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<br /> TABLE 3 <br /> 6-HOUR HYPOTHETICAL STORM DISTRIBUTION <br /> RALSTON CREEK, LOWER REGION <br /> Rainfall (inches) for <br />Time specified Recurrence Interval <br />(Min) 10-vr SO-vr lOO-vr SOO-vr <br />00 .00 .00 .00 .00 <br />30 .04 .04 .06 .10 <br />60 .05 .06 .07 .12 <br />90 .06 .06 .08 .14 <br />120 .10 .11 .15 .17 <br />150 .11 .12 .16 .31 <br />180 .44 .63 .70 .89 <br />210 .92 1. 34 1.53 2.02 <br />240 .12 .14 .19 .35 <br />270 .11 .11 .17 .18 <br />300 .06 .07 .09 .15 <br />330 .06 .06 .07 .12 <br />360 .04 .04 .06 .10 <br />Total 2.21 2.79 3.35 4.66 <br /> <br />b. Reservoir Routina <br />Three existing reservoirs were included in the analysis. <br />Ralston and Blunn Reservoirs are located just below the <br />foothills on Ralston Creek. Leyden Reservoir is located just <br />upstream of Indiana street on Leyden Creek. Reservoir storage <br />and outflow was determined by receiving upstream inflows and <br />routing these inflows through the reservoir according to the <br />modified PuIs routing method. This method uses a storage <br />volume verses elevation relationship and an outflow capacity <br />verses Elevation relationship. Assumptions used in the <br />modified PuIs routing method are: 1) the reservoirs were <br />assumed filled to the elevation of the spillway crest so that <br />the only effects in reducing flows was from surcharge routing <br />and not retention; and 2) the routing assumes a level water <br />surface behind the reservoir. Table 4 lists the reservoirs <br />characteristics. <br /> <br />TABLE 4 <br />RESERVOIR INFORMATION <br /> <br />Reservoir <br /> <br />River <br /> <br />size at <br />Normal Pool <br />(Acres) <br /> <br />spillway <br />Capacity <br />(cfs) <br /> <br />Use <br /> <br />Ralston Ralston Cr <br />Blunn Ralston Cr <br />Leyden Leyden Cr <br />Note: Spillway capacity <br />is at top-of-dam. <br /> <br />155 <br />144 <br />69 <br />reported <br /> <br />37,000 <br />60,000 <br />2,800 <br />when water <br /> <br />Water Supply <br />Water Supply <br />Water Supply <br />surface level <br /> <br />is <br /> <br />6 <br />