Federal Water Tap, December 2: Enough Salty Groundwater Beneath South-Central U.S. to Fill Great Lakes Twice, USGS Finds

Lots of Water
Aquifers beneath parts of 17 states in the south-central United States hold more than enough salty water to fill the Great Lakes twice, according to a first-of-its-kind U.S. Geological Survey report.

Freshwater aquifers in the region, including the famed Ogallala, which irrigates the Great Plains, are well-known, but the last general surveys of salty and brackish aquifers in the U.S. were completed a half-century ago.

Saline groundwater has attracted interest recently because of concerns that drought and climate change are hacking away at freshwater supplies, said Stan Paxton, the hydrological studies chief at the USGS Oklahoma Water Sciences Center, which carried out the study. Salt-removing technology is improving too, and desalination is moving away from the coasts to places like El Paso, which runs the world’s largest inland desalination plant.

Paxton told Circle of Blue that to his knowledge this is the first time the volume of saline groundwater in this region has been estimated. Saline groundwater ranges from 1,000 milligrams of salt per liter to 35,000 milligrams per liter.

The study reckoned that 49,215 cubic kilometers (39.9 billion acre-feet) of saline groundwater is held in 22 distinct aquifers beneath a patch of land that stretches from the Gulf Coast to South Dakota.

Most of the water assessed in the study, some 54 percent, is slightly saline, meaning a salt concentration less than one-third that of the ocean. Geographically the lands along the Gulf Coast from Texas to Alabama hold about 40 percent of the saline water covered in the report.

The study, the largest of three current USGS saline groundwater pilot studies and the first to be completed, did not assess how deep the aquifers are. Funding for the studies comes from the SECURE Water Act, which Congress passed in 2009. That legislation authorized an investigation of saline water volumes but not depths, said Paxton, who noted that information on the latter, which exists but is not in one place, is vital for fully assessing saline water resources.

“The depth to salinity is what people really need to evaluate the economics of drilling,” Paxton said.

Farmland Conservation
The U.S. Department of Agriculture agency that handles farm conservation will carry out an environmental review of proposed changes to the program. The changes are part of the new farm bill wending through Congress. The environmental review will help the Farm Service Agency put the new law into practice.

Earlier this year the two chambers passed similar, yet not-identical bills that still must be reconciled. The Senate’s version would reduce by 22 percent the acreage allowed in the conservation reserve program by 2018. The House version would cut slightly deeper, dropping the cap by 25 percent.

Arizona Mining Review
The U.S. Forest Service claims a copper mine proposed for southern Arizona would meet most state requirements for groundwater and surface water quality but still needs federal permits to satisfy the Clean Water Act, the Arizona Daily Star reports.

In addition, Arizona regulators would have to approve the mine’s plan to protect two streams in the area that the state has identified as “outstanding waters.”

Drinking Water Advisory Council
The EPA needs to fill five seats on the council that whispers recommendations for drinking-water policy in the agency’s ear. Self-nominations are accepted. All the procedural details for nominations are found here. The deadline is December 20.

Federal Water Tap is a weekly digest spotting trends in U.S. government water policy. To get more water news, follow Circle of Blue on Twitter and sign up for our newsletter.

Brett Walton

Brett writes about agriculture, energy, infrastructure, and the politics and economics of water in the United States. He also writes the Federal Water Tap, Circle of Blue’s weekly digest of U.S. government water news. He is the winner of two Society of Environmental Journalists reporting awards, one of the top honors in American environmental journalism: first place for explanatory reporting for a series on septic system pollution in the United States(2016) and third place for beat reporting in a small market (2014). He received the Sierra Club’s Distinguished Service Award in 2018. Brett lives in Seattle, where he hikes the mountains and bakes pies. Contact Brett Walton