Wichita — A $5 million study recently completed by the U.S. Geological Survey clears the way for the city of Wichita to recharge the Equus Beds aquifer with water from the Little Arkansas River.
The study, paid for by the city and the USGS, examined 400 different pollutants and decided the water was clean enough to use if the city treated the river water and used caution.
The city hopes to deposit into the aquifer 65 billion gallons of river water, the same amount held by Cheney Reservoir. The water could then be withdrawn later from the aquifer during a drought.
For the past five years the city has been experimenting with taking water out of the Little Arkansas River and pumping it into the Equus Beds, an aquifer that is one of the city's main sources of drinking water.
Without a new water source, the city predicts it could run short of water in the next eight to 13 years. The recharge plan may provide residents with all the water they need for at least the next 50 years.
If the city's plan works, the city says it will have the water necessary to grow and attract new industry. Residents will be able to water their lawns and fill their swimming pools with few restrictions.
The study found contaminants such as bacteria and salt in the river water. It also found atrazine, a pesticide that has been linked to breast cancer, and arsenic, which causes skin cancer. The city has built a treatment plant to remove atrazine from the river water before it goes into the Equus Beds. The city may have to build another plant to remove the arsenic.
By treating the river water and exercising caution, the city can use it without polluting the aquifer, said Andy Ziegler, a water quality specialist with the USGS in Lawrence and author of the study.
Ziegler concluded that the 1 billion gallons of river water put into the aquifer so far have not measurably affected water quality.
"This is good news," he said.
Ziegler also has devised an early-warning system to tell the city when large amounts of atrazine and bacteria are likely to be present in the water, so the city can shut off its pumps.
Anytime two sources of water are mixed, there is a risk that one will contaminate the other, he said.
For 40 years, the city pumped water out of the Equus Beds faster than rainfall replenished it. Water levels in Wichita's well field dropped by 40 feet between the 1940s and the late 1980s.
The excessive pumping created a void. A giant body of salt water, which is used in oil drilling, is slowly moving in to fill that void.
Raising the levels in the aquifer will create a barrier to keep the salt water out of the city's well field and give the city a water supply to use during a drought, when levels in Cheney Reservoir drop.
The city plans to take bids on the next step of its project. It plans to spend $17 million on equipment to capture and store up to 10 million gallons of river water a day in the Equus Beds. The project should be operating by mid-2003.
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