This data set consists of digitized aquifer boundaries for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers approximately 82 square miles and supplies water for irrigation, domestic, municipal, and industrial use for the City of Enid and western Garfield County. The Quaternary-age Enid isolated terrace aquifer is composed of terrace deposits that consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer is unconfined and is bounded by the underlying Permian-age Hennessey Group on the east and the Cedar Hills Sandstone Formation of the Permian-age El Reno Group on the west. The Cedar Hills Sandstone Formation fills a channel beneath the thickest section of the Enid isolated terrace aquifer in the midwestern part of the aquifer. The aquifer boundaries were digitized and created from information and maps in a ground-water modeling thesis and report of the Enid isolated terrace aquifer. The map digitized was published at a scale of 1:62,500.

This data set consists of digitized water-level elevation contours for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers approximately 82 square miles and supplies water for irrigation, domestic, municipal, and industrial use for the City of Enid and western Garfield County. The Quaternary-age Enid isolated terrace aquifer is composed of terrace deposits that consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer is unconfined and is bounded by the underlying Permian-age Hennessey Group on the east and the Cedar Hills Sandstone Formation of the Permian-age El Reno Group on the west. Cedar Hills Sandstone Formation fills a channel beneath the thickest section of the Enid isolated terrace aquifer in the midwestern part of the aquifer. The water-level elevation contours were digitized from a photocopy of a paper map in a ground-water modeling thesis and report. The map digitized was published at a scale of 1:62,500 shows that the ground-water elevations in 1973 ranged from about 1,360 feet above sea level at the northwestern edge to about 1,150 feet above sea level at the southeastern edge of the aquifer.

This data set consists of a digitized polygon of a constant recharge value for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers approximately 82 square miles and supplies water for irrigation, domestic, municipal, and industrial use for the City of Enid and western Garfield County. The Quaternary-age Enid isolated terrace aquifer is composed of terrace deposits that consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer is unconfined and is bounded by the underlying Permian-age Hennessey Group on the east and the Cedar Hills Sandstone Formation of the Permian-age El Reno Group on the west. Cedar Hills Sandstone Formation fills a channel beneath the thickest section of the Enid isolated terrace aquifer in the midwestern part of the aquifer. The polygons boundary was digitized from a photocopy of a paper map from a ground-water modeling thesis and report. The map digitized was published at a scale of 1:62,500. The recharge value reported in the ground-water modeling thesis and report for the Enid isolated terrace aquifer is 2.3 inches per year. 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 recharge 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.

This data set consists of digitized water-level elevation contours for the High Plains aquifer in western Oklahoma. This area encompasses the panhandle counties of Cimarron, Texas, and Beaver, and the western counties of Harper, Ellis, Woodward, Dewey, and Roger Mills. The High Plains aquifer underlies approximately 7,000 square miles of Oklahoma and is used extensively for irrigation. The High Plains aquifer is a water-table aquifer and consists predominately of the Tertiary-age Ogallala Formation and overlying Quaternary-age alluvial and terrace deposits. In some areas the aquifer is absent and the underlying Triassic, Jurassic, or Cretaceous-age rocks are exposed at the surface. These rocks are hydraulically connected with the aquifer in some areas. The High Plains aquifer is composed of interbedded sand, siltstone, clay, gravel, thin limestones, and caliche. The proportion of various lithological materials changes rapidly from place to place, but poorly sorted sand and gravel predominate. The rocks are poorly to moderately well cemented by calcium carbonate. The water-level elevations were measured in January, February, and March 1980 and ranged from about 4,650 feet above sea level in Cimarron County to about 2,000 feet above sea level in Woodward County. The water-level elevation contours were digitized from folded paper maps in a published report. The source maps were published at a scale of 1:250,000.

This data set consists of digitized water-level elevation contours for the Central Oklahoma aquifer in central Oklahoma. This area encompasses all or part of Cleveland, Lincoln, Logan, Oklahoma, Payne, and Pottawatomie Counties. The Central Oklahoma aquifer includes the alluvial and terrace deposits along major streams, the Garber Sandstone and Wellington Formations, and the Chase, Council Grove, and Admire Groups. The Quaternary-age alluvial and terrace deposits consist of unconsolidated clay, silt, sand, and gravel. The Permian-age Garber Sandstone and Wellington Formations consist of sandstone with interbedded siltstone and mudstone. The Permian-age Chase, Council Grove, and Admire Groups consist of sandstone, shale, and thin limestone. The Central Oklahoma aquifer underlies about 3,000 square miles of central Oklahoma where the aquifer is used extensively for municipal, industrial, commercial, and domestic water supplies. Most of the usable ground water within the aquifer is from the Garber Sandstone and Wellington Formations. Substantial quantities of usable ground water also are present in the Chase, Council Grove, and Admire Groups, and in alluvial and terrace deposits associated with the major streams. The water-level elevation map was created from digital data sets developed to produce a map for a previously published report. Water-levels measured in wells during the winter of 1986 and 1987 were used to construct the map. The digital data set contains water-level elevations that range from 850 to 1,350 feet above sea level or the National Geodetic Vertical Datum of 1929 (NGVD29).

This data set consists of digitized water-level elevation contours for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers Sandstone is an important source of water in an area that underlies about 4,400-square miles of all or part of Atoka, Bryan, Carter, Choctaw, Johnston, Love, Marshall, McCurtain, and Pushmataha Counties. The Antlers aquifer consists of sand, clay, conglomerate, and limestone in the outcrop area. The upper part of the Antlers aquifer consists of beds of sand, poorly cemented sandstone, sandy shale, silt, and clay. The Antlers aquifer is unconfined where it outcrops in about an 1,800-square-mile area. The water-level elevation contours were digitized from a mylar map at a scale of 1:250,000 that was used to prepare a final map published at a scale of 1:500,000 in a ground-water modeling report. Water levels measured in wells in 1970 were used to construct the map. The water-level elevation contours for the Antlers aquifer in Texas are not included in this data set. The digital data set contains water-level elevations that range from 300 feet (in the east) to 900 feet (in the west) above sea level or the National Geodetic Vertical Datum of 1929.