180-400ft Aquifer Subbasin Map

Situated in the northern region of Monterey County, the 180/400-foot Aquifer Subbasin encompasses Castroville, Salinas and Gonzales. Most of the subbasin has a layered aquifer system with three aquifers separated by aquitards. The upper two aquifers have seawater intrusion, which is why the state categorized the subbasin as critically overdrafted and requires earlier implementation of SGMA.

The 180/400-Foot Aquifer Subbasin Committee meets on the first Thursday of even months at 1 p.m. Get meeting information.

Groundwater Sustainability Plan:

Groundwater Sustainability Plans provide a long-term framework for managing groundwater in accordance with California’s Sustainable Groundwater Management Act (SGMA). The 180/400 Subbasin GSP describes groundwater conditions, establishes measurable sustainability goals, and identifies the projects and management actions needed to achieve and maintain groundwater sustainability.

As needed, a GSA may amend its GSP.  A GSP Amendment formally revises an adopted GSP when changes are needed to its management approach, sustainability criteria, projects, management actions, or other core elements. Amendments must be submitted to DWR with a Periodic Evaluation that explains and supports the changes. SVBGSA and partner GSAs prepared the 180/400 GSP Amendment 1 in 2022 and submitted in 2025 to align the plan with the Salinas Valley GSPs adopted in 2022. In response to DWR’s required revisions to the sustainability goals, SVBGSA and partner GSAs are preparing GSP Amendments for submittal with the 2027 Periodic Evaluations. The 180/400 GSP Amendment 2 will replace Amendment 1. For more information on the 2027 Salinas Valley GSP Amendments and Periodic Evaluations, see the Fact Sheet.

Draft 180/400 Foot Aquifer Subbasin GSP Amendment 2

Public comments received by  Nov. 18, 2026, will be included in the agenda packet for the Board meeting on Dec. 10, 2026. At this meeting, the Board will discuss and provide input on the draft GSP amendments prior to the public hearing. Please submit comments on the draft amendment by this date. All comments received by Nov. 18, 2026, as well as any subsequent comments, will also be included Jan. 14, 2027, public hearing record and in the final GSP appendix of public comments.

Submit comments for inclusion in the public hearing record using this webform.

Submit proposed Projects and Management Actions (PMAs) using this webform.

SVBGSA intends to hold a public hearing on Jan. 14, 2027, on the proposed GSP Amendment.

To submit general questions, email clerk@svbgsa.org.

Periodic Evaluations are comprehensive assessments of GSP implementation prepared at least once every five years. They evaluate whether implementation is meeting interim milestones and remains on track to achieve the groundwater sustainability goal. They also consider new information, changes in groundwater conditions, monitoring improvements, and whether revisions to the GSP may be warranted.

Annual Reports provide a yearly update on groundwater conditions and GSP implementation. They summarize monitoring data from the previous water year, evaluate conditions in relation to the GSP’s sustainability criteria, and report progress on projects, management actions, and efforts to address data gaps. Annual Reports are submitted to the California Department of Water Resources (DWR) by April 1 each year.