BOARD AGENDA MEMORANDUM
Government Code § 84308 Applies: Yes ☐ No ☒
(If “YES” Complete Attachment A - Gov. Code § 84308)
SUBJECT: Title
Conduct Public Hearing on Valley Water’s 2026 Groundwater Management Plan (Five-Year Update to Approved Sustainable Groundwater Management Act Alternative Plan) for the Santa Clara and Llagas Subbasins; Adopt Resolution Adopting 2026 Groundwater Management Plan.
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RECOMMENDATION: Recommendation
A. Open and conduct a public hearing to receive comments on Valley Water’s 2026 Groundwater Management Plan, the five-year periodic update to Valley Water’s approved Alternative Plan under the Sustainable Groundwater Management Act, for the Santa Clara and Llagas Subbasins;
B. Close the public hearing; and
C. Adopt the Resolution ADOPTING THE 2026 GROUNDWATER MANAGEMENT PLAN FOR THE SANTA CLARA AND LLAGAS SUBBASINS.
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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 under Water Code § 10733.6 (Alternative Plan). Santa Clara Valley Water District (Valley Water) is the GSA for the Santa Clara and Llagas subbasins, which are both located in Santa Clara County.
In 2016, Valley Water submitted its 2016 Groundwater Management Plan for the Santa Clara and Llagas Subbasins (GWMP) to the Department of Water Resources (DWR) as a GSP Alternative, and DWR approved this Alternative Plan in 2019. As required by SGMA, in 2021 Valley Water submitted its first five-year Periodic Evaluation, or update, to the Alternative Plan in its 2021 GWMP, and DWR approved it. This 2026 GWMP is the second required five-year Periodic Evaluation, or update, to Valley Water’s Alternative Plan for these subbasins; it must be submitted to DWR by December 17, 2026.
Like the 2016 and 2021 GWMPs, the proposed 2026 GWMP describes Valley Water goals, strategies, activities, and metrics to ensure continued groundwater sustainability. This memo provides an overview of the major elements of the 2026 GWMP and describes notable changes and updates from the 2021 GWMP.
Valley Water posted its draft 2026 GWMP for public review on Valley Water’s Sustainable Groundwater Management website from August 13 to September 25, 2026. During the public review, four sets of comments were received (Attachments 6 to 9). Valley Water’s responses to the comments are Attachments 10 to 13. All comments and responses will be included in Appendix A of the 2026 GWMP. This hearing provides an additional opportunity for the public to provide comment or input to the Board prior to its decision whether to adopt the 2026 GWMP. If the Board adopts the 2026 GWMP, it will be submitted to DWR by December 17, 2026.
2026 GWMP Overview
While the organization name and purpose have evolved over time, Valley Water was originally formed as a special act district in 1929 for the purpose of managing groundwater. Historically, unsustainable pumping in Santa Clara County resulted in chronic overdraft, land subsidence, and seawater intrusion. While similar problems persist in groundwater basins throughout California, Santa Clara County is recognized as an area where these issues have been, and continue to be, successfully addressed through sustainable groundwater management.
Valley Water’s comprehensive groundwater management framework has maintained sustainable conditions in the Santa Clara and Llagas subbasins over many decades. The 2026 GWMP provides detailed information describing this framework, including the following major elements:
• Valley Water history, groundwater management authority, structure, and finances
• Basin setting and conditions including geology, groundwater levels and quality, groundwater dependent ecosystems, land subsidence, and seawater intrusion
• Water supplies, demands, and the groundwater budget
• Sustainable management criteria, including goals derived from Board Ends Policy E-2, effective strategies, and outcome measures to gauge performance
• Basin management programs and activities
• Groundwater monitoring and modeling
• Potential actions to address outcome measure performance and plan recommendations
While all sections are being updated to represent current basin conditions and Valley Water activities, the fundamental structure and content of the GWMP are largely unchanged as implementation of the plan has proven to be effective in maintaining sustainable groundwater conditions.
Notable updates from the 2021 GWMP include the following, with the first two items supporting related DWR recommendations:
• Summary of coordination with adjacent GSAs
• Monitoring data consistency with DWR’s Monitoring Network Module webpage
• Modified outcome measures
A summary of these changes is provided below.
