Groundwater pumping in California has land sinking

Vast areas of California’s Central Valley are sinking faster than in the past as massive amounts of groundwater are pumped during the historic drought, state officials said Wednesday, citing new research by NASA scientists.

This NASA map shows the California regions experiencing the highest levels of subsidence – the scientific term for the gradual caving in or sinking of an area of land. However, local officials have until 2020 and in some cases until 2022 to write and enforce their plans, so it could take another decade or two before California has a handle on groundwater use, Cowin said. “Because of increased pumping, groundwater levels are reaching record lows – up to 100 feet (30 meters) lower than previous records”, he said. “As extensive groundwater pumping continues, the land is sinking more rapidly and this puts nearby infrastructure at greater risk of costly damage”.

The report said land near the city of Corcoran sank 13 inches in eight months and part of the California Aqueduct sank eight inches in four months past year. An area in the Sacramento Valley was sinking at half-an-inch per month, which is faster than previous measurements.

The DWR says increased subsidence rates have the potential to damage local, state, and federal infrastructure, including aqueducts, bridges, roads, and flood control structures. In addition, wells are being depleted, he said.

This July 23, 2015 photo provided by the California Department of…

The department said long-term sinking has already destroyed thousands of private and public groundwater well casings in the agriculture-dependent valley, adding that over time more sinking could permanently reduce how much water can be stored in the underground aquifer. The department said that program would be funded through the $7.5 billion water bond passed by state voters last November, which was the most significant statewide investment in water supply infrastructure in decades.