UAV-BASED PHOTOGRAMMETRY APPROACH TO ASSESS INTER-HEMISPHERIC INTERACTION AND LOCAL ANTHROPIC VARIABLES INFLUENCE ON THE SEDIMENTARY BALANCE OF A COASTAL STRETCH

Considering the high dynamicity of atmospheric and oceanographic variables in coastal processes, local sedimentary balance is a matter of great interest for Integrated Coastal Zone Management. The diversity of environmental factors associated to a remarkable history of anthropic interventions, in addition to detailed topographic changes related to storm surge events, are assessed in this research for a small stretch of the Northeastern Brazilian coast. For this purpose, an association of conventional and improved digital methods was applied for data acquisition and processing. Remote sensing techniques with Unmanned Aerial Vehicle (UAV), 3D modelling and sedimentary analysis were performed, as well as detailed monitoring of meteorological and oceanographic variables with in situ sources and environmental modelling. The results of one-year monitoring revealed a sedimentary balance with different variations in response to high-energy events associated to extratropical cyclones on the North Atlantic. Liquid volume balance showed an erosional rate of 25.5%, reflected in a 17.4% diminution in the area’s mean topographic level. Beach erosion was correlated to long period waves and great variability of wave types. Positive volumetric changes were correlated to softer environmental conditions. Swell waves presented a significant role in both beach erosion and topographic recovery. There was an asymmetric susceptibility to volume losses in different beach sectors. In order to record and correlate these dynamic interactions, the aerophotogrammetric tool was far more efficient in terms of detailed resolution and data robustness than direct methods of topographic profiling previously applied.