A California tunnel could save storm water for millions — why then is it so divisive?


A California tunnel could save stormwater for millions. Why is it so divisive?

Even after storms drenched the drought-parched Golden State, a plan to capture more water and send it southward remains controversial

By Scott Dance

March 1, 2023 at 7:00 a.m. EST

As drought-weary Californians watched trillions of gallons of runoff wash into the Pacific Ocean during recent storms, it underscored a nagging question: Why can’t we save more of that water for not-so-rainy days to come?

But even the rare opportunity to stock up on the precious resource isn’t proving enough to unite a state divided on a contentious idea to siphon water from the north and tunnel it southward, an attempt to combat the Southwest’s worst drought in more than a millennium. The California Department of Water Resources said such a tunnel could have captured a year’s supply of water for more than 2 million people.

“People are naturally focused on, are we doing everything we can to capture the water when we can?” said Karla Nemeth, the agency’s director.

The proposal from Gov. Gavin Newsom’s administration — one that would cost $16 billion to help 27 million water customers in central and southern California — is spurring fresh outrage from communities that have fended off similar plans over four decades, including suggestions to build other tunnels or a massive canal. Before and since storms in December and January, there have been packed town halls and stern pleas to the Democratic governor from those for and against the idea. The appeals have come from state and federal lawmakers, including one pushing legislation in Congress to block the tunnel from receiving a key permit.

The conflict underscores the increasing difficulty of keeping taps running in communities far from the sources of the water they drink, and underlines thorny questions about the consequences of taking water from one place and giving it to another. There are concerns the tunnel would hurt farmers while failing to solve California’s larger water woes, stoking long-simmering state divisions: north versus south, inland versus coast, agricultural versus urban. Nevertheless, the water crisis demands solutions.

California faces a future climate marked by both extended drought and increasingly intense rainstorms, known as atmospheric rivers, like the onesthat repeatedly lashed the state in late December and January. Warming temperatures and dry conditions mean snowpack isn’t translating to as much river flow as it once did, and at the same time, the West is struggling to develop a plan to sustainably drink from the dwindling Colorado River, another key source of water there.

To be built, the idea would have to withstand a long vetting process and any expected legal challenges. Even then, the tunnel likely wouldn’t be functional until maybe 2040. But the future of what would be one of California’s largest infrastructure investments ever could come to a head much sooner. Nemeth expects to decide whether and how to proceed by the end of the year.

How California gets water where it’s needed

California has been moving water southward for generations— an effort to get water where it’s not. While its largest population centers are clustered along the coast and across valleys in the lower half of the state, most of its precipitation falls on its northern half and inland mountains. Besides that, about half the state’s annual precipitation typically falls on just 15 days, if not fewer.

To fix that imbalance, California built what is known as the State Water Project, a more than 700-mile system of canals, pumps, aqueducts, reservoirs and hydroelectric dams that date to the 1960s. It delivers water to 750,000 acres of farmland and to communities across the Bay Area and Southern California.


The tunnel would be a key new element of that system, allowing it to take better advantage of the state’s boom-and-bust precipitation patterns that climate change is forecast to make only more pronounced. It would carry water 100 feet beneath the delta — an estuary where the Sacramento and San Joaquin rivers meet, and which receives about half of all of California’s streamflow. The tunnel would take water in from a location near Sacramento and bring it to a reservoir about 45 miles south.

Newsom emphasized the project’s importance in August when he announced a new approach to water management. The new strategy acknowledges that rising global temperatures mean more water is being lost to evaporation and to parched soil and vegetation.

If the proposed tunnel had been in place when the series of rainstorms battered Californiabeginning in December, it could have saved 202,000 acre-feet of water, state water managers said. That’s about 35 percent of what the State Water Project delivered to customers in all of 2022. They estimated that there was an even larger missed opportunity to increase water stores during a series of storms at the end of 2021.

“This project would have enabled a significant amount of water to be moved in a short amount of time into storage, and that’s what makes it so important,” Nemeth said.

A thirsty state, divided

It’s one piece of a larger strategy to “modernize” California’s water systems, Nemeth said. Other efforts aim to improve efficiency, promote reuse, adapt to a warming climate and prepare for damaging earthquakes, which the Army Corps of Engineers has said could damage levees that protect the water supply.

Nemeth said if there is a levee breach, it could allow salt water to taint the State Water Project system. But if there is a tunnel, she said it could bypass the contamination and ensure a continuous supply of fresh water from the north side of the delta.

Opponents question the risk of a breach. John Herrick, general counsel for the South Delta Water Agency, called it a strategy to justify routes for the tunnel that take water from farmers to give to desert communities east of Los Angeles. “It’s going to be operated at the detriment of farmers in the delta,” said Herrick, whose agency defends the water supply of farmers.

