As record California snowpack begins to thaw, flood worries deepen - The Washington Post

As record California snowpack begins to thaw, flood worries deepen - The Washington Post

SACRAMENTO — Across California’s long, flat, usually parched and dusty Central Valley, farmers and residents are used to waiting for water to come. But not like this.

As California’s brutal winter gives way to the warmth of spring, that deep snowpack will eventually melt, sending a massive amount of water into the vulnerable, low-lying valley below — and toward flood control systems that in many cases are woefully unprepared to handle it.

The possible slow-moving disaster looming above the Central Valley — a densely populated agricultural powerhouse that produces a fourth of the nation’s food — has the potential to cause billions in loss and damage, submerge towns and affect tens and thousands of residents, many of them farmworkers and families with low incomes who have already this year endured significant flooding and sodden crops.

This devastating oversaturation comes after the state experienced its three driest years on record, which will make the flooding impacts worse. The southern part of the valley, known as the San Joaquin Valley, is especially prone to flooding because the land and waterways have been manipulated since the Gold Rush. To endure California’s crippling droughts, farmers and agricultural businesses have been incessantly pumping the ground for more and more water, causing the region to sink at a rapid rate, damaging wildlife and infrastructure needed to control massive floods.

“We knew this type of sprawling disaster was coming,” said Jeffrey Mount, a senior fellow at the Public Policy Institute of California’s Water Policy Center. “And it’s the rural communities who get very little help, struggle to rebuild, and then get hit again.”

What makes the impending “big melt” even more worrisome is that the San Joaquin Valley does not have a centralized, well-funded flood management system. Instead, a patchwork of local water managers, counties and private land owners are largely in charge of their own flood prevention.

California’s water history and issues are complex. Agricultural companies, the Army Corps of Engineers and the state have all been key players in planning and funding projects in areas they deemed most worthwhile to protect. As a result, more rural, disadvantaged and predominantly Latino communities with little political clout have seen far less investment, experts said.

Decades of disorganization and disinvestment have left the San Joaquin Valley’s flood management system outdated and dilapidated. Reservoirs feed into too few channels that are often too narrow to handle an incessant barrage of water. Drought, neglect and past floods have eroded earthen levees. Rivers and reservoirs in need of expansion are already swollen, with many at capacity.

All this made the recent decision by Gov. Gavin Newsom (D) to cut $40 million earmarked for flood restoration projects from the 2023-2024 budget baffling and frustrating to local communities and environmental groups.

“This system has been neglected, and comprehensively rethinking and working on it has never been a priority,” said Mount. “That has consequences.”

For the past few weeks, towns along the valley’s four major rivers have been laying thousands of sandbags, as some dams have exceeded 70 percent of their capacity. Officials have declared emergencies. Farmers have been pacing along the levees on their land around-the-clock.

The state, meanwhile, has been scrambling to work with locals on an “extraordinary plan needed to move an extraordinary amount of water,” Karla Nemeth, director of the California Department of Water Resources, said in an interview, adding that officials are also working to shore up shrinking levee systems.

Still, Nemeth said she knows there is “going to be significant damage” to canals, well systems, roads, farm lands and homes in the region and in other parts of the state likely starting in May and lasting through the summer.

For many communities across the valley, there is not much they can do about the looming catastrophe except wait.

How fast will California’s snow melt?

Earlier this week, electronic readings from 130 snow sensors around the state show that California’s snowpack contains more than 61 inches of “snow water equivalent” — a metric that illustrates just how much water could come tumbling downhill once melting begins. The Southern Sierra snowpack is currently 300 percent of its April 1 average.

“The million-dollar question is, how fast is it going to melt?” said Andy Bollenbacher, a meteorologist with the National Weather Service in Hanford, Calif. “It’s difficult to speculate when this is going to happen. … There’s no real good analogue, especially because there’s so much water up there.”

Watching the warming temperatures, experts predict that the intense flooding could start in May or June, depending on what happens in April. Warmer days this month could significantly soften, or “ripen,” the massive snowpack.

Ideally, the snowpack will melt slowly at a more measured pace over the spring and summer. But so-called “rain on snow” events, or a scorching and extended heat wave, could send catastrophic amounts of water racing toward communities downstream.

Bollenbacher said he and other forecasters are keeping a close eye on a number of spots, including the Kings River and Kaweah River, as well as communities along the San Joaquin River, and even the Merced River, which passes through Yosemite National Park.

The Sierra’s snowpack also could threaten mountain and foothill communities like Mammoth and Orange Cove, east of Fresno, Nemeth, of California’s Department of Water Resources, said. On the eastern side of the mountains, she said, creekside towns such Lone Pine could have issues and there could be a “tremendous amount of road damage once the snow melts.”

