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25-4181 storm calcs - proposed 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 8 Summary for Subcatchment 2S: Proposed Site [47] Hint: Peak is 126% of capacity of segment #3 Runoff = 2.00 cfs @ 11.99 hrs, Volume= 4,350 cf, Depth= 0.98" Routed to Pond 3P : Underground Detention 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 5,900 98 Roofs, HSG D 20,800 98 Paved parking, HSG D * 1,604 98 Sidewalks 24,735 80 >75% Grass cover, Good, HSG D 53,039 90 Weighted Average 24,735 46.64% Pervious Area 28,304 53.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 27 0.0400 0.10 Sheet Flow, Grass: Dense n= 0.240 P2= 2.50" 0.6 34 0.0210 1.00 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.50" 2.5 307 0.0020 2.03 1.59 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.013 Corrugated PE, smooth interior 7.4 368 Total Page 38 of 65