Use of LiDAR shoreline extraction for analyzing revetment rock beach protection: A case study of Jekyll Island State Park, USA

This research was aimed at developing a method for evaluating and monitoring revetment rock emplacements used for protection of ocean beaches. The method was tested by applying it to identification of potentially vulnerable portions of beach and revetment rocks at Jekyll Island State Park in Georgia. Revetment rocks were placed along the Jekyll Island beach in the 1960s to protect against storm surges. In some stretches this revetment has been buried by sand and no longer provides protection for the island's ocean side beach. Revetment rocks are commonly used to mitigate storm damage to structures, facilities and wildlife habitats. Because islands and beaches are dynamic, monitoring the condition and protection potential of revetment can be highly important. This research demonstrates that tracking shoreline changes using LiDAR and other data sources can identify whether stretches of beach and revetment rocks are vulnerable to storm surges and sea level rise. Shoreline movement data included historical tide records for the years 1857-1870, 1924-1971 (at the high water levels), 1971-73, 1999 and 2008 (at the mean high water levels). This research demonstrated that data and methods are available to guide coastal managers and planners in long-term conservation planning, such as for Jekyll Island State Park, which is an Atlantic coastal barrier island. Using the approach described in this paper, high tides and storm surges can be simulated and interpreted for current shoreline and revetment conditions. Perhaps even more important, tide and surge simulations can show possible future inundation patterns under different sea level rise scenarios. Being able to predict future inundation patterns is likely to become more important over time as climate change continues and sea levels rise.