July 15, 2025
Draft Water Supply Master Plan (WSMP) 2050 Sierra Club Loma Prieta Chapter Comments
The Sierra Club Loma Prieta Chapter appreciates the opportunity to provide comments on the Draft Water Supply Master Plan (WSMP) 2050. We commend Valley Water staff and the Board of Directors for making many updates that improve upon the WSMP 2040. Still, we see many opportunities to provide additional contextual information. We also have some suggestions for future Monitoring and Assessment Program topics. Our comments are as follows.
Planning Context for the WSMP 2050
It would be helpful to add a section to the WSMP to provide context about the relationship between the WSMP and other water supply related plans and regulations. This could be added to the Introduction.
Explain the relationship between the WSMP and the Urban Water Management Plan (UWMP), and the associated Drought Response Plan and Water Shortage Contingency Plan. How will the updated WSMP impact these plans?
Describe the significance of the upcoming Bay-Delta Water Quality Control Plan and proposed Voluntary Agreements (alternative implementation pathways) in relation to water supplies delivered by the State Water Project (SWP), Central Valley Project (CVP), and San Francisco Public Utilities Commission (SFPUC).
Affordability
The Draft WSMP describes affordability/cost concerns related to potable reuse and water conservation, identifies cost as one of the most important factors when prioritizing portfolios, and focuses on the Lower Cost Strategy. However, the Draft WSMP does not include any policies to address affordability related to high-cost projects and does not include any triggers or indicators (metrics) related to affordability.
On June 24, 2025 the Valley Water Board of Directors received information on a consultant study regarding Valley Water’s Water Use Projections, Water Demand Elasticity, and Customer Affordability Study. The presentation describes upcoming Affordability Analyses including “Modeling local/statewide affordability metrics – AR20, hours at minimum wage, and lowest quintile income for Santa Clara [C]ounty, by Retailer.” This could be a starting point for metrics in the WSMP.
For these reasons, we recommend a future Monitoring and Assessment Program (MAP) topic to develop specific affordability policies and metrics for integration into the Draft WSMP, after the consultant studies are completed.
Water Supply System
In section 2.2, Local Surface Water, information should be added to explain that Anderson Reservoir and Calero Reservoir can also be used to store imported Delta water from the San Luis Reservoir.
In section 2.3, Groundwater, the Draft WSMP says “The estimated operational storage capacity of the groundwater subbasins is up to 548,000 AF. Valley Water’s managed recharge capacity is up to approximately 144,000 AFY.” However, there is no explanation of how these two numbers relate to each other, or what it means for water supply. Some explanation should be added to make this information useful in the context of the WSMP.
In Section 2.4, Imported Water, the Draft WSMP says “... imported water is pumped out of the Sacramento-San Joaquin Delta and brought into the county through the complex infrastructure of the SWP and CVP.” A figure (map) showing this infrastructure should be added to illustrate this complexity. Figure 2-5 Imported Water Delivery from 2010 to 2024 should also be updated to show years on the x-axis and to add notations for dry and wet years, to make the chart more useful and readable.
In section 2.7, Water Conservation and Demand Management, there is a discussion about the Water Conservation Strategic Plan which includes a “link” to www.watersavings.org. This link does not work. Typing www.watersavings.org into a browser leads to https://www.valleywater.org/watersavingsorg, but there is no information about the Strategic Plan on that webpage. Please provide a working link that links directly to the Strategic Plan.
Water Supply Challenges
In section 3.2.2, Forecast Development, the Draft WSMP says that Plan Bay Area 2040 projections are used for housing development and CII growth in the model because Plan Bay Area 2050+ blueprint projects are not available at a census tract level. Hopefully this break-down will be provided soon. If the refined projections are made available, we suggest including a MAP topic to update WSMP demand projections to use the latest regional planning analysis.
Table 3-3. Forecasted Santa Clara County water demands through 2050 shows demand starting at 330,000 AFY in 2030 with conservation. This appears to be unreasonably high given current demand is less than 300,000 AFY and demand has not been at 330,000 AFY since 2014. Figure 3-4 illustrates this well, with the steep demand curve increase between now and 2030. This should be updated to a more reasonable 5-year increase like the increases shown in Table 3-3 (5,000 – 10,000 AFY increases every 5 years). At least this 30,000 AFY jump in demand between now and 2030 needs to be explained.
