Parts of California are sinking at a rate of two inches … a month!
That's the astonishing conclusion from a report this week from NASA's Jet Propulsion Laboratory in Pasadena. “Progress Report: Subsidence in the Central Valley, California” was prepared at the behest of the California Department of Water Resources.
JPL researchers used interferometric synthetic aperture radar (InSAR) from satellites and aircraft to measure the exact position of the ground in parts of the produce capital of the nation, California's Central Valley.
The scientists found the worst rate of sinking in the San Joaquin Valley, where those inches of subsidence were observed. While many California residents are under drought-fueled water restrictions, groundwater is not as strictly regulated for farmers.
So they've been dipping their straws into that milkshake with abandon.
“Because of increased pumping, groundwater levels are reaching record lows — up to 100 feet lower than previous records,” said Water Resources director Mark Cowin. “As extensive groundwater pumping continues, the land is sinking more rapidly, and this puts nearby infrastructure at greater risk of costly damage.”
While the sinking has been happening for decades as a result of our use of groundwater, it's happening now with alarming speed, experts said.
Some of the shocking evidence:
-Land near Corcoran in the Tulare basin sank 13 inches in eight months, JPL says.
-One part of the Sacramento Valley was sinking approximately one-half inch a month.
-Areas near the California Aqueduct sank up to 12.5 inches, including eight inches in just four months of 2014.
So what, you ask? JPL explained in a statement what can go wrong when California starts sinking beneath our feet:
The increased subsidence rates have the potential to damage local, state and federal infrastructure, including aqueducts, bridges, roads and flood control structures. 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.
“Groundwater acts as a savings account to provide supplies during drought, but the NASA report shows the consequences of excessive withdrawals as we head into the fifth year of historic drought,” Cowin said. “We will work together with counties, local water districts and affected communities to identify ways to slow the rate of subsidence and protect vital infrastructure such as canals, pumping stations, bridges and wells.”
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