Should Wichita buy El Dorado's extra water?

El Dorado is on the cusp of finding new ways to sell millions more gallons of water from its massive reservoir, perhaps including a pipeline that links with Wichita's system.

The city will likely pick a firm this week to find uses for millions of gallons that it otherwise discharges down the Walnut River, which meets the Arkansas River before it merges with the Mississippi River and, finally, flows into the Gulf of Mexico.

"Rather than flushing that water downstream, why not make beneficial use of that water?" asked Kurt Bookout, El Dorado's director of public utilities.

Meanwhile, a group of Wichita State University graduate students may have found a use that could save El Dorado and Wichita a lot of money.

The 19-member student group researched regional water supplies this spring and recommend Wichita strike a deal with El Dorado to construct a $40 million pipeline to carry water from the reservoir to the Equus Beds wellfield north of Wichita.

The study says the El Dorado pipeline could reduce the need for the third and fourth phases of the aquifer recharge project, which takes water from the Little Arkansas River, treats it to remove farm chemicals and injects it into the aquifer.

But the recharge project pumps water into the aquifer only about a third of the time because the river isn't always running above its average flow level. The city also extracts water from the aquifer to supply about 40 percent of its municipal supply.

A pipeline between the two cities' supplies could help Wichita's pumping facilities to operate more often and perhaps delay or eliminate the need for the third and fourth phases of the recharge project, the students wrote.

Those phases are expected to cost millions and provide an additional 60 million gallons per day of recharge water.

The city started the recharge project because decades of over pumping had lowered water levels in the wellfield. That created another problem.

A salty plume of groundwater caused by oil exploration is slowly moving toward the city's water wells. As the groundwater level dropped, it accelerated the flow of contaminated water toward the wells. The city hopes that raising the groundwater levels will push the saltwater away from the city's wells.

El Dorado Reservoir was created in 1981 to control flooding, and the U.S. Corps of Engineers discharges water over a certain level to provide for additional storage in the event of a flood.

El Dorado could lower its minimum lake level by about five feet without disrupting boating, and the move would reduce the number of walleye flushed out near the dam, said Bookout, the El Dorado utility director.

El Dorado could sell 25 million gallons a day about three quarters of the time.

To put that into perspective, Wichita uses an average of 67 million gallons a day. It's expected to use 101 million gallons a day by 2050.

The students calculated that raw water from El Dorado is 40 percent less expensive than the raw water Wichita pumps from the river.

That's based on all the money Wichita has invested in the aquifer project and El Dorado has invested in its water system.

The El Dorado Reservoir water could be sold to more small communities, used as a source of raw water for the aquifer recharge project or as treated water sold to Wichita.

But Herb Llewellyn, El Dorado's city manager, said the city is mostly interested in selling treated water that is ready to drink.

That allows other cities to tap into the pipeline without building treatment plants.

"We want to make sure we understand the cost associated with it and kind of figure out what we would sell water for," Llewellyn said.

Wichita City Manager Robert Layton said he's open to the idea and wants to see the study and consider other options before the city moves on to the third and fourth phases of the aquifer recharge project.

Wichita and El Dorado will likely have to address water supply issues along the corridor between the two cities someday, he said.

"If it's cost effective, I think it could make a lot of sense for the region," Layton said.