Multicriteria GIS-based estimation of coastal erosion risk: Implementation to Aveiro sandy coast, Portugal

Coastal risk assessments have an essential role in decision making and coastal management. In this context, this work presents a new assessment process for the Coastal Erosion Risk Assessment (CERA2.0). This methodology aims to perform coastal erosion risk assessments for a medium-term horizon, over a wide range of coastal environments and scales, with considerable accuracy and efficiency. It follows closely the SPRC (Source - Pathway - Receptor - Consequence) conceptual model by evaluating risk propagation in four modules: susceptibility, value, exposure and hazard (coastal erosion). Subsequently, these are combined to generate vulnerability, consequence and risk maps. A total of twelve indicators are considered. For easier application of the methodology, a QGIS plugin was developed. Given the required inputs, the plugin computes all procedures and provides the results in a georeferenced format. The new procedure is demonstrated for the Aveiro district coastal region, a sandy coast in Portugal. The results indicate that Aveiro has a coastline with predominantly high to very high risk to coastal erosion. The most threatened areas are the coastlines near Furadouro and Vagueira. The method showed to be easily applicable without the necessity of highly detailed data, albeit is still requires a fair amount of it, representing an advantage not common in these types of methodologies. Hence, CERA2.0 is intended to be applied by entities that do not have access to large amounts of data in their study areas or that require coastal erosion risk assessments in limited time windows.