GSAs and Groundwater Sustainability Plans

Groundwater Sustainability Agencies (GSAs) are the central actors in California’s Sustainable Groundwater Management Act. GSAs are responsible for developing and implementing groundwater sustainability plans (GSPs) that achieve sustainability across the groundwater basin. GSAs located in basins designated as critically over-drafted must develop GSPs by 2020, while GSAs located in other high and medium priority basins have until 2022 to develop GSPs. 

In developing groundwater sustainability plans, GSAs must:

  • Characterize and assess the groundwater basin, including the physical structure and properties of the aquifer, historic water levels, abstractions, recharge, quality, land subsidence, interconnected surface waters, etc.
  • Develop sustainable management criteria, including setting sustainability goals; establish minimum thresholds to avoid the six undesirable results of groundwater depletion; and define measurable objectives and interim milestones for achieving sustainable groundwater management
  • Identify specific policies, projects, and management actions to implement in order to acheive the sustainability goals
  • Outline how the GSA(s) will monitor groundwater conditions in the basin, the impacts on water users, and progress towards the sustainability goals.

As part of the process of developing groundwater sustainability plans, GSAs must engage with stakeholders and coordinate with systems for land and surface water governance. Where multiple GSAs have formed in a basin, GSAs also must coordinate with one another to ensure sustainability is achieved across the basin.

Across the 21 basins initially identified as critically over-drafted, 104 GSAs formed. In 5 of these basins, a single GSA covers the entire basin. In the other 16, multiple GSAs formed. GSAs who share a basin must work together to achieve groundwater sustainability, either by jointly developing a groundwater sustainability plan, or by coordinating separate groundwater sustainability plans. Where GSAs are coordinating separate groundwater sustainability plans, they must develop coordinated data management systems. They also must ensure the separate plans are developed and implemented utilizing the same data and methodologies and that elements of the plans necessary for achieving the sustainability goal for the basin are based upon consistent interpretations of the basin setting. The GSAs must also demonstrate how the separate groundwater sustainability plans, implemented together, satisfy the requirements of SGMA.

Relationship between Groundwater Sustainability Agencies and Groundwater Management Plans

Image modified from CA DWR (2016) Groundwater Sustainability Plan Emergency Regulations Guide