In: Proceedings Coastal Sediments '03. 2003. CD-ROM Published by World Scientific Publishing
Corp. and East Meets West Productions, Corpus Christi, Texas, USA. ISBN 981-238-422-7.
HYPOTHETICAL RELOCATION OF FIRE ISLAND INLET, NEW YORK
Nicholas C. Kraus1, Gary A. Zarillo2, and John F. Tavolaro3
of Fire Island Inlet
as a thought
exercise in regional sediment management. Subjects considered include morphologic behavior
of the inlet, hydrodynamics of the present and hypothetical relocated inlet, collapse of the
existing ebb-tidal shoal and formation of new ebb and flood shoals, sand bypassing, navigability,
and stability of the beaches east and west of the inlet. The relocated inlet would be more
hydraulically efficient than the present inlet, increasing tidal exchange (prism), promoting
circulation in Great South Bay, and increasing sand storage in the inlet shoals. Collapse of the
abandoned ebb shoal would feed the eroding beaches to the west, such as Gilgo Beach, for 50-
100 years. Oak Beach would no longer experience an erosional ebb current and wave action.
The east jetty would impound sediment, gradually building the width of the fragile beaches of
Fire Island located to the east. Several sediment-sharing projects would benefit from the inlet
relocation, a goal of regional sediment management. Potentially unacceptable negative
consequences that require study, such as increased storm surge susceptibility, are identified.
The U.S. Army Corps of Engineers has recently launched a Regional Sediment Management
Research (RSM) Program to advance knowledge and develop predictive tools for the Corps and
society to effectively manage water resource projects and associated sediments. Significant cost
savings and reduced environmental stress are anticipated by taking a sediment-sharing system
approach among multiple projects and locations. Products of the RSM Program will be focused
on project design, operation, and maintenance methods that (1) minimize disruption of natural
sediment pathways and processes, and (2) mediate natural processes that have adverse
environmental or economic consequences. The physical processes governing regional water and
sediment movement are under investigation, as well as new predictive technology at the project
and intra-project level. For example, Larson et al. (2002) and Larson and Kraus (2003) describe
a new type of model called Cascade that is under development and testing in the RSM Program
for prediction of shoreline change at regional scale (tens to hundreds of kilometers, tens to
hundreds of years) including longshore sand transport, evolution of inlet geomorphology within
the domain, sand bypassing at inlets, and overwash. The former reference applied the model to
the south shore of Long Island, New York, from Fire Island Inlet to east of Shinnecock Inlet, and
the latter reference applied Cascade to the Delmarva Peninsula for a stretch of coast including
two inlets and the beaches of three states.
1. U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory,
3909 Halls Ferry Road, Vicksburg, MS 39180. .
2. Department of Marine and Environmental Systems, Florida Institute of Technology, 15 West
University Boulevard, Melbourne, FL 32901. firstname.lastname@example.org.
3. U.S. Army Engineer District, New York, Operations Division, 26 Federal Plaza, New York,
NY 10278-0090. .