California has turned to pumping groundwater to combat a years-long drought and the move, it turns out, is causing the state to sink faster than ever before.
Known as subsidence, sinking land has occurred for tens of years in California due to excessive pumping of groundwater to address drought conditions. However, a NASA report has shown that subsidence is happening faster than projected, putting surface infrastructure at high risk of damage. According to Mark Cowin, director of the California Department of Water Resources, groundwater levels have dropped to record lows, reaching up to 100 feet lower than previously recorded.
In just eight months, for instance, land close to Corcoran in the Tulare basin sunk by 13 inches, or 1.6 inches for every month. A portion of the Sacramento Valley was recorded as sinking at about half an inch per month. Based on satellite data obtained by NASA, areas close to the California Aqueduct have also sunk 12.5 inches, eight inches of which occurred within just four months in 2014.
Aside from damage to infrastructure on the surface, continued subsidence also has the ability reduce the water storage capacity of an underground aquifer permanently.
In response to the NASA report, the Drought Task Force set up by California Governor Jerry Brown has committed to developing measures with communities that will help reduce subsidence and address threats to infrastructure. This move builds upon the Sustainable Groundwater Management Act which calls on local governments to create sustainable groundwater agencies responsible for regulating pumping groundwater and managing overall groundwater supplies.
"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," added Cowin.
The DWR is also set to launch a $10-million program that will help counties home to stressed groundwater basins to come up with or bolster local laws and conservation efforts. Funds for the program came from the Water Bond passed in 2014 across the state. There is also room in the state's budget for the year to streamline environmental reviews for county ordinances developed for reducing groundwater pumping.
NASA will also keep on monitoring subsidence using information gathered by the European Space Agency's Sentinel-1 mission, covering broader areas to identify more vulnerable communities.
