COMMITTEE AGENDA MEMORANDUM
Water Supply and Demand Management Committee
Government Code § 84308 Applies: Yes ☐ No ☒
(If “YES” Complete Attachment A - Gov. Code § 84308)
SUBJECT: title
Receive a Status Report on the Development of the Five-Year Update (Periodic Evaluation) to the North San Benito Subbasin Groundwater Sustainability Plan; and Recommend Bringing Periodic Evaluation to the December 8, 2026 Board of Directors Meeting for Public Hearing and Adoption.
End
RECOMMENDATION: Recommendation
A. Receive a status report on the development of the five-year update, or Periodic Evaluation, to the North San Benito Subbasin Groundwater Sustainability Plan; and
B. Recommend that the Board hold a public hearing on the Periodic Evaluation (updated plan) at its December 8, 2026 meeting and consider adopting the updated plan.
Body
SUMMARY:
The Sustainable Groundwater Management Act (SGMA) requires that groundwater sustainability agencies (GSAs) managing medium or high-priority basins prepare and implement a groundwater sustainability plan (GSP) or an authorized alternative to a GSP and prepare a Periodic Evaluation at least every five years. The North San Benito Subbasin is about 200 square miles and largely in San Benito County with small areas (about 5 square miles) in Santa Clara County. Valley Water is the GSA for the portion of the GSP area in Santa Clara County. In 2022, San Benito County Water District (SBCWD) and Valley Water agreed to collaborate in preparing the GSP with SBCWD taking the lead and with cooperative implementation of the GSP in the future. The 2022 GSP was approved by the California Department of Water Resources (DWR) with four Recommended Corrective Actions. As the GSAs for the medium priority North San Benito Subbasin, SBCWD and Valley Water have prepared a Periodic Evaluation and GSP Amendment that respond to the DWR feedback.
This memo provides an overview of the major elements of the North San Benito GSP, Valley Water’s roles and responsibilities, and the process to submit the final GSP to DWR. A draft GSP Amendment will be posted to SBCWD’s website.
The SBCWD Board of Directors will hold a public hearing as to whether to adopt the Updated Plan on December 16, 2026. As required by SGMA, the Periodic Evaluation and any GSP Amendment is due to the DWR by January 12, 2027.
GSP Amendment Overview
The GSP Amendment updates the original 2022 GSP, including revised groundwater conditions through WY 2025, updates to the groundwater model, and revision to the water quality sustainable management criteria. Based on sustainability indicators defined by SGMA, the GSP describes that the North San Benito Subbasin has been managed sustainably, given the availability of imported Central Valley Project (CVP) water. Accounting for current conditions, climate change, and anticipated growth, future projections indicate that the basin can continue to remain sustainable, assuming reasonable availability of CVP water, with implementation of projects and management actions to avoid undesirable results. These projects and management actions do not include any long-term planned reduction in groundwater pumping.
GSP Development and Sustainability Goals
The North San Benito GSP was prepared with the participation of the public, local water and planning agencies, state agencies, and non-governmental organizations. SBCWD organized a Technical Advisory Committee (TAC) to support GSP development with multiple meetings open to the public; Valley Water staff served on the TAC. Additionally, SBCWD conducted six public workshops, provided regular updates at public meetings of the SBCWD Board of Directors, and distributed outreach materials.
The goal of the GSP is to sustain groundwater resources for the current and future beneficial uses of the North San Benito Subbasin in a manner that is adaptive and responsive to the following objectives:
• to provide a long-term, reliable, and efficient groundwater supply for agricultural, domestic, and municipal and industrial uses
• to provide reliable storage for water supply resilience during droughts and shortages
• to protect groundwater quality
• to prevent subsidence
• to support beneficial uses of interconnected surface waters, and
• to support integrated and cooperative water resource management.
Plan Area
The North San Benito Subbasin is about 200 square miles and largely in San Benito County with only about 5 square miles in Santa Clara County. The plan area of the GSP includes the valley areas characterized by productive agriculture, urban areas including the cities of Hollister and San Juan Bautista, rural communities, and upland areas with grazing land. Groundwater is the main source of water in the plan area, supplied to municipal, agricultural, and domestic users through more than 1,000 production wells. Imported water from the CVP is the other major source of water.
Current and Historical Groundwater Conditions
The North San Benito groundwater storage has been stable for the long term, given availability of imported CVP supplies since 1987. The basin’s groundwater levels have been near historical highs for the last twenty years. Inelastic (permanent) subsidence has not been a known issue in the North San Benito Subbasin. Nonetheless, the GSP recommends monitoring of land surface elevation and maintaining groundwater levels above the historical lows levels to avoid inelastic subsidence. SBCWD will continue to monitor groundwater levels and quality in the basin. The GSP also identifies interconnected surface water and groundwater, including the location of groundwater dependent ecosystems.
Project and Management Actions
The GSP notes that groundwater conditions are sustainable in the North San Benito Subbasin. However, long-term sustainability requires continuation of monitoring, reporting, and management actions that are adaptive to climate change, water supply, and water demand conditions. The GSP presents ongoing, new, and recommended projects and management actions needed to maintain sustainability.
Potential projects will either increase water supply or reduce water demand, and include the following categories:
• develop surface water storage
• expand managed aquifer recharge
• enhance conjunctive use
• enhance water conservation.
Given the small area of the basin in Santa Clara County, these potential projects are largely focused on the San Benito County portion of the basin, within the jurisdiction of SBCWD.
Potential management actions provide a framework for groundwater management, and include the following categories:
• improve monitoring program and data management system
• develop response plans
• enhance water quality improvement programs
• reduce potential impacts to groundwater dependent ecosystems
• provide long-term basin-wide funding mechanisms
• provide administration, monitoring, and reporting.
Again, these management actions are applicable mostly to the San Benito County portion of the basin, within the jurisdiction of SBCWD. However, Valley Water and SBCWD will continue to share information and coordinate on actions benefiting both counties.
Implementation Plan
Since over 97% of the basin is in San Benito County, SBCWD is largely responsible for the implementation of the GSP. Implementation will begin in 2027 and continue until 2042, and includes SGMA compliance and administration, basin monitoring, expanded reporting, and five-year updates. SBCWD’s expanded management will involve increased annual costs. As described in the GSP, funding methods include an acreage-based fee for parcels in the basin benefitting from groundwater management and a groundwater-extraction based fee that supports annual measurement of groundwater pumping. A groundwater management fee was established by SBCWD Board of Directors Resolution No. 2021-13.
The Santa Clara County portion of the basin includes 2,724 acres; related Valley Water costs for the next five years of GSP implementation will be $1,634 annually, or $8,170 total, as described in the MOU between Valley Water and SBCWD executed on June 23, 2026. Throughout GSP implementation, Valley Water and SBCWD will continue to coordinate on basin data and conditions and on potential management actions affecting the portion of the basin in Santa Clara County.
Coordination and Outreach
Throughout preparation of the GSP, periodic updates have been provided to the Committee and interested parties. SBCWD hosted a virtual public meeting to describe the draft GSP on September 15, 2026.
Public Hearing and Plan Adoption
Valley Water is targeting the December 8, 2026 Board of Directors meeting for a public hearing on the North San Benito GSP, followed by Board consideration of the plan for adoption. After plan adoption, SBCWD will submit the GSP to DWR by January 12, 2027, as required by SGMA.
ENVIRONMENTAL JUSTICE IMPACT:
There are no environmental justice impacts associated with this item.
ATTACHMENTS:
Attachment 1: PowerPoint
UNCLASSIFIED MANAGER:
Manager
Gregory Williams, 408-630-2867