Assessing CA groundwater management one year after landmark legislation

September 17, 2015 | Water in the West | Insights

Leon Szeptycki and Tara Moran

One year ago, California Gov. Jerry Brown signed the Sustainable Groundwater Management Act of 2014 into law. Commonly referred to as SGMA, the legislation created a statewide framework for sustainable groundwater management – and, potentially, regulation of groundwater pumping – for the first time in California’s history. The law does so by imposing a mandate for sustainable groundwater management on local agencies, but gives them a great deal of latitude in how to accomplish that objective.  This legislative choice makes a great deal of sense, given the diversity of California’s landscape and the groundwater management problems across the state.  Localities take the lead in dealing with groundwater overdraft in their basins, while the state can provide guidance and funding, and, if necessary, enforcement. 

It is well worth marking this anniversary, but it is also important to note the barriers to SGMA’s implementation, and the work needed to overcome them.  Groundwater management under SGMA will not formally begin until local agencies finalize their groundwater sustainability plans, beginning in 2020. In the meantime, fundamental problems with California’s groundwater management continue, including the ongoing decline of groundwater levels across the state and a highly fractured governance structure.  Agencies implementing SGMA will have to cope with both challenges.

While the state has shown tremendous resilience in the face of ongoing drought, in many cases, it has it has done so at the expense of groundwater aquifers (Howitt et al. 2015). Groundwater levels in nearly all basins in the state have declined, and many areas of the state are reporting levels more than 100 feet below previously historic lows (DWR 2014a). These dramatic declines in groundwater elevations have caused some areas of the Central Valley to sink nearly by nearly 2 inches per month and have placed overlying infrastructure at an increased risk of damage (DWR 2015a).  California’s water users have leaned hard on groundwater during the current drought, and will continue to do so if dry conditions persist.  This raises the legitimate concern that the state’s aquifers will be depleted even more between now and 2020, the first year local agencies that local agencies need to be managed under a groundwater sustainability plan.  We are indeed digging a deeper hole to dig ourselves out of once the law begins to really kick in after 2020.

While there are many potential options for mitigating further groundwater depletion during SGMA implementation, two common suggestions are to: (1) to accelerate the implementation of SGMA, and (2) place a moratorium on new wells. Neither option would be easy or ensure the desired outcomes. Between now and 2020, local interests must both designate or create the agency to implement the law locally (the “Groundwater Sustainability Agency), and write the plan to achieve “sustainable groundwater management” (the “Groundwater Sustainability Plan”).  To be clear; the four to six year window for doing this is incredibly ambitious. This work must be done by local governments and water management agencies, many of which are short of staff and strapped for resources.  It also must be done against a backdrop of a very high degree of fragmentation in groundwater management across the state:  approximately 2,300 independent local agencies play some role in managing groundwater in California (Nelson, 2012). Negotiating the roles of this crowd of local agencies under SGMA is a challenge in itself.

Accelerating SGMA implantation is unrealistic and would place an undo burden on already resource limited local and state agencies. The only real option for accelerating SGMA more rapidly would be for the state government to play a much larger, more aggressive role, a role inconsistent with the core of the law and the delicate politics required to get it passed. 

Another alternative to staunch the bleeding is to declare a moratorium on new wells.  At least one local government, San Luis Obispo County, took this step in light of severe overdraft (in fact, before SGMA’s passage).  This step might help to some degree, and would send an important message, but it does have limitations in light of the overall overdraft picture.  The total number of new water supply wells drilled in California has declined substantially between 1990 and 2014 (Figure 1). However, during this time, the absolute number of new irrigation wells drilled each year has remained relatively stable – particularly since the mid-1990s (DWR, 2014b).   Only 10 percent of new water supply wells drilled between 1977 and 2010 were irrigation wells (DWR 2015b). In 2014, irrigation wells accounted for nearly 50 percent of all of all new water supply wells drilled that year. Nearly 60 percent of the new wells drilled in 2014 were in eight Central Valley counties (Fresno, Merced, Tulare, Butte, Kern, Kings, Shasta and Stanislaus) (DWR 2014b). In Fresno and Tulare counties new irrigation wells in 2014 accounted for approximately 60 and 70 percent of all new water supply wells, respectively. 

Given that agricultural use accounts for nearly 80 percent of all water used in California, the fairly constant pace of drilling of new irrigation wells in recent years may help to explain why groundwater use across the state continues to increase even with a reduction in the total number of wells. It also points to some of the difficulties that local agencies are likely to face if they need to require cutbacks in pumping for some basins to balance their groundwater budget under SGMA. 

wells drilled

Figure 1. New water supply wells drilled annually in California between 1990 and 2014. Note that the 2014 data is from January 1 to September 31, inclusive. Figure from the Department of Water Resources November 2014 Public Update on Drought Response available at:

These data suggest that limiting the number of new water supply wells in an area is unlikely to result in significant reductions in groundwater use if the action is undertaken in isolation.  In some basins, overdraft will continue even without new drilling, and groundwater sustainability agencies will have to confront the need to cut back on existing withdrawals starting in 2020.  Cutting back on established pumping in many areas of the state is a very difficult political nut to crack both political and economically, given both the value of many crops being irrigated and the close link between land ownership and groundwater pumping rights in the state.  

It is troubling and frustrating that a year after the passage of such a historic law, California’s groundwater aquifers are in substantially worse shape.  SGMA gives localities a lot of hard work to do to implement the law, and it would be very difficult to shortcut that work.  The twin issues of fragmented governance and the challenges of cutting back on existing pumping present extraordinary challenges for these localities.  However, it is worth remembering that while SGMA gives localities primary control, the state plays a critical role by providing funding, oversight, and expertise while sustainability agencies are formed and plans written, and a back stop role if these agencies do not take the steps needed to deal with the law’s considerable challenges.  


DWR (2014a). Public Update for Drought Response Groundwater Basins with Potential Shortages and Gaps in Groundwater Monitoring, April, 2014. Department of Water Resources, Sacramento, CA. Available at:

DWR (2014b). Public Update for Drought Response: Groundwater Basins with Potential Shortages, Gaps in Groundwater Monitoring, Monitoring of Land Subsidence, and Agricultural Land Fallowing, November, 2014. Department of Water Resources, Sacramento, CA. Available at:

DWR (2015a). Progress Report: Subsidence in the Central Valley, California. A report prepared for the Department of Water Resources by NASA’s Jet Propulsion Laboratory. Available at:

DWR (2015b). California’s Groundwater Update 2013: A Compilation of Enhanced Content for California Water Plan Update 2013, April, 2015. Department of Water Resources, Sacramento, CA. Available at:

Howitt, R., D. MacEwan, J. Medellin-Azuara, J. R. Lund, and D. A. Summer. (2015). Economic Analysis of the 2015 Drought For California Agriculture. Center for Watershed Science, University of California, Davis, CA. Available at:

Nelson, R. (2012). Nelson, R.L. (2012). Assessing local planning to control groundwater depletion: California as a microcosm of global issues. Water Resources Research, 48: W01502. doi:10.1029/2011WR010927.