Urbanization and industrial growth have increased demands on water supplies in the vicinity of the Wichita Mountains in southwestern Oklahoma. The principal city, Lawton, uses surface water, supplemented by small quantities of ground water from the Arbuckle Group (Cambrian-Ordovician), for industrial and recreational use. During periods of drought, surface-water supplies in the Wichita Mountains area are not adequate to meet fully the increased water demands. An alternative source of water may be ground water from the Arbuckle Group. Other urban and rural consumers use ground water from Quaternary alluvium, the Rush Springs Formation (Permian), or the Arbuckle Group.