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TABLE 13-3[-7 <br />• Weighted "k" Factor <br />Pond 005 - SVS-3 <br />Soil Type k Aree (AC) k x Aree <br /> <br />2VD 0.26 5.3 1.38 <br />46D 0.22 0.9 0.20 <br />%8F 0.25 10.4 2.60 <br />11D 0.27 0.9 0.24 <br />35E 0.24 1.0 0.24 <br />12D, 12E 0.25 0.7 0.17 <br />bbD 0.25 0.1 0.03 <br />34D 0.24 1.3 0.31 <br />Haul Road 0.24 11_1 2.66 <br /> Total 31.7 7.83 <br /> Weighted Average k = 7.83 = 0.247 <br /> 31.7 <br />~~ Precioitation and Storm Tvoe. The precipitation amounts at the Seneca II-W Mine permit <br />area for the 10-yea r, 25-year, and 100-year storms were obtained from NOAA Precipitation <br />Frequency Atlas Precipitation - Freauencv Atlas of the Western States - Volume II - <br />Colorado, 1973. A standard SCS Type 11 storm was utilized for each analysis. <br />Unit Hvdrouraoh end Surface Condition. The SEDCAD computer program provides three unit <br />hydrograph shapes to choose from in determining the runoff characteristics of a watershed. <br />Time of Concentration. The time of concentration, tc, is defined as the time required for <br />water to flow from the hydraulically most remote point in the watershed to the watershed <br />outlet. <br />The time of concentration for Pond 005 was calculated using the SEDCAD computer program. <br />The program determines overland flow to a pond structure by utilizing the Seven SCS Upland <br />Curves which yield velocity as a function of slope end land use (Barfield et al., 1983). <br />Listed below is a summary of the time of concentration for the subwatersheds. <br />• <br />13-3-7 Revised 08/11/92 <br />