The harbor structures/shoreline armoring on the southern Lake Michigan shoreline interrupt sand migration.Ogden Dunes, Indiana, and the nearby Indiana Dunes National Lakeshore observed shoreline erosion due to engineered structures associated with Burns Waterway Harbor (east of Ogden Dunes) impeding natural east-to-west sediment migration.To remedy this, USACE placed over 450,000 cubic meters (m 3 ) of dredged material post-2006 in the nearshore of Ogden Dunes.However, the effectiveness of nearshore placements for shoreline protection and littoral nourishment is not fully established.To improve nearshore placement effectiveness, USACE monitored the June/July 2016 placement and subsequent movement of 107,000 m 3 of dredged material in the nearshore region at Ogden Dunes.This involved an extensive monitoring scheme (three bathymetry surveys, and two acoustic Doppler current profiler deployments), a Coastal Modeling System (CMS) numerical model of the changes following placement, and a prediction of sediment transport direction using the Sediment Mobility Tool (SMT).The SMT-predicted sediment migration direction was compared to observations.Observations indicated that between 10/11/2016 and 11/15/2016 the centroid of the sediment above the pre-placement survey moved 17 m onshore.These observations agreed with SMT predictions -onshore migration under storm and typical wave conditions.CMS accurately reproduced the hydrodynamic features.

Shoreline erosion downdrift of littoral barriers, such as harbor breakwaters, is a universal concern. The beneficial use of dredged sediment through placement in the nearshore downdrift of littoral barriers is common place, but key questions about the sediment transport and shoreline response remain challenging. To that end, the shoreline at Ogden Dunes, Indiana, along the southern shores of Lake Michigan is investigated with historical aerial photographs, nearshore placement records, hydrodynamic and bathymetric field data, and numerical models.

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.