Laserfiche WebLink
<br />. <br />., I <br /> <br />.' <br /> <br />TABLE 2 <br />6-HOUR ACCUMULATED POINT RAINFALL VALUES <br />CLEAR CREEK BASIN <br /> <br />Frequency <br />(vears) <br /> <br />2 <br />5 <br />10 <br />50 <br />100 <br />500 <br /> <br />Rainfall <br />(inches) <br /> <br />0.9 <br />1.2 <br />1.4 <br />1.8 <br />2.0 <br />2.4 <br /> <br />Adjusted Rainfall <br />(inches) <br /> <br />0.70 <br />1.02 <br />1.24 <br />1.59 <br />1.77 <br />2.12 <br /> <br />TABLE 3 <br />6-HOUR HYPOTHETICAL STORM DISTRIBUTION <br />CLEAR CREEK BASIN <br /> <br />Rainfa1~Intensity (inches/hour) for <br />Recurrence Interval <br />2-yr s-yr lo-yr so-yr 100-yr <br /> <br />Time <br />(Min) <br /> <br />~- - <br /> <br />30 <br />60 <br />90 <br />______120 <br />150 <br />180 <br />210 <br />240 <br />270 <br />300 <br />330 <br />360 <br /> <br />0.02 <br />0.03 <br />0.04 <br />0.06 <br />0.10 <br />0.24 <br />0.58 <br />0.15 <br />0.07 <br />0.05 <br />0.03 <br />0.02 <br /> <br />0.03 <br />0.04 <br />0'.06 <br />0.09 <br />0.15 <br />0.35 <br />0.81 <br />0.22 <br />0.11 <br />0.07 <br />0.05 <br />0.04 <br /> <br />0.04 <br />0.05 <br />0.07 <br />0.10 <br />0.18 <br />0.42 <br />1.05 <br />0.26 <br />0.13 <br />0.08 <br />0.06 <br />0.04 <br /> <br />0.04 <br />0.06 <br />0.08 <br />0.12 <br />0.22 <br />0.55 <br />1.42 <br />0.32 <br />0.16 <br />0.10 <br />0.07 <br />0.05 <br /> <br />0.05 <br />0.07. <br />0.09 <br />0.14 <br />0.25 <br />0.60 <br />1.53 <br />0.36 <br />0.18 <br />0.11 <br />0.08 <br />0.06 <br /> <br />specified <br />soo-yr <br /> <br />0.06 <br />0.08 <br />0.11 <br />0.17 <br />0.30 <br />0.72 <br />1.83 <br />0.44 <br />0.22 <br />0.14 <br />0.09 <br />0.07 <br /> <br />Five existing reservoirs were included in the SWMM. Four <br />of the reservoirs are located on South Clear Creek and the fifth <br />is located on Clear Creek downstream of South Clear Creek near <br />Georgetown. Reservoir storage and outflow was determined using <br />the equation for discharge over a rectangular weir. Assumptions <br />used in determining the reservoir storage and outflow were that <br />1) the surface area of the reservoirs shown on the quadrangle <br />maps correspond to the water surface elevation at the crest of <br />the spillway; 2) the slope of the surrounding area is so steep <br />that the lateral surface area increase is negligible and 3) the <br />reserviors were assumed filled to the crest so that the only <br />effects in reducing flows was from surcharge routing and not <br />detention. Table 4 lists reservior characteristics. <br /> <br />4 <br />