About seven miles from the Sacramento International Airport, crews are putting the finishing touches on a project meant to provide massive flood relief to a wide swath of the Sacramento region during intense storms.
As soon as this winter, the Lower Elkhorn Basin project area will become a larger overflow area for the Sacramento River when it rises. Crews pushed seven miles of levee back around 1,500 feet, expanding the capacity of the existing Sacramento and Yolo bypass areas.
When another nearby project to widen the Sacramento Weir is complete, the two infrastructure updates could lower the Sacramento River’s water level by up to two feet during flood events.
Climate change is driving more extreme weather events like atmospheric rivers. These intense storms bring precipitation and potential flooding to the Sacramento region. After last winter’s intense storms and ahead of an unpredictable El Niño year, state and local leaders are hoping new flood control strategies will help them better prepare.
A new system-wide approach
The Lower Elkhorn Basin Levee Setback project was first proposed in 2012 as part of the Central Valley Flood Protection Plan and construction began in 2020. While some final work remains for next year, it could begin serving as a flood bypass — or overflow area — this winter.
“We are reducing flood risk for Natomas, for downtown Sacramento, for the Pocket area, all the way down to Courtland; all the way up to Verona by reducing the surface of the water during high water events,” said David Pesavento, an engineer for the California Department of Water Resources and manager of the Lower Elkhorn Basin project.
David Pesavento, an engineer for the California Department of Water Resources and manager of the Lower Elkhorn Basin project.Nicole Nixon/CapRadio
The project site is north of West Sacramento, west of Natomas and is more than 10 years and $270 million in the making.
It also marks a new turn in California’s flood strategy, Pasavento said: In the past, people built on existing floodplains and used levees to try to protect the newly-developed land. Land which, for millennia before settlers arrived in the 1800s, had regularly flooded.
These levees, many of which are decades old, weren’t made with California’s changing climate in mind. Experts say they’re not equipped to deal with the increasing severity of atmospheric rivers and their aging infrastructure can pose dangers to communities, as was the case with a levee breach in Pajaro earlier this year.
A map of the Lower Elkhorn Basin Levee Setback project.California Department of Water Resources
In recent years, flood control managers say working with natural landscapes around the state’s rivers, rather than trying to restrict water to certain areas, is a better approach.
“Rather than continuing to just reclaim land and try to restrict flow into the river, projects like this are enhancing the bypass system that mimics that natural process that was going on before we became involved,” Pesavento said, gesturing at the empty basin where construction crews wound down work before the wet season.
The Lower Elkhorn Basin project is the first to be completed under the new approach, he said.
The result is that during high water events, the Sacramento and American rivers will have more area to spill into, ideally before flooding happens in a neighborhood.
“You look at some of the other projects where we're just building levees higher,” he said. “That's a great example of benefits to that one area but the system-wide approach has much bigger benefits to a much bigger area.”
The large, system-wide updates to California’s flood control infrastructure provide “a more resilient levee and a more resilient system so that we can withstand those bigger events,” Pesavento said.
Preparing for an unpredictable season of storms
As atmospheric rivers become more frequent and more intense with climate change, experts say California needs to prepare.
California officials have worked to improve technologies that predict the intensity and timing of atmospheric rivers. Expansions to the state’s research on these storms aim to help reservoir and flood control operators plan around them.
“Every year, we think it's game time and we're just [hoping] we're ready,” said Tim Kerr, general manager for the American River Flood Control District. “We're always learning. We're always improving the levees.”
Kerr said that for now, there are usually reports indicating the possibility of a big storm two weeks before it happens. At that point, he said the exact route of the storm or its severity is unclear. More reliable reports on the details of a potential storm are released about a week before they happen.
Kerr said the two major factors local flood control operators must be aware of are localized storm events — like an atmospheric river coming to Sacramento — or large amounts of snowmelt flowing downstream.
During intense periods of precipitation, he said the ARFCD will have staff patrolling levees 24 hours a day. These staff members are looking out for any signs of levee distress or erosion.
The Sacramento River as viewed near the Tower Bridge in Sacramento, Calif., Tuesday, Jan. 10, 2023.Andrew Nixon / CapRadio
During last January’s series of atmospheric rivers, he said they also had to deal with removing 32 trees that had fallen on top of or around levees.
“It took us, in total, about six weeks to clean up all the downed trees just from that one storm,” Kerr said. “So for us, it was mainly just making sure … the roadways on the levees were passable, so we could continue patrolling.”
Kerr said there aren’t any trees that the ARFCD is concerned about this year, but last January was a helpful lesson in learning how to deal with a storm of that level.
Then there’s the upcoming El Niño winter, the first of its kind in years. Periods of El Niño weather typically mean more precipitation in Southern California. But it’s not so easy to predict for Northern California.
“Experience has shown that the big El Niño years — ‘82, ‘83, ‘97, ‘98 — impacted Southern California heavily,” said Nicholas Pinter, a professor in the Department of Earth and Planetary Sciences at UC Davis. “But looking backwards, El Niño years don't always mean big rainfall up here.”
Pinter said Northern California weather during El Niño years is too inconsistent to make an accurate prediction. He pointed to 2015 as an example: At the time, there was a big El Niño winter brewing. To prepare for it, he and other area flood experts came together to make predictions and express concerns about the upcoming season.
“What happened to that big El Niño? Nothing,” Pinter said. “It petered out and in Northern California, it ended up being a dry winter.”
But he said Northern California is in a better spot than usual this year. There weren’t any massive wildfires in the summer, and there’s been a healthy amount of rainfall so far.
“I don't think anyone should be placing bets on what's going to take shape, except to say that it's sort of heartening that … we have measurable rainfall,” he said. “That beats the alternative, which is going in high and dry with nothing in the bank.”
How you can prepare for wet weather and flooding
During heavy rain, storm drains can quickly become clogged, flooding roads, yards, and even lower levels of homes.
This is known as localized flooding and it’s one of the biggest problems the region faces during storms, particularly areas near rivers and creeks, said Matt Robinson, a spokesperson for Sacramento County.
“It's important — before the rain falls — to clear your area of any type of debris within your storm drain areas,” Robinson said. “Only rain down the drain.”
Residents can use sandbags to divert water away from homes and into the gutter. The county has four open sites to fill sandbags for free — just bring your own shovel.
If your sandbags from last winter are still outside, Robinson advises replacing them. “When you have a sandbag out in the hot summer sun, the bag starts to degrade and it won't be as useful the second time around,” he said.
Those who live near rivers or creeks may want to monitor the Sacramento County ALERT (which stands for Automated Local Evaluation in Real Time) page, which shows live water levels during storms.
Homeowners in areas at high risk of flooding may be required to have flood insurance, but the city of Sacramento encourages all property owners to have a flood insurance policy. Most regular home insurance policies do not cover flood damage.
“If you need flood insurance, it's better to get it early because it takes 30 days for a policy to take effect,” Robinson said.