Can floodplains save California from future disasters?

Record ID: 1709983

  • Title: Can floodplains save California from future disasters?
  • Date: 4th February 2023
  • Summary: MODESTO, CALIFORNIA, UNITED STATES (JANUARY 25, 2023) (Reuters) VARIOUS DRONE SHOTS OVER SAN JOAQUIN RIVER AS IT CUTS THROUGH FARMLAND (MUTE) JULIE RENTNER, PRESIDENT OF NON-PROFIT ORGANIZATION RIVER PARTNERS, DRIVING IN CAR, SAYING: "So everything we're driving past here is floodplain of the San Joaquin River. The water that you see here is spreading out because the river got high enough to overtop the berms that are on the edge of the fields here." FLOODPLAIN OVER FORMER FARMLAND RENTNER DRIVING FRONT OF VEHICLE AS IT DRIVES RENTNER DURING INTERVIEW LOGO FOR RIVER PARTNERS (SOUNDBITE) (English) JULIE RENTNER, PRESIDENT OF THE NON-PROFIT ORGANIZATION RIVER PARTNERS, SAYING: “You know, as of the end of 2022, everybody was in drought-relief mindset, right? We've got a crisis where wells hundreds and 1,000s of wells have gone dry. People are without drinking water. Farms are without water to keep their businesses up and running. It was very disruptive. And, you know, the state was taking, really is, continues to take amazing steps towards trying to rectify that problem and respond to that emergency. But then what the storms of January showed us is that the state also has this backlog of flood safety issues that only come up as a priority once the disaster has already happened.” VARIOUS OF FLOODWATERS VARIOUS OF FARMLAND THAT WILL EVENTUALLY BE CONVERTED INTO FLOODPLAIN DRONE SHOT SHOWING PAN FROM SAN JOAQUIN RIVER TO RESTORED FLOODPLAIN ON DOS RIOS RANCH (MUTE) (SOUNDBITE) (English) JULIE RENTNER, PRESIDENT OF THE NON-PROFIT ORGANIZATION RIVER PARTNERS, TALKING ABOUT FLOODPLAIN RESTORATION PROJECT AT DOS RIOS RANCH, SAYING: “So they simultaneously deliver flood safety by reducing water surface elevations when the floods come through. We have more space for the water to spread out, and we've modified some of the components of the flood system here so that the water surface elevations are lower for neighborhoods like Grayson or even for our neighbors downstream in Stockton.” VARIOUS OF FLOODWATERS FROM SAN JOAQUIN RIVER ON A RESTORED FLOODPLAIN ON DOS RIOS RANCH
  • Embargoed: 18th February 2023 10:57
  • Keywords: California California flood protections California flooding California floodplains climate change restoring California floodplains weather
  • Location: Grayson + Modesto + Sacramento + Stockton, California, United States
  • City: Grayson + Modesto + Sacramento + Stockton, California, United States
  • Country: US
  • Topics: Climate Change,Climate Policy and Regulation,Environment,General News,North America
  • Reuters ID: LVA001714302022023RP1
  • Aspect Ratio: 16:9
  • Story Text: When devastating floods swept California last month, the community of Grayson - a town of 1,300 people tucked between almond orchards and dairy farms where the San Joaquin and Tuolumne rivers converge - survived without major damage. 
    In the minds of some townspeople and experts that was thanks partly to the 2,100 acres (850 hectares) of former farmland just across the river that have been largely restored to a natural floodplain.
    Advocates for floodplain restoration say it can help solve California's dual dangers of flooding and drought, replenishing ground water for future drought relief while protecting towns from the catastrophic flooding that scientists predict will come from climate change.
    “So they simultaneously deliver flood safety by reducing water surface elevations when the floods come through. We have more space for the water to spread out, and we've modified some of the components of the flood system here so that the water surface elevations are lower for neighborhoods like Grayson or even for our neighbors downstream in Stockton," said Julie Rentner, president of the non-profit organization River Partners, which bought the land off private owners and has revived much of the natural landscape, enabling floodwaters that had once been confined by levees to meander across the plain, recharging the aquifer below. 
    The $50 million project was funded mostly by federal, state and local grants, Rentner said. Last month came the first major test since the landscape was reshaped by degrading levees, creating swales and, with the help of about 40 volunteers from the nearby community of Grayson, exchanging invasive plant species for native ones.
    One of the volunteers was David Guzman, who works in an almond processing plant and lives right up against a slough of the San Joaquin River.
    “It means a whole lot to me because it doesn’t flood out no more like it used to. With these floodplains that they got back here that they made, all the water goes down there now and it’s not coming up to the town no more. It stays level to the top of this levee here almost,” Guzman said.
    Just last year, Guzman and his neighbors had to evacuate as wildfire tore through the dried-out slough. The deluge reminded them of the extremes created by climate change.
    The challenges posed by the extremes reminded Rentner that when managing for drought, the state must not forget about floods either.
    “You know, as of the end of 2022, everybody was in drought-relief mindset, right? We've got a crisis where wells, hundreds and 1,000s of wells have gone dry. People are without drinking water. Farms are without water to keep their businesses up and running. It was very disruptive. And, you know, the state was taking, really is, continues to take amazing steps towards trying to rectify that problem and respond to that emergency. But then what the storms of January showed us is that the state also has this backlog of flood safety issues that only come up as a priority once the disaster has already happened,” she said.