Summary of Coordination with Adjacent GSAs
Coordination with adjacent GSAs on key inter-basin items is an important and ongoing activity that helps Valley Water and its partners meet groundwater sustainability goals. The Alameda County Water District (ACWD) is the GSA for the medium-priority Niles Cone Subbasin (DWR Basin 2-9.01) located to the northeast of the Santa Clara Subbasin. As part of ongoing coordination, Valley Water and ACWD staff compared approaches for modeling future groundwater conditions to support SGMA-related activities and 2026 GWMP, have shared technical presentations on their respective hydrogeologic conceptual models and groundwater monitoring networks, and routinely reach out and discuss groundwater management related questions.
The San Benito County Water District (SBCWD) is the GSA for the medium-priority North San Benito Subbasin (DWR Basin 3-3.05) located to the south of the Llagas Subbasin. As part of ongoing coordination, Valley Water and SBCWD staff routinely reach out with groundwater management related questions and share groundwater level data annually for wells adjacent to the subbasin boundary, which are important data for the evaluation of groundwater flow, groundwater model calibration, and refinement of water budgets. Valley Water staff served on the Technical Advisory Committee for the 2021 GSP development and 2026 GSP Periodic Evaluation and GSP Amendment for the North San Benito Subbasin.
Monitoring Data Consistency with DWR’s Monitoring Network Module Webpage
Valley Water updates DWR’s Monitoring Network Module (MNM) database on a quarterly basis with monthly water level data for the Santa Clara and Llagas subbasins. Additionally, Valley Water updates well attributes in MNM, including monitoring point and reference elevations, in a timely manner. Water level data are publicly available through Valley Water’s Groundwater Elevations webpage.
Modified Outcome Measures
The outcome measures and associated lower thresholds are quantifiable metrics to track performance in meeting sustainability goals and define undesirable results, respectively, and have performed well since new and modified metrics were introduced in the 2021 GWMP based on DWR recommendations. As part of the periodic evaluation for the 2026 GWMP, Valley Water evaluated and further refined the water quality outcome measures and lower thresholds for the Santa Clara and Llagas subbasins based on actual groundwater conditions and recent trends in subbasin specific criteria, including water supply well type (public and private), land-use characteristics, and changing drinking water regulations. The refined water quality outcome measures and lower thresholds better characterize whether each subbasin is meeting or making progress toward the sustainability goals. A detailed description and rationale of the refined water quality outcome measures and lower thresholds are in the draft 2026 GWMP. No changes were made to the outcome measures for groundwater storage, levels and subsidence, or seawater intrusion.
Outreach and Next Steps
Throughout development of the 2026 GWMP, regular updates have been provided to the Board’s Water Supply and Demand Management Committee, as well as to the Agricultural Water Advisory Committee, Water Retailers Joint Water Supply and Groundwater Subcommittee, and interested parties. Valley Water also hosted a well-attended public meeting on July 30, 2026 on this subject.
Assuming the Board adopts the 2026 GWMP, staff will then submit it to DWR for its review.
ENVIRONMENTAL JUSTICE IMPACT:
There is no environmental justice impact associated with this item.
FINANCIAL IMPACT:
There is no financial impact associated with this item. Activities described in the 2026 GWMP are addressed as part of the annual budget approved by the Board. Water utility projects supporting the protection and augmentation of water supplies are funded through the Water Utility Enterprise fund, which includes revenue from groundwater production charges, treated water charges, and other sources.
CEQA:
This project is exempt from CEQA Guidelines Section 15262, which exempts planning studies.
ATTACHMENTS:
Attachment 1: Public Hearing Notice
Attachment 2: Resolution
Attachment 3: PowerPoint
Attachment 4: 2026 Groundwater Management Plan
Attachment 5: Change List
Attachment 6: Comments from Dave Hook
Attachment 7: Comments from Doug Muirhead
Attachment 8: Comments from Libby Lucas
Attachment 9: Comments from SJWC
Attachment 10: Response to Dave Hook
Attachment 11: Response to Doug Muirhead
Attachment 12: Response to Libby Lucas
Attachment 13: Response to SJWC
UNCLASSIFIED MANAGER: Manager
Greg Williams, 408-630-2867