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HomeMy WebLinkAboutStormwater Runoff Calculations 02.23.22 Upland Way 9/30/2021 2775 Baxter Lane Revised 2/23/22 Basin A Stormwater Run-off Calculation Calculation of Required Volume for Storm Water Retention & Infitration System Design Rainfall Freq. 10 year-2 Hour event OF coefficient a 0.64 OF coefficient b OF coefficient n 0.65 Post-development Calculations: Total Basin Area: 4,225 sf C Areas(ft): Impervious 1,970 0.90 Landscaped 2.255 0.20 Total: 4,225 0.53 Retention Basin Calculation: Required Storage Q=CIA C= 0.53 (post-development) I = 0.41 in/hr(10-yr,2-hr storm) A= 0.10 acres QPOSt= 0.02 cis Required retention storage(ft3)= 151 ft" (10-yr,2-hr storm) Volume held between contours: Cumulative Contour Area(ft2) Delta V(ft) Volume(ft) 4697.75 10 4698.00 95 13 13 4699.00 395 245 258 Design storage provided at 1'depth(ft3)= 258 ft3 ti',r�tlTAly �i� s . •CHRIS G. '• • - BUDES'I ' (QO� N�1 ����Z Z n Basin-A.xls