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The Equus Beds aquifer northwest of Wichita, Kansas, was developed to supply water to Wichita residents and for irrigation in south-central Kansas beginning on September 1, 1940. Ground-water pumping for city and agricultural use from the aquifer caused water levels to decline in a large part of the area. Irrigation pumpage in the area increased substantially during the 1970s and 1980s and accelerated water-level declines. A period of water-level rises associated with greater-than-average precipitation and decreased city pumpage from the study area began in 1993. An important factor in the decreased city pumpage was increased use of Cheney Reservoir as a water-supply source by the city of Wichita; as a result, city pumpage from the Equus Beds aquifer during 1993-2002 went from being greater than one-half to slightly less than one-third of Wichita's water usage. Since 1995, the city also has been investigating the use of artificial recharge in the study area to meet future water-supply needs and to protect the aquifer from the intrusion of saltwater from natural and human-related sources to the west.
During January 2003, the direction of ground-water flow in the Equus Beds aquifer in the area was generally from west to east similar to predevelopment of the aquifer. The maximum water-level decline since 1940 for the period January 2000 to January 2003 was 29.54 feet in July 2002 at well 3 in the northern part of the area. Cumulative water-level changes from January 2000 to January 2003 typically were less than 4 feet with rises of less than 4 feet common in the central part of the area; however, declines of more than 4 feet occurred in the northwestern and southern parts of the area.
The recovery of water levels and aquifer storage volumes from record low levels in October 1992 generally continued to April 2000. The recovery of about 182,000 acre-feet of storage volume in the area from October 1992 to April 2000 represents about a 64-percent recovery of the storage depletion that occurred from August 1940 to October 1992. About 47 percent of this recovery was lost from April 2000 to October 2002 when storage volume in the area decreased by about 86,000 acre-feet. Major contributors to the decreases in water levels and storage volumes were reduced recharge associated with precipitation that was less than in the preceding 5 years and increased irrigation pumpage. The loss of storage probably would have been larger if the continued decrease in city pumpage, which is closely associated with the water-level rises in the central part of the study area, and increased city use of water from Cheney Reservoir had not occurred. The effect of artificial recharge on water levels and storage volume probably was masked by the generally larger decreases in city pumpage in the area.
Additional Publication Details
USGS Numbered Series
Status of ground-water levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2000-January 2003