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: 2 <br />User-Supplied Data <br />Pervious Area Impervious Area <br />Pervious Area, SF0 11,041 Pervious Area, Acres 0.00 0.25 <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 0.25 Total Project Area, Square Feet 11,041 <br />Recurrence Interval WQ 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr <br />Peak Flow Rate, Qpeak, cfs 0.09 0.21 0.24 0.30 0.35 0.40 0.43 <br />Total Runoff Volume, V, cubic feet 1,087 2,657 3,097 3,887 4,548 5,301 5,743 <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, CNimp0.000.050.100.150.200.250.300.350.400.450.500 500 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