The U.S. Army Corps of Engineers, Chicago District, and the Engineer Research and Development Center (ERDC) are conducting a study to better understand the effectiveness of nearshore placement of dredged sediment to reduce shoreline erosion.
In Southern Lake Michigan, sandy dredged sediment suitable for beach nourishment has repeatedly been placed in designated nearshore areas just offshore of reaches subjected to natural littoral forces and impacted by coastal erosion.
While current nearshore placement practices are designed with the goal of replenishing the coast, reducing shoreline erosion, and minimizing material placement costs, the effectiveness of this practice has not previously been monitored or modeled.
The Town of Ogden Dunes, Indiana has experienced significant shoreline erosion and reduction of beach areas since the construction of the Burns Waterway Harbor, just east of Ogden Dunes.
More than 1.8 million cubic yards of material has been placed in the nearshore area of Ogden Dunes since 1980, including nearly 140,000 cubic yards placed in the summer of 2016 by the Corps and Northern Indiana Public Service Company.
Monitoring and analyzing the impact and effectiveness of this 2016 placement will be a major component of this study.
In support of the study, the United States Geological Survey Indiana and Illinois Water Science Centers conducted a baseline bathymetric and topographic survey of the Ogden Dunes coast before the start of the 2016 dredging.
The results of this survey will be compared to three post-placement surveys conducted between July and late-fall, 2016. The USGS also deployed two Acoustic Doppler Current Profiler monitors to collect information about offshore and nearshore wave height and velocity. This analysis will help define the impact of submerged sediment ‘berms’ placement on shoreline wave impacts.
This study, which is expected to be completed in late 2017, is being conducted as part of the Corps’ Regional Sediment Management Program, which is designed to manage sediments in ways that contribute to sustainable water resource projects, environments, and communities.