Opening the box is what coastal preservation groups feared after state regulators approved the Bald Head Island tubes. So far, the commission hasn't been flooded with similar requests, but wait, warn state officials. Mr. Schecter said. To homeowners looking out their window at the approaching sea, a concrete wall or tons of rock is as good as building more land. Engineers, typically paid for by homeowners supporting hardened structures, say seawalls don't contribute to the widening or narrowing of the beach because that's something that happens anyway.
Coastal geologists disagree.
Besides establishing the back boundary of a moving beach, seawalls also slow the natural movement of sand down the beach. Sand moves in different directions - drifting southward along the shore, moving off shore in storms and coming back in waves. But when sand moving south comes to an eroding beach in front of a wall, the sand is transported offshore and out of the system, amplifying erosion in nearby areas. Dr. Cleary said. Other critics, like Duke University professor Orrin Pilkey, have their own reasons to oppose seawalls.