Progress Report on the Ground-Water Hydrology of the Equus-Beds Area, Kansas--1966

Abstract

The drought of the 1950's resulted in a continual water-level decline as reported in Kansas Geological Survey Bulletin 119, Part 1. Since 1957, however, substantial quantities of recharge have occurred, and as a result the water table has shown a net rise. In addition, Wichita's withdrawals from the newly completed surface-water reservoir, commencing in 1965, has resulted in a reduced and dispersed draft from the Equus-beds well field, thus affecting the water levels.

The maximum decline in water level since 1940 was 33 feet in 1956; by December 31, 1965, the maximum decline had decreased to approximately 20 feet. Thus, the maximum net rise in the center of the well field has been 13 feet. The zone of pumping influence encompassed an area somewhat in excess of 120 square miles by 1956, but by December 31, 1965, the affected area had been reduced to about 98 square miles. The storage capacity of the zone of pumping influence had dropped from 111,000 acre-feet in 1956 to 95,800 by the end of 1965, indicating that recharge more than balanced withdrawals. During this period, the City of Wichita had pumped 306,000 acre-feet of water from the well field.

From September 1940 to December 31, 1965, the historical period of pumping, the City of Wichita pumped 636,000 acre-feet of water from the well field. The reduction in storage amounted to 95,800 acre-feet. Thus, about 85 percent of the water pumped from the Wichita well field since 1940 has been replaced by recharge.

The Wichita well field, and certainly the greater Equus-beds area as a whole, can stand substantial increase in development. The full potential of the Equus beds will never be realized unless water levels are lowered to points lower than they have been in the past. The Little Arkansas River, the spillway to the Equus beds, is still a gaining stream, and thus considerable water is discharged from the Equus beds and flows from the area unused. Proper water management in the Equus-beds area must include the development of the unused surface waters of the Little Arkansas River.