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<br />~i <' .. <br /> <br />UPPER KIOWA CREEK BASIN <br /> <br />May 30 - 31, 1935 Storm Cells A-2 and A-3 <br /> <br />Hydrologic Modeling Analysis <br /> <br />By Douglas J, Trieste, P.H., Flow Technologies <br /> <br />PURPOSE AND METHODOLOGY <br /> <br />A rainfalllrunoff(RF/RO) modeling study was performed on Upper Kiowa Ck Basin for the <br />purpose of evaluating if the May 30-31, 1935 storm (as documented) can explain measured peak <br />discharge data on Upper Kiowa Ck. <br /> <br />The centers ofthe May 30-31,1935 A-2 and A-3 Cells were positioned over Kiowa Ck basin <br />such that their consequent runoff happened to have peak discharge measurements at critical <br />locations, That is, Cell A-2 is centered over both Kiowa Ck above Elbert and West Kiowa Ck, <br />and a discharge measurement is available just downstream of Elbert (confluence of West Kiowa <br />Ck and Kiowa Ck) (Fig 1 and Table 1). Cell A-3 is centered between Elbert and Kiowa, with an <br />available discharge measurement at Kiowa (Fig 1 and Table 1), The positioning of the cells and <br />measured discharge lends itself to RF/RO modeling of the cells to determine if they can <br />reasonably simulate the measured peak discharge. <br /> <br />HEC-l was the model of choice. Model components most appropriate for this study included <br />Snyder Unit Hydrograph, initiallconstant rainfall loss, and rainfall mass curves specific to the <br />rainfall. <br /> <br />Although numerous sub-basins can be input into HEC-I, modeling resolution was low with only <br />three sub-basins considered - Kiowa Ck at Elbert (above the confluence with West Kiowa Ck), <br />West Kiowa Ck, and Kiowa Ck between Elbert and Kiowa (refer to Fig. 1). Such low modeling <br />resolution was used because of budget constraints, and because the desired modeling results were <br />"ball park;" that is, if results were within the range of hydrologic uncertainty and reasonable, <br />they were deemed sufficient for the purpose of this study. <br /> <br />In addition to May 30-31, 1935 measured peak discharge data, USGS peak discharge data, and <br />storm isohyetals, are available on Kiowa Creek for the June 17, 1965 floods (Table I and Figure <br />1), Because the 1965 isohyetals are well documented and considered accurate, those can be <br />applied for model testing, USGS discharge data is available for Kiowa Creek at Elbert (above <br />West Kiowa Ck confluence), and West Kiowa Ck at Elbert for the 1965 flood, but not for 1935. <br /> <br />The HEC-1 model was tested for reasonableness for Kiowa Ck at Elbert, and West Kiowa Ck at <br />Elbert based on the June 17, 1965 rainfall, and USGS discharge measurements. That model was <br />