Sustainable Groundwater Management Act (SGMA)
What is the Sustainable Groundwater Management Act?
In California groundwater typically accounts for 40% to 60% of the State’s water supply depending on the amount of precipitation in a given year. Unfortunately, groundwater throughout California has been over-pumped for decades, causing groundwater levels to get lower and lower. In addition, challenges caused by climate change have made groundwater a scarce resource
In 2014, the State enacted three bills that make up the Sustainable Groundwater Management Act (SGMA). The act marks the first time in the State’s history that local water providers were given a set of guidelines and framework to sustainably manage groundwater resources.
First, SGMA defined sustainable groundwater management as using groundwater in such a way that it avoids undesirable results such as chronic lowering of groundwater levels, significant depletion of supplies, reduction of groundwater storage, seawater intrusion, degraded water quality, and land subsidence caused by lowering groundwater levels.
The state Department of Water Resources (DWR) then identified existing groundwater basins and established basin priority—high, medium, low, and very low—based on groundwater levels and over-draft. Water providers pumping from high and medium basins were required to form a Groundwater Sustainability Agency by June 30, 2017 to sustainably manage groundwater in their basin.
The Groundwater Sustainability Plans are due by January 31, 2020 for high and medium priority basins that are critically over-drafted. Non-critically over-drafted, high and medium priority basins need to complete a Groundwater Sustainability Plan by January 31, 2022.
What water providers need to do?
Now that Groundwater Sustainability Agencies have been formed, they need to develop Groundwater Sustainability Plans. Per State guidance documents, there are four milestones to complete and implement a Groundwater Sustainability Plan. The first step, which already passed was to form a Groundwater Sustainability Agency. The second is to prepare and submit a Groundwater Sustainability Plan. The third will be the plan’s review and evaluation by the State DWR, and the fourth and final step is plan implementation and reporting.
The general steps to complete a Groundwater Sustainability Plan are below:
In developing a Groundwater Sustainability Plan, agencies first need to have an understanding of the basin’s characteristics and groundwater conditions. This step will likely include preparing and/or updating a conceptual model of the basin, which will help identify how groundwater reacts over time to hydrogeological stresses (drought, over-pumping, etc.). The model should identify the following:
- Surface water interaction
- Stresses over time
- Historical and present groundwater conditions
- Water budget
- Outflows and inflows
- Potential overdrafts
- Supply, demand, hydrology and surface water supply reliability
Once the model is complete, the next step is identifying any management areas that may require different minimum thresholds, management objectives, monitoring, or project management actions. The management areas can be created for different land use types (residential vs. agricultural), based on geology, or other factors. Each management areas must be defined in the Groundwater Sustainability Plan and include the reasoning for the management area and how it can be managed differently without causing undesirable effects.
The next step is to identify sustainable management criteria. The plan needs to identify goals and minimum thresholds to meet those goals. Typically the criteria will be the sustainability indicators identified by SGMA regulations:
- Groundwater Levels
- Groundwater Storage
- Seawater Intrusion
- Water Quality
- Land Subsidence
- Interconnected Surface Water
Monitoring Network and Reporting
Once the goals and minimum criteria have been established, the Groundwater Sustainability Plan needs to identify and describe the basin’s monitoring network used to measure each sustainability indicator. Monitoring well locations need to be grouped based on geological and hydrogeological conditions in the basins. The plan should also identify a data management plan that will be used to store and report data annually to the State DWR.
Project and Management Actions
The next section of the Groundwater Sustainability Plan is to identify actions to achieve sustainability indicators, and identify permitting, regulations, and ordinances needed to implement corrective actions. Also, important are the timetable for completion, costs, and legal authority to raise revenue and impose fines or other corrective measures to achieve basin sustainability.
Once the steps are completed and the Groundwater Sustainability Plan is submitted, the State Department of Water Resources reviews and evaluates the plans. Once approved, Groundwater Sustainability Agencies need to provide yearly reporting, and by 2040 and 2042, the basins must achieve sustainability.
How can GEOSCIENCE help?
At GEOSCIENCE, we only do one thing: groundwater resources management and consulting. In our 40 year history, we have completed each type of study and assessment needed to complete a Groundwater Sustainability Plan, and can help guide you through the process. We can help you develop thorough studies and comprehensive groundwater models to help you accurately identify current conditions and plan ahead to attain basin sustainability.
Although this is a new regulation, we are one of the first firms in California that focused solely on groundwater management and sustainability. We can help you meet SGMA requirements efficiently and help you sustainably manage your groundwater resources for this and future generations.
Where can I get more information?
State SGMA website containing complete regulations, additional resources, and contact information:
Groundwater Sustainability Plan requirements and resources:
Water Education Foundation SGMA information page, contains basic information and commentary:
Maven’s Notebook SGMA page, contains news and updates on SGMA guidelines and implementation: