Study finds Iowa groundwater is extracted at unsustainable rate


jordan-aquifer
The Jordan Aquifer lies beneath most of Iowa; locations with water use permits for tapping into the aquifer are shown above. (Iowa DNR)
Jenna Ladd | February 7, 2017

A recent study found the groundwater in Iowa’s Jordan Aquifer to be much older than previously known, and scientists say that could have implications for water use in the state.

Researchers from the Iowa Geological Survey at the University of Iowa in collaboration with Grinnell College, the UI Geology Department and Iowa Department of Natural Resources used isotopic age dating to estimate the age of groundwater in the Jordan Aquifer. The study measured major and minor ions, stable isotopes (d18O and dD) and
the radioactive isotope Chlorine 36 in eight wells scattered across the aquifer. The peer-reviewed journal article explains that the groundwater in northern and central Iowa is somewhere between 70,000 to nearly 180,000 years old.

The study points out that ethanol production in the state relies heavily on groundwater from the Jordan aquifer, which also provides roughly 300,000 residents with drinking water. From 2003 to 2013, annual use of groundwater from the aquifer for ethanol production increased by 7.4 billion liters per year.

Keith Schilling is a research scientist at the Iowa Geological Survey at the University of Iowa and the study’s leading author. He said,

“The implications for biofuel refineries and any water use of the aquifer is the realization that the groundwater is very old. It is not going to be recharged in any human timeframes so we should make sure that water from the aquifer is being managed appropriately.”

Beyond the lagging groundwater regeneration rate, the study also notes that increased groundwater pumping can result in detrimental water quality changes such as radium contamination. The authors conclude with a call for new ethanol refineries to steer clear of the Jordan Aquifer and utilize more sustainable groundwater sources instead.

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