Historic water battles collide with climate change

The collision of climate change, historical water battles and flaring tensions over resources to save flooding land is playing out dramatically in Tulare County, an agricultural juggernaut located at the southern end of the San Joaquin Valley. More than 4 million people live in the Tulare Basin, where torrential rain and floods have begun to refill a massive dried lake for the first time since 1997.

A new problem has emerged: Years of extracting water from the ground during extremely dry years has sunk parts of the basin, including in and around Tulare Lake. Such pumping has weakened what flood infrastructure the area did have, altering canals and making them less effective, Mount said.

“Its an elaborate tragedy of the commons,” he said. “That with their historic pumping and their inability to manage groundwater, these areas are now going to be flooded.”

From the citrus, olive and pistachio trees that line parts of the valley floor to the fields of alfalfa and corn, farmers and workers in recent weeks have been grappling with the loss of crops and wages. Dairy farmers have been forced to abandon fields and move thousands of cows to higher ground, costing the industry millions of dollars, said Tricia Stever Blattler, executive director of the Tulare County Farm Bureau. Things could get far worse, she said.

Just east of Tulare county stands the 14,000-foot peak of Mount Whitney, part of the Sierra Nevada’s southern range, which is holding more than 300 percent of average snowpack. And when the Central Valley begins to bake in June, as it always does, devastating amounts of water could further overwhelm the dam and spillways.

“To be very clear, we do not have the type of water storage and infrastructure designed to handle these kinds of years,” said Blattler, who faults the state for not investing in building new reservoirs or expanding older ones. “It just doesn’t exist.”

In addition, many of the county’s farmworkers are undocumented, Blattler said, and do not have access to federal relief programs.

If disaster does strike, Blattler said, the ripple effects in the county will leave almost no one untouched.

“We are going to see hundreds of millions in damages,” she said. “It will transcend the farm and the non-farm community.”

Long-standing flood management issues in a booming Central Valley

California has always had problems managing for floods, said Jay Lund, a professor of civil and environmental engineering at the University of California at Davis, because protecting profitable crops from drought usually takes precedent.

The state needs to spend more on flood control measures, according to a 2022 state government report that called for “the need to act with renewed urgency and purpose before the next large flood event occurs in the Central Valley.” Currently, the state allocates $250 million a year on flood management in the region — a quarter of what is needed, the report states.

That has come with a cost.

“We are losing small communities,” Lund said. “Those that are rural, often in lowlands, often poor, often less organized. It’s harder to bring attention and resources to them.”

The Central Valley’s population has ballooned in recent decades. It also has some of the most disadvantaged communities in the state. Many of these neighborhoods sit behind old reservoirs and around weakened levees that have flooded significantly in the past. Still, it has not been able to leverage and secure anywhere near the amount of funds as Sacramento Valley to the north, whose flood control system runs much more like a well-oiled machine.

Several cities and towns have worked together to raise money and organize a regional system that would attract major investments and state funding, said Chris Elias, executive director of the San Joaquin Area Flood Control Agency. He said climate change was a huge driver toward working together.

“In the next 50 years we will be having the atmospheric rivers we experienced much more frequently,” he said. “We got a taste of what is to come. And it’s sobering.”

‘We are operating in extremes’

An hour south of Stockton, Wes Monier and his colleagues at the Turlock Irrigation District are preparing to shepherd the coming snowmelt through the Don Pedro Reservoir and down the Tuolumne River, which courses for nearly 150 miles until it meets the San Joaquin River in the Central Valley.

It’s a job that has proved more challenging over time, as stretches of deep drought have given way to incredibly wet years, followed by more severe drought.

“We are operating in extremes,” said Monier, the district’s chief hydrologist. “We’re in an environment where you can’t really rely on the past.”

Thankfully, he said, advancements such as more accurate data about snowpack and more detailed forecasting, as well as the district’s own modeling, have allowed officials to manage flows along the river with more confidence and less guesswork.

“We’re able to adapt,” Monier said. “And we’re going to need to continue to adapt.”

His colleague, utility analyst Olivia Cramer, said one example of that adaptation came earlier this year. The district had just endured a three-year drought and had planned on a fourth. But after significant amounts of precipitation began to fall and staffers tracked the building snowpack in the mountains, they made a decision to begin releasing more water from the reservoir to prepare for the potential melt to come.

“You have to be creative, you have to be flexible,” Cramer said, adding that the goal was to release water in a more controlled fashion now rather than more urgently later. “It’s going from reactive to proactive.”

The melting snow, however fast in arrives, will probably bring more than a colossal amount of water to the valleys below the Sierra Nevada. It will also bring with it renewed questions about how California should deal with similar winters of the future, and the weather extremes that are becoming more common.

“Every time you have a flood it’s an opportunity to rethink things. Do we raise communities up, move them out of the way, or build flood infrastructure around them?” Lund said. “The state has a choice of trying to fix these problems now or see the cost of them later. It’s now more clear than ever if we don’t fix these problems we will see them again.”

More on climate change

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