Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma

This data set consists of digitized polygons of constant
hydraulic conductivity values for the Elk City aquifer in
western Oklahoma. The aquifer covers an area of approximately
193,000 acres and supplies ground water for irrigation,
domestic, and industrial purposes in Beckham, Custer, Roger
Mills, and Washita Counties along the divide between the Washita
and Red River basins.

The Elk City aquifer consists of the Elk City Sandstone and
overlying terrace deposits, made up of clay, silt, sand and
gravel, and dune sands in the eastern part and sand and gravel
of the Ogallala Formation (or High Plains aquifer) in the
western part of the aquifer. The Elk City aquifer is unconfined
and composed of very friable sandstone, lightly cemented with
clay, calcite, gypsum, or iron oxide. Most of the grains are
fine-sized quartz but the grain size ranges from clay to cobble
in the aquifer. The Doxey Shale underlies the Elk City aquifer
and acts as a confining unit, restricting the downward movement
of ground water.

Values of hydraulic conductivity used as input to the
ground-water flow model and in this data set are: 50 gallons per
day per foot squared or 6.7 feet per day for the Elk City
Sandstone; 500 gallons per day per foot squared or 66.8 feet per
day for the Quaternary terrace deposits and dune sand; and 750
gallons per day per foot squared or 100.3 feet day for the
Ogallala Formation.

The hydraulic conductivity polygons from a ground-water modeling
thesis were transferred to a photocopy of a paper map and
digitized. The source map was published at a scale of 1:63,360.

Ground-water flow models are numerical representations that
simplify and aggregate natural systems. Models are not unique;
different combinations of aquifer characteristics may produce
similar results. Therefore, values of hydraulic conductivity
used in the model and presented in this data set are not
precise, but are within a reasonable range when compared to
independently collected data.