In section 3.3.3, Regulation, there is a discussion about the Bay-Delta Plan which has been modeled into the water supply needs assessment assuming implementation of voluntary agreements (Healthy Rivers and Landscapes Program). The model needs to be revisited once the Bay-Delta Plan is approved, preferably as a MAP topic (if the adopted Plan differs from this current assumption).
Water Supply Needs Assessment
In section 4.3.1, WEAP, it says that WEAP uses the historic hydrologic sequence of 1922 through 2015. It would improve the model to use data through at least 2020. According to section 4.3.2, this is not possible due to missing data from SFPUC. This needs to be addressed or the model will become increasingly out of date. The model needs to be revisited once the SFPUC data is available, preferably as a MAP topic.
In section 4.3.3, Analysis Results, the charts analyzing a 6-year drought are confusing and need to be explained in more detail. It is unclear why the demand lines are different for the two stable demand futures and the two high demand futures. It is also unclear why Delta-conveyed supply goes up and down during the drought. This should be explained.
In the text explaining Figure 4-13 Average Shortage During the Six-year Drought, the Draft WSMP says “The projected shortages represent future water supply needs in the [C]ounty that Valley Water aims to meet to achieve its LOS goal.” We assume the LOS goal is 80% of pre-drought demands, but it would be very helpful to clarify that in relation to this chart. Also, it is unclear why supply is different between the two moderately impacted imports futures and the two severely impacted imports futures. These differences need to be explained.
In section 4.4, Needs for Investment, it is unclear whether the 10% rationing used to evaluate cost of shortage is 10% in addition to the 80% level of service goal, 10% below pre-drought demands, or something else. Please explain the baseline for the 10% rationing.
Project Options
In section 5.2.5, Delta Conveyance Project, the Draft WSMP says the project “would enhance and/or complement the benefits of other projects that are being considered under the WSMP 2050.” More information is needed about projects that would benefit and how the DCP would provide that benefit. This section also notes opposition due to cost and environmental concerns. This is true, but the main opposition is due to equity concerns related to communities in the Delta. This needs to be added for full transparency.
In section 5.2.8, Pacheco Reservoir Expansion, information should be added about the 30% partnership goal and the provision of water for environmental public benefit. Please discuss the amount of storage that will be dedicated to partners and to fish in Pacheco Creek, and the amount dedicated to Valley Water water supplies.
In section 5.3.1, Evaluation Criteria and Process, the evaluation process is not completely explained. A table should be provided with evaluation of all 14 criteria for each project, for transparency and completeness. The usefulness of the evaluation is also unclear since there is no ranking of projects for each criterion or in general. It would be helpful if the WSMP explained how these evaluations will be used.
In section 5.4.1, Cost Analysis Methodology, the Draft WSMP says “lifecycle cost includes capital and annual operations and maintenance (O&M) costs over a project’s useful service life with financing.” It does not say that mitigation and monitoring costs are included. Information about the inclusion or exclusion of mitigation and monitoring costs needs to be added.
Water Supply Strategies
In section 6.2.1, Portfolio Evaluation Approach, The Draft WSMP says that second-tier criteria can help to identify backup projects for each major project, but no backup projects are identified in the Plan. It is unclear whether these backup projects will be identified in the future or this information is superfluous. Please add some explanation or remove this if no follow-up is planned.
Table 6-2 Portfolio Rate Impacts in North County Zone W-2 includes average monthly impact to a household, but this information is confusing without more explanation. What is being averaged? Is this the average of all households in the County? Also, what does the dollar figure represent? Is this the projected increase to the monthly water bill over the 5-year period? Please add some explanation to clarify the meaning of average monthly impact.
Adaptive Management
In section 7.3, Annual Monitoring and Assessment Program, the WSMP says a standard report will be devised to include key elements of the WSMP, including “Any adjustments should be made.” Perhaps the word “that” is just missing, but it would still be unclear. It would be helpful to clarify what kind of adjustments would be recommended. Would it just be adjustments to projects and portfolios, or some other aspect of the WSMP?