SBUH Calculation Worksheet for City of Eugene Storm Events <br />Project Name: Braewood Date: 12/18/2023 <br />Designer: Anna Backus Basin: Full Existing Study Area <br />User-Supplied Data <br />Pervious Area Impervious Area <br />Pervious Area, SF 539,556 <br />Pervious Area, Acres 12.39 0.00 <br />Pervious Area Curve Number, CNperv 76 98 <br />Time of Concentration, Tc, minutes 17 Note: minimum Tc is five minutes <br />City of Eugene 24-Hour Rainfall Depths (NRCS Type 1A distribution) <br />Recurrence Interval WQ 2 5 10 25 50 100 <br />Inches 1.4 3.12 3.6 4.46 5.18 6 6.48 <br />Calculated Data <br />Total Project Area, Acres 12.39 Total Project Area, Square Feet 539,556 <br />Recurrence Interval WQ 2 5 10 25 50 100 <br />Peak Flow Rate, Qpeak, cfs 0.15 2.28 3.26 5.19 6.93 9.01 10.27 <br />Total Runoff Volume, V, cubic feet 6,762 49,310 64,671 94,329 120,706 151,980 170,760 <br />Time to Peak Runoff, hours 24.00 8.00 8.00 8.00 8.00 8.00 8.00 <br />Runoff Hydrograph <br />Impervious Area, SF <br />Impervious Area, Acres <br />Impervious Area Curve Number, CNimp <br />0.00 <br />2.00 <br />4.00 <br />6.00 <br />8.00 <br />10.00 <br />12.00 <br />0 500 1000 1500 2000 2500Runoff, cfsTime, minutes <br />WQ <br />2-Year <br />5-Year <br />10-Year <br />25-Year <br />50-Year <br />100-Year <br /> 800 Willamette Street, Suite 400 Eugene, OR 97401 541.684.4902 kpff.com