SBUH Calculation Worksheet for City of Eugene Storm Events <br />Project Name: Bushnell University Duke Commons Date: 5/1/2026 <br />Designer: Taylor Hood, Maria Talero Basin: 3 <br />User-Supplied Data <br />Pervious Area Impervious Area <br />Pervious Area, SF0 9,722 Pervious Area, Acres 0.00 0.22 <br />Pervious Area Curve Number, CNperv 80 98 <br />Time of Concentration, Tc, minutes5 Note: minimum Tc is five minutes <br />City of Eugene 24-Hour Rainfall Depths (NRCS Type 1A distribution) <br />Recurrence Interval WQ 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr <br />Inches 1.4 3.12 3.6 4.46 5.18 6 6.48 <br />Calculated Data <br />Total Project Area, Acres 0.22 Total Project Area, Square Feet 9,722 <br />Recurrence Interval WQ 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr <br />Peak Flow Rate, Qpeak, cfs 0.08 0.18 0.21 0.26 0.30 0.35 0.38 <br />Total Runoff Volume, V, cubic feet 957 2,340 2,727 3,422 4,005 4,668 5,057 <br />Time to Peak Runoff, hours 7.83 7.83 7.83 7.83 7.83 7.83 7.83 <br />Runoff Hydrograph <br />Impervious Area, SF <br />Impervious Area, Acres <br />Impervious Area Curve Number, CNimp0.000.050.100.150.200.250.300.350.400.450 500 1000 1500 2000 2500Runoff, cfsTime, minutesWQ2-Year5-Year10-Year25-Year50-Year100-Year 800 Willamette Street, Suite 400 Eugene, OR 97401 541.684.4902 kpff.com