COMMITTEE AGENDA MEMORANDUM
Santa Clara Valley Water Commission
Government Code § 84308 Applies: Yes ☐ No ☒
(If “YES” Complete Attachment A - Gov. Code § 84308)
SUBJECT: title
Receive Information on Valley Water’s Water Supply Master Plan 2050.
End
RECOMMENDATION: Recommendation
Receive Information on Valley Water’s Water Supply Master Plan 2050.
Body
SUMMARY:
The Water Supply Master Plan (WSMP) is Santa Clara Valley Water District’s (Valley Water) guiding document for long-term water supply investments to ensure water supply reliability for Santa Clara County. Updated approximately every five years, this long-range plan assesses projected future county-wide demands and evaluates and recommends water supply and infrastructure projects to meet those demands to achieve Valley Water’s level of service goal through the planning horizon. Valley Water’s level of service goal, as established in Board Ends Policy E2, is to “Meet 100 percent of annual water demand during non-drought years and at least 80 percent of demand in drought years.”
Valley Water developed the WSMP 2050 to evaluate and respond to changing conditions such as severe drought, reductions in imported water supplies, shifting water demands, and concerns about affordability. The WSMP 2050 addresses both existing and emerging challenges and identifies strategies to maintain the reliable water supply system for Santa Clara County through 2050. The WSMP 2050 planning effort spanned two years with three updates to the commission. The resulting plan was adopted by the Board of Directors (Board) in November 2025 and is attached (Attachment 1).
Planning Approach
The WSMP 2050 analyzes four alternative futures based on the combination of demand projections and forecasted imported water supplies. This approach is intended to account for uncertainty in forecasted future demand and supply and provide an adaptive framework for decision-making.
A. Stable Demand and Moderately Impacted Imports
B. Stable Demand and Severely Impacted Imports
C. High Demand and Moderately Impacted Imports
D. High Demand and Severely Impacted Imports
The stable demand assumes demands stay flat at 2030 levels through 2050 at 330,000 acre-feet per year (AFY), while the high demand is projected to be 350,000 AFY by 2050. Demand projections assume Valley Water achieves its long-term conservation goals. The imported water baseline supply scenarios were selected from the Department of Water Resources (DWR) modeling. The moderately impacted imports scenario represents imported water deliveries with small impact from climate change, while the severely impacted imports scenario represents significantly impacted deliveries, particularly during droughts.
Need for Investment
Under each of the four future conditions, water supply needs under the baseline condition were assessed using modeling analysis, to serve as a basis for identifying project options for potential investment. The baseline condition assumes completion of local dam seismic retrofits by 2035, achieving long-term water conservation goals, maintaining Valley Water assets, and expanding recycled water use.
Valley Water’s current system and sources of water supply can meet demands during wet and normal years, but extended droughts remain the biggest water supply challenge. Under all four potential 2050 futures, Valley Water will experience water shortages if relying only on existing supplies and infrastructure during multi-year droughts. The shortages may start as early as 2030. In 2050, the average shortage over a six-year drought could be as much as 70,000 AFY, depending on the projected demand and imported water supply conditions. These shortages are large and already take into account meeting drought water use reduction calls and achieving long-term conservation goals. Valley Water needs to invest in new projects to address those shortages to ensure long-term water supply reliability for Santa Clara County. Without additional investments, the predicted shortages mean Valley Water will have a reduced service level, and therefore less water available to the community. A reduced level or service could have an immediate and real impact on residents and businesses including lower quality of life, disruption of business operations, and loss of agricultural production. If the shortage condition becomes chronic, it could lead to land subsidence and potentially billions of dollars in economic losses, and adversely and chronically affect economic development in the county.
Water Conservation and Reuse Goals
As part of this plan development, Valley Water developed water conservation and reuse goals to address future shortages. The established water conservation goal for 2050 is 126,000 AFY, which is considered ambitious but implementable and balances benefits with affordability concerns. This goal is additional to the previously established conservation goals of 99,000 AFY by 2030 and 110,000 AFY by 2040.
The goal for water reuse is to develop 24,000 AFY of potable reuse by 2035, with a long-term vision to maximize water reuse in the county up to 32,000 AFY by 2050. The inclusion of a 2035 goal with the long-term vision promotes a phased approach that accounts for uncertainty with future demand and wastewater availability while balancing affordability and risk of overinvestment.
Water Supply Strategy
Valley Water considers and evaluates a broad range of projects in the WSMP 2050 to address future water supply needs, including alternative supply projects, local and imported surface supply projects, storage projects, and recharge projects. The projects were evaluated using a number of criteria, including supply benefit, cost, reliability, likelihood of success, environmental impacts, jurisdiction and partnership, and public acceptance.
The water supply strategies were developed through portfolio analysis and evaluation. To help outline investment options and present tradeoffs, three potential investment strategies were developed - lower cost, local control, and diversified, and one representative portfolio for each strategy was selected and summarized in Table 1, along with the total lifecycle cost in 2025 dollars and expected supply or storage benefits. These portfolios can all meet future water supply needs and serve as the basis for an adaptive management framework.
Adaptive Management
Since there are different strategies to achieve future water supply reliability and given uncertainty in project development and future supply and demand conditions, an adaptive management approach was developed to provide the Board with flexibility and the ability to make incremental investment decisions. The adaptive framework includes a roadmap and annual reporting. The roadmap outlines near- and mid-term actions and defines indicators and conditions to guide project decisions. The annual reporting tracks project progress and provides up-to-date information to help inform decision-making.
The roadmap includes recommended actions at different timelines, especially immediate actions as the starting point of the adaptive management framework:
• Now - focus on the Lower Cost strategy, which includes San Jose Potable Reuse, B.F. Sisk Dam Raise, Delta Conveyance Project, Groundwater Banking, and South County Recharge; Continue planning for Sites; Continue the Desalination feasibility study; Continue implementing conservation programs.
• Near-term (2-3 years) - Assess success/progress on project planning and implementation; Make project funding, participation, or go/no-go decisions based on indicators, new information, and actual conditions; Continue planning for other projects.
• Mid-term (5 years) - Assess progress on project implementation; Update demand projections and water supply outlook; Update WSMP
Annual reporting through the Monitoring and Assessment Program (MAP) will be a critical component of the adaptive management framework. A standard MAP report will be devised to track key elements of the WSMP, including progress on projects, conditions of indicators, and whether any adjustments are recommended. The timing of the MAP will be aligned with the annual Capital Improvement Program (CIP) Five-Year Plan and water rate-setting cycle to support related decision-making. The annual process will also serve as the venue to evaluate any emerging opportunities in between the WSMP planning cycles.
Next Steps
Starting this year, staff will bring the annual MAP update to the Board in the Fall, to track the WSMP 2050 implementation as part of adaptive management.
ENVIRONMENTAL JUSTICE IMPACT:
The Water Supply Master Plan addresses water supply equity by ensuring a cost-effective, high-quality supply is available for all of Santa Clara County, including disadvantaged communities.
ATTACHMENTS:
Attachment 1: WSMP 2050
Attachment 2: PowerPoint
UNCLASSIFIED MANAGER:
Manager
Kirsten Struve, 408-630-3138