Beach protection and replenishment, Long Island, New York

On October 29, 2012, Hurricane Sandy caused extensive erosion and redistribution of sediments on the south shore of Long Island. Long Beach, a barrier island on the south shore of Long Island, experienced erosion. Large volumes of sand were deposited in Jones Inlet, an inlet that provides Atlantic Ocean access to fishing, tourism, and recreation for several Long Island towns.

The US Army Corps of Engineers, New York District, is designing beach nourishment and groin fortification for Point Lookout in the Town of Hempstead, and maintenance dredging of Jones Inlet. To provide measurements for these efforts, e4sciences mapped and sampled the subsurface sediments and rock groins with core borings, geophysical methods, and land surveying. The geophysical methods included reflection seismology, side-scan orthosonography, single-beam bathymetry, and 3D sonar imaging.

The e4sciences findings indicate that although the groins have somewhat disintegrated, they remain effective in interrupting westerly drift and protecting Point Lookout from severe damage. An unintended consequence of this protection is to limit the amount of sand depositing on the beach to the west. Also, the narrowing and stabilizing of Jones Inlet has pushed sand deposits to an offshore shoal and to the west. The sand obtained by dredging of the inlet and the shoal was sufficient to fully replenish the beach.