Alameda County charts path for new groundwater plant, keeps potable reuse on distant horizon

Alameda County charts path for new groundwater plant, keeps potable reuse on distant horizonCalifornia’s Alameda County Water District has detailed an adaptive, phased roadmap for its 2050 water supply plan, prioritizing the exploration of a major new groundwater facility while setting up a decades-long evaluation path for potable reuse as a final backstop against severe climate change.

The plan's centerpiece is the exploration of a 'Southern Groundwater Facility' to increase local supply, with a potential capital cost previously estimated at around $400 million.

A large-scale potable reuse project is preserved as a long-term option, but major investment decisions are deferred until at least 2035, with construction not envisioned before 2050.

Implementation will be guided by an 'adaptive management' framework, with project advancements contingent on triggers like State Water Project reliability, feasibility study outcomes, and new regulations.

The strategy's near-term 'no-regrets' phase focuses on optimizing the district's existing Newark brackish water desalination plant and building treatment for PFAS and hardness.

Board debate highlighted ongoing tension between pursuing potable reuse versus desalination for future supply, though the current plan gives staff a clear focus on the former for long-range planning.

The Alameda County Water District (ACWD) in the San Francisco Bay Area has laid out an implementation roadmap for its multi-decade Water Resources Master Plan that prioritizes developing a new local groundwater source while deferring a decision on a major potable reuse project for at least a decade. During a board workshop on 20 November, district staff and consultants presented a phased and adaptive strategy designed to navigate the uncertainties of climate change, declining imported water supplies, and evolving regulations through 2050. The plan, which builds on a preferred portfolio approved by the board in August, is structured in three distinct phases. The first is a 'no-regrets' phase focused on optimizing existing assets. This includes enhancing the performance of the district’s 20-year-old Newark brackish water desalination facility and moving forward with treatment solutions for PFAS and hardness. These near-term, lower-cost actions are designed to maximize the utility of current infrastructure. The second, more ambitious phase hinges on the exploration of a new 'Southern Groundwater Facility'. This project represents a significant potential investment, previously ballparked at $400 million, to further develop the local Niles Cone groundwater basin. The goal is to increase local supply and reduce the district's reliance on increasingly vulnerable imported water from California’s State Water Project (SWP). However, the project's viability is uncertain, and a significant feasibility study is required before the district commits to design and construction. The outcome of this study is a critical internal 'driver' that will shape the district's future supply portfolio. The plan’s third phase preserves a pathway for a large-scale, climate-proof supply: a 'purified water for recharge' project, also known as potable reuse. Reflecting the district’s historically cautious approach, this project is positioned on a distant horizon. The implementation schedule presented at the meeting shows no major activity for several years, with the first key decision point not occurring until 2035. Construction, and its associated costs previously estimated at over $600 million, is not envisioned until after 2050. Water Supply and Planning Manager Thomas Neiser noted this mirrors the district's past prudence, where it studied but ultimately avoided building a non-potable recycled water system that would have lacked customers, thereby preserving the option for a more valuable potable reuse supply. A core tenet of the entire strategy is 'adaptive management'. Progress from one phase to the next is not pre-ordained but will depend on a series of triggers and decision points. Key external triggers the district will monitor include the reliability of SWP supplies, changes in state and federal regulations, the availability of grant funding, and advancements in water treatment and energy technology. As Director Judy Huang noted, 'If that 40% [of supply from SWP] is in jeopardy earlier than we expected, then all these project schedules and your decision point will have to change.' The long-term focus on potable reuse over bay water desalination sparked considerable debate among the board directors. While staff explained that potable reuse was selected based on criteria including cost, public support, and greater local control, several directors argued for keeping desalination in consideration. Director Patrick Seppi highlighted rapid advancements in offshore and brackish water desalination technology that could reduce costs and environmental opposition. 'Technology is moving really fast,' he urged. 'You have to be agile enough to be able to respond to these events.' While the board reached a consensus that the adaptive nature of the plan allows future leadership to revisit these choices, the current roadmap provides staff with a clear directive to focus planning efforts on the potable reuse pathway. Preliminary capital expenditure forecasts show spending concentrated on planning studies in the near term, followed by significant construction cost spikes in the 2030s for PFAS treatment and the potential Southern Groundwater Facility. The full financial analysis, including O&M and potential revenue offsets, is still being developed. The district will now move to draft the full Water Resources Master Plan document, with a public draft expected in early 2024 and final board adoption targeted for April 2024.