The Mississippi River-Gulf outlet is a channel 36 ft deep and 500 ft wide extending from a point south of Michoud, Louisiana, southeastward across the marshes and Breton Sound into the Gulf of Mexico. The outlet was constructed by the U.S. Army Corps of Engineers to provide additional access to the Port of New Orleans and thereby ease traffic on the Mississippi River. The channel crosses a delta lobe constructed when the Mississippi River flowed down a course east of its present course. The sedimentary environments and the features formed by the destruction of the now abandoned and subsiding lobe have a great influence on sedimentation in the outlet and, conversely, the outlet has had a profound effect on the environments on which it has been superimposed. The outlet has ncountered an excessive amount of shoaling in its Breton Sound reach. In an effort to determine the cause(s) of the shoaling and the source(s) of the shoal material, a study was made of the factors influencing sediment distribution in the Breton Sound area (e.g., tides, winds, spoil, and sediment distribution, salinity, current directions, and velocities). The principal source of the shoal material was determined to be the spoil dredged from the outlet itself which returns to the channel by density flow rather than by normal deposition of suspended material.

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