City of Tybee Island, GA Dept. Natural Resources, GA Dept. Community Affairs, US Army Corps of Engineers
In natural systems, coastal sand dunes have always been the first line of defense in protecting against shoreline erosion during periods of elevated sea level and wave attack during storms.
Dune creation as a way to protect upland infrastructure is not a new idea, but one that has taken on new prominence with increases in coastal development, rates of sea level rise, and storm intensity in the past decades. Recently, the wide availability and ease of use of unmanned aerial systems (UAS; i.e., drones) has provided a comprehensive, rapid, efficient way to collect data for man-made dunes systems, at a frequency that is responsive to seasonal changes of the beach. New dunes constructed on Tybee Island in March 2020 provide an exceptional opportunity to develop protocols for monitoring these features. Quarterly drone surveys combined with aerial photogrammetry of the beach and dune system on Tybee are being used to develop digital surface models of the system. These surfaces will allow us to address questions related to sediment volumes within the system, shoreline change rates and future shoreline positions, whereas the techniques used to develop these surfaces and derivative data will be documented in a best practices manual.
Provide guidance to Tybee Island on rates, processes and future distribution of renourished beaches and man-made dunes, and develop a best practices manual for monitoring constructed beach systems. These specific shoreline process results can be used by the City to plan for targeted beach rebuilding activities, and the manual will have wide-ranging use throughout the southeastern US as dune building become more common as a tool for coastal resiliency.