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Cities Push to Fight Sea-Level Rise in San Diego County

Sea-level rise and erosion will eventually defeat any replenishment project. However, the ocean rises relatively slowly over the years, and restoring sand to the eroded beaches can protect coastal homes and property.

San Diego
(TNS) - A regional planning group is laying the groundwork for another large-scale sand project like the one that widened San Diego County beaches a decade ago.

The previous effort, completed in 2012 at a cost of $28.5 million, required nearly a decade of planning and the coordinated work of local, state and federal agencies, according to members of the Shoreline Preservation Working Group, an advisory arm of the San Diego Association of Governments.

Still, some of the restored beaches were swept clean to the rocks in just a few years.

Other areas kept their fresh coat longer, but by now almost everywhere the sand has disappeared. Various grades of sand were used, and studies show the replenishment stuck best where the restored material had the largest, heaviest grains.

Lessons like that can help make another effort more economical and long-lasting, scientists and coastal planners say.

“We should do it again,” said Dr. Reinhard Flick, a researcher at UC San Diego’s Scripps Institution of Oceanography, at the shoreline preservation group’s meeting earlier this month.

Sea-level rise and erosion will eventually defeat any replenishment project, Flick said. However, the ocean rises relatively slowly over the years, and restoring sand to the eroded beaches can protect coastal homes and property until the day people are forced to move inland.

Retention devices such as artificial reefs and groins, structures that can be controversial, also need to be considered, Flick said.

“Eventually, we will have to retreat from the coast, but that's decades away,” he said. “In the meantime, sand retention and sand nourishment, if we want to keep sand on our beaches .... go hand in hand.”

Sand is vital to San Diego County for a number of reasons. Wide beaches protect bluff-top homes, highways, parks and campgrounds from erosion, the ocean surf and powerful storms. Also, the attractive shoreline is vital for the tourism that feeds the region’s economy.

SANDAG completed its first regional sand project in 2001. The material used then was relatively fine, and a series of bigger-than-usual winter storms soon washed away a large part of it. Scientists say a third project could focus more on delivering the heavier, longer-lasting sediment that accumulates in ocean deposits outside the surf zone.

Funding is the biggest hurdle for every sand replenishment project, another lesson learned from past efforts. The first step is getting coastal cities to make a financial commitment, preservation group members said.

“We’re all in support of that,” said Del Mar Mayor Dwight Worden, the group’s acting chair. “A regional solution is the way to go.”

The renewed effort to find a regional solution follows a solo Oceanside proposal that appeared to get off on the wrong foot last year.

The Oceanside City Council, without consulting its coastal neighbors, voted 4-1 in August 2021 to spend $1 million on plans and permits to build rock groins and a sand bypass system. Mayor Esther Sanchez opposed the project, saying the California Coastal Commission, which generally opposes building permanent structures on the beach, will never approve it.

Oceanside’s move surprised coastal cities to the south, who worry that the groins would block them from the downstream flow of sand along the coast. Studies show the devices slow or stop the steady migration of sand carried by ocean currents, which helps some areas, but hurts others.

Carlsbad, Solana Beach and Del Mar each adopted resolutions opposing the Oceanside project. A better plan would be for SANDAG to take the lead on a regional plan that helps all the cities, they said.

Several San Diego County coastal cities have occasionally used local replenishment projects to build up their beaches for decades.

Oceanside’s northernmost beaches get sediment dredged annually from the mouth of the city’s harbor.

But the harbor sediment is fine-grained, doesn’t last long and is never carried very far south. The lower two-thirds of Oceanside’s coast has eroded to a narrow beach that’s usually completely underwater at high tide.

Most years, the harbor dredging yields about 250,000 cubic yards of sand, enough to keep the channel open and place material on beaches nearest the harbor.

SANDAG’s 2012 regional project produced a total of 1.4 million cubic yards, taken from three different offshore deposits. The sand was placed at eight different San Diego County locations from Oceanside on the north to Imperial Beach on the south.

The previous regional project in 2001 was even larger, pumping a total of 2.1 million cubic yards of material onto beaches.

