NASA research has shown that ground in California’s Central Valley sinks at an alarming rate. This is because farmers are pumping groundwater as fast as possible to alleviate the drought. Some areas are seeing ground sink by nearly 2 inches each month. The infrastructure, including roads, bridges, buildings and roads on the ground, is being seriously affected by this. Mark Cowin of California Department of Water Resources stated that the sinking of land has affected major waterways in California and that the wells are becoming depleted. Cowin stated in a statement that groundwater levels have fallen to record levels due to increased pumping. This is 100 below previous records. He said that groundwater pumping is continuing at a rapid pace, which puts infrastructure nearby at higher risk for costly damage. Groundwater pumping was required due to four years of drought. Aquifer levels dropped to new lows, and subsidence rates rose to levels that were much higher than the previous dry period. Between June 2007 to December 2010., there was total subsidence in San Joaquin Valley. Cowin said that groundwater is a form of savings to supply water during droughts, however the NASA report showed the effects of large-scale withdrawals. The data was collected from areas in which state officials consider the problem to be the most serious. The research showed that land near Corcoran fell 13 in just eight months, and that a portion of the California Aqueduct went down 8 inches in only four months. According to NASA, subsidence is caused by water level being too low. Pumping water causes the aquitards to recharge and the starker expands. If water levels get too low, it can cause irreversible compaction in the fine-grained Aquitards. According to the report, the water can’t recharge the layers and causes permanent subsidence as well as loss of groundwater storage capability. Source: Progress Report: Subsidence, Central Valley, California Tom G Farr, Cathleen James, Zhen Liu Jet Propulsion Laboratory at California Institute of Technology
California’s Central Valley sinks at an unprecedented rate.
