Groundwater pumping causing California Central Valley to sink

Credit: Amy Quinton, Capital Public Radio
Credit: Amy Quinton, Capital Public Radio

California has mostly nonexistent rules regulating groundwater pumping. Other western states regulate the amount of water that can be pumped up from wells. California’s negligence here (and it is negligence) combined with the ongoing nasty drought is causing land to sink at unprecedented rates in some areas of the agricultural Central Valley. Oh, California did pass a bill last year regulating groundwater pumping. However local water agencies have 5-7 years to work out details and reporting on usage is voluntary. Right, that’ll work just fine.

Not only is way too much water being sucked out of aquifers, the resulting subsidence can and is causing serious problems, as roads, bridges, pipelines, and canals sink in places. Houses and buildings can sink too. And, oh yeah, maybe the proposed high-speed rail line too.

The data shows the ground is sinking nearly two inches each month in some places, putting roads, bridges and vital canals that deliver water throughout the state at growing risk of damage.

The NASA data shows land near the city of Corcoran sank 13 inches in eight months, and part of the California Aqueduct dropped eight inches in four months last year. The aqueduct spans hundreds of miles and provides water to millions of people and vast areas of farmland.

Long-term subsidence has already destroyed thousands of public and private groundwater well casings in the San Joaquin Valley. Over time, subsidence can permanently reduce the underground aquifer’s water storage capacity.

After a certain point of depletion, aquifers lose the ability to hold water.

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