Carlsbad wants to officially oppose Oceanside’s plan to build groynes on the beach to stop the sand from migrating south.
The Carlsbad Beach Preservation Commission voted unanimously on Tuesday to recommend that Carlsbad City Council pass a resolution against its northern neighbor’s efforts to build sand containments.
“The biggest swells from the North Pacific approaching the northwest and west carry sand south,” Carlsbad Parks and Recreation Director Kyle Lancaster said during a presentation at the commission. “Oceanside experiences a net southward transfer of 100,000 to 200,000 cubic meters of sand per year.”
Much like Oceanside hates wasting its sand, Carlsbad is happy to get at least some of it. The transfer continues along the coast to Encinitas, Solana Beach and Del Mar.
Hard structures such as groynes, piers and pavements interfere with the natural flow of sand from the beach. Although the devices can protect some areas, they cut off the flow of sand to other places and can accelerate erosion.
Numerous studies since the 1950s have shown that piers at the mouths of harbors built for Camp Pendleton and Oceanside interrupt the flow of coastal sediment to the south.
Despite these well-documented concerns, Oceanside City Council voted 4-1 on August 11, 2021, with opposition from Mayor Esther Sanchez, to spend up to $ 1 million on plans and permits for a water retention project. sand, including ears.
Sanchez said preparing the project was a waste of money because the California Coastal Commission, which generally opposes such structures, is unlikely to approve it. Other council members, after listening to community members in favor of the plan, said they would support it.
“I want us to do everything we can to bring sand to our city,” board member Ryan Keim said in August.
The proposed project involves the initial installation of four groynes of rock 600 feet long, 1,000 feet apart, constructed perpendicular to the rock coverings that protect coastal homes in Oceanside. Groynes could be changed, if necessary, and more could be added to extend the Oceanside Municipal Pier project to the Buena Vista Lagoon if successful.
While groynes were the top-rated proposal in Oceanside, the city also looked at the possibility of installing artificial reefs and other sand protection devices. The project could include a sand diversion system to route sand over or around the ports of Camp Pendleton and Oceanside.
So far, Oceanside has no money to build any of the sand retention projects, which could cost $ 50 million or more.
Southern California beaches have been shrinking for decades, in large part due to coastal development. Another factor in the mix is sea level rise.
Many areas depend on periodic sand replenishment projects to keep their shores attractive to tourists and wide enough to protect homes and highways from ocean waves.
Oceanside derives most of its replenishment of sand from the harbor’s annual dredging. Carlsbad depends on periodic dredging of the Agua Hedionda and Batiquitos lagoons.
Carlsbad’s resolution could be submitted to city council for approval later this month.
The resolution will be worded in general terms to cover groynes, jetties, artificial reefs and any other hard structure that could be built to hold back the sand on the beach, Lancaster said.