Laserfiche WebLink
<br />3.1.6 Reach Routing <br /> <br />The Kinematic Wave method was used to route the hydrographs down <br />the reaches. More details are available in the hydrologic supporting <br />computations. <br /> <br />3.2 HEC-HMS Results and Feasibility <br /> <br />Very little gage data was available for the area, thus in order to <br />determine the reasonableness of the HEC-HMS model results, <br />comparisons were made to four published regional regressIOn <br />equations as described below. <br /> <br />3.2.1 CWCB Regression Equations <br /> <br />roO-year peak discharges were determined for the four basins using <br />the recommendations outlined in "Guidelines for Determining 100- <br />Year Flood Flows For Approximately Floodplains in Colorado" <br />(Reference 3). Because the drainage areas fall on the boundary of two <br />different regression equations, comparisons were made to both <br />equations. <br /> <br />SPL-l: Eastern Plains Subregion <br /> <br />Q100 = 707.9(A)654 <br /> <br />Where A = Drainage Area in square miles (I <A<I090) <br /> <br />SPL-2: Southern Foothills Subregion <br /> <br />Q100 = 10055(A)638 <br /> <br />Where A = Drainage Area in square miles (I <A<I70) <br /> <br />3.2.2 ASFPM Regression Equations <br /> <br />100-year peak discharges were determined for the four basins using <br />the recommendations outlined in "Regional Flood Frequency Analysis <br />In The Plains Region of Colorado And Kansas" (Reference 4). <br /> <br />QIOO = 734.8(DA)1l32(DAn-o.1) <br /> <br />Where D A = Drainage Area in square miles <br /> <br />3.2.3 USGS Regression Equations <br /> <br />IOO-year peak discharges were determined for the four basins using <br />the recommendations for the plains region of Colorado as outlined in <br /> <br />4 <br />