ERDC/CHL CHETN-II-47
March 2004
proposed or recently constructed nourishment projects were discussed. These case studies cover a
wide geographic area of the Atlantic Ocean, Gulf of Mexico, and Pacific Ocean and include:
U.S. Army Engineer District, New York
Coney Island, NY
Sea Bright, NJ (3 hot spots)
U.S. Army Engineer District, Philadelphia
Ocean City, NJ
U.S. Army Engineer District, Baltimore
Ocean City, MD (5 hot spots)
U.S. Army Engineer District, Wilmington
7 projects w/hot spots
U.S. Army Engineer District, Charleston
Myrtle Beach, SC
Folly Beach, SC (3 hot spots)
U.S. Army Engineer District, Savannah
Tybee Island, GA
U.S. Army Engineer District, Jacksonville
Dade County, FL (5 hot spots)
U.S. Army Engineer District, Mobile
Panama City, FL
Perdido Key, AL
U.S. Army Engineer District, Los Angeles
Surfside CA
Seal Beach, CA
Peninsula Beach, CA
Figure 1 shows the location of the projects on the Atlantic and Gulf of Mexico coasts. The California
project locations are shown in a later figure. A short summary of each project follows with (a) an
identification of the hot spot problem(s), (b) type of hot spot and probable cause if known,
(c) remedial action taken, and (d) vulnerabilities.
Coney Island, NY. Coney Island, the westernmost barrier island on Long Island had its first beach
nourishment in 1922-23. The latest U.S. Army Corps of Engineers project placed approximately
1.8 million cu m (2.3 million cu yd) of sand along 5.6 km (3.5 miles) of the beach between June
1994 and January 1995 (Bocamazo and Rahoy 1999). A hot spot developed west of the terminal
groin at West 37th Street, at Sea Gate, which is downdrift from the project. Net drift is to the west
along this coast. Figure 2 shows the location of the hot spot. Rapid erosion of the Sea Gate fillet was
anticipated on the downdrift side of the terminal groin through numerical shoreline change modeling
using GENESIS and the hot spot development was identified through profile and air photo analysis.
Wave focusing by the East Bank Shoals and interruption of longshore transport by the terminal groin
has contributed to the Sea Gate hot spot. Within 2 years of fill placement the hot spot was
pronounced (Figure 3). Nearshore wave transformation modeling together with shoreline change
modeling provided an indication of rapid sand loss from the Sea Gate fillet. The loss of sand from
the Sea Gate beach is most likely from episodic storm events, with no post-storm recovery.
Mitigation was performed by trucking approximately 22,938 cu m (30,000 cu yd) of sand from east
of the terminal groin and placing it immediately west of the groin. A plan for stabilization through
compartmentalization using T-head groin structures is being developed for a long-term solution at
the Sea Gate hot spot. A 10-year renourishment schedule is planned with annual fill monitoring.
Sea Bright to Manasquan Inlet, NJ. Construction of the Sea Bright to Manasquan Inlet, NJ, fill
project was initiated in June 1994. The project extends 33.8 km (21 miles) from just south of the
Gateway National Seashore (Sandy Hook) area in northern New Jersey to Manasquan Inlet. Net drift
in this area is to the north. To date, 27 km (17 miles) have been constructed and 37 km (23 miles) are
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