Understanding flood risk and climate change impacts for Portugal

Understanding flood risk and climate change impacts for Portugal

In News by Stephanie Brain

Understanding flood risk and climate change impacts for Portugal

Understanding flood risk and climate change impacts for Portugal

For the first time there now exists a full national flood model built at 5 metre resolution and which reveals the impact of flood hazards from from rivers, the sea and also surface water.

Across mainland Portugal extreme hydrologic events are known to occur, varying from slow building and long duration widespread events, through to very fast spreading, short duration events with concentrated impacts. Flash floods occur mainly within small watersheds or in urban areas, whereas larger, more progressive floods usually occur in the Tagus, Guadiana, Mondego and Douro river basins. Further