Seawalls seen at Shore

In 2011, a Spring Lake, N.J., officer inspected part of the boardwalk damaged by Tropical Storm Irene. It was rebuilt, and then came Sandy. Now a seawall is being contemplated.
In 2011, a Spring Lake, N.J., officer inspected part of the boardwalk damaged by Tropical Storm Irene. It was rebuilt, and then came Sandy. Now a seawall is being contemplated. (AP)

Some feel the effect on beaches outweighs the safety they provide.

Posted: January 24, 2013

BELMAR, N.J. - As Jersey Shore towns spend millions of dollars to rebuild boardwalks wrecked by Sandy, some are opting for an additional layer of protection in the form of steel seawalls placed between the boards and the shoreline.

The idea is to protect the boardwalks - and the homes and businesses nearby - from the destructive power of storm surges.

"It has to be an engineered seawall-and-dune system that will protect the boardwalk and mitigate against the storm surge going into the neighborhood," Belmar Mayor Matthew Doherty said.

Doherty's town was the first to begin rebuilding its boardwalk after Sandy and the first to decide it wanted to protect that new boardwalk with a seawall.

"This way, instead of washing away the boardwalk, the storm surge will be stopped by the seawall," he said.

Not everyone is convinced the costly add-ons will work. Some environmentalists and scientists say hard barriers worsen erosion.

"They just don't work. You're going against the forces of nature. It's a false sense of security," said Jeff Tittel, director of the New Jersey Sierra Club.

He and other environmentalists say the energy of the waves smacks up against the steel and is channeled up and down, washing away sand at the base of the wall.

Jon Miller, a professor of coastal engineering at Stevens Institute of Technology, said seawalls could help protect boardwalks - but only when they themselves are protected by a constantly nourished and replenished beach between the walls and the surf.

"If it's done correctly, it can be part of the solution," he said. "The key is to maintain the beach in front of it. Otherwise it just becomes a vertical wall and just accelerates erosion."

A case in point has been the severe erosion that has plagued beaches in Sea Bright and Monmouth Beach. Most of those towns is protected by a giant rock-and-concrete seawall.

But the wall has functioned as Miller described, forcing the pounding of the waves downward and washing away most of the sand in front of it. Consequently, those two communities are among the most needy at the Shore in terms of requiring constant beach replenishment projects.

A Duke University study of shoreline protection in the Carolinas and New Jersey reached the same conclusion: that seawalls accelerate erosion even as they protect property.

"Unquestionably, many buildings along many miles of long-stabilized U.S. shorelines owe their existence to the presence of seawalls," the study read. "The fact that beaches along these same stretches of stabilized shoreline are frequently narrow and even absent altogether has captured the attention of coastal managers everywhere.

Two states, North Carolina and Maine, anxious to avoid 'New Jersey-ization' of their own shores, prohibit altogether hard stabilization.

Supporters say the seawalls being contemplated since Sandy are much more modest and would be covered with sand and dune grass that should withstand at least the initial stages of a storm surge.

Miller said it "does make some sense" to locate a small seawall east of the boardwalk as an added protection measure for the walkway, as long as there is an adequate beach between the wall and the surf.

Given the expense involved in rebuilding boardwalks, some communities are willing to consider seawalls.

Seaside Heights is spending $3.6 million on the first phase of its boardwalk reconstruction, and Belmar is spending $6.6 million. Spring Lake is rebuilding its two-mile-long boardwalk for the second time in little over a year. Tropical Storm Irene destroyed it in 2011, the town rebuilt it, and Sandy wrecked it again in 2012.

Spring Lake is considering various options, including a seawall, but has yet to decide. A sea wall in Spring Lake could cost as much as $18 million, the mayor estimated. Belmar's lowest bid on a seawall came in at $4.5 million.

"We need to figure out how to finance that," Doherty said.

That poses another problem. The Federal Emergency Management Agency generally will pay only to restore public property to its pre-storm state. Protective measures beyond what was in place when Sandy hit would need new funding, such as hazard mitigation grants.

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