Improvement of Bypassing and Backpassing at Tidal Inlets

Abstract

Tidal inlets present a major barrier to the longshore littoral drift, particularly when they have been improved for navigation by dredged channel and/or jetties. This paper discusses improvements of present procedures of bypassing and backpassing. Bypassing is transfer parallel to shore, backpassing is transfer perpendicular to shore from the ocean, bay, or lagoon. It is now possible to improve available bypassing techniques by much larger traps to intercept the littoral drift toward the inlet from all directions. The same equipment used for transfers can be applied for maintenance of the navigation channel. With present technology, too much material is lost to the ocean and to bay shoals. It may be recovered by the use of the same technology as for bypassing. We are in the process of developing greatly improved bypassing and backpassing technologies combining conventional dredge pumps and fluidization pumps or jet pumps. Better shallow-water and dredge-barge equipment is needed and will undoubtedly become available from dredging industries overseas and in the United States.