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r <br />r- <br />Wig <br />I. PEAK RUNOFF RATE FOR 10-YEAR STORM <br />RATIONAL METHOD Q = CIA <br />UNDEVELOPED CONDITIONS <br />A = 1.22 Acre <br />REVISED 3/30/81 <br />C = Runoff Coefficient <br />I = Rainfall Intensity <br />A = Acres, Area <br />Tc = Time of Concentration <br />LANDSCAPING GRAVEL DRIVEWAY ROOFTOP, PAVING UNDEVEL. <br />C = �17,772 x 0.20) + (1,500 x 0.6) + (2,572 x 0.9) + (31,800x.10) <br />EXIST 539143 539143 53,143 53,143 <br />CEXIST = 0.19 <br />I = 1.36 in/hr <br />TL <br />C = 10 + 60(.5) <br />TC = 10 + 30 <br />T = 18.07 min. <br />C <br />B = 0.32 CFS <br />II. RUNOFF COEFFICIENT AVERAGE <br />ROOFTOP, PAVING LANDSCAPING <br />_ (27,411 x 0.9) + (25,713 x 0.2) <br />CD 53,143 <br />CD = 0.56 <br />III. 11AX111UH OUTFLOW PER ACRE IMPERVIOUS (CFS/AC) <br />O = Allowable Outflow <br />o Acreage x RuiofF Coefficien-tCrDT <br />0.32 <br />UO = O- 756 1.22 <br />qo = 0.47 CFS/AC <br />611 medical -dental bldg i everett. wo 98201 206/259.2118 <br />