Posted on August 17, 2021
Plans to salvage the eroding Capistrano Beach could have a rocky start.
OC Parks is proposing cobblestone buffers that could be topped with sand dunes and vegetation to salvage what’s left of the battered Dana Point beach.
The county agency, which manages the 1,500-foot-long shoreline wedged between Doheny State Beach to the north and a row of beachfront homes to the south, will give a presentation on its suggested pilot program to the California Coastal Commission at its meeting Friday, Aug. 13, as a short-term solution while county officials try to figure out a long-term plan for the disappearing beach.
No action is expected at the meeting, but the report to commissioners on the proposal gives a glimpse at how the county is responding to the sliver of shrinking coast, which may serve as a blueprint as more California beaches grapple with the loss of sand to erosion and sea-level rise.
The Coastal Commission, the state agency charged with overseeing significant man-made changes along the coast, in recent years has pushed governmental agencies to come up with plans that avoid hard armoring, such as adding large boulders or sea walls to protect infrastructure, which could have negative impacts on the coast.
Like many other stretches of Southern California beaches, Capistrano Beach was once flush with sand, enough to hold a row of fire rings and volleyball courts. The sandy landscape was created when the Dana Point Harbor was built and dredged, adding hefty sand deposits to create a wide beach.
Over the years, the fire rings and the volleyball courts had to be removed as the sand started disappearing. Then, in 2018, a series of strong winter storms battered the beach, toppling decades-old palm trees and crumbling a pedestrian walkway and sea wall.
A popular basketball court buckled and had to be removed, as did the adjacent public restroom and 55 beachfront parking spots.
The county placed large white bags filled with sand, or sand cubes, as well as boulders to try to mitigate further damage and created a beach terrace area filled with sand and a few benches and picnic tables for the public to replace lost amenities.
As a stipulation of permit approval for all that work, OC Parks was required to submit an update to the commission – the 2021 Sea Level Rise Adaption Briefing – to show it is making progress. That is what is being presented on Friday.
The nature-based pilot project would replace some of the sand cubes and rock armoring with the cobblestone berm.
“Although the project would only be implemented on a small scale … a key objective is to test the effectiveness of cobble as an alternative solution for shoreline protection and for understanding potential long-term park and coastal impacts,” the report to the commission says.
Cobblestone material, a mixture of small cobble-sized stones, is found naturally along shorelines in Southern California and around the world.
Nearby San Onofre State Beach and Doheny State Beach have larger stones that are part of the landscape, while stretches of San Clemente are covered with piles of smaller rocks. Sometimes, the rocks are covered by sand, while other times they are exposed when waves and tides batter the beach and sand erodes.
OC Parks officials looked south and north for inspiration on how natural landscapes have been used to fight back against the ocean.
The Cardiff Beach Living Shoreline in San Diego was designed with a vegetated sand dune and a buried rock revetment and cobblestone for a stretch of beach that’s nearly double the size of Capistrano Beach.
That project imported about 30,000 cubic yards of sand and about 7,000 cubic yards of 2-ton rock. Sand was put on top, which increased beach widths by up to 300 feet. Since construction in spring 2018, the project has experienced minimal erosion and rapid growth of dune vegetation, the report to the commission said.
While the Cardiff project receives a regular sand supply from the San Elijo Lagoon inlet, Capo Beach does not have a partner to add sand to its shore, so it may instead need a larger cobblestone berm, officials said.
Another project, the Surfer’s Point Living Shoreline in Ventura used cobblestone topped with sand and vegetation to protect bike paths and other infrastructure that would have suffered further damage.
“The Surfer’s Point project site is comparable to that of the Capo Beach pilot project, as it is located along a very exposed and historically eroded reach of shoreline,” staffers told commissioners.
Long-term plans for Capo Beach are still in the works, but a “landward relocation of park infrastructure,” such as reducing the parking lot’s size and losing some park amenities, may allow for a buffer from the waterline and wave action, staffers said in their report.
The plan also suggests looking for sand nourishment to widen the beach using an offshore borrow area or San Juan Creek as a viable source for a larger, potentially regional project. Capo Beach could be widened initially by up to 40 feet, though natural wave action and storm events would cause the initial nourishment sand to move offshore and down the coast over time and regular nourishment would be required to maintain a sandy beach.
For the proposed near-term pilot project, three early design concepts were developed for two potential locations, at the north and south end of the site.
Some concepts call for just a cobblestone berm, others would add a layer of sand and vegetation on top. In some plans, a portion of the parking would be removed to widen the beach area. Sand dunes and vegetation could be planted and maintained with help from local environmental nonprofit organizations, officials said.
Adding a sand dune could also provide a natural habitat for supporting protected bird species.
But it also has its downsides, staffers warn the commissioners in their report.
It could mean less lounge space for beachgoers. The cobblestone material can be difficult to walk and rest on, making beach recreation less attractive.
Also, it’s difficult to anticipate if the cobblestone material could be thrown about by wave action, becoming damaging to other nearby resources, the report said.
The pilot project would start construction next June and take the rest of 2022, if approved after a series of reports and design reviews that are expected to happen this year.
Public outreach and workshops are expected to be held through the remainder of this year for the Capistrano Beach Master Plan, with a long-term plan expected to be finalized by October 2022.
