To remedy the impacts of climate change on local beaches, the Los Angeles County Board of Supervisors voted to create a coastal resiliency plan on Tuesday, Nov. 7.
The plan calls for reusing sediment that is scooped out of flood control channels, mountain river dams and harbors to augment some of the 18 L.A. County beaches that have grown narrower due to loss of sand. It also calls for creating hybrid shoreline devices that combine manmade materials with natural elements to lessen the impact of waves that cause erosion.
“L.A. County’s beaches are iconic. They define our region and our identity,” said Third District Supervisor Lindsey Horvath, co-author of the board motion approved by unanimous vote. “If we don’t act soon the public may lose access to these beaches forever.”
According to the California Regional Assessment National Shoreline Management Study in 2018, Southern California’s ocean economy in 2013 was valued at about $27 billion. L.A. County’s ocean-related tourism and recreation industries generated more than $2.2 billion in 2020.
“The county’s beaches are more than just cultural touchstones: They provide a critical public resource to residents seeking respite from extreme heat, access to the water and nature, and recreational opportunities,” the motion reads.
Every year about 70 million people visit the county’s beaches, which stretch more than 75 miles from Malibu to Redondo Beach to San Pedro.
“Many residents and children in my district have never been to the beach,” said First District Supervisor Hilda Solis. “Everything we do to help preserve that shoreline and access for the public is of paramount importance.”
Erosion wiped out a key access road at Point Dume Beach, said Horvath. The beaches at Redondo Beach and at Zuma Beach near Malibu have significantly narrowed, she said.
The action asks the county to step up efforts with nonprofits, such as the Bay Foundation, which is working on a plan to use “living shorelines.” They are hybrid devices that create a berm with cobble rocks as a base, and are filled in and topped with sand and native vegetation to secure the existing shoreline.
L.A. County Public Works estimated that it will need to remove about 15 million cubic yards of sediment from behind dams and flood control channels over 10 years, costing $570 million. Horvath wants to turn this problem into a possible solution to beach erosion.
Currently, dredged material is dumped in the Angeles National Forest, in empty gravel pits and in regional landfills, according to the county staff report.
Mark Pestrella, director of L.A. County Public Works, said in an interview before the vote that replacing lost sand at beaches is not a new idea. But the action by the board is focused on how the county would move sediment dredged from flood control channels and dams onto affected beaches.
“There would be a tremendous cost to manually take it to the beach, such as your trucking costs and placement,” Pestrella said, adding that his department is in favor of the proposal.
The county would seek state and federal grant dollars to implement these strategies, Pestrella said. “By perfecting our proposals, we will absolutely be a great candidate for federal and state grants.”
“During energetic wave events, you have erosion,” said Timu Gallien, professor in civil and environmental engineering at UCLA whose expertise is in coastal engineering. Studies from UCLA predict the coastline in L.A. County will experience more intense storms, producing more waves and beach erosion.
“We are expecting atmospheric river (storms) to intensify and become more dominant in Southern California,” she said. “They generate more intense local wave climates.”