In communities that would have to live around the tunnel, many say there are only costs, and no benefits. In the Sacramento-San Joaquin Delta region, where a patchwork of Central Valley farmland meets the Bay Area, the tunnel is viewed as a threat.

Worries are high there that it would reduce natural water flows enough to hurt farming communities and struggling fisheries, making the delta saltier and more prone to drought. Already there are concerns that, as water is pumped from the delta toward the 444-mile-long California Aqueduct, too much salty water flows in from the brackish bays to the west.

“We don’t believe one piece of infrastructure is going to solve California’s water woes with the extremes of climate change,” said Barbara Barrigan-Parrilla, executive director of Restore the Delta. “They’re really not planning for the future.”

For proponents of the project like Heather Dyer, general manager of the San Bernardino Valley Municipal Water District, separating into north vs. south or rural vs. urban factions misses a key point: That all of California needs water to support an economy, fifth-largest in the world, that likewise buoys all corners of the state.

Storms raise urgency — and opposition

The series of storms in the state that began in December, and killed at least 19 people, stoked strong opinions about the water supply.

As the rain fell, a bipartisan group of state lawmakers urged water managers to pump as much of the excess water as possible from the delta into the State Water Project — the amount of water that can be pumped into the system is, at times, restricted.

State Sen. Melissa Hurtado (D), for one, pushed for relaxing any restrictions, and collecting available water while it was plentiful. Hurtado argued there was “no reason” that more water could not be exported southward from the delta.

Similarly, Assemblyman Vince Fong (R) criticized constraints that made it harder to bring water where it’s needed. “When Mother Nature blesses us with rain, we need to save the water, instead of dumping it in the ocean,” he said.

But other lawmakers took the storms as an opportunity to push back against the tunnel proposal. Rep. Josh Harder (D-Calif.) and three colleagues in Congress wrote to the Army Corps demanding in-person hearings — so constituents could voice their concerns about the tunnel. A week later, about 150 people gathered at a town hall Harder organized in the delta region to air those grievances, including concerns that the tunnel would draw down water levels in the Sacramento-San Joaquin delta even during drier spells, allowing salinity to concentrate at harmful levels.

“This is not a solution to our drought issue,” Harder, who introduced the Stop the Delta Tunnels Act in Congress in September, said in an interview. “This exacerbates the drought issue.”

Barrigan-Parrilla said opponents are eyeing potential regulatory and legal challenges to the project as the Army Corps and the State Water Resources Control Board review it, and in December joined with Indigenous groups in filing a civil rights complaint with the Environmental Protection Agency.

The complaint asks the EPA to update water-quality standards for the delta and require increased river flows into the estuary, keeping water and salinity levels at safe and healthy levels for aquatic life and farming communities. It argues that reducing water levels in the delta violates the civil rights of groups including the Shingle Springs Band of Miwok Indians and the Winnemem Wintu Tribe, harming their ability to carry on cultural traditions that center on the estuary and its wildlife.

Barrigan-Parrilla said the tunnel would only exacerbate problems related to high salinity and low water levels in the delta, reducing the Sacramento River’s flow into the estuary.

In the meantime, the tunnel is in the midst of a review process under California environmental law. The Army Corps is accepting public input through March 16 on a draft environmental impact statement for the project, a document that will guide any detailed plans for the tunnel. If Nemeth decides to move it forward later this year, further hurdles include reviews under endangered species and water pollution laws.

What about an entirely new water strategy?

There’s a challenge in relying on an old water delivery system to fix present problems, said Jeffrey Michael, a professor of public policy at the University of the Pacific’s McGeorge School of Law in Sacramento. He questioned why, as the home of Silicon Valley, California isn’t more focused on meeting water needs through new technologies, instead of updating the State Water Project.

“They’ve got an interest in making that system last forever,” Michael said. “They’re simultaneously trying to do what’s best for the State Water Project and what’s best for the state. Those two objectives are not equivalent.”

The state’s water strategy does include a diverse set of solutions, Nemeth said, including investments in water recycling, exploration of desalinization and efficiency mandates to permanently lower demand in urban areas.

Still, she said adapting to climate change means not missing a chance to collect extra water from the delta when the weather allows.

“We need to be able to capture and store water when it’s available, and then we have to reuse that water, and we have to be more efficient across the board,” Nemeth said. “I don’t think of it as an either-or; we have to do all of it.”

But there are also those who watched the long-awaited rain, and did not mind seeing so much of it wash away. To Herrick, it was a vital natural process that needs to be protected. It flushed the system, and primed it for fish.

“It’s improved hundreds of miles of channels and open waters,” he said. “It’s not a waste.”

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