flow (cfs) 3 2 1 0.08 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)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 17 Hydrograph for Pond 17P: Porous pavement system 4 Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.00 0.00 0 585.00 0.00 1.50 0.01 5 585.00 0.00 3.00 0.03 122 585.03 0.00 4.50 0.05 359 585.09 0.00 6.00 0.07 685 585.17 0.00 7.50 0.10 1,136 585.28 0.00 9.00 0.14 1,776 585.44 0.00 10.50 0.25 2,802 585.69 0.00 12.00 2.45 6,360 586.54 0.00 13.50 0.39 13,733 588.22 0.00 15.00 0.20 15,230 588.56 0.00 16.50 0.15 16,164 588.78 0.00 18.00 0.11 16,879 588.95 0.00 19.50 0.10 17,339 589.07 0.04 21.00 0.09 17,515 589.11 0.08 22.50 0.08 17,537 589.11 0.08 24.00 0.07 17,512 589.11 0.07 25.50 0.00 17,270 589.05 0.03 27.00 0.00 17,141 589.02 0.02 28.50 0.00 17,077 589.00 0.01 30.00 0.00 17,038 588.99 0.01 31.50 0.00 17,007 588.98 0.01 33.00 0.00 16,981 588.98 0.00 34.50 0.00 16,960 588.97 0.00 36.00 0.00 16,943 588.97 0.00 37.50 0.00 16,929 588.96 0.00 39.00 0.00 16,918 588.96 0.00 40.50 0.00 16,908 588.96 0.00 42.00 0.00 16,901 588.96 0.00 43.50 0.00 16,895 588.96 0.00 45.00 0.00 16,890 588.96 0.00 46.50 0.00 16,885 588.95 0.00 48.00 0.00