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E3i11 Murtay-Drainage Smdy <br />DRAINAGE CALCULATIONS <br />BILL MURRAY <br />Total Arca of thc Site = 18,610 SF (0.427 Acres) <br />Development Area = 0.427 Acres <br />As per the Soil Survey of the Snohomish County Ama, the entire site is Aldcrwood-urban <br />land, complex, 2 to 8 percent, which corresponds to a Type C soil. For calculation <br />purposes, a Type C soil was used. <br />EXISTING SITE: <br />Site is subjcct to Evcrett re-development standards. Therefore, for the purposes of <br />drainage design, the entire site is considered second growth forest and brush for drainagc <br />calculations. <br />CN=81 <br />Tc =14.9 Min. (240' Shcet ilow @ 10% avgJ <br />DEVELOPED SITE: <br />Developed Impervious: <br />Rooftops = 5,420 Sq. Ft. <br />Walkways = 1,070 Sq. Ft. <br />Pavement . = 5.110 Sq. Ft. <br />Total <br />Developed Pervious: <br />= 11,600 Sq. Ft. = 0.266 Acres CN = 98 <br />Landscapcd Arcas = 0.427 — 0.2G6 = 0.161 Acres <br />CN=86 <br />Tc = 10.0 Min. (Assumed minimum) <br />�eornfarr <br />6-Month = 099 in. <br />2- Ycar = 1.55 in. <br />10- Ycar = 2.25 in. <br />100- Ycar = 3.25 in. <br />N'Ii57liRK C\GINI![RS.INC PROIECT:01-211-A <br />t <br />