Shoal-Reduction Strategies for Entrance Channels
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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Purpose This Coast Engineering Technical Note CETN presents several methods for reducting sediment in navigation channels at coastal inlets and entrances. Background From fiscal year FY 1995 through 1998, the US Army Corps of Engineers USACE dredged between 200 and 300 million m3yr from Federal channels. Maintenance dredging accounted for an average of 89 percent of this volume, and new work and emergency dredging comprised the remainder. Total dredging expenditures increased from approximately 532 to 713 million in FY 1995 through FY 1998, with maintenance dredging accounting for 78 percent of the cost see U.S. Army Corps of Engineers Navigation Data Center Long-Term Dredging web site at httpwww.wrsc.usace.army.milndcddhisbth.htm. A reduction in maintenance dredging can represent a significant cost and timesaving measure to the operation and maintenance of USACE waterways. The focus of this CETN is how sediment shoals into open-coast channels. The primary sediment-transport pathways can be referenced to the jetties stabilizing the inlet entrance. Sediment can move around the tip of a jetty, entering directly into the channel around the tip of the jetty, on to the ebb shoal and into the portion of the channel that transverses the ebb shoal, through a jetty, over a jetty, and around the landward side see green arrows in Figure 1. Pope 1997 gives a classification system of channel shoaling based on general considerations of geomorphology.
- Physical and Dynamic Oceanography