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Levee Breach Marks Completion of the Delta’s Largest-ever Tidal Wetland Restoration Project

Sep 19, 2024 12:16PM ● By Department of Water Resources News Release

An excavator removes 600 feet of dirt for the first of nine levee breaches as part of the Lookout Slough Project. Photo courtesy of the Department of Water Resources


SACRAMENTO, CA (MPG) -  For the first time in 100 years, tidal waters are flowing to 3,400 acres of restored habitat that will support fish and wildlife species and provide new flood capacity in Solano County. Sept. 18, the Department of Water Resources (DWR) and Ecosystem Investment Partners (EIP) held a levee breaching ceremony to celebrate the completion of the Lookout Slough Tidal Habitat Restoration and Flood Improvement Project (Lookout Slough). This multi-benefit project restores tidal wetland habitat and produces food for Delta smelt and other fish species, while reducing overall flood risk in the Sacramento area.

“Lookout Slough is the biggest environmental restoration project in the Delta in decades. And a critical feature of it is the improved flood protection it provides to surrounding communities. Protecting people from flooding doesn’t have to be at odds with the environment – it can actually work with it,” said DWR Director Karla Nemeth. “More intense droughts and floods require these solutions. Congratulations to our local, state, federal, tribal, private, and non-profit partners who made this happen.”

“The Delta is a biodiversity hotspot where we’re making progress on a large scale to restore natural habitat for fish and wildlife,” said California Natural Resources Secretary Wade Crowfoot. “This project is a big step forward toward our ambitious restoration goals, and we’ll continue to build momentum and make more progress in the months and years to come.”

At 3,400-acres, Lookout Slough is the largest single tidal wetland restoration project to date in the Delta. After breaking ground in June 2022, construction included building over 3-miles of a 25-foot-tall setback levee, which provides 100-year flood protection with allowances for future sea level rise, excavating 26 miles of open tidal channels, and restoring native habitat through grading, fill placement, and natural revegetation. Lookout Slough is part of the state’s bold effort to build more, faster through upgrades to critical infrastructure and other projects across California.  

The breached site also provides over 40,000-acre feet of additional flood storage within the Yolo Bypass, which will help protect surrounding communities and infrastructure during future flood events.

Today’s levee breaching ceremony featured speakers from the Solano County Board of Supervisors, EIP, DWR, and the California Natural Resources Agency. Following remarks, attendees watched as an excavator breached the levee on the southeastern end of the site, allowing tidal waters to flow in. This is one of nine total breaches that will occur on the eastern edge of the project. Today’s breach removed 600-feet of dirt from the old levee and is the largest of the nine breaches. 

Key to this project’s success is the innovative public-private partnership between DWR and EIP, which took less than six years from conception to restoration completion on the ground.

"The Lookout Slough project represents a new way forward for restoration projects that are urgently needed as a changing climate requires a better balance between nature and human needs for water,” said Adam Davis, Managing Partner of EIP. “DWR’s leadership and commitment to success made our investment in land and project delivery possible.”

Along with environmental and flood prevention benefits, Lookout Slough also provides recreational opportunities. Once all of the levee breaches are complete, the public may access the new tidal channels for wildlife viewing, fishing, and hunting via the created non-motorized boat ramp at the northern most breach.

The Delta is the hub of California’s two largest surface water delivery projects, the State Water Project and the federal Central Valley Project, and provides a portion of the drinking water for 27 million Californians and irrigation water for large portions of the state’s agricultural industry. Lookout Slough is one of more than a hundred ongoing projects statewide led or supported by DWR aimed at creating habitat and protecting special status species in California’s waterways to help manage the water needs of millions of Californians and balance that with the needs of our environment and ecosystems.

For more information about the Lookout Slough project, visit DWR’s Delta projects webpage.