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� <br /> CALCULATION OF UNDEVELOPED RUNOFF <br /> Area Determined by Planimeter <br /> A1 = 3.79 Acres <br /> A2 = 1.07 Acres <br /> Total = 4.86 Acres <br /> IN GENERAL : C.I.A. <br /> WHERE: <br /> Q = Maximum rainfall intensity for each subarea in Ft3/sec. <br /> C = Runoff coefficient (see table 1 attached) . <br /> I = Rainfall intensity for given time of concentration "Tc" <br /> for each subarea in In./hr. (see table 2 attached) . <br /> A = Area in acres for each subarea. <br /> Tc = Time of concentration (velocities from chart l�3 attached) . <br /> A1 <br /> Ground Cover - Woodland - Rolling 6% & 0.5% <br /> C = 0.05 Area = 3.79 <br /> Distance = 260 feet @ 6% ------------- Velocities = 0.6 ft./sec. <br /> 600 feet @ 0.5% ---------- Velocities = 0.175 ft./sec. <br /> T = 150 feet + 150 f.eet + 10 minutes <br /> (60 sec.) (0.6 ft.Isec.) (6Q sec.) (O.11S ft./sec.) <br /> = 4.17 r,un + 14.29 min. + 10 mi.n. <br /> = 28.46 min. <br /> I7.0 = 1.08 in./hr. <br /> Q = C.I.A. <br /> _ (0.05)(1.�8 in./lir.) (3.79 Ac.) <br /> = 0.20 �cs <br /> AZ <br /> Ground Cover - Woodland - Rolling 3"/, <br /> C = 0.05 Area = 1.07 Acres <br />