Drainage Report

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 29 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 0.03 38 585.01 0.00 3.00 0.07 314 585.08 0.00 4.50 0.09 759 585.19 0.00 6.00 0.11 1,324 585.33 0.00 7.50 0.16 2,070 585.51 0.00 9.00 0.22 3,104 585.76 0.00 10.50 0.42 4,803 586.18 0.00 12.00 4.00 10,671 587.52 0.00 13.50 0.62 20,093 589.74 0.70 15.00 0.32 19,134 589.51 0.52 16.50 0.24 18,377 589.32 0.32 18.00 0.18 18,067 589.24 0.22 19.50 0.16 17,906 589.20 0.17 21.00 0.14 17,828 589.19 0.15 22.50 0.12 17,768 589.17 0.13 24.00 0.11 17,711 589.16 0.12 25.50 0.00 17,350 589.07 0.04 27.00 0.00 17,181 589.03 0.02 28.50 0.00 17,097 589.01 0.01 30.00 0.00 17,052 588.99 0.01 31.50 0.00 17,018 588.99 0.01 33.00 0.00 16,991 588.98 0.00 34.50 0.00 16,968 588.97 0.00 36.00 0.00 16,949 588.97 0.00 37.50 0.00 16,934 588.97 0.00 39.00 0.00 16,922 588.96 0.00 40.50 0.00 16,912 588.96 0.00 42.00 0.00 16,904 588.96 0.00 43.50 0.00 16,897 588.96 0.00 45.00 0.00 16,891 588.96 0.00 46.50 0.00 16,887 588.95 0.00 48.00 0.00

43.50 0.00 16,897 588.96 0.00 45.00 0.00 16,891 588.96 0.00 46.50 0.00 16,887 588.95 0.00 48.00 0.00 16,883 588.95 0.00 49.50 0.00 16,880 588.95 0.00 51.00 0.00 16,878 588.95 0.00 52.50 0.00 16,876 588.95 0.00 54.00 0.00 16,874 588.95 0.00 55.50 0.00 16,873 588.95 0.00 57.00 0.00 16,872 588.95 0.00 58.50 0.00 16,871 588.95 0.00 60.00 0.00 16,870 588.95 0.00 61.50 0.00 16,870 588.95 0.00 63.00 0.00 16,869 588.95 0.00 64.50 0.00 16,869 588.95 0.00 66.00 0.00 16,869 588.95 0.00 67.50 0.00 16,868 588.95 0.00 69.00 0.00 16,868 588.95 0.00 70.50 0.00 16,868 588.95 0.00 72.00 0.00 16,868 588.95 0.00

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 30 Stage-Discharge for Pond 17P: Porous pavement system 4 Elevation Primary Elevation Primary Elevation Primary Elevation Primary (feet) (cfs) (feet) (cfs) (feet) (cfs) (feet) (cfs) 585.00 0.00 587.55 0.00 590.10 1.47 592.65 6.91 585.05 0.00 587.60 0.00 590.15 1.72 592.70 6.98 585.10 0.00 587.65 0.00 590.20 2.00 592.75 7.04 585.15 0.00 587.70 0.00 590.25 2.28 592.80 7.10 585.20 0.00 587.75 0.00 590.30 2.51 592.85 7.16 585.25 0.00 587.80 0.00 590.35 2.70 592.90 7.22 585.30 0.00 587.85 0.00 590.40 2.87 592.95 7.28 585.35 0.00 587.90 0.00 590.45 3.03 593.00 7.34 585.40 0.00 587.95 0.00 590.50 3.18 585.45 0.00 588.00 0.00 590.55 3.32 585.50 0.00 588.05 0.00 590.60 3.45 585.55 0.00 588.10 0.00 590.65 3.58 585.60 0.00 588.15 0.00 590.70 3.71 585.65 0.00 588.20 0.00 590.75 3.82 585.70 0.00 588.25 0.00 590.80 3.94 585.75 0.00 588.30 0.00 590.85 4.05 585.80 0.00 588.35 0.00 590.90 4.16 585.85 0.00 588.40 0.00 590.95 4.26 585.90 0.00 588.45 0.00 591.00 4.37 585.95 0.00 588.50 0.00 591.05 4.47 586.00 0.00 588.55 0.00 591.10 4.56 586.05 0.00 588.60 0.00 591.15 4.66 586.10 0.00 588.65 0.00 591.20

