Equus Beds are slowly refilling
04/05/2011 6:09 AM
04/05/2011 6:09 AM
Farmers and city residents spent decades depleting portions of the Equus Beds aquifer, drying out part of the aquifer roughly the size of Cheney Reservoir.
But now 65 percent of that water is back, thanks mostly to several rainy years and reduced pumping by Wichita, according to a new report by the United States Geological Survey that focused on 55 square miles north of Wichita where most pumping happens.
"It's good news for the area," said Andy Ziegler, director of USGS Kansas Water Science Center.
The Equus Beds aquifer is south-central Kansas' primary fresh water source. It lies under parts of Sedgwick, Harvey, Reno and McPherson counties.
The portion of the aquifer studied by USGS reached an all-time low in 1992, when several dry years led to continued heavy pumping by Wichita and farmers. That left that section of the aquifer short about 283,000 acre feet of water — about the same amount Cheney Reservoir holds.
Through the years, the city has drawn roughly 25,000 acre feet a year from the ground and farmers have pulled about 30,000 acre feet annually, according to Ziegler.
An acre foot is about 326,000 gallons or the volume of water it would take to cover an acre with water a foot deep.
Though farmers and city residents have sufficient water now using Cheney Reservoir and the aquifer, the aquifer's improved health benefits many.
The clean water creates more supply during future droughts and provides a barrier from saltwater that is moving from old oil well fields toward shallower parts of the aquifer pumped mostly for municipal supply and farming.
The saltwater barrier has been aided by the first phase of the city's aquifer recharge project, a $27-million effort that pipes above-normal water flows from the Little Arkansas River near the city of Sedgwick back into the aquifer close to where the high chloride water is inching in.
About 1 percent of the aquifer's rebound is attributed to the first phase of the city's aquifer recharge project.
But the vast majority of the recharge project hasn't started pumping water yet.
Just a few miles from Bentley and Sedgwick, construction crews pound and weld together the frameworks for the second phase of the project.
On a recent visit, Dennis H. Sanders, the construction administration manager for the project, showed the maze of pipes that raw river water will one day travel through before being sucked through straw-like tubes to filter out sediment.
After that, pumps draw the water into the next building where it's treated with ozone and hydrogen peroxide to eliminate herbicides and other chemicals that have contaminated the river water.
Finally, in a separate building, three large pipes will pump the water out to well fields to be injected into the ground.
Sanders said he expects the project to begin pumping water in the fall. But that's a shaky estimate because it can't start pumping water until river flows are above average and crews finish a series of tests.
City Council members have approved $250 million for the project thus far, and the money is going further than expected, officials said. That's because the down economy has brought many of the costs down as well.
The cost of recharging the aquifer is one of the biggest reasons city water rates have climbed several years in a row — sometimes more than once a year.
It's unclear how rates will change this year, though city officials have said through the years that increases will undoubtedly be necessary.
The city is working with a contractor on a rate study that could alter how the city charges customers for water, said Joe Pajor, assistant public works director.
The study will factor in demands created by residential, commercial and industrial customers while producing options that may encourage conservation and rate stability, he said.
The City Council will likely review the study in coming months.