Nearshore Placement Techniques in Southern Lake Michigan
Army Engineer Research and Development Center VICKSBURG United States
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The shorelines near the Port of Indiana and Waukegan Harbor in southern Lake Michigan were analyzed using historical aerial photography, direct beach and nearshore placement records, and the U.S. Geological Survey Digital Shoreline Analysis System. The shoreline analysis was compared to the results of the U.S. Army Corps of Engineers Sediment Mobility Tool. High water levels and significant storms led to erosive conditions in the 1980s. During the 1990s and 2000s, nearshore placement of locally dredged sediment likely contributed to the recovery of these shorelines. The current nearshore placement technique consists of placing sediment in 5.5 meters 18 feet of water in small discrete mounds to prevent the sediment from obstructing the hanging gates of the scow from closing. The sediment will be mobilized more frequently, and more energy will be dissipated if the dredged sediment is placed in shallower depths in the shape of an elongated bar or mound. Two potential methods to accomplish this are to restrict the placement area for a project to a much smaller area in the larger permitted nearshore placement area and to light load the scows to reduce the draft for shallower placement.
- Physical and Dynamic Oceanography