We analyze the hydrologic budget and quantify the ground-water recharge impact of the Great Flood of 1993 on the Great Bend Prairie portion of the High Plains aquifer in south-central Kansas. During the summer of 1993, rainfall totals exceeded normal levels by 200% in the northern portion of the study area, while at the same time air temperature and evapotranspiration were below normal levels. Average ground-water recharge at four index sites was estimated at 178 mm (from January to July 1993) using the hybrid water-fluctuation method of Sophocleous. Employing the recharge-estimation multiple-regression equation of Sophocleous for the area based on 1985-1990 data, we estimated recharge at 145 mm. Both estimates are higher than the maximum annual recharge observed at the recharge index sites during the 1985-1992 period. A January to July 1993 hydrologic balance analysis for a major portion of the study area resulted in a total recharge of 130 mm. The southern portion of the study area was outside the brunt of the summer storms. The recharge amounts caused by the flood in the study area were 3 to more than 4 times the average recharge amounts of the previous 8 years. The regression-based recharge-estimation methodology proved to be generally reliable, even under extreme conditions. Despite the severity of the 1993 flood in the upper Mississippi River basin and northern and central Great Plains, the impact of the "Great Flood of 1993" in south-central Kansas was serious but not catastrophic.
Kansas Geological Survey
Updated April 17, 1997
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