was constructed by local interests from 1952 to 1953. Approximately 1.6 km west of
Shinnecock, a salient feature in the present-day shoreline and offshore bathymetry provide
morphologic evidence of littoral material transport from the Shinnecock Inlet ebb tidal shoal
to the adjacent beaches.
The Westhampton Reach extends from Shinnecock Inlet to Moriches Inlet (24.8 km).
From Shinnecock Inlet, the barrier beach continues west 14.8 km at which point the
Westhampton Groin Field begins. The 16 groins comprising the Westhampton Groin Field
were constructed in three phases, the first two extending from March 1965 to October 1966
(Groins 1 through 11) and 1969 to 1970 (Groins 12 through 15) to stabilize the barrier island
over a 5-km reach. The original plan called for 23 groins and beach fill, but was not
implemented due to political decisions at the state and local levels (Heikoff 1976). The third
addition to the groin field in 1998 included shortening Groin 15, adding Groin 14a (located
between Groins 14 and 15) to create a transition section between the groin field and barrier
beach, and beach fill within the groin field extending west to Moriches Inlet. Two significant
breaches occurred due to storms in 1980 and 1991 within the remaining 5-km of the
Westhampton barrier island reach.
Moriches Inlet was formed during a 1931 storm, migrated west, widened during the 1938
hurricane, then closed by natural forces in May 1951. Jetties were constructed on the barrier
beach in 1952-1953, and a channel was dredged, beginning from the bay shore. In September
1953, before the channel was completed, storm waves breached the island and, since that
time, the inlet has remained opened (Taney 1961a,b). It is believed that the 1980 breach
initiated from the bay during the January 14-16, 1980 storm with high bay water levels and
strong currents (Schmeltz and McCarthy 1982). Similar to Shinnecock Inlet, a salient feature
in the present-day beach approximately 1.5-km west of Moriches Inlet indicates sediment
transfer from the inlet' ebb shoal to the adjacent beach.
s
The Fire Island Reach extends 49.2 km from Moriches Inlet to Fire Island Inlet. A
historically eroding barrier beach extends 20-km west from Moriches Inlet. The central
portion of Fire Island (approximately 13. 2 km) is the oldest portion of the barrier island and
has been relatively stable. The stability of this region and shoals located offshore have led
researchers to postulate that either the inner shelf or relic Fire Island Inlet ebb shoals provide
a source of littoral sediment to this region (e.g., Schwab 1999). West of this region, the
barrier developed as a prograding spit prior to stabilization of Fire Island Inlet.
Fire Island Inlet, unlike Shinnecock and Moriches Inlets, has been a permanent feature
since mapping of the shoreline began. From 1834 to 1940, Fire Island Inlet migrated from
east to west at a rate of 62.5 m/yr prior to stabilization in 1941 (derived from Taney 1961a).
West of Fire Island Inlet is Gilgo Beach, which has been the recent site for placement of
dredged material obtained from Fire Island Inlet.
Previous Studies
In this section, several studies pertinent to the present work are briefly reviewed, and
net longshore sand transport (LST) rates at boundaries of the primary morphologic zones
are noted. The first four columns of Table 1 summarize these studies.
3
Rosati et al.
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