On Estuarine and Continental-Shelf Circulation in the Middle Atlantic Bight

We shall attempt in this chapter to trace the development of ideas about circulation over the continental shelf in the Middle Atlantic Bight and in the major estuaries which drain into the Middle Atlantic Bight. The term Middle Atlantic Bight refers to the curved section of the continental shelf off the eastern United States stretching between Cape Hatteras to the south and Cape Cod and Nantucket Shoals to the northeast. The New York Bight is a subsection of the Middle Atlantic Bight and refers to the shelf region stretching between the New Jersey and Long Island coasts. A schematic version of Uchupi's (1965) topographic map is shown in figure 7.1, indicating both the general shape of this shelf region plus the names and locations of the major estuaries and key positions discussed in the text. We have decided to focus this review of estuarine and shelf cirulation on the Middle Atlantic Bight and its estuaries for several reasons. The major Middle Atlantic Bight estuaries have been extensively examined and have provided several important case studies in the development of new ideas about circulation and turbulent-mixing processes in moderately stratified coastal-plain-type estuaries. These estuaries and the adjacent continental shelf border on one of the world's largest urban complexes; a better description and understanding of the circulation and dominant mixing processes occurring in this particular region is clearly needed for a more effective management of the regional estuarine and shelf resources in the face of man's many conflicting uses of the water bodies. Fostered in part by increased environmental concerns, more adequate research funding, and the availability of new instrumentation and observational techniques, many new circulation and related physical studies have been undertaken in the last two decades, and a synthesis of both old and new material into a review of the regional estuarine and shelf circulation seems particularly appropriate at this time. While a few scientists have made important contributions in both fields and have thus helped to carry new ideas and techniques from one field into the other, basic research on problems conceming estuarine and continental-shelf circulation have evolved more or less independently in time, so that we will present here separate reviews of the historical and the modem ideas about estuarine and shelf circulation in the Middle Atlantic Bight. One important research objective in the 1980s will be to develop a better kinematic and dynamic description of the physical coupling between estuarine and shelf waters. Our present meager knowledge about the different physical processes that connect the shelf and estuary together prevent a more unified discussion.