Evaluating coastal flood impacts at the EU-scale: the ECFAS approach

Extreme marine storm events have the potential to produce coastal flooding among other hazards. Flood-related impacts are expected to intensify in the future due to climatological factors. Thus, forecasting the impacts generated by marine storms on coastal areas is a key aspect for risk management plans and cost benefit analysis of measures. An integrated approach for the evaluation of coastal flood impacts at the EU scale was developed in the framework of the ECFAS project (EU H2020 GA 101004211), whose main objective is to develop a coastal flood awareness system for the evolution of the Copernicus Emergency Management Service (CEMS).

The approach consists in the integration of literature-based methodologies that were adapted and/or improved to evaluate direct impacts on population, assets (buildings, roads, railways, agriculture, ecosystems, power and nuclear plants) and points of interest. The approach relies on publicly available EU-scale datasets of population, land use/cover, buildings, transport networks, and others. Micro-scale (object-based) and probabilistic methods were applied when data and model availability allowed it, in order to provide a reliable evaluation of the damage and its uncertainty. Otherwise, grid-based exposure methods were used.

A partial validation of the approach was performed by comparing the numerical results with reported qualitative and quantitative information on a few significant extreme events: Xynthia (2010) at La Faute-sur-Mer (France), Xaver (2013) at Norfolk (UK) and Emma (2018) at Cadiz (Spain). At this stage, the impacts were calculated using the LISFLOOD-FP flood maps produced in the framework of the ECFAS project. According to the analysis, this impact approach provides reliable results for the damage to buildings and roads, which represent two of the most important sectors when evaluating flood-related damages. Integrating the ECFAS awareness flood system, this approach will be extensively applied to provide impact results for flood scenarios (1-20 years return period) along the European coastal flood-prone areas.