Wichita Recharge Project: Sustaining and Preserving the Equus Beds Aquifer

Abstract

The Wichita well field is developed in the Equus Beds aquifer, the easternmost extent of the High Plains aquifer in Kansas. Pumping began in 1940 and increased in volume until the early 1990's. Surrounding agricultural withdrawals increased substantially in the 1970's and 1980's and currently are similar in magnitude to the City's withdrawals. Groundwater-level declines began in the 1940's as withdrawals exceeded recharge from precipitation. In 1976, the Equus Beds Groundwater Management District (GMD2) was formed to manage groundwater resources in the area. Policies of the district prevented further increases in groundwater pumpage in most parts of the well field area, encouraged conservation, and explored ways to sustain groundwater resources.

The city of Wichita and the U.S. Geological Survey (USGS) have closely monitored groundwater levels since pumping began. The USGS also has documented movement of water with large chloride concentrations from the Arkansas River toward the well field as flow gradients changed with increasing pumping stresses. Infiltration from the Arkansas River and substantial natural recharge have moderated large-scale water-table declines; however, the excellent water quality of the Equus Beds aquifer is threatened by migration of the saline water from natural and anthropogenic sources.

In 1993, the City adopted an 'Integrated Local Water Supply Plan' in which its future water needs would be met through several local sources. The plan established a priority of water use whereby water that would normally flow through the area would be used first, saving slowly replenished water resources for times when the first-priority water is not available.

Key components of the plan are capture of 'above-base-flow' water from the Little Arkansas River, recharge and storage of this water in the Equus Beds aquifer, and recovery for use in times of drought. In the storage area, water levels will be maintained within 5 feet of predevelopment levels, to be used when needed and to preserve the aquifer's water quality by preventing salinity migration into the well field area.

Additional information on the Equus Beds Project can be found at: http://ks.water.usgs.gov/studies/equus/

Stous, D.H., Aucott, W.R., Blain, G.T., and Dealy, M.T., 1999, Wichita Recharge Project: Sustaining and Preserving the Equus Beds Aquifer [abst.], in Proceedings of the Geological Society of American, October 25-28, 1999.

To request a paper copy of this abstract, email: GS-W-KS_info@usgs.gov