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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Table ID-5 <br /> <br />Hazard Classification Summary <br /> <br /> <br />Westerdoll <br /> <br />.......................................-.-..-.-.-.-.....-.................-.',...........................................................-. <br />II~ft~I~I&~~!ljj~. l~fjjj~11 <br />.................................................-.....-................................................. <br />....... ..........------.-.............. ......... <br />50 % PMP(Class IT) <br />100- Y ear <br /> <br />Class III (Future Class IT) <br />Class III <br /> <br />Upper and Lower Hoffinans <br />Heinricy <br /> <br />Non-Jurisdictional <br /> <br />N/A <br /> <br />Boyd <br /> <br />Class I <br /> <br />75 % PMP <br /> <br />Horseshoe <br /> <br />Class IT <br />Class III (Future Class I) <br /> <br />50 % PMP <br /> <br />Equalizer/Houts <br /> <br />75 % PMP <br /> <br />To determine the critical design PMP, two storms were considered: 1) local storm and 2) <br />general storm. The local and general storms were calculated based on the National Weather Service <br />publication Hydrometeorologic Report No. 55A. The 100-year storm was calculated based on the <br />National Oceanic and Atmospheric Administration (NOAA), Precipitation-Frequency Atlas of the <br />Western United States, Volume Ill- Colorado. The precipitation resulting from these storms for the <br />four models are summarized in Tables Ill-6 through Ill-9. <br /> <br />The United States Army Corps of Engineers computer model, HEC-1, was used to evaluate <br />the inflow design floods for each of the reservoirs based on the storm precipitation depths in the <br />previous listed tables. The storm precipitation depths were used to create a hypothetical storm. A <br />runoffhydrograph based on the storms was determined in HEC-1 using the United States Bureau of <br />Reclamation (USBR) dimensionless unit hydrograph procedure. The dimensionless unit hydrograph <br />developed for Urban and Great Plains regions were used to develop the synthetic unit hydro graphs <br />as input into the HEC-1 models. <br /> <br />E:\G&LREPOR. WPD <br /> <br />17 <br />