Major East Bay Reservoir Expansion Is Axed After Years of Rising Costs, Waning Interest

A long-percolating expansion of Los Vaqueros Reservoir in Contra Costa County will not move forward after costs and delays mounted in recent years, ending a project that would have significantly boosted the Bay Area’s water supply.

The project, first proposed in 2017, would have increased the reservoir’s capacity by more than 70% and distributed water to residents across the Bay Area. In a statement on Monday, Contra Costa Water District Board President Ernesto A. Avila announced the agency would end its participation in the project, citing increasing costs and declining participation from other local water agencies.

“As difficult as the decision was … we have reached the point where the facts show that this well-intended project is not viable,” he wrote.

The project’s costs have grown steadily over the years, from $980 million in 2017 to nearly $1.6 billion, due to inflation and scheduling delays.

“We need to be very responsible with public dollars,” said Jennifer Allen, director of public affairs for the Contra Costa Water District. “If we see that there is no path to go forward with this expansion, it is important to have that discussion now.”

On top of the increased costs, the California Department of Fish and Wildlife recently updated the district’s incidental take permit, which dictates how much water it can divert from the Sacramento-San Joaquin River Delta to fill the reservoir.

“Because of additional restrictions to maintain more water in the Delta for aquatic species, we saw a decrease in yield by up to 30%,” Allen said.

The project was governed by a conglomerate of Bay Area water agencies, including the Alameda County Water District, East Bay Municipal Utility District, San Francisco Public Utilities Commission, Valley Water and others.

Over time, Allen said, those agencies pulled back on their requests for storage.

“We went from being oversubscribed to being undersubscribed, and pretty significantly in a short period of time,” she said.

Water agencies also disagreed on who should shoulder any additional costs. Contra Costa Water District thought it should be the partners.

“We’d already built the original reservoir,” Allen said. “The expansion was to the benefit of the partners. And so those costs would have been directed at the partners.”

“There were definitely some challenges and issues that came up around that concept,” she said.

Los Vaqueros Reservoir underwent a previous expansion that was completed in 2012, which expanded storage from 100,000 to 160,000 acre-feet. This second phase would have expanded the reservoir to 275,000 acre-feet.

The news comes as Gov. Gavin Newsom’s administration works to expand reservoir capacity in the state, including the Sites Reservoir in the Sacramento Valley.

“These are projects that will address our state’s biggest challenges faster, and the Sites Reservoir is fully representative of that goal – making sure Californians have access to clean drinking water and making sure we’re more resilient against future droughts,” Newsom said in a statement.

Allen, the Contra Costa Water District spokesperson, said agencies are starting to look at other ways to fortify the Bay Area’s water supply.

“Even though we don’t see a path for this project to move forward, we are still dedicated to working with partners to look at regional solutions,” Allen said.

KQED’s Katherine Monahan contributed to this story.