To appear: Shore & Beach, Vol 72, No. 1, 2004.
Barrier Island Migration and Morphologic Evolution, Fire Island Inlet, New
Jamie M. Bonisteel, Michelle Peters-Snyder, and Gary A. Zarillo
Florida Institute of Technology
Department of Marine and Environmental Systems
150 W. University Blvd.
Melbourne, FL 32901
Fire Island Inlet, New York, is an overlapping barrier inlet system where
the inlet channel lies on an east-west orientation with Fire Island to the south and
east and Cedar Island and Jones Beach to the north and west.
purpose of this study was to examine the response to inlet stabilization of inlet
geomorphology and adjacent shoreline behavior over a time scale of decades.
This study quantifies inlet migration, spit extension, and shoreline change in the
areas surrounding Fire Island Inlet, describes major long-term influences to the
inlet system, and interprets the consequences of engineering operations to the
position of neighboring shorelines.
The analysis was performed using ESRI
Arcviewtm GIS and the BeachTools extension, which was developed specifically
for this purpose. The available data to perform this analysis consisted of aerial
photography covering the period from 1936 to present, historical shoreline data
from the U. S. Coast & Geodetic Survey land surveys dating back to 1834, and
topographic data from NOAA hydrographic surveys and recent SHOALS data.
Fire Island Inlet's evolution has been a trend of downdrift erosion and
updrift accretion. The addition of a jetty on Fire Island's western tip in 1941 and
a sand dike within the inlet in 1959 did not halt this trend. Excess sediment
bypasses the jetty and migrates into the inlet area, forming spits and shoals.
This deprives the downdrift areas of Oak Beach and Gilgo Beach of sediment.