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25-4181 storm calcs - existing Type II 24-hr 1-Year Rainfall=1.87" Prepared by Carmina Wood Design Printed 2/11/2026 HydroCAD® 10.20-8a s/n 05019 © 2025 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 1S: Existing Site Runoff = 2.03 cfs @ 12.06 hrs, Volume= 5,636 cf, Depth= 1.28" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.50-70.02 hrs, dt= 0.04 hrs Type II 24-hr 1-Year Rainfall=1.87" Area (sf) CN Description 8,670 98 Roofs, HSG D 31,405 98 Paved parking, HSG D 12,963 80 >75% Grass cover, Good, HSG D 53,038 94 Weighted Average 12,963 24.44% Pervious Area 40,075 75.56% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.1 94 0.0250 0.11 Sheet Flow, Grass: Dense n= 0.240 P2= 2.50" Subcatchment 1S: Existing Site Hydrograph Runoff 2.03 cfs 2 Type II 24-hr 1-Year Rainfall=1.87" Runoff Area=53,038 sf Runoff Volume=5,636 cf Flow (cfs) Runoff Depth=1.28" 1 Flow Length=94' Slope=0.0250 '/' Tc=14.1 min CN=94 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Time (hours) Page 27 of 65