Alternative Groundwater Sustainability Plan and Updates


Zone 7 proactively manages our groundwater basin to ensure this valuable resource remains a sustainable source of water for future generations of the Tri-Valley.

As the designated agency for managing the groundwater basin (called a Groundwater Sustainability Agency or GSA), the state requires a Groundwater Sustainability Plan (GSP); however, the Agency has been monitoring the basin since 1974 and managing groundwater since the early 1960s. Because Zone 7 had an existing plan in place in advance of state requirements, staff was able to submit an Alternative GSP, one of only nine accepted by the Department of Water Resources across the state, marking a big win for the Agency and a testament to proactive and sustainable groundwater management that is central to the Agency’s mission and history.

Grant Funded Updates

Our Alternative GSP received a half million dollar grant to help us update the plan, and specifically, expand our knowledge of the fringe and upland basins – the unincorporated areas, hills, and recharge areas on the outlying areas of the basin and how they relate to the main basin. This planned update is an important part of our groundwater management process and applying for state grants is an example of our strategies to leverage available resources for responsible fiscal management.

Groundwater Management Timeline

1900 - 1962 – The groundwater basin level declines to an all time low of 182 feet above mean sea level or from near the ground surface to roughly 200 feet below ground surface.

1962 – Zone 7 begins artificial groundwater recharge of the basin using purchased water from the newly formed State Water Project and newly constructed South Bay Aqueduct.

1983 – The groundwater basin level recovers to a more recent high of 312 feet above mean sea level with sustainable management practices and has stayed within a target zone for over 40 years.

2016 – Zone 7 submits an Alternative Groundwater Sustainability Plan (Alternative GSP) for compliance with Sustainable Groundwater Management Act (SGMA) regulations.

2019 – DWR approved Zone 7’s Alternative GSP, recommends Zone 7 extend the criteria of minimum thresholds developed for the Main Basin (e.g. historic low water levels) into the Fringe and Upland portions of the Basin. This will require extending geologic cross-sections and the existing model.

2019 – Zone 7 receives two comment letters from The Nature Conservancy on the Alternative GSP, which recommended further evaluation of Groundwater Dependent Ecosystems. DWR has provided the Natural Communities Commonly Associated with Groundwater (NCCAG) mapping, which is a useful tool to help in identifying potential groundwater-dependent ecosystems.

2019 – Zone 7 staff submit a detailed grant proposal in November for a DWR-administered Proposition 68 grant for $666,500, of which $499,875 was to be reimbursed by the grant, for the update of the Alternative GSP.

2020 – DWR approved the grant proposal and Zone 7 entered into an agreement with DWR for the project. The DWR-approved work plan addresses the comments received on the 2016 Alternative GSP.

2020 – In June, Zone 7 staff presented a summary of the grant project at a public Zone 7 Board meeting (see AGSP Agenda and AGSP Presentation). During that meeting, the Board also authorized a contract (see AGSP Contract Approval) with a consultant, (EKI Consultants, Inc.) to assist staff on some portions of the project.

Learn More

  • View the Stakeholder Communication and Engagement Plan to learn how we will support stakeholder outreach during the 2022 Alternative GSP process: AGSP SCEP

  • View the Grant Work Plan to see details of the grant requirements: AGSP Work Plan

Join our E-newsletter