Will the Bay-Delta Plan Succeed? It Has a Good Chance if the Healthy Rivers and Landscapes Alternative is Allowed to Work
On July 24, 2025, the State Water Resources Control Board released an updated Bay-Delta Water Plan, a critical framework designed to protect the ecological health of the Sacramento-San Joaquin Delta while addressing California’s diverse water demands. The plan outlines two primary approaches—the Unimpaired Flow Alternative and the Healthy Rivers and Landscapes (or Voluntary Agreements) alternative, to balance water quality, ecosystem restoration, and water supply needs. So, what are the key differences between these approaches? How is their success evaluated? And what is the unimpaired flow alternative water users may have to adopt?
A dive into the Plan helps answer those questions, and more.
Key Differences Between Approaches
The Bay-Delta Water Plan presents two distinct strategies for managing water quality and ecosystem health in the Delta. The Unimpaired Flow Alternative focuses on maintaining a specific percentage of natural river flows, typically set at 55% but adjustable between 45% and 65% depending on water year types (e.g., wet or dry conditions). This approach prioritizes flow as the primary mechanism to support water quality and habitats for native species, such as salmonids and Delta smelt. In contrast, the HRL program integrates water flow with non-flow measures, such as restoring spawning grounds, rearing habitats, and floodplains. This pathway provides greater flexibility, allowing water users to adjust flow releases and construct habitat projects to meet specific needs according to local conditions. The unimpaired flow alternative relies on regulatory enforcement through water right curtailments whereas Healthy Rivers and Landscapes emphasizes collaborative agreements and adaptive management, enabling water users to adjust strategies based on real-time ecological data and adaptive management.
Measuring Success
The plan outlines distinct criteria for evaluating the success of each approach. For the unimpaired flow alternative, success hinges on maintaining the required instream flow and achieving biological goals, which has been the way much of the system has been managed for several decades while fish populations continue to decline. The goal of increasing the “abundance, productivity, genetic diversity, and spatial distribution of native fish populations” seems unattainable without a new, more comprehensive restoration effort.
Regular monitoring and annual reports track compliance and ecological outcomes, which would be demonstrated by increased fish populations and improved water quality, including meeting salmon doubling objectives. For the HRL program, success is measured by fulfilling flow commitments above baseline conditions, completing habitat restoration projects within its planned eight-year term, and evaluating success on the quality of improved habitat and the benefits it provides species that depend on the system. Regular reporting on flow and habitat benefits will demonstrate whether or not the Healthy Rivers and Landscapes alternative will be successful. I believe it will because fish need more than just more water to thrive, they need a healthy place to live and that’s what HRL is all about.
Compliance with Unimpaired Flow Rules
The Water Quality Control Plan specifies when water users must comply with unimpaired flow rules. Water users on certain tributaries, such as the Stanislaus, Tuolumne, Merced, and other Sacramento/Delta tributaries, are subject to these rules if they are not part of an approved HRL plan. If a water user under this alternative fails to meet flow, habitat, or monitoring commitments, the State Water Board may terminate their participation in the alternative HRL plan, requiring compliance with unimpaired flow rules. The Board may also enforce these rules if water users fail to protect beneficial uses, jeopardize native fish survival, or if they violate water quality or temperature objectives.
During water scarcity, junior water rights holders may face curtailments to meet flow objectives. Additionally, according to the Bay-Delta Plan, applicants for new water rights or changes to existing rights may need to adhere to unimpaired flow rules as a condition of approval. These rules automatically apply to specified tributaries unless a water user is in an approved HRL Landscapes plan or qualifies for an exception, such as minimal diversions.
The Bay-Delta Water Plan’s dual approaches offer distinct paths to address the Delta’s ecological challenges. The unimpaired flow alternative continues to lean on the failed, flow-centric strategy that has led to the near total demise of the Delta smelt and lackluster salmon recovery. On the other hand, Health Rivers and Landscapes creates collaboration and flexibility, combining flows with habitat restoration and a better chance at succeeding in species recovery.
Both approaches rely on robust monitoring and adaptive management, but their quantifying success differs, with unimpaired flows focusing on flow compliance and biological outcomes, and HRL emphasizing integrated ecosystem recovery.
The State Water Board retains its authority to enforce unimpaired flow rules to ensure compliance with Bay-Delta Plan objectives, particularly if the HRL alternative falls short, which is unlikely, based on the success of similar efforts already underway throughout the Sacramento River and San Joaquin River watersheds.
Comment on the Draft Plan
The public comment period is open until September 10, 2025. The water user community and the public have a critical opportunity to provide input, shaping the plan’s implementation to safeguard the Delta’s ecosystem while meeting California’s water needs, hopefully through the implementation of sensible, science-driven projects.
To read or comment on the Bay-Delta Plan, visit:
