Aquifers provide a natural source of groundwater, and a new study from the University of Illinois examines the possible consequences of over-drawing from three major aquifers in the United States.
Megan Konar and other researchers examined the Central Valley, High Plains and Mississippi Embayment aquifers. She says reliance on these three aquifers accounted for 93 percent of groundwater depletion in the U.S. between 2000 and 2008.
"Ground water aquifer is like a bank," she states. "So, if you're just drawing out a lot more money than you're putting in, then eventually, your finite supply is going to end. And so, we're just using a lot more water than is being recharged."
The study found Illinois is transferring large volumes of water from the High Plains and Mississippi Embayment aquifers.
Konar suggests policies be enacted to slow groundwater depletion, including creating groundwater property rights, or a market for water, in which it is allocated to farmers and they can then sell or buy it.
Konar says depleting the aquifers could lead to difficult choices that affect food security.
The report found agriculture uses the majority of water from aquifers, and Konar says a reliable water source is essential to producing staple commodities, such as rice, wheat and corn.
"We found that they contribute to 18.5 percent of domestic cereal supply in the U.S. and that interestingly, they also contribute a large fraction to a few countries internationally," she explains. "They contribute almost 10 percent to the cereal supply of Japan, Taiwan and Panama."
Urban areas also rely heavily on aquifers, and Konar contends that groundwater depletion will affect their ability to meet normal water demands and respond to climate changes.
"Projections for the future climate are that it's going to increase in variability and so, having these groundwater resources to buffer against variability is really important," she points out. "They're likely going to be more valuable in the future. So, we should really start thinking of them as a strategic natural resource."
Chicago relies on 2 percent of the water from the High Plains aquifer, and 1 percent of the Mississippi Embayment aquifer.