The floodplain is being restored to 2,100 acres (1.100 ha) located at the confluence the Tuolumne, San Joaquin and San Joaquin Rivers in the state’s Central Valley. This means that if heavy rains cause rivers to overflow their banks, water will run onto land. Traditional ecosystems can flourish and flood risk downstream is reduced.
California’s Dos Rios Ranch Preserve, the largest single floodplain restoration effort, is part of the country’s most extensive effort to rethink the flow of rivers as climate change affects the environment. It was once a farm. However, the owners of the land sold it to River Partners for wildlife habitat restoration.
The state seeks to prioritize projects similar to those that pose less risk to property and homes, and also provides other benefits such as habitat enhancement, water quality improvement, and possibly recharging groundwater supplies. Swollen rivers can flow onto land where it is not necessary to keep dry by removing or notching levees.
Rivers Partners president Julie Rentner stated, “It’s giving life ecologically, but in a way consistent with, complementing, the human systems which have developed over the 150-years since the Gold Rush,”
The Central Valley is approximately 20,000 sq. miles (51,800 km2) and is a major agricultural center. More than 250 crops can be grown there. It accounts for approximately 1% of U.S. farmland, but 25% of America’s food production.
The potential for disaster was demonstrated by a flood that occurred in the 1860s. Up to 6,000 miles (15,500 kilometers) of the valley were submerged. The state experienced rapid growth in population and agriculture boomed throughout the 20th century. To supply the growing population, the government created vast water transportation systems and levees to protect crops and cities.
These levees can cut rivers off from their natural floodplains. Climate change is causing temperatures to rise. Mountain snow that normally flows into the state’s watershed could fill rivers faster than usual, increasing the flow beyond what the levees can handle.
Floodplain restoration can help. Dos Rios is a project that transforms land farmers don’t want to manage into space where rivers can flow. Further north, the Feather River has seen its barriers removed to allow water to flow more freely into an area of wildlife. The levee that runs along the Sacramento River in West Sacramento is being reconstructed for 4 miles (6 km).
California officials started centralizing valley flood planning 10 years ago. Although New Orleans and Houston have been the most affected by floods, California is at risk. This is due to climate change. Major storms in 1997 caused major flooding throughout the valley, including along the Tuolumne River. This resulted in nearly $2 billion of damage and the destruction of more than 20,000 houses. Nine people died.
This week, the Central Valley Flood Protection Plan will be updated. The update will provide information on ways to reduce flood risk and protect approximately 1.3 million floodplain residents, as well as key infrastructure and agricultural lands.
The state placed a premium on floodplain restoration projects in the most recent update, five years ago. Dos Rios is among 17 projects identified by the state. Three of the four projects have been completed, three more are in construction and ten more are being considered. The total cost of the projects has been $300 million. Funding came from local and federal dollars as well as bond funds.
Jane Dolan, chairperson of the Central Valley Flood Protection Board, stated that “Dos Rios” is an incredible example. However, we still need 30 more.
California is not the only state that has floodplain restoration. Washington launched Floodplains by Design in 2013. Projects are being built along the Mississippi River. Experts say California is the best because it focuses on ecological support projects.
“There is tremendous potential for such work,” stated Todd Bridges, the head of the Army Corps’ Engineering With Nature program. He takes a similar approach.
The Biden administration earmarked at least $1.75 Billion in infrastructure bills for multipurpose projects that reduce flood risk.
Climate change is expected to make California’s wetter periods dryer. It saw an atmospheric river October, major snowfall and rain in December. Then came its driest January and March ever.
Barry Nelson, a water consultant and a Dos Rios participant, said that one of the things that drives him crazy about California’s water supply is the desire for decision-makers to discuss floods in flood years as well droughts in drought years. “We need to break the weather whiplash that we are seeing this year.”
According to state flood planners, 95% have been destroyed from the Central Valley’s historic wetlands and river habitats since the 1850s. In a state with 40 million residents, it would be difficult to restore all that. Major cities such as Sacramento and Stockton were built in floodplains.
The valley’s vast open spaces provide opportunities for people who aren’t interested in farming. River Partners approached the owners of the property Dos Rios to sell it for conservation in mid-2000s.
River Partners has erected berms that allow river water flow onto 1,000 acres (400 ha). The nonprofit is currently attempting to break a federal levee that keeps the Tuolumne River away. Dos Rios will eventually be able to hold flood water up to 10,000 feet in length, stopping it from flooding cities like Stockton. A mile is approximately 325,850 gallons or 1.23 million liters.
There are 14 types of woody shrubs and trees. They’re planted in a way to attract native species. Dos Rios is home to the riparian brush rabbit and the steelhead trout, chinook salmon, yellow warbler, as well as the steelhead trout and the steelhead trout. It is also home to the Aleutian cackling Goose, once listed as endangered.
These advocates would love to see such projects built quicker in California and elsewhere. River Partners’ Rentner said that while there is broad agreement about the importance of restoring floodplains and the benefits of doing so, concerns over the effects of land conversion on local tax bases, as well as debates about expanding public access, can slow down things.
Nelson, a water consultant, stated that floodplain restoration is a standout in the chaotic world of California’s water.
He stated that flood management was the place where “in this kind of ocean of disagreements over water policy, about all other issues, flooding management has been this place where tremendous change has occurred in the past decade in a manner that is incredibly broadly supported.”
