3D MONITORING OF COASTAL EROSION CONTROL STRUCTURES USING UAV

Abstract. Coastal erosion has increasingly become a problem in recent years due to rising sea levels caused by global warming. To prevent further coastal erosion and damage, control structures like seawalls and breakwaters have been installed along vulnerable coastlines. However, it is crucial that these structures are regularly and thoroughly inspected for any abnormalities or deformations. At present, inspections are done manually by visual surveys which are time-consuming and inefficient. There is great potential to optimize this process using drone technology equipped with 3D laser scanners. In this study, we utilized a drone with a green laser scanner to inspect and diagnose control structures along the coast. We conducted surveys to determine the basic performance of this approach and used ICP algorithms to extract any deformations in vanishing wave blocks over two time periods. Our results showed high variability in basic performance due to the influence of waves during the surveys. However, we were still able to detect strain of around 50 cm in a submerged breakwater located 3 meters below the water's surface. Furthermore, an overall settlement of approximately 34 cm was observed in the vanishing wave blocks along with some localized movements. This demonstrates that drones can be successfully implemented for efficient inspection, diagnosis and detection of abnormalities and deformations in coastal structures that are extremely difficult to identify through visual surveys alone. The use of this advanced technology will allow for quicker identification of at-risk structures, enabling timely maintenance and prevention of further coastal erosion.