SBUH Calculation Worksheet for City of Eugene Storm EventsProject Name: BraewoodDate: 10/30/2025Designer: Anna BackusBasin: Full Existing Study AreaUser-Supplied DataPervious AreaImpervious AreaPervious Area, SF539,556Pervious Area, Acres12.390.00Pervious Area Curve Number, CNperv7698Time of Concentration, Tc, minutes17Note: minimum Tc is five minutesCity of Eugene 24-Hour Rainfall Depths (NRCS Type 1A distribution)Recurrence IntervalWQ25102550100Inches1.4 3.12 3.6 4.46 5.18 6 6.48 <br />Calculated DataTotal Project Area, Acres12.39Total Project Area, Square Feet539,556Recurrence IntervalWQ25102550100Peak Flow Rate, Qpeak, cfs0.152.283.265.196.939.0110.27Total Runoff Volume, V, cubic feet6,76249,31064,67194,329120,706151,980170,760Time to Peak Runoff, hours24.008.008.008.008.008.008.00Runoff HydrographImpervious Area, SFImpervious Area, AcresImpervious Area Curve Number, CNimp0.002.004.006.008.0010.0012.000 500 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