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<br />I <br />I <br />I 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 />18 <br /> <br />ADDITIONAL HEC-l RUNS <br />The above data on improved Inlets and available storage were used In the existing <br />HEC-I model to determine their effects on the water surface elevation upstream of <br />the railroad. This study represents a refinement of the current FHAD analysis. The <br />same assumptions were used as in the original FHAD study: fully developed, unde- <br />tained flows and the same floodway criteria. This study does reflect the reduced <br />outflows from Ketner Reservoir after completion of the recent construction and the <br />inclusion of the effects of floodway storage. These changes represent a more de- <br />tailed, In-depth study of the flood elevations during the 10o-year event at a specific <br />location on Big Dry Creek. The results of these changes are shown in Table 3. <br /> <br />During this study, the UDFCD and the city of Westminster redefined what .adequate <br />assurances. In regards to Standley Lake means. In the original FHAD study, the <br />HEC-l model included a constant outflow of 430 cfs from the principal spillway plus <br />an outflow hydrograph from the emergency spillway which peaked at 1,043 cfs. The <br />sum of these two peak flows is about 1,470 cfs. Using the new definition of .ade- <br />quate assurances', there Is assumed to be a constant outflow of 1,470 cfs from <br />Standley Lake. <br /> <br />In addition, the UDFCD and the city of Westminster also requested a study of what <br /> <br /> <br />Increase In the water surface would take place upstream of the railroad jf land not <br /> <br /> <br />owned by the Bruchez family were excluded from the floodway storage volumes. <br /> <br /> <br />The results of the change in assumption for "adequate assurances' and reduced <br /> <br /> <br />storage volume are also shown in Table 3. <br />