California approves Delta tunnel project, pitting water agencies against environmentalists

California’s leading water agency approved a controversial water infrastructure project to build a tunnel underneath the Sacramento-San Joaquin River Delta Thursday, marking a significant step in a decades-long effort to advance it.

Governor Gavin Newsom has long advocated for the tunnel, called Delta Conveyance, as a key way to protect water supply from climate change. The Department of Water Resources’ decision is expected to usher in extensive legal challenges.

Despite consistent opposition to the tunnel from the state’s leading environmentalists, state officials celebrated the approval of the multi-billion dollar project as a step toward modern and affordable water management.

“Today marks another significant milestone in our efforts to modernize state water infrastructure and adapt to the challenges of changing precipitation patterns,” said Karla Nemeth, the department’s director. “The State Water Project is one of the most affordable sources of water in California, and we need to help local water agencies in protecting both reliability and affordability for their ratepayers.”

For decades, water has been pumped directly out of the Delta estuary and shipped south to 30 million Californians and 6 million acres of farmland through the State Water Project. But state agencies predict that climate change and environmental regulations will lead to a decreasing supply.

State officials say the tunnel is intended to slow that decline by capturing water upstream on the Sacramento River, bypassing the Delta. They estimate it would yield about 500,000 acre-feet per year — a significant amount but a fraction of annual water needs.

DWR released its final environmental impact report for the project earlier this month. It found the tunnel’s construction and operations would significantly affect the Delta’s endangered and threatened fish species, tracts of important regional farmland and tribal cultural resources that include human remains.

The final approval was met with support from the municipal and agricultural water agencies that receive water through the State Water Project, calling it a “critical step” to securing California’s water future.

“With this certification, the state is recognizing that the time to modernize the SWP’s infrastructure is now — improving the way we capture and move water during high-flow weather events to store for later use when it’s dry,” said Jennifer Pierre, General Manager of the State Water Contractors, in a statement.

The last time California finalized an environmental impact report for a similar Delta project was in 2016. That plan, which constituted a pair of tunnels, stumbled amid high costs and Newsom eventually withdrew support.

Even as a slimmed down version, the price tag for this tunnel will be high. In 2020, the estimated cost of one of the alternate paths was just under $16 billion.

Negotiations will need to take place between major urban water agencies across the state, including Los Angeles and the Bay Area, to determine who pays how much. Significant bonds will be issued to fund design and the construction process.

The Delta, the central hub of California’s water system, is home to hundreds of thousands of people and 415,000 acres of farmland. Its fragile ecosystem has been deteriorating for years as more water is exported or used upstream.

Delta residents, farmers, Native American tribes and environmental groups vigorously oppose the tunnel projects. Opponents say drawing freshwater from the historic region coupled with years of construction will endanger native fish, imperil farms and destroy vulnerable communities.

“We and our broad coalition of partners will engage in all necessary processes, and when necessary, litigation, to stop the Delta Conveyance Project once and for all,” said Barbara Barrigan-Parrilla, executive director for Restore the Delta in a statement Thursday.

With this approval, DWR will now pursue several state and federal permits, including through the Endangered Species Act and a water right required by the State Water Resources Control Board.

Jay Lund, director of the center for watershed sciences at UC Davis, said to expect around 2 additional years of obstacles before the project breaks ground. That means Gov. Newsom may not be around to see it through.

“There’s a very long process still so it might well take longer than this governor is sitting,” Lund said. “This is already at least a two governor project, and the previous governor worked on it since his first term in the 1970s and 80s. I think you basically have to set it up for the next.”