This just in … Updated Report: Groundwater Resources Depleted By Drought

From the Department of Water Resources:

NEW_DWR_LOGO_14inchFollowing one of the driest years on record when groundwater resources have provided an increasing percentage of California’s water supply, the Department of Water Resources (DWR) today released an updated report on groundwater basins that details groundwater level changes, potential water shortages, land subsidence, farmland fallowing and gaps in groundwater monitoring.

Drought conditions typically result in an increase in groundwater well activity and pumping to compensate for surface water supply shortages. Collectively, groundwater basins are the state’s largest reservoir, 10 times the size of all its surface reservoirs combined. More than 80 percent of Californians rely, in part, on groundwater for their drinking water.

Directed by Governor Edmund G. Brown Jr.’s Proclamation of a State of Emergency in April and following a previous DWR report on groundwater in April, the report shows groundwater basins in most areas of the state at historically low levels.

In September, Governor Brown signed a package of three bills which together create a framework for sustainable, local groundwater management for the first time in state history.  The legislation, known as the Sustainable Groundwater Management Act, allows local agencies to tailor groundwater sustainability plans to their regional economic and environmental needs.  For more information about the legislation, visit

“If we fail to manage our groundwater basins sustainably, we risk losing the water supply savings account that can help cities, farms, and businesses survive drought with minimal disruption,” said DWR Director Mark Cowin. “The Sustainable Groundwater Management Act will help us head off problems such as subsidence and overdraft, which may damage aquifers permanently, and allow local agencies to establish groundwater pumping levels that yield reliable supplies for generations to come.”

State and local agencies will be working together over the next several years to craft local sustainability plans in regions where groundwater basins are vulnerable to overdraft. Groundwater accounts for approximately 40 percent of the state’s total annual water supply, and in some regions of the state, as much as 60 percent of the supply during dry or drought years.

In the meantime, as documented in the report released today, California’s three-year-long drought is taking a heavy toll on many groundwater basins.  Basins with notable decreases in groundwater levels are in the Sacramento River, San Joaquin River, Tulare Lake, San Francisco Bay, Central Coast and South Coast hydrologic regions.

Key findings of the report include:

  • Based on data received this year through September, more than 350 new water supply wells are reported in Fresno and Tulare counties, the most in the state.  More than 200 new water supply wells were reported in Merced County and more than 100 were reported in Butte, Kern, Kings, Shasta, and Stanislaus counties.
  • As of October 7, 2014, 34 of California’s 127 high- and medium-priority basins and sub basins are either partially or fully unmonitored under the California Statewide Groundwater Elevation Monitoring Program (CASGEM).
  • While the collection and evaluation of both seasonal and long-term groundwater level data are critical to assess conditions of alluvial groundwater basins, significant data monitoring gaps exist in the San Joaquin River, Tulare Lake, and Central Coast hydrologic regions.
  • Subsidence is occurring in many groundwater basins of the state, especially in the southern San Joaquin River and Tulare Lake hydrologic regions.
  • Due to ongoing decline of groundwater levels, areas with a higher potential for future subsidence are in the southern San Joaquin, Antelope, Coachella, and western Sacramento valleys.
  • A multi-agency research project led by National Atmospheric and Space Administration estimated that peak summer acreage of farmland idled in California in 2014 was 1.7 million acres, almost 700,000 acres more than in 2011, a recent wet year.

To review the report, click here or visit

DWR is developing strategies for implementation of the various components of the legislation and will work with local agencies throughout the process. Geographic, geologic, and hydrologic differences exist across the state and the SGMA allows for flexibility in groundwater stewardship. DWR will seek input from local agencies and the public to develop regulations that ensure groundwater management plans result in sustainable groundwater management statewide.

Groundwater management is a critical element of the governor’s California Water Action Plan.  Developed by the Natural Resources Agency, California Environmental Protection Agency and Department of Food and Agriculture and released in January 2014, the action plan recognizes that all of California’s water resources are interconnected.  Besides sustainable groundwater management, the plan’s five-year goals include making conservation a way of life, expanding water storage capacity, and protecting and restoring important ecosystems.  The plan can be accessed by clicking here or visit

As directed by the January drought emergency declaration, DWR is working to update monitoring of land subsidence in the Central Valley. DWR has also been working with county agencies to ensure that water well drillers submit required well logs for newly constructed and deepened wells in a timely manner to facilitate tracking of areas that are experiencing drought-related groundwater problems.

Additional groundwater information is available at the DWR Groundwater Information Center located here or by visiting  To learn more about the state’s efforts to improve groundwater management, visit Groundwater.CA.Gov.

Governor Brown has called on all Californians to reduce their water use by 20 percent – visit to find out how everyone can do their part, and visit Drought.CA.Gov to learn more about how California is dealing with the effects of the drought.



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