586.00 0.00 588.55 0.00 591.10 4.56 586.05 0.00 588.60 0.00 591.15 4.66 586.10 0.00 588.65 0.00 591.20 4.75 586.15 0.00 588.70 0.00 591.25 4.84 586.20 0.00 588.75 0.00 591.30 4.93 586.25 0.00 588.80 0.00 591.35 5.02 586.30 0.00 588.85 0.00 591.40 5.11 586.35 0.00 588.90 0.00 591.45 5.19 586.40 0.00 588.95 0.00 591.50 5.27 586.45 0.00 589.00 0.01 591.55 5.36 586.50 0.00 589.05 0.03 591.60 5.44 586.55 0.00 589.10 0.07 591.65 5.52 586.60 0.00 589.15 0.11 591.70 5.60 586.65 0.00 589.20 0.17 591.75 5.67 586.70 0.00 589.25 0.23 591.80 5.75 586.75 0.00 589.30 0.30 591.85 5.82 586.80 0.00 589.35 0.36 591.90 5.90 586.85 0.00 589.40 0.43 591.95 5.97 586.90 0.00 589.45 0.47 592.00 6.04 586.95 0.00 589.50 0.52 592.05 6.12 587.00 0.00 589.55 0.56 592.10 6.19 587.05 0.00 589.60 0.60 592.15 6.26 587.10 0.00 589.65 0.63 592.20 6.32 587.15 0.00 589.70 0.67 592.25 6.39 587.20 0.00 589.75 0.70 592.30 6.46 587.25 0.00 589.80 0.73 592.35 6.53 587.30 0.00 589.85 0.76 592.40 6.59 587.35 0.00 589.90 0.79 592.45 6.66 587.40 0.00 589.95 0.89 592.50 6.72 587.45 0.00 590.00 1.05 592.55 6.79 587.50 0.00 590.05 1.24 592.60 6.85

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 10-Year Rainfall=5.22" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 31 Stage-Area-Storage for Pond 17P: Porous pavement system 4 Elevation Storage Elevation Storage (feet) (cubic-feet) (feet) (cubic-feet) 585.00 0 590.10 21,552 585.10 407 590.20 21,959 585.20 814 590.30 22,366 585.30 1,221 590.40 22,773 585.40 1,628 590.50 23,180 585.50 2,036 590.60 23,588 585.60 2,443 590.70 23,995 585.70 2,850 590.80 24,402 585.80 3,257 590.90 24,809 585.90 3,664 591.00 25,216 586.00 4,071 591.10 25,623 586.10 4,486 591.20 26,030 586.20 4,908 591.30 26,437 586.30 5,334 591.40 26,845 586.40 5,762 591.50 27,252 586.50 6,193 591.60 27,659 586.60 6,626 591.70 28,066 586.70 7,061 591.80 28,473 586.80 7,497 591.90 28,880 586.90 7,934 592.00 29,287 587.00 8,373 592.10 29,694 587.10 8,812 592.20 30,101 587.20 9,251 592.30 30,509 587.30 9,691 592.40 30,916 587.40 10,132 592.50 31,323 587.50 10,572 592.60 31,730 587.60 11,013 592.70 32,137 587.70 11,453 592.80 32,544 587.80 11,894 592.90 32,951 587.90 12,333 593.00 33,358 588.00 12,772 588.10 13,211 588.20 13,648 588.30 14,084 588.40 14,519 588.50 14,952 588.60 15,383 588.70 15,811 588.80 16,237 588.90 16,658 589.00 17,074 589.10 17,481 589.20 17,888 589.30

14,952 588.60 15,383 588.70 15,811 588.80 16,237 588.90 16,658 589.00 17,074 589.10 17,481 589.20 17,888 589.30 18,295 589.40 18,702 589.50 19,109 589.60 19,516 589.70 19,923 589.80 20,331 589.90 20,738 590.00 21,145

