Maps showing saturated thickness, January 1979, and percentage decrease in saturated thickness, 1950-79, of unconsolidated aquifer, west-central Kansas

The principal water-yielding formation (unconsolidated aquifer) supplying water to wells in west-central Kansas is comprised of the Ogallala Formation and undifferentiated Pleistocene deposits. About 1,860 square miles of the area are underlain by sufficient saturated material to supply groundwater for irrigation. Saturated thickness in the area ranges from less than 50 feet to about 270 feet. Thickness of saturated deposits in the unconsolidated aquifer in west-central Kansas has decreased as a result of groundwater withdrawals, principally for irrigation. From 1950 to 1979, the decrease in saturated thickness was negligible in some areas and as much as 80 feet in other areas. The decrease, in a few areas, was nearly an 80% reduction of the initial (1959) saturated thickness.