Groundwater

What is SGMA?

On September 16, 2014, Governor Jerry Brown signed into law a three-bill legislative package, collectively known as the Sustainable Groundwater Management Act (SGMA). For the first time in its history, California has a framework for sustainable, groundwater management – “management and use of groundwater in a manner that can be maintained during the planning and implementation horizon without causing undesirable results.”

SGMA requires governments and water agencies of high and medium priority basins to halt overdraft and bring groundwater basins into balanced levels of pumping and recharge. The Cosumnes Basin is a medium priority basin. Under SGMA, we should reach sustainability within 20 years of implementing our sustainability plan, which must be submitted to the Department of Water Resources in January, 2022.

SGMA empowers local agencies to form Groundwater Sustainability Agencies (GSAs) to manage basins sustainably and requires those GSAs to adopt Groundwater Sustainability Plans (GSPs) for crucial groundwater basins in California. In the Cosumnes Basin, there are 7 GSAs: Sloughhouse Resource Conservation District, Clay Irrigation District, Galt Irrigation District, Omochumne Hartnell Water District, Amador County, Sacramento County, and the City of Galt. These organizations meet as a Working Group and these meetings are open to the public and there are opportunities for public comment.

Who represents you?

7 Groundwater Sustainability Agencies (GSAs) represent the Cosumnes Sub-basin. Click on the map to find which GSA represents you! These GSAs are now engaged in a collaborative group, called the Cosumnes Sub-basin SGMA Working Group, to discuss developing a roadmap for creating a groundwater sustainability plan.

If you don’t live within the Cosumnes Sub-basin, you can use the Dept. of Water Resources SGMA Portal to find your local GSA.

Using funds from a grant from the Dept. of Water Resources as well as local contributions, the Working Group has hired a consultant, EKI Water Environment, to prepare the groundwater sustainability plan. To prepare the plan, data on current groundwater conditions at selected sites, land uses, pumping, and other relevant information has been collected. This information has been used to develop a water budget – how much water enters and leaves the basin. The consultants are also working on developing a numeric model. Using sophisticated computer programs, estimates will be made of the movement of water into and out of the basin for decades to come.

Preliminary estimates suggest that greater than 10,000 acre/feet (AF) of water per year leaves the basin than enters the basin. In other words, we are running a deficit, an unsustainable condition. SGMA identifies 6 unsustainable or undesirable conditions that must be reviewed and addressed in the plan that is under development. The following table identifies the indicators of these undesirable conditions and the way that conditions is measured (the metric).

Of particular importance in our basin is the potential effect of the falling water table on the Cosumnes River.  In many reaches of the river, there is no connection between surface and groundwater.  Given that the Cosumnes River is the only river on the western slopes of the Sierras that does not have a permanent dam makes it a unique river on which dozens of studies have been conducted.  The adverse effects of declining groundwater on the vegetation along the river is the focus of careful review (sustainability indicator #6 above) and will be an important part of the GSP.

After evaluating conditions, starting in 2015 (as defined by law) and into the future for these sustainability criteria, management measures must be developed to ensure we achieve sustainability by 2042.  These measures could include developing aquifer recharge projects to increase the total volume of water stored in the basin, limiting the use of water by farmers, and/or placing meters on wells of agriculturalists.  Those property owners who use less than 2 AF/year, typically rural residential landowners, are considered de minimis users and are not subject to metering.  However, all landowners within the basin could have a fee or levy placed on their pump or property to cover the costs of long term monitoring and reporting required by law.

From SGMA, Water in the West

In 2014, after three years of severe drought, the California legislature passed the Sustainable Groundwater Management Act (SGMA), creating a statewide framework for groundwater regulation in California. Prior to passage of SGMA, groundwater use in California was largely unregulated.1 The unconstrained use of this resource has led to widespread lowering of water tables, drying of domestic wells, land subsidence and corresponding damage to infrastructure, increased energy costs from pumping from greater depth, the reduction or elimination of baseflow to streams and rivers, diminished water quality, and the loss of groundwater- dependent ecosystems.

SGMA presents a significant opportunity to address these impacts and ensure that groundwater resources are available to meet the state’s long-term water needs. Developing solutions to support the successful implementation of SGMA will require a breadth of expertise. Local, state and federal governments and agencies will need to work closely with research institutions, policy centers, non-governmental organizations, trade associations, facilitators, groundwater users, and the public to develop robust and timely solutions that address all interests. Failure to do so may result in legal battles and continued degradation of groundwater resources.

Stanford University’s Water in the West program, in partnership with The Nature Conservancy of California, hosted an Uncommon Dialogue2 with groundwater managers, state officials, special interest groups, legal and policy experts, technical experts, land use planners, facilitators, and researchers to discuss the changing landscape of groundwater management in California. Held in January 2015, just four months after passage of SGMA, the dialogue identified challenges that local agencies are likely to face during SGMA implementation, plus potential short-term solutions to address these challenges.

Groundwater is an important part of California’s water supply system supplying between 30 to 60 percent of the state’s water supply depending on climatic conditions. • Groundwater is commonly used in dry years to supplement reductions in surface water flows. However, our over reliance on the resource in the last several decades has led to long-term declines in groundwater levels in many parts of the state. • Chronic declines in groundwater levels have been exacerbated by four years of severe drought. • The severity of groundwater overdraft in many groundwater basins in California prompted the passage of the Sustainable Groundwater Management Act of 2014.

California receives an average of 200 million acre-feet (an acre-foot of water is enough to supply two to four families with enough water for a year) of precipitation each year (DWR 2013).• Just over 70 million acre-feet of the precipitation flows to rivers and streams or infiltrates into groundwater aquifers where it can be used – the remainder is lost through evaporation and transpiration from plants.• Between 2005 and 2010 groundwater supplied more than 16 million acre-feet per year or approximately 38 percent of the state’s water supply (DWR 2013). This percentage increases to nearly 50 percent of the state’s water supply during dry years and to nearly 60 percent in drought years (DWR 2013; DWR 2014a). • There is broad regional variation in groundwater use across the state, which varies between 9 and 86 percent of the total water supply by hydrologic region. • Agricultural, urban and managed wetlands account for approximately 76 percent, 21 percent, and 2 percent of all groundwater used in the state, respectively (DWR 2013). • Many groundwater basins throughout the state manage groundwater conjunctively, drawing the aquifers down during dry years, when there are diminished surface water flows, and recharging aquifers during wet years (e.g., Santa Clara Valley Water District, Orange County Water District).• Other areas of the state are experiencing chronic groundwater level declines. The California Department of Water Resources (2013) estimates that statewide overdraft of groundwater may be as high as 2 million acre-feet per year, with 1.4 million acre-feet year of that occurring from agricultural use in the Tulare Lake region and San Joaquin River region.