Malibu is known for its 21 miles of scenic coast, but due to rising sea levels, the shoreline continues to diminish each year.
County stakeholders like Caltrans, the Los Angeles County Department of Beaches and Harbors and the Bay Foundation implemented solutions to preserve Malibu roads and beaches, each weighing the costs and benefits of their projects.
“Erosion is very unpredictable,” said Nicole Mooradian, LA County Beaches and Harbors public information officer. “While you might be able to get a general idea of where the wave energy is directed, you never know for certain.”
Caltrans and the Big Rock Project
Caltrans began the State Route 1 (SR-1) Permanent Slope Restoration project in 2021 to support a seawall near Big Rock Drive.
The southbound shoulder and lane of PCH was first damaged in 2015 following winter storms, said Bartt Gunter, senior project manager for Caltrans District 7. Caltrans’ solution at the time was to use shotcrete — a sprayable wet-mix concrete solution — to reinforce the existing wall.
Shotcrete needs to be embedded into a hard surface like bedrock, Gunter said, and at this site, it can’t be embedded deeper into the beach. Eventually, the shotcrete would wash away, making it a temporary solution.
“Our new project is to replace the wall that we put in temporarily to stabilize the area and to have more of a long term stabilization,” Gunter said.
The permanent solution is a $12.4 million secant wall, Gunter said. To build the wall, Caltrans will drill into the bedrock and install a series of overlapping concrete piles and reinforce the pile with beams, creating a wall.
The most obvious benefit: The project’s lifespan. The secant wall is designed to last between 75-95 years, making it a more solid solution and overall cost effective, as Caltrans won’t have to review the site for decades.
While the project proposal states utility relocation would begin in September 2021, Caltrans faces delays, Gunter said.
The project location presents problems, Gunter said. One side of the road is the Santa Monica Mountains and the other, the Pacific Ocean.
“I always kind of laugh — we’re between a rock and a hard place,” Gunter said. “It’s almost literal.”
Creating a work schedule has also proved challenging as Caltrans works to accommodate the community as well. Utility relocation will cause lane closures on PCH and noise for residents so Caltrans proposed two possible timelines to Malibu locals — night shifts between 10 p.m. and 6 a.m. or day shifts during business hours — hoping to strike a balance in disruptions.
“Daytime affects everyone in the city and affects other travelers who are going between Santa Monica and Oxnard,” Gunter said. “Nighttime affects those who live close by, so we’re trying to figure out — thread the needle, you know — what’s the best approach, and we may even have a hybrid approach.”
Caltrans met with locals over Zoom in November to discuss possible solutions and continues to seek community feedback.
LA Beaches and Harbors and Road Reconstruction
Over the summer, sea level rise eroded the Westward Beach access road. Despite officials’ attempts to mitigate erosion, the road washed out the weekend of Aug. 20, according to the Malibu Times.
“We piled up a bunch of sand so the waves would eat at the sand and not actually at the bluff — and, well, the waves obliterated that,” Mooradian said.
While county roads are normally under the jurisdiction of Caltrans, due to its location, the Los Angeles County Department of Beaches and Harbors repaired the access road. This is the first year the road was threatened by the waves, Mooradian said.
LA Beaches and Harbors estimated work to cost around $1.2 million and utilized funds from the LA County Extraordinary Maintenance fund, according to the Malibu Times.
While Westward Beach reopened a few months later in November, LA Beaches and Harbors will not repair every eroded road.
Nicholas Beach Road, another coastal access point in West Malibu, eroded over several years, eventually collapsing in 2017 after winter storms.
LA Beaches and Harbors does not have a formalized process or flowchart in place when a road gets destroyed as it’s a rare problem of the past decade, but the organization is working on one, Mooradian said.
The Bay Foundation and the Living Shoreline Project
The Bay Foundation has a different end goal in armoring the coast — the organization looks to restore beaches and natural wildlife.
The Malibu Living Shoreline Project targets three acres of Zuma Beach and Point Dume Beach very near the Westward Beach access road and has three goals: To create shoreline resiliency and enhance biodiversity, to establish a nature-based solution to sea-level rise and foster eco-tourism and community engagement.
Graphic courtesy of the Bay Foundation
“What we’re doing here is bringing back natural processes that help to establish the ecology here and help capture sand to build up dune hummocks that will hopefully set off the coastal erosion and sea level rise,” said Sara Cuadra, Watershed program coordinator for the Bay Foundation.
To kickstart biodiversity, the Bay Foundation must first remove all invasive species, namely the South African ice plant, and replant native ones, such as the beach bur.
“Some of our results like increase in topography, sand sediment deposition, that will take some time,” Cuadra said. “If you look at our Santa Monica Beach dune pilot project, we’ve seen an increase of one meter in sand sediment there, but that was over five years. So we’re looking at a similar timeline there.”
The third goal has proven to be the most difficult, Cuadra said. The Zuma Beach cleanup and seeding started winter 2020, in the middle of state and county stay-at-home orders that prevented some types of outreach.
“For these types of projects, we’d like to get the community involved in implementation, you know, have them help us pull ice plant, plant some container stock, but it’s been challenging,” Cuadra said. “So now that we’re in a better place, we have been talking to the City of Malibu to try to have community events at this project, just so that we can do site maintenance and just get the community involved.”
The City of Malibu, LA Beaches and Harbors and the California Coastal Conservancy are all partners in the Malibu Living Shoreline project, Cuadra said.
The project costs are minimal, Cuadra said, especially when compared to the cost of a seawall or more permanent, non-natural solution.
The Bay Foundation plans to publish an annual review early this year, Cuadra said.
Follow the Graphic on Twitter: @PeppGraphic
Email Karl Winter: firstname.lastname@example.org