California’s Heavy Rainfall Causes Dozens of Highway Closures and Challenges to Flood Control Management

California has been hit with back-to-back atmospheric rivers that have dropped staggering amounts of rain on the state and left dozens of highways inoperable. The state relies on a system of about 1,400 human-made surface reservoirs and thousands of miles of levees to manage surface water.

Will Arnold, spokesman for the state’s department of transportation, told CNN that at least 40 state routes were closed statewide as of Wednesday night. He asked the public to avoid any non-essential trips. The reservoirs are designed to store water and manage streamflows during periods of heavy rainfall or snowmelt to prevent downstream communities from flooding.

In 16 days, swaths of California received 50% to 70% of the amount of precipitation that they would usually get in a whole year, according to the National Weather Service. With the warmer climate of the last decade, more rain is expected in the future, creating a tension between storing water for flood control and managing water for drought.

“To do flood control, you want dams as empty as possible,” said Jay Lund, director of the Center for Watershed Sciences at the University of California, Davis. “We are in this constant tension.”

The state is expecting more rain in the coming days, and officials are urging the public to take caution and avoid non-essential trips. California is relying on its system of reservoirs and levees to manage the surface water and prevent flooding in downstream communities.