Water Board Draft Update Includes Healthy Rivers and Landscapes
The Healthy Rivers and Landscapes program achieved a key milestone July 24 when the State Water Resources Control Board embraced the program as a potential way for water users to comply with updated water quality rules in the Sacramento-San Joaquin river watershed.
The State Water Board’s draft update of its 30-year-old Bay-Delta Water Quality Control Plan incorporates for the first time the HRL program and its voluntary agreements with water users, including municipal water agencies, agriculture, and other water rights holders. The State Water Board will solicit public comments at a hearing September 8 and 9. The draft plan and information on how to comment are available here. The State Water Board members are expected to consider adoption of the draft plan after the public comment period ends September 10.
The State Water Board’s proposed updates include two distinct pathways for water users and agencies to comply with water quality requirements: one that incorporates the HRL program, and a regulatory pathway for those who are not parties to the HRL programs agreements. Both pathways will create legally enforceable requirements.
The Bay-Delta Plan, which was first adopted by the board in 1978, identifies beneficial uses of water in the Delta watershed, water quality and flow objectives to protect those uses, and an implementation program that includes monitoring and reporting requirements.
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Aerial view of Dutch Slough.
Photo courtesy of the California Department of Water Resources.
Dutch Slough: Capturing Carbon, Nurturing Birds and Fish
Dutch Slough is a channel in the western Delta near Jersey Island and the town of Oakley. In the early 1900s, people scraped up earthen levees to separate the tidally-influenced slough from adjacent marshland. Over generations, they used the dried former marshland to graze cattle, grow grapes, and operate a dairy. More recently the site was slated for development.
In November 2021, the California Department of Water Resources breached the levee, returning the historical tidal flows to the site after 100 years. Dutch Slough flowed again across land that had been planted with tens of thousands of plugs of tules, plus other native species including California sycamore, hibiscus, and creeping wild rye.
It was the equivalent of opening a laboratory designed to inform other tidal marsh restoration projects. Now, nearly four years into the experiment, scientists have drawn a few conclusions.
According to UC Berkeley researchers, the site captures carbon from the atmosphere at a rate higher than most other ecosystems across the world, including rainforests.
According to UC Davis and state researchers checking water samples for the DNA of different fish species, salmon, splittail, and sturgeon are using the site. So are plenty of bird species, including Sora rail, Swainson’s hawk, and osprey.
DWR project manager Katie Bandy said it’s clear that making the early effort to revegetate the marsh helped kick-start the carbon and biodiversity benefits. The abundance of mature tules limits invasion by non-native plants such as water hyacinth. The site also buffers nearby Oakley from sea-level rise.
Restoration like this – and the science to learn from it – will advance tremendously under the Healthy Rivers and Landscapes (HRL) program. Under the program, dozens of water districts that depend upon the Sacramento and San Joaquin river system have committed to 5,350 acres of tidal wetland construction, restoration, and enhancement, in addition to thousands of acres of other kinds of habitat improvements. The water districts committed to pay for the restoration, along with federal and state agencies. HRL parties also will support a science program to understand how restoration projects and environmental flows are performing.
The first phase of Dutch Slough restoration covers about 700 acres. Another 477 adjacent acres will be restored as tidal marsh and uplands starting next summer. That second phase of Dutch Slough will plug into the detailed, collaborative science and monitoring program being created under the HRL program.
“Science works best if you can talk in long-term trends,” said Bandy.
Dutch Slough
Photo courtesy of California Department of Water Resource.
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Independent Peer Review Lauds Healthy Rivers and Landscapes Science Plan
As part of their commitment to advancing science to inform management, the HRL parties have produced a comprehensive Science Plan to understand how integrated flow and habitat measures are supporting native fishes as the HRL Program is implemented. In the interest of developing the best possible science plan for this ambitious program, the HRL parties engaged the help of the Delta Stewardship Council’s Science Program to facilitate an independent expert review of the draft Science Plan. On July 15, the reviewers’ letters were released by the Delta Science Program and are available on the Delta Science Program webpage for this review effort. The peer review was voluntary on the part of HRL parties to inform how the Science Plan could be improved to best support adaptive management and analysis of restoration and environmental flows.
Three independent reviewers shared their expertise in decision science, Central Valley Chinook salmon population and biostatistics, and Delta monitoring and food web ecology (final Peer Review letters available here). The reviewers praised the HRL Science Plan for its structure, clearly laid-out hypotheses, with recognition that it is “based on an extensive review of the science,” with strengths of providing a platform for transparency and collaboration. The reviewers offered constructive feedback with particular attention to the areas of adaptive management, methods to estimate population sizes of wild Chinook salmon, and best metrics to assess HRL program impacts, among other topics. The HRL Science Committee is discussing this valuable feedback from independent reviewers and plans to revise the HRL Science Plan.
