Six states are facing significant declines in groundwater resources, according to a study published in Nature.
The report looked at “excessive groundwater withdrawals” by studying 170,000 monitoring wells in over 40 countries, as well as in the U.S., where several states, the most severe being California, must contend with a decline in groundwater reserves, according to an analysis from Saul Elbein, an environmental reporter for The Hill.
According to the report, “Groundwater is the primary water source for many homes, farms, industries and cities around the globe,” on which over 145 million Americans, as well as much of the nation’s food supply, depend.
“We show that rapid groundwater-level declines (>0.5 m year−1) are widespread in the twenty-first century, especially in dry regions with extensive croplands,” the report states. “Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the world’s regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion.”
In a state that has been plagued by droughts, California is having the most issues, according to the report.
The state “accounts for 21 percent of total groundwater usage in the United States,” Mr. Elbein reported while using “67 percent of its fresh water from its groundwater reserves.”
The report states that three-quarters of the state’s 183 groundwater basins are in rapid decline.
“The most significant of the losses are hitting the state’s Central Valley—a result of 25 percent of the nation’s agriculture being concentrated in less than 1 percent of its area, in a region that combines near-desert aboveground conditions with rich reserves of underground water that have accumulated over thousands of years,” Mr. Elbein said.
The report blamed “a heating planet and expanding commercial agriculture” for the depletion of groundwater resources, of which Texas will see the next to most severe issues after California.
Mr. Elbein reported that eighty-two percent of Texas aquifers are in decline.
“While the story for most state aquifers is a more protracted decline than punctuated drop-off, in more than a quarter of Texas’s underground basins—28 percent—groundwater loss is speeding up,” Mr. Elbein reported. “Levels in those basins are receding at twice the rate in the 21st century as they did at the end of the 20th.”
A Rapid Collapse
Idaho was reported to have the most rapidly collapsing aquifer, according to the report, which is facing a loss of over 7 feet of water a year.Up to 200,000 people rely on the Mill Creek Aquifer, the report stated.
“While Mill Creek is the only aquifer in Idaho experiencing rapid decline, levels are falling in 60 percent of the state’s other groundwater stores, and in 11 percent of them, that decline has more than doubled since the last century,” Mr. Elbein reported.
The diminishing of the Colorado River is contributing to Arizona’s decrease in water supply from aquifers, the report said, which supplies the state with over a third of its water.
“With surface water supplies diminishing and rain famously scarce in the desert, 41 percent of Arizona’s water supply comes from wells — and according to the Nature study, 70 percent of these are in decline across the state,” Mr. Elbein reported.
Other states impacted are Utah and Mississippi, the report stated.
Sixty percent of Utah relies on groundwater, 80 percent of which is used by agricultural production, the report stated.
Unparalleled Dependence
Though the state was built around the Mississippi River, 82 percent of its water supply comes from aquifers, the report said.“That level of dependence on underground water is unparalleled in the eastern United States,” Mr. Elbein reported. “And it’s exacerbated by the fact that farmers and cities in neighboring states—from the rice farmers of Arkansas to the city of Memphis, Tennessee—depend on many of the same subterranean reservoirs.”
Fifty-seven percent of Mississippi’s aquifers are lessening, with 53 percent of the aquifers in the United States in decline, the Nature report stated.
“Groundwater levels are declining rapidly in many areas,” Scott Jasechko, a co-author on the Nature report, told The Hill. “And what’s worse, the rate of groundwater decline is accelerating in a large portion of areas.”
However, the report said the conditions could be reversed through water diversion engineering, regulation, and, most successfully, through municipalities enacting groundwater fees.
In El Dorado, Arkansas, Mr. Elbein reported, county officials initiated groundwater fees, “which helped take the strain off of underground wells” and facilitated in the aquifer underneath the town experiencing “the most recovery.”
For local governments willing to come up with “clever, locally relevant interventions,” Mr. Jaechko said. “Groundwater depletion is not inevitable.”
