An underground aquifer that provides drinking water for 300-thousand Iowans is the subject of intense study. That’s because a state law passed three decades ago forbids draining the “Jordan Aquifer” below 200 feet of its 1975 water level.
“One of the questions that we have about these deep, underground water sources is, since we use them quite heavily: How long can we do so?” says Bob Libra of the Iowa Geological and Water Survey. “And can we look, can we ballpark, crystal-ball out in the future and say, ‘If we are using water in this manner for the next 20, 40, 60 years will we be running into problems? Should we think about managing things differently now?'”
The Jordan Aquifer is the most-widely used aquifer in Iowa, with the city of Fort Dodge and many more moderate-sized cities throughout the state pumping water from the aquifer for drinking water, as well as industrial use.
“When you are pulling out an awful lot of water — and we’re moving around billions of gallons every year — one of the big concerns we have is changes in the quality of the water. Will we be pulling water in from above or below (the aquifer)…and then impacting the quality of the water we’re trying to get out and drinking?” Libra asks. “And will we see increases in certain constituents in the water just because of the effect of the pumping?”
Libra and others have been reviewing mountains of paperwork, as pumping records for the Jordan Aquifer date back to the 1880s. They’re trying to figure out when the aquifer might reach the level that late-1970s law set as a stopping point.
“Locally there are places where, when the water levels have fallen a couple of hundred feet and we can ballpark into the future and see that continuing to happen, there’s a the day-to-day cost of just how much more dollars, energy it takes to extract the water,” Libra says. “So there are a bunch of factors like that are involved.”
According to Libra, way before all the water is pumped out of the aquifer, the quality of the water that remains may be less than desirable. As for that 1975 water line that was to serve as a cut-off for pumping, Libra says water users throughout the state are “pushing that limit” on the Jordan Aquifer.
“That limit — we have exceeded it some places and, again, projecting into the future, into that even 20 year time frame, if we keep using the aquifer as we are now, we will be exceeding that over fairly large areas,” Libra says. “And if use increase, say, 25 or 50 percent which would be in keeping with how the increased use has been going of the last 50 years, then those areas would be larger and larger.”
Officials in the “Water Allocation” program at the Department of Natural Resources have the authority to stop pumping from the Jordan Aquifer. Libra says they’re “grappling” with that.
“It’s not doomsday around the corner, but we know we’ve got something going on and we know we’re in a very long-term business here. It’s not the problem du jour. It’s how do you manage things for the very, very long-term for the best interests of the state,” Libra says. “And so what we’re trying to do is come up with recommendations for how that limit should be handled. Is it the correct number? Are there other ways of thinking about this? And what we’ve been doing, really, is try to build the tools so we can do this in an intelligent manner in the long run.”
According to Libra, the Jordan Aquifer provides water for many of the state’s ethanol plants, too. The Department of Natural Resources will hold meetings in the Cedar Rapids and Fort Dodge areas in December to discuss Libra’s study of the aquifer and plans for future use of the underground water source.