OFFSHORE SEDIMENTARY PROCESSES AND RESPONSES NEAR BEACH HAVEN-LITTLE EGG INLETS, NEW JERSEY

Thomas McKinney, Joseph DeAlteris, Yung Y. Chao, Lloyd Stahl, James Roney

Abstract


The offshore region in the vicinity of the Beach Haven and Little Egg Inlets of New Jersey is the site of the proposed Atlantic Generating Station, a floating nuclear power plant to be constructed 2.8 n. mi. offshore by Public Service Electric and Gas Company (Figure 1A). In order to assess the impact of this proposed project on the region, a comprehensive study of the nearshore and offshore region was conducted. A complete synopsis of this study is available in PSESG (1976). This paper presents the results of the investigations into the sedimentary processes operative in the offshore region. The dynamics and coastal evolution of the nearshore region is summarized in DeAlteris et al, (1976; this conference). The proposed Atlantic Generating Station (AGS) is located offshore of the complex and transi.ent tidal inlet system of Beach Haven and Little Egg Inlets. These inlets are the major hydraulic connections between the Atlantic Ocean and the Great Bay and Little Egg Harbor estuaries. A large, roughly triangular ebb-tidal delta is present at the mouths of and between the two inlet channels. The major offshore bathymetric feature is a broad linear sand ridge, the Beach Haven Ridge, which trends northeast and reaches a maximum elevation of -28 feet (NLW) (Figure 1A). The AGS site is located on the landward flank of the ridge and partially in the adjacent trough in about 40 feet of water. Landward of the wide, northward-deepening trough, the ocean bottom slopes gently up towards the ebb-tidal delta of Beach Haven and Little Egg Inlets. The offshore zone adjacent to the proposed AGS is separated from an extensive tidal marsh lagoon system by a broken chain of barrier islands, from Long Beach Island on the north to Little Beach and Brigantine Islands on the south. The Beach Haven Ridge is one of a system of sand ridges which occur on the shelf surface. In recent years the origin of these features has been the subject of a number of studies. Duane et al, (1972) studied the sand shoals on the inner portions of the eastern continental shelf of the United States. Swift et al, (1973) review the question of the ridge and trough topography of the Middle Atlantic Bight. A detailed description of the geomorphic elements of the inner New Jersey continental shelf for this region is presented in PSESG (1975). Duane et_al, (1972) suggested that the shoreface- connected ridges originated in a shallow nearshore environment in response to the interaction of south-trending, shore-parallel, wind-driven currents and waves during winter storms. They suggest that as sea level rises, and the shoreface retreats, the shoals are abandoned and isolated as "relict" features on the shelf surface. This .concept was proposed i(n part by Moody (1964) from studies of the ridge system at Bethany Beach, Delaware.

Keywords


sedimentary processes; Beach Haven Inlet; Little Egg Inlet; New Jersey

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