2009 Fire Island Beach Renourishment Project

The purpose of the recently constructed project was to restore protective features of the beach and dune system in Ocean Bay Park for short-term storm protection and enhance recreation.  Periodic beach nourishment is a normal maintenance activity for waterfront communities that are subjected to erosion of their beach and dune systems.  Shoreline recession coupled with the April 2007 nor’easter had resulted in critical erosion in sections of Ocean Bay Park.

The beach and dune nourishment consisted of constructing a beach berm with an elevation of 7.9 ft NAVD and a dune elevation of 13.9 ft NAVD along the community’s length of 2,281 ft.  The beach is stabilized by a taper section to the east and similar fill projects to the west. The 13.9 ft NAVD dune elevation is the same as the 15.0 ft NGVD elevation discussed in the Corps studies, but is just a newer datum.  The NAVD datum approximates mean sea level.  Dune slopes were built to be 1 ft vertical to 4 ft horizontal between the dune crest and beach berm.

The constructed beach berm was built wider than the expected equilibrium profile.  The construction profile will lose up to half its width and reach the equilibrium profile in a period of months to a year, which is demonstrated in the figure below.  The equilibrium profile will intersect the existing bottom at approximately -19 ft NAVD, which is the seaward limit of the active beach profile.

cfi-profile-adjustment1

Overall, 159,000 cubic yards of sand were placed onto the project area in Ocean Bay Park.  However, only 96.7% cubic yards of the placed volume was eligible for pay.  The project area will be surveyed periodically in order to monitor the performance of the project.