    It is impossible to determine for certain that the floodplain saved Grayson. But experts say floodplain restoration can help spare adjacent towns, and they envision a day when a proliferation of projects will prevent wider flooding throughout the state.
    River Partners has restored 20,000 acres (8,100 hectares) on some 200 sites over the past 25 years at a cost of $185 million, and has identified another 100,000 acres for floodplain restoration across the San Joaquin Valley. Other NGOs and the state also restore floodplains.
    Future drought relief or flood protection may take years to measure, but the fish have benefited from the January storms already.
    At the Willow Bend floodplain along the Sacramento River, amid the sparsely populated farmland of Colusa County, another recent restoration was just tested for the first time. A team from the Center for Watershed Sciences at UC Davis found the floodplain was teeming with native fish that had exited the fast-moving river, enabling them to fatten up and rest before returning. Among them were threatened spring-run salmon.
    But there are limits. Many potential projects are blocked by development. The city of Stockton, population 322,000, is built on an expansive inland delta.
    In Stockton, Barbara Barrigan-Parrilla, executive director of the grassroots education and outreach group Restore the Delta, says they and others have identified one spot that would make for a perfect floodplain restoration project were there funding to make it happen.
    The spot is the former municipal golf course in Stockton at the Van Buskirk Community Park, part of which runs along the San Joaquin River and one of its adjoining sloughs.
    “There are 17,000 homes behind us that were redlined into floodplain housing 40, 50, 60 years ago. This levee is inadequate and levees alone aren't going to do the trick. We want to invest in levees throughout the system. But for major ARk storms, we have to have floodplains where we can have water spill over so that we take the pressure off levees and save people's lives,” she said.
    More sites lie on land occupied by California's $50 billion agricultural industry, which consumes 80% of the state's water.
    For example, Levees failed in the town of Wilton, on the Cosumnes River near Sacramento, cutting off Highway 99. While there are restoration projects downstream of Wilton, researchers from the Center for Watershed Sciences at UC Davis said there are several good candidate sites upstream that could have prevented flooding, but on private land.
    DOOMSDAY SCENARIO
    Severe as the recent storms were, they amount to less than half what could fall with a potential ARkStorm, said Daniel Swain, a UCLA climate scientist and co-author of the ARkStorm 2.0 report published last year. 
    The biblical-sounding name stands for Atmospheric River 1000. Such a megastorm would likely exceed that of the Great Flood of 1862, which inundated an area 300 miles (480 km) long and 20 miles (32 km) wide in
    California's Central Valley. The valley lies west of the north-south Sierra Nevada mountain range and includes the
    smaller San Joaquin Valley. 
    An 1862-like event could cause $1 trillion in damage, Swain said. The worst-case scenario has about a 1% likelihood of happening next year and the chances grow incrementally in subsequent years "because our climate is making it more likely over time," Swain said.
    There is also a lesser ARkStorm scenario that would still be one-fourth to one-third greater than the recent downpour. 
    "The cumulative risk of seeing an ARk historical-level event, which again would be about 20 to 30% larger than what we just saw, is now greater than about 65%, so essentially, there’s about a two and three chance of seeing an event that is about 20 or 30% larger than what we just experienced over the next 40 years or so," Swain told California State Assembly members during a recent Joint Oversight Hearing on the state's preparedness for and response to extreme atmospheric river incidents.
    Swain, who is unconnected to River Partners, said he was "baffled" to see flood protection cuts in Governor Gavin Newsom's 2023-24 budget proposal published in January, coincidentally amid peak flooding. 
    At least for now, $40 million in floodplain restoration spending was cut that would have funded nine River Partners-led projects throughout the San Joaquin Valley, an area especially vulnerable to the drought/flood dynamic.
    "The funding specific to the San Joaquin Valley could be restored if general fund conditions improve," Lisa Lien-Mager, a senior advisor for the California Natural Resources Agency, told Reuters by email, citing the recent storms as "a prime example of why we need to invest in these solutions."
    The Central Valley Flood Protection Plan drawn up by a state agency calls for investing $360 million to $560 million per year on flood management while the state is currently spending about $250 million annually.
    That sum compares with $5 billion to $7 billion in losses that Moody's RMS estimated statewide from the recent storms. 
    Much of the Central Valley was once a vast wetlands until 20th Century engineering bent nature to its will, rerouting the diluvial menace through dams, concrete irrigation channels and flood-control projects. 
    While enabling economic boom, the colossal reconfiguration also presaged today's predicament of endangered fish and salinated soil.
    Restored floodplains stand to improve water quality in towns like Grayson, where the groundwater is so polluted by nitrates that water authorities must treat it by ion exchange.
    The mostly Latino town is so poor that kids used to play soccer in the graveyard, until a community center was built in 2005, and the water is so unpleasant that many people buy water from a machine at the One Stop Market for $2.50 per five-gallon jug.
    John Mataka, 71, a retired drug and alcohol counselor and one of the restoration volunteers, said the restored floodplain project at Dos Rios Ranch also helped bring a sense of importance to the community.
    “It was a community effort. People were laughing and having a good time. And feeling like, you know, they were being a part of something new out here,” Mataka said.
    (Production: Nathan Frandino, Mike Blake, Daniel Trotta)
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