UAV applications to coastal engineering

The use of UAVs (Unmanned Aerial Vehicles) as a mapping and measurement tool has grown significantly in recent years, such that the potential for coastal engineering applications is beginning to be realised. Whereas more-traditional land-based (e.g. RTK-GPS) or airborne (e.g. LiDAR) methods of collecting topographic data over large areas can be labour-intensive and/or costly and physically restrictive, UAV surveying now has the ability to provide a cost-effective solution for rapid airborne sampling of the coastal zone at high-accuracy and very high spatial resolution. This paper presents an overview of the use of UAVs for coastal engineering applications, starting with the different types of systems available, practical considerations such as UAV regulations and flight planning considerations, photogrammetric data postprocessing techniques (the Structure-from-Motion algorithm) and examples of resulting data products. A number of coastal engineering case studies that have been conducted recently by the authors using UAV technology are then presented. These applications include rapid pre- and post-storm UAV deployment for quantifying coastal impacts of a major storm event that struck Sydney in April 2015; an evaluation of a rubble-mound breakwater on the mid NSW coast for structural damage and armour volume analyses; and vegetation mapping at a coastal estuary entrance using a near infra-red sensor. The coastal engineering applications presented highlight the enormous potential of UAV technology to significantly improve and potentially revolutionise the future of coastal zone monitoring.