County completes first segment of $250M plan to prep flood channel for 100-year storm

County officials Tuesday convened in Huntington Beach to celebrate the revitalization of a 1-mile segment of a flood control channel, a vital first step in a $250-million collaboration with federal partners to reduce Orange County’s flood risk.

During an on-site news conference near a portion of the East Garden Grove-Wintersburg channel north of Warner Avenue, between Goldenwest and Springdale streets, Orange County Board of Supervisors Vice Chair Andrew Do explained the significance of the project.

“We are standing in Orange County’s largest floodplain. [It] covers a very large portion of Orange County west of the Santa Ana River,” said Do, whose district encompasses cities within the 74-square-mile Westminster Watershed, including Huntington Beach, Seal Beach, Anaheim and Fountain Valley.

“What you have is a lot of sediment, a lot of dirt and a lot of sand with no real natural topography to channel water out to the ocean.”

O.C. Supervisor Andrew Do speaks Tuesday at a news conference in Huntington Beach, with O.C. Public Works Director Jim Treadaway and project manager Melissa Pasa.

(Courtesy of the office of Supervisor Andrew Do)

Built in 1959, the East Garden Grove-Wintersburg channel extends from the northeast corner of Garden Grove downstream to Huntington Beach, carrying stormwater runoff to the ocean near the Bolsa Chica Reserve.

Designed to respond to a 20-year flood, its construction and capacity does not live up to modern standards or weather patterns, O.C. Public Works Director Jim Treadaway explained Tuesday.

“Since then the county has grown and the design requirements for flood control channels have evolved,” he said. “Channels of today are required to handle a greater amount of water and more effectively manage that stormwater to protect our neighborhoods and businesses.”

County officials began working in 2017 with the U.S. Army Corps of Engineers to come up with a plan for completely renovating the 11.8-mile channel to withstand a 100-year storm, paying for the work through a combination of federal and local funds.

An image shows a portion of the East Garden Grove-Wintersburg Channel in Huntington Beach, east of Springdale Street, before and after an $83-million revitalization project designed to reduce flood risk.

(Courtesy of the office of Supervisor Andrew Do)

Work on the Huntington Beach segment began in October 2020, as crews excavated the sloped earthen sides of the channels, installing 19,400 feet of sheet piles — the length of 54 football fields — to bolster levees and increase the segment’s capacity by more than 50%.

Completed in March, the $83-million segment overall constitutes the first of many phases expected to take place over the next decade. Because about 4,500 homes and businesses surrounding the channel fall within FEMA’s Special Flood Hazard Area, where flood insurance rates are typically high, a reduced risk could lead to reduced premiums.

“All of these improvements will enable us to remove a large part of the floodplain from the designation of being a flooding risk,” Do said. “This will help homeowners and business owners to pay less in flood insurance premiums each year, to the tune of hundreds of millions of dollars.”

Public Works Department spokesman Shannon Widor said the work began in Huntington Beach because that segment of the channel was the most downstream location, and work typically progresses in an upstream direction.

The next phase, slated to begin next month, involves making improvements to three nearby bridges that span the channel to ensure the structures are watertight.