California gives the river room to stop the risk of flooding

Modesto, California (AP) — Between the vast almond orchards and meadows in the heart of California’s farmland, there is land that has been redesigned as it was 150 years ago. After that, the embankment restricted the flow of the river across the landscape.

The 2,100 acres (1,100 hectares) at the confluence of the Tuolumne and San Joaquin rivers in the state’s Central Valley have been returned to the floodplain. This means that if a river crosses an embankment due to heavy rain, water will flow into the land, prospering traditional ecosystems and reducing the risk of floods downstream.

The Doslios Ranch Reserve is California’s largest single floodplain restoration project and is part of the country’s most extensive effort to rethink how rivers flow as climate change changes the environment. The land covered was formerly a farm, but the owner sold it to a non-profit River Partners for use to restore wildlife habitat.

The state has funded similar projects to reduce risk to housing and property, while offering other benefits such as habitat expansion, improved water quality, and potential recharging of depleted groundwater supplies. I want to prioritize. By making cuts in the embankment or removing the embankment, the swollen river can flow into land that no longer needs to be kept dry.

“It gives ecologically new life, but in a way that is consistent and complementary to the human system developed over the 150 years since the gold rush,” said Julie Renter, President of Rivers Partners.

The Central Valley covers approximately 20,000 square miles (51,800 square kilometers) and is the driving force of agriculture, where more than 250 crops are grown. The region occupies about 1% of US farmland, but accounts for one-fifth of all US groundwater pumping while producing 25% of the country’s food.

Floods in the 1860s indicate the possibility of disaster. Up to 6,000 square miles (15,500 square kilometers) of valleys have been submerged. As the state’s population grew rapidly and agriculture grew rapidly throughout the 20th century, the government designed huge systems to move water to supply people and farms, embankments to protect cities and crops. Was built.

Some of those embankments blocked the river from natural floodplains. As climate change raises temperatures, mountain snow that normally flows into state basins can fill rivers much faster and increase flow beyond what embankments can take.

Restoration of the floodplain will help. In projects like Dos Rios, lands that farmers don’t want to manage are turning into spaces where rivers can breathe. Further north, the Feather River barriers have changed to allow more water to flow into existing wildlife areas. In West Sacramento, a four-mile (6.4 km) embankment along the Sacramento River is receding.

California authorities began centralizing valley flood plans 10 years ago. Some of the worst and most notable floods in decades have occurred in places like Houston and New Orleans, but parts of California are exposed to serious risks that are expected to increase due to climate change. It has been. In 1997, a storm destroyed embankments across the valley, including the Chuolam River, causing damage of nearly $ 2 billion and destroying more than 20,000 homes. Nine people have died.

An update to the Central Valley Flood Conservation Plan will be released this week. Learn more about how to protect about 1.3 million people living in floodplains and the key infrastructure, farmlands and ecosystems.

In the last update five years ago, the state focused on floodplain restoration projects. Dos Rios is one of the 17 identified by the state. Since 2013, four have been completed, three are under construction, and ten have been proposed. They have cost $ 300 million so far, and the money comes from bond funds and local and federal dollars.

“Dos Rios is a great example, but we need about 30 more,” said Jane Doran, chairman of the Central Valley Flood Conservation Commission.

Floodplain restoration is not unique to California.Washington started a program called Floodplains by Design in 2013, and the project Mississippi River.. However, experts say California stands out for its focus on projects that provide ecosystem support.

“There is great potential for this kind of work. I was very impressed with how cautious and thoughtful California is in this area,” said Todd Bridges, head of the Army Corps. I am. Engineering with nature A program that takes a similar approach.

The Biden administration has secured an infrastructure bill of at least $ 1.75 billion for a multipurpose project aimed at reducing flood risk.

It is expected to make the wet season more moist, just as climate change makes California’s dry season drier.State Atmospheric river Heavy rain and snowfall in October, followed by The driest January to March On record.

“One of the things that makes California water crazy is that decision makers want to talk about the floods of the flood year and the drought of the drought year,” said Barry, a water consultant involved in the Doslios project. Nelson says. “The weather whiplash we see this year really tells us that we need to get out of that pattern.”

Since the 1850s, 95% of Central Valley’s historic wetlands and river habitats have been eliminated, according to state flood planners. In a 40 million state where major cities like Sacramento’s capital and Stockton were built on floodplains, it is impossible to recover all of them.

However, the vast open space of the valley offers opportunities such as thighs and unused farmland. The real estate where Dos Rios sits is nowadays dairy products, and owners approached their river partners to sell their land for conservation in the mid-2000s.

River Partners have cut the berm so that the river water flows to 1,000 acres (400 hectares). Nonprofits are passing government hurdles to break the federal embankment to keep the Chuolam River away. Ultimately, Doslios can hold floods of up to 10,000 acre feet and prevent them from flowing towards cities like Stockton. Acre-foot is about 325,850 gallons (about 1.23 million liters).

14 species of wood and shrubs are planted to attract native species. River Partners said the Aleutian tick geese have been delisted as an endangered species due to the habitat available in Doslios. Species that call Doslios home include the Liparian brush rabbit, Chinook salmon, rainbow trout, American yellow warbler, and sandhill crane.

Proponents of such projects want them to build faster in California and beyond. While there is broad consensus on the value of restoring floodplains, River Partners Renter is concerned about the impact of land conversion on local tax bases and is debating how widespread public access will be. Said that it could delay.

But in the messy world of water in California, the restoration of floodplains stands out, said water consultant Nelson.

“Amid this kind of disagreement on water policy and all other issues, flood management is the place where major changes have taken place over the last decade in an incredibly widely accepted way.” He said.