The combined effects of climate change and human activities has increased the frequency and severity of natural disasters and hazards, resulting in negative impacts on the environment, economy, and human life. To address this issue, many institutions, organizations and stakeholder authorities are shifting their focus from emergency response to disaster risk reduction, planning and mitigation. In this sense, to address the issue of coastal erosion, the Managing Authority of the Central Macedonia Region has funded a project for the creation of a digital Observatory the serves as a source of vital information on the state of coastal erosion within the region.
Consortis, through the project employed advanced geospatial, data processing and erosion vunerabiity algorithms, developed dedicated models, exploited Earth Observation and in-situ data with the aim to enhance knowledge on hazardassessment and vulnerability. The methodology used in this project involved three thematic phases. Phase A focused on designing a web GIS system to host the observatory, its services, and the resulting datasets. Phase B involved creating algorithms and tools to calculate the necessary indicators, and Phase C focused on evaluating the current state of the coastal area and propose alternatives for risk management. Throughout the project, the spatial databases were continuously re-evaluated to accommodate the digital products created by applying specialized algorithms. These algorithms referred to the automated pre- and post-processing of optical images from Sentinel-2 to create timeseries of multiple indeces anf KPIs referring to the land/sea buondary and the marine environment. Sentinel-1 SAR data have been also used to infer land deformation, derive bathymetry estimates and create a time-series, along with Sentinel-2 data, of coastine spatiotemporal variations. Finally, satellite altimetry observations from the Cryosat-2, Jason1/2/3, SARAL and the Sentinel-3a/3b missions were used to monitor Sea Level Anomalies and variations in Sea Surface Temperature. In-situ observations of the coastal area were also conducted, utilizing techniques such as GNSS, UAV mapping, and echo sounding to calculate high-resolution models of the topography and bathymetry.
The indexes and products obtained are frequently updated to display the most recent information about the environmental parameters of the area, creating a digital replica that accurately represents it. To assess the vulnerability of the coastal area due to sea level forcing, simulations have been conducted for both a 50- and 100-year period. Additionally, a tool has been developed that can determine flood mapping passively for four different sea level rise scenarios. These scenarios, which are based on the vulnerability and flooding assessments, are already in use to aid local authorities in making decisions and evaluating alternative strategies for the development of the coastal zone.
