Eugene Stormwater Facility Calculator Project Name: Bushnell University Duke Commons <br />Basin: 4 <br />Instructions:Date: 5/1/2026 <br />1. Choose Facility Type <br />2. Choose shape <br />3. Complete information in highlighted cells <br />Facility Raingarden <br />Grassy <br />Shape Rectangular Below-Grade <br />Bottom Area:25 sf 40 <br />Bottom Width:10 ft 12 <br />Side Slope:4to 1 0.40 <br />Storage Depth:6in <br />Growing Media:18 in 1.00 <br />2.00 <br />Surface Storage Capacity 22 cf <br />Infiltration Area @ 75%72 sf <br />GM Infiltration Rate 2.5 in/hr <br />Infiltration Capacity (avg)0.004 cfs <br />Results <br />SURFACE CAPACITY <br />Recurrance <br />Interval <br />Peak Flow <br />(cfs) <br />Volume <br />(cf) <br />Meets <br />Infiltration? <br />WQ 0.0041 150 Filtration Only <br />2-Yr 0.0311 381 <br />5-Yr 0.0361 448 <br />10-Yr 0.0450 567 N/A <br />25-Yr 0.0524 668 <br />50-Yr 0.0609 783 <br />100-Yr 0.0658 850 <br />N/A <br />69% <br />N/A <br />N/A <br />Rock Capacity <br />N/A <br />N/A <br />N/A <br />N/A <br />Impermeable Liner <br />10-Yr Infiltration <br />Volume (cf): <br />WATER QUALITY EVENT PASS ROCK CAPACITY N/A <br /> 800 Willamette Street, Suite 400 Eugene, OR 97401 541.684.4902 kpff.com