The 2012 regional project used the 2001 effort as a model, and took sand from some of the same places, SANDAG officials said. But escalating costs in 2012 forced the agency to downsize the project, so less material was obtained.

As a result, some sites that received sand in 2001, such as Torrey Pines State Beach, got nothing in 2012. Also, the city of San Diego had recently received sand at Mission and Pacific beaches from dredging the mouth of Mission Bay, so it needed no material from the second regional effort.

Several other San Diego County beaches also receive regular replenishment from local projects.

Carlsbad gets much of its sand from the Agua Hedionda Lagoon, which has been dredged about every two years since the 1950s. Initially, the excavation was required to keep the lagoon deep enough to feed ocean water to the cooling system of the Encina power plant.

Another benefit of the ongoing maintenance is that Agua Hedionda is the only San Diego County lagoon deep enough to allow boating, paddle-boarding and other activities. Today it continues to be dredged because the seawater feeds the Carlsbad desalination plant, which provides 10 percent of the county’s drinking water.

One of the county’s most recently restored shorelines is on its central coast at Cardiff State Beach in Encinitas.

Completed in 2019, the project took sand from the environmental restoration of the San Elijo Lagoon, which had been filling with silt for decades. Unlike other beach nourishment projects in the region, the beach restoration there included wind fences and the establishment of native plants to help hold the sand in place.

Multiple stages of time-consuming planning, environmental and engineering work are required before any replenishment project can begin. Environmental concerns such as grunion and lobster seasons need to be considered, also the presence of marine mammals, turtles, and nesting birds. But most important, money is needed.

SANDAG’s shoreline preservation group includes elected officials from each of the coastal city councils. They work with planners, property owners, AND community and environmental groups to study projects such as sand retention and beach replenishment.

The group, which normally meets quarterly, has scheduled a special session in April to further discuss the details of recruiting cities to contribute to the costs of another regional sand project.

Local money pays a small percentage of the total project costs. Generally, it’s used for things such as feasibility studies and early planning to get the effort started.

Construction costs are the largest part of the expense. In 2012 that included the huge cost of bringing to San Diego a dredge large enough for the job from the East Coast, said Shelby Tucker, the project manager for SANDAG.

Grants pay about 85 percent of the project costs and the remaining 15 percent comes from local agencies such as cities, Tucker said.

Even though the actual construction only took a few months in 2012, planning, engineering and efforts to find funding began about 2005, she said.

“We didn’t receive all the money at once,” Tucker told the working group. “We received it in three different fiscal years ... divided into $6.5 million for three years.”

The largest single source of money for the 2012 project was the state Department of Boating and Waterways. Other sources included the federal Minerals Management Service’s Coastal Impact Assistance Program and the California Coastal Commission’s sand mitigation fund.

Different funding sources could be available for the next sand project, said Anna Van, an associate regional planner at SANDAG.

“Funding to mitigate for climate disasters and risks have been hot topics at the federal and state level lately,” Van said, so federal sources could include FEMA, the Federal Emergency Management Agency.

Other possibilities include the California Office of Emergency Services, the state Department of Boating and Waterways, the U.S. Army Corps of Engineers, and the U.S. Navy.

“It will take time and effort for us to pursue these opportunities,” Van said.

Oceanside Councilmember Ryan Keim and Encinitas Councilmember Kellie Hinze both said they would ask their city councils to contribute to a regional project.

Oceanside relies heavily on tourism and has been hit hard by beach erosion.

The southern two-thirds of Oceanside’s coastline has been scoured down to the rock revetments, and at high tide there’s no beach at all. Residents and elected officials have been working for years to protect the homes and vacation rentals from erosion.

Encinitas and Solana Beach have been working together with the U.S. Army Corps of Engineers and other agencies for more than a decade on a major beach restoration project that is finally ready to start. The collaboration will take sand from offshore deposits and place it onto the cities’ shores every five to 10 years for the next 50 years.

“We are looking forward to the 50-year-sand replenishment,” Hinze said.

But that sand will only be distributed south of Beacon’s Beach, while Encinitas and Solana Beach, like much of California, have other beaches that need nourishment.

This story originally appeared in San Diego Union-Tribune.

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