The U.S. Army Corps of Engineers on Saturday updated Fire Islanders on its anti-flood plans, which have encountered delays and hitches.

The agency, now building dunes on one-third of the barrier island, already has done emergency repairs to the new dunes it had built at Robbins Rest and Smith Point County Park, Fire Islanders said.

Army Corps Col. David A. Caldwell assured about 75 people in attendance of the agency’s commitment to request extra funds for emergency dune repairs during construction — and finishing them as quickly as possible.

Francine Haselkorn of Ocean Bay Park said the need for such swift repairs suggested a flawed design, noting in some areas the beach has rebuilt itself four years after superstorm Sandy.

“It should be looked at,” she said after the Fire Island Association’s annual meeting in Ocean Beach.

“The beach is higher and wider and has more sand than it’s had in its life.”

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However, Lynn Bocamazo, with the Army Corps engineering division, pointed to the success of the dunes the agency built to protect the TWA Flight 800 Memorial. They are the same size and withstood superstorm Sandy in 2012, allowing only one minor overwash.

Once the dunes Sandy leveled are restored, perhaps by 2018, Fire Islanders will no longer be allowed to carry out their own sand replenishment projects because that could prevent the new 15-foot-high dunes from working properly, officials said.

Caldwell announced the next contract to finish work in Robert Moses State Park and pour sand from Seaview to Fair Harbor should be awarded in the coming days, with construction starting in the fall.

Chris Soller, Fire Island National Seashore superintendent, announced his office was beginning an initiative with New York State to study back bay erosion.

Dunes are not being built in federal tracts because that conflicts with the National Park Service’s policies and overwashes are needed to deposit sand in the bays, Soller said. That helps stabilize the barrier island.

And even without the hazards of rising seas, barrier islands like Fire Island are sandbars that constantly shift, he said.

“There’s nothing permanent out here.”