New data released by NASA shows that parts of California are sinking rapidly, and state water managers say groundwater over-pumping must be restricted to protect aqueducts and flood control structures.
Citing the report from NASA, California Department of Water Resources Director William Croyle called the situation “untenable.”
“The rates of San Joaquin Valley subsidence documented since 2014 by NASA are troubling and unsustainable,” he said in a statement issued by the department. “Subsidence has long plagued certain regions of California. But the current rates jeopardize infrastructure serving millions of people. Groundwater pumping now puts at risk the very system that brings water to the San Joaquin Valley.”
State water managers said that in some areas, the ground is dropping up to one foot per year, according to the Associated Press. The sinking threatens to curtail as much as one-fifth of water deliveries through the vital California Aqueduct to San Joaquin Valley farms and millions of Southern California residents.”
As a result, the department is pressing for “new laws to limit drilling,” the AP reported. Current regulations say property owners can pump unlimited water from their own land with restrictions that will be phased in by 2040. Now, however, officials want to limit pumping on a faster timeline.
The NASA report is the “most comprehensive study yet” on this issue.
“NASA satellites found the ground subsiding up to 20 inches in a seven-mile area near the Fresno town of Tranquillity, because the state’s subterranean water supply was drained to record lows by farms and towns coping with the recent drought,” the Daily Democrat reported.
Environmentalists say rainfall in California in recent months cannot offset the effects of over-pumping.
“Many groundwater aquifers — the only source of drinking water for many rural communities in the San Joaquin Valley — remain at very low levels. And while rainfall can help replenish groundwater, a few wet months can’t offset decades of overpumping,” according to the Environmental Defense Fund.
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Image credit: "san joaquin valley," Doug Letterman © 2009, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/