Surface-water supplies are diminishing in the Hayes-Red Willow and Frenchman Irrigation Districts in soutwest Nebraska. Stream depletions due to ground-water withdrawals upstream from Enders Reservoir have resulted in a shortage of about 8,700 acre-feet per year. The availability of ground water in two surficial aquifers was examined as a possible supplemental supply. The most productive aquifer comprises alluvial deposits in the valleys of the Republican River and Frenchman Creek. The Ogallala Formation, which underlies the remainder of the area is a less productive aquifer except locally. Water levels have risen as much as 20 feet north of the Republican River and as much as 40 feet south of the river. Ground water inflow to the Republican River has increased about 3 percent. A digital model of the aquifer system was used to assess the potential for providing supplemental supplies from two well configurations and from existing irrigation wells. The first well configuration could sustain a maximum of 25 percent of the 1976 deficit with maximum stream depletions of 11 percent to Frenchman Creek and 60 percent to Blackwood Creek. The second well configuration could sustain 25 percent of the 1976 deficit with stream depeletions of less than 5 percent at the end of 19 years. Existing wells are adequate to irrigate district lands on which they are located for at least 19 years.
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USGS Numbered Series
Ground-water availability in the Hayes-Red Willow, Frenchman, and Meeker-Driftwood irrigation districts, Southwest Nebraska