SBUH Calculation Worksheet for City of Eugene Storm EventsProject Name: BraewoodDate: 8/28/2025Designer: ALBBasin: Swale 6User-Supplied DataPervious AreaImpervious AreaPervious Area, SF13,89717,092 Pervious Area, Acres0.320.39Pervious Area Curve Number, CNperv7698Time of Concentration, Tc, minutes5Note: minimum Tc is five minutesCity of Eugene 24-Hour Rainfall Depths (NRCS Type 1A distribution)Recurrence IntervalWQ2-Yr5-Yr10-Yr25-Yr50-Yr100-YrInches1.56 3.12 3.6 4.46 5.18 6 6.48 <br />Calculated DataTotal Project Area, Acres0.71Total Project Area, Square Feet30,988Recurrence IntervalWQ2-Yr5-Yr10-Yr25-Yr50-Yr100-YrPeak Flow Rate, Qpeak, cfs0.150.390.470.620.760.911.00Total Runoff Volume, V, cubic feet2,1525,3836,4608,44610,14912,12113,288Time to Peak Runoff, hours7.837.837.837.837.837.837.83Runoff HydrographImpervious Area, SFImpervious Area, AcresImpervious Area Curve Number, CNimp0.000.200.400.600.801.001.200 500 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