Hydrology and chemical quality of ground water in Crowley County, Colorado

Significant quantities of groundwater can be obtained from several alluvial water-table aquifers possibly from two deep confined sandstone aquifers in Crowley County, Colo. The major water-table aquifer is the alluvium along the Arkansas River valley where well yields may be as much as 2,000 gallons per minute. Minor alluvial aquifers with well yields ranging from 5 to 200 gallons per minute occur in the drainage basins of Horse Creek, Bob Creek, and Sand Arroyo, and in alluvium underlying dune sand in the western part of the county. The Dakota Sandstone and the underlying Cheyenne Sandstone are the confined aquifers. The depth to the top of the Dakota Sandstone ranges from 700 to 3,600 feet below land surface. These aquifers are currently undeveloped but well yields may be as much as 275 gallons per minute. The chemical quality of water in the aquifers varies widely with dissolved solids ranging from about 400 to 8,000 milligrams per liter. On the basis of 35 analyses of water samples, only 2 samples met drinking-water standards for all constituents determined. In most instances, the water is suitable for agricultural uses. (USGS)