Posted on April 8, 2024
A contractor will begin testing offshore sand deposits along the Oceanside coastline next week in search of possible sources for the city’s beach replenishment project.
About 30 samples will be taken at depths up to 55 feet along an ocean shelf that extends from the mouth of the San Luis Rey River to the Buena Vista Lagoon, Oceanside Coastal Zone Administrator Jayme Timberlake said in an email.
“The boat taking the samples will be visible offshore,” Timberlake said. “We’ll only be investigating areas where a dredge could extract material for placement on the beach.”
Kinnetic Environmental Inc. of Aptos will use a vibratory corer with a steel barrel casing that can penetrate the seafloor to a depth of 20 feet, she said. The work will take about three days. Results should be available in six to eight weeks.
Oceanside completed a year-long feasibility study in 2021 that looked at possible solutions to protect its beaches from the erosion affecting most of the California coast.
The study recommending finding a new source of sand, but it also raised regional concerns that the project could reduce sand carried by ocean currents to downstream cities. As a result, Oceanside boosted its public outreach efforts and launched an international design competition in hopes of finding an innovative solution with widespread support.
Sand has diminished along the Oceanside coast, shown here along The Strand on Thursday. The city approved a plan to build artificial headlands to restore and retain beach sand.
Three finalists chosen for what Oceanside calls its Re:Beach project worked for months with the city, the public and a jury of experts to refine their proposals.
In January 2024 the Oceanside City Council voted unanimously, based on the jury’s recommendation, to award a contract to the Australian firm International Coastal Management for its plan called “Living Speed Bumps.”
The ICM concept calls for a pilot project that includes the construction of two small headlands about the size of the one that supports the lifeguard headquarters below the Oceanside Municipal Pier. The headlands, or “speed bumps,” would help hold sand on the beach, while providing a flat surface above the waves with walkways and public space.
The design firm’s concept also includes the construction of an artificial underwater reef in the ocean beyond the headlands to slow the approach of erosive waves. A third element in he plan is to replenish the beach with quality sand dredged from outside the surf zone.
“Right now we are in this phase of developing the design a little more … and where the site will be,” Timberlake said.
Oceanside’s northernmost beaches are replenished annually, usually in the spring, with sand dredged from the channel into the city’s harbor. However, the dredging does not produce enough sediment to cover the badly eroded beaches south of the pier. Also, the material from the harbor is so fine-grained that it’s often washed away within months.
City officials expect to find a better quality of sand with larger grains in the offshore deposits.
Oceanside has allocated $2.59 million from its share of American Rescue Plan Act funds for the initial stages of the project. So far there is no money available for construction, which could be the project’s biggest hurdle. Preliminary estimates show the costs could be $30 million to $50 million.
The goal is to have the project shovel-ready in 2026, Timberlake said, which would make it eligible for state and federal grants.
