The California Department of Water Resources has released a new report from NASA showing that areas of the San Joaquin Valley are sinking, which could lead to serious water crisis that would impact California’s commercial and industrial sector. According to Water World, the problem is known as “subsidence” and has caused damage to state and federal water infrastructure.
“As multiple scenes were acquired during these periods, we can also produce time histories of subsidence at selected locations and transects showing how subsidence varies both spatially and temporally,” says the NASA report.
The problem is exacerbated during times of drought. Over time, according to Water World, subsidence can permanently reduce an underground aquifer water storage capacity.
The San Joaquin Valley is located in Central California and is home to about 3 million people and untold commercial and industrial sites. It includes Fresno, Kern, Merced, and Stanislaus counties, and portions of Madera, San Luis Obispo, Tulare counties.
The data show that areas of subsidence in Corcoran and near Chowchilla, which were previously identified by NASA in August 2015, have grown wider and deeper, while a third area of significant subsidence in Fresno County has been identified. In a seven-mile area near Tranquility in Fresno County, land has settled up to 20 inches, according to the report.
“The rates of San Joaquin Valley subsidence documented since 2014 by NASA are troubling and unsustainable,” said California’s Department of Water Resources Director William Croyle, in a statement. “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. The situation is untenable.”
Subsidence already has caused sections of the California Aqueduct to sink by more than two feet in some areas, says NASA. That means water project operators have been forced to reduce flows in those sections by 20% to avoid overtopping the concrete banks of the aqueduct. The Department of Water Resources warns in the release that if the State Water Project allocation reaches 85% or greater this year, water deliveries may be impaired.
California is working with water companies to improve groundwater pumping curtailment and the creation of groundwater management zones near critical infrastructure. Additionally, the Department of Water Resources is working with local water managers to identify specific actions to reduce long-term subsidence risk, the release adds, giving greater assurances to the homes and businesses in the region.
California has record rainfall this winter, although this had little impact on the underground water storage levels.