Final Monitoring Results for Kaumalapau Harbor Breakwater, Lanai, Hawaii

The Kaumalapau Harbor Breakwater Repair Project has been monitored since late 2006 as part of the US Army Corps of Engineers' (USACE) Monitoring of Completed Navigation Projects (MCNP) Program. Various aspects of the structure's post-construction performance have been investigated in order to gather information that will improve the knowledge available in planning the design, construction, and overall effectiveness of future coastal navigation structures. Goals of the monitoring program for this project include monitoring armor layer and cap settlement in the years following completion, evaluating the structure toe stability, gathering strength data for the Core-Loc armor unit used on the breakwater, and determining the effectiveness of the breakwater in reducing wave energy inside the harbor. Data collected in support of the above goals included: deepwater and shallow water wave measurements, underwater and above water visual inspection, underwater multi-beam survey, above water Tripod-LiDAR (Light Detection and Ranging) surveys, and concrete strength measurements. In addition, wave transformation modeling has been completed in order to evaluate the wave climate at the harbor, and all data have been included into the USACE Enterprise Coastal Inventory GIS Database. A summary of the data and findings are presented, with a discussion of lessons learned as well as areas where further research is needed.