Putting Water Back in the Ground
The water supply for the city of Wichita in south-central Kansas currently comes from two primary sources - the Wichita well field in northern Sedgwick and southwestern Harvey Counties and Cheney Reservoir in southeastern Reno County. Officials have ascertained that these sources will not be adequate to meet the projected city water needs in the 21st century. Artificially recharging the Equus Beds aquifer, which underlies the city well field, is one alternative being considered to meet future demands for water.
"God will naturally recharge the aquifer," engineer Gerald Blain, the water supply projects manager for city government in Wichita, recently told the Kansas City Star. "We're just going to speed the process along."
The primary purpose of the Equus Beds Ground-Water Recharge Demonstration Project, which began in 1995, is to evaluate artificial recharge techniques from two supply sources and to determine how these techniques would affect the water quality, design criteria and problems associated with the infiltration of high streamflows from the Little Arkansas River to the Equus Beds aquifer. Three recharge techniques are being evaluated - direct well injection, surface-spreading basins and a recharge trench.
This is the first time artificial ground water recharge is being tested in Kansas. The technique already is being used by California and Florida.
At the Halstead recharge site near Wichita, the aquifer is being artificially recharged by water pumped from a diversion well immediately adjacent to the Little Arkansas River. Pumping induces flow from the river into the adjoining Equus Beds alluvial aquifer; the flow is then captured by the diversion well. The diverted water (about 1,000 gal./min.) is piped to the recharge site and artificially recharged by direct well injection, through surface-spreading basins and through a recharge trench. Changes in water levels and water quality are monitored before and after recharge in shallow and deep monitoring wells at the recharge site.
Water intended for artificial recharge at the Sedgwick site comes from a surface-water intake in the Little Arkansas River. The surface water is treated with powdered activated carbon and polymers to remove organic contaminants and sediments. The treated water is then piped about three miles to the recharge site and recharged through surface-spreading basins. The recharge water quality and quantity and changes in water levels are monitored before and after recharge in monitoring wells adjacent to the recharge site.
The Equus Beds Ground-Water Recharge Demonstration Project is funded through a cooperative effort among the city of Wichita, Bureau of Reclamation and USGS.