Cimarron Alluvium & Terrace

The Cimarron Alluvial and Terrace aquifer located in north-central and north-western Oklahoma is composed of loose sediments, mostly made of gravel, medium to fine sands, and some mud. Underlying the newer geological formations are several older formations including the Flowerpot Shale and Hennessy. The underlying formations do not act as an impermeable unit; however, their aquifer properties are significantly lower and they are not considered part of the Cimarron alluvium and terrace. Aquifer thickness ranges from near zero feet at its boundary to over 100 feet in the central areas with an average of approximately 30 feet.

The aquifer is primarily used for irrigation and public water supply purposes, with some oil and gas and domestic water use. Wells commonly yield 50 to 200 gallons per minute (gpm), with some wells reportedly reaching up to 2000 gpm. The higher yield wells tend to be located in the thicker parts of the aquifer.

Water quality has been described as adequate for most purposes, but can be hard and variable over short distances; especially if well penetrate the Permian units under the aquifer. Wells that do have less than adequate water can have high concentrations of calcium sulfate or sodium chloride.