Navigation Improvement Monitoring

POTENTIAL SAVINGS OF MILLIONS OF DOLLARS IN MITIGATION REQUIREMENTS

Improvements to Corps navigation projects located near environmentally sensitive habitats or critically eroding shorelines require rigorous analyses of vessel traffic behavior impacts. Many projects are subject to review and subsequent mitigation, where modifications to the navigation channel have resulted in increased shoreline erosion attributed to vessel wake. Mitigation costs are substantial and often required well after the appropriated budget for the navigation project improvement is completed.

PROBLEM: The Charleston Harbor Post-45 Navigation Improvement Project included channel deepening and required monitoring of vessel-induced wake along several adjacent critically eroding islands protected by the State Historical Preservation Office of South Carolina and the National Park Service. This problem occurs in many other locations.

SOLUTION: A suite of Corps R&D technologies provided a baseline for quantifying mitigation measures related to deepening the navigation channel. Information included a combination of wave- and water-level field data collection, Automatic Identification System vessel transit analyses, and rigorous analyses of nonanthropogenic background energy, such as wind and tides. This provided a real-time, operational picture of change to the wave energy received along critical shorelines within the estuary.

IMPACT: Collected baseline data and analysis of vessel wake and ambient wave energy post-project demonstrated the limited impact to critical resources at the project. The analysis resulted in a positive relationship with stakeholders at the state and federal level. The baseline information gathered for this study and the validation of numerical tools have the potential to save the Corps millions of dollars in mitigation requirements.