Detection and Monitoring of Maltese Shoreline Changes using Sentinel-2 Imagery

The Coastal zone of Maltese islands is one of the representative areas holding significant attention for relevant social and economic interests. Therefore, acquiring continuous and high quality information on the beaches morphology and evolution is considered very important for the monitoring and management of Maltese coasts. Due to its greater spatial and temporal resolution compared to traditional methods, the remote sensing techniques were exploited recently to detect and monitor Maltese coastal area morphologic variability. The main purpose of this work is to extract and assess the shoreline variations on the Maltese sandy beaches using multispectral Sentinel-2 images, between May and October 2019. A simple shoreline detection model based on a water index known as Normalized Difference Water Index (NDWI), was adapted to determinate the appropriate threshold value. This procedure is a key step in separating land-water areas. The Shoreline precision is validated using Digital Elevation Model (DEM) data collected by LIDAR system and, it exhibits a high spatial and temporal resolution. The analysis of shoreline change results, on four studied sites covering the most important sandy beaches in Malta, shows small uneven variations on the Maltese beach morphology. The observations indicate that most of the shorelines displacements do not exceed few meters.