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 100-Year Rainfall=8.66" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 32 Time span=0.00-72.00 hrs, dt=0.03 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 16S: Basin 4 Porous pvmt Runoff Area=85,708 sf Runoff Depth=7.59" Flow Length=509' Tc=8.1 min CN=74/98 Runoff=14.11 cfs 1.245 af Subcatchment 18S: OL-4 Runoff Area=11,273 sf Runoff Depth=5.60" Flow Length=96' Slope=0.0573 '/' Tc=8.7 min CN=74/98 Runoff=1.50 cfs 0.121 af Subcatchment 19S: pre-dev basin 4 Runoff Area=96,981 sf Runoff Depth=5.04" Flow Length=190' Tc=15.9 min CN=70/0 Runoff=9.38 cfs 0.934 af Pond 17P: Porous pavement system 4 Peak Elev=591.49' Storage=27,199 cf Inflow=14.11 cfs 1.245 af Outflow=5.25 cfs 0.858 af Total Runoff Area = 4.453 ac Runoff Volume = 2.300 af Average Runoff Depth = 6.20"

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 100-Year Rainfall=8.66" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 33 Summary for Subcatchment 16S: Basin 4 Porous pvmt [47] Hint: Peak is 575% of capacity of segment #3 Runoff = 14.11 cfs @ 12.15 hrs, Volume= 1.245 af, Depth= 7.59" Routed to Pond 17P : Porous pavement system 4 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 100-Year Rainfall=8.66" Area (sf) CN Description * 61,324 98 roof and parking 24,384 74 >75% Grass cover, Good, HSG C 85,708 91 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 100 0.0520 0.26 Sheet Flow, grass Grass: Short n= 0.150 P2= 3.44" 0.6 100 0.0300 2.60 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 1.0 309 0.0261 5.35 2.45 Pipe Channel, 15.0" Round w/ 9.0" inside fill Area= 0.5 sf Perim= 2.9' r= 0.16' n= 0.013 Corrugated PE, smooth interior 8.1 509 Total Subcatchment 16S: Basin 4 Porous pvmt Hydrograph Runoff 15

Hydrograph Runoff 15 14.11 cfs 14 NOAA 24-hr D 13 12 100-Year Rainfall=8.66" 11 Runoff Area=85,708 sf 10 Runoff Volume=1.245 af 9 Flow (cfs) 8 Runoff Depth=7.59" 7 Flow Length=509' 6 Tc=8.1 min 5 4 CN=74/98 3 2 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)

Basin 4 without exfiltration Proposed basin 4 R5 NOAA 24-hr D 100-Year Rainfall=8.66" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 34 Hydrograph for Subcatchment 16S: Basin 4 Porous pvmt Time Precip. Perv.Excess Imp.Excess Runoff (hours) (inches) (inches) (inches) (cfs) 0.00 0.00 0.00 0.00 0.00 1.50 0.15 0.00 0.04 0.08 3.00 0.33 0.00 0.17 0.14 4.50 0.52 0.00 0.34 0.18 6.00 0.74 0.00 0.54 0.20 7.50 1.01 0.03 0.80 0.30 9.00 1.37 0.11 1.16 0.41 10.50 1.94 0.32 1.71 0.77 12.00 4.15 1.71 3.91 7.10 13.50 6.72 3.80 6.48 1.07 15.00 7.29 4.29 7.05 0.56 16.50 7.65 4.61 7.41 0.41 18.00 7.92 4.85 7.68 0.30 19.50 8.14 5.05 7.90 0.27 21.00 8.33 5.23 8.09 0.24 22.50 8.51 5.38 8.27 0.21 24.00 8.66 5.52 8.42 0.18 25.50 8.66 5.52 8.42 0.00 27.00 8.66 5.52 8.42 0.00 28.50 8.66 5.52 8.42 0.00 30.00 8.66 5.52 8.42 0.00 31.50 8.66 5.52 8.42 0.00 33.00 8.66 5.52 8.42 0.00 34.50 8.66 5.52 8.42 0.00 36.00 8.66 5.52 8.42 0.00 37.50 8.66 5.52 8.42 0.00 39.00 8.66 5.52 8.42 0.00 40.50 8.66 5.52 8.42 0.00 42.00 8.66 5.52 8.42 0.00 43.50 8.66 5.52 8.42 0.00 45.00 8.66 5.52 8.42 0.00 46.50 8.66 5.52 8.42 0.00 48.00 8.66 5.52 8.42 0.00 49.50 8.66 5.52 8.42 0.00 51.00 8.66 5.52 8.42 0.00 52.50 8.66 5.52 8.42 0.00 54.00 8.66 5.52 8.42 0.00 55.50