Wednesday March 29, 2023
San Francisco Estuary Magazine —
Restoring marsh and wetland habitat can have significant benefits for dozens of species throughout the Bay and Delta—that’s beyond dispute. But when it comes to saving the Estuary’s most imperiled fish, how much habitat improvements can help in the absence of dramatically increased freshwater flows is a question that has dogged and divided scientists and policy makers for years. As the State Water Resources Control Board considers the latest proposal from the State and water agencies for a flows agreement that would restore thousands of riparian and wetland acres—while dedicating less water to the environment than proposed under an alternative regulatory framework—critics argue that science doesn’t support its underlying assumptions. The debate highlights how much there still is to learn about what restoration efforts can and cannot do for the Delta’s ravaged ecosystem.
In January the State Board released the Draft Scientific Basis Report analyzing a voluntary agreement (VA) on freshwater flows into and through the Delta from the Sacramento and Mokelumne Rivers that was proposed by a group of water districts and state and federal resource agencies last spring. The Board is considering adopting the agreement as a pathway to implementing its long-delayed update to the Bay-Delta Plan Water Quality Control Plan. The new report supplements a 2017 Scientific Basis Report supporting Board staff recommendations for minimum unimpaired flows to protect native fish and wildlife.