An interactive Web-GIS fluvial flood forecast and alert system in operation in Portugal

Floods are one of the natural disasters not preventable, affecting people and causing significant damage to economic activities and infrastructures. Thus, it is of foremost importance to, within a disaster risk-reduction strategy, develop a useful flood forecast and alert system to prevent people from suffering flood disasters and mitigate its consequences. This article presents the Flood Forecast and Alert System in operational mode since 2019 for the Águeda river basin located in Portugal’s centre region. This system is technologically advanced, differing from others since it uses a coupled real-time hydrologic and 2D hydrodynamic modelling supported on numerical weather prediction and a high-resolution digital terrain surface model. The system components are automatically activated and linked: i) a rainfall forecasting model (WRF), ii) a hydrological model (HEC-HMS), iii) a hydraulic model (HEC-RAS 2D), and a iv) Web-GIS platform. The hydrological model is forced with forecast precipitation for the next three days and updated every 6 h, which is crucial to generate pre-flood hazard maps. It also includes a Web GIS service for flood hazard dissemination available for civil authorities and citizens. A flood forecast and alert system is highly relevant to the community since, by enhancing knowledge, it provides the authorities responsible for assessing and managing the flood risk, responsiveness to disasters and timely decision-making, which is even more evident in the context of climate change.