Drainage Report

Basin 3 without exfiltration proposed basin 3 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 21 Summary for Subcatchment 34S: Basin 3 [47] Hint: Peak is 136% of capacity of segment #4 Runoff = 6.79 cfs @ 12.17 hrs, Volume= 0.615 af, Depth= 3.37" Routed to Pond 35P : Basin 3 Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 10-Year Rainfall=5.22" Area (sf) CN Description 32,412 98 Paved parking, HSG C 63,013 74 >75% Grass cover, Good, HSG C 95,425 82 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 100 0.0800 0.21 Sheet Flow, Grass: Dense n= 0.240 P2= 3.44" 0.1 20 0.0800 4.24 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 0.4 100 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.8 450 0.0600 8.91 5.00 Pipe Channel, 15.0" Round w/ 8.0" inside fill Area= 0.6 sf Perim= 3.1' r= 0.18' n= 0.013 Concrete sewer w/manholes & inlets 9.2 670 Total, Increased to minimum Tc = 10.0 min