Study: A third of global groundwater basins are overstressed



The Indus Basin of northwestern India and Pakistan is the second-most overstressed groundwater basin in the world and is suffering rapid depletion from human use, scientists have found.

Scientists using satellite data have found that a third of the world’s largest aquifers are being rapidly depleted and are seriously threatened.

Making matters worse, researchers say in a pair of new studies, we don’t know how much water is left in these massive aquifers – which water resources scientists often refer to as Earth’s water savings accounts.

The researchers used NASA’s GRACE satellites to take precise measurements of the world’s groundwater aquifers.

The research team employed data gathered by NASA’s GRACE satellites over the course of a decade.

“As we’re seeing in California right now, we rely much more heavily on groundwater during drought”, Famiglietti said. There is need for collaborative effort so that it can be known how much groundwater is left.

Michael Campana, a professor of hydrogeology and water resources at Oregon State University who was not involved in the study, praised the research and said he hopes it will be a “wakeup call” to convince policymakers it’s important to study how much water is stored in aquifers.

Because of increasing droughts and water shortages, the practice of drilling for water is increasing worldwide, putting additional stress on underground reservoirs. Farmers in California’s Central Valley are slurping up so much groundwater that the state is actually sinking by up to a foot per year in some spots.

“The situation is quite critical”, said Jay Famiglietti, senior water scientist at NASA’s Jet Propulsion Laboratory and the studies’ principal investigator.

Drought-stricken California is not the only place draining underground aquifers in the hunt for fresh water.

“There’s no way we can keep using these aquifers at the rates that we are without understanding what some of the tipping points are”, Richey said in a telephone interview. Only a few of the aquifers have been mapped in detail and most estimates of aquifer water reserves have “uncertainty ranges across orders of magnitude”, according to the studies. It has been done to increase the oil supply, however, so it should be done for the water supply, Famiglietti said.

Famiglietti said problems with groundwater are exacerbated by global warming, which has caused the regions closest to the equator to get drier and more extreme latitudes to experience wetter and heavier rains.

Bottom line: the Earth is running out of water.

The result is that significant segments of the planet’s population are consuming groundwater quickly without knowing when it might run out, researchers said.

Also running a negative balance was the Atlantic and Gulf Coastal Plains Aquifer, which stretches across the southeast coast and Florida.

They concluded that the time to depletion of many aquifers is likely far less than previously estimated by researchers decades ago.

“The bigger issue is it’s not enough”, Famiglietti said. “Estimates of remaining storage might vary from decades to millennia”, said Richey.

“We’re in trouble, and it’s not just California”. “I do feel sometimes that my research can be a tiny depressing, but I’m also really encouraged by it because I know that getting this information out now can hopefully help implement strategies today so that we can make sure we have reliable resources”. Those aquifers were still being depleted but had some water flowing back into them.

Richey is lead author on both studies, and conducted the research as a University of California – Irvine, doctoral student.

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p style=”text-align: center;”>Study: A third of global groundwater basins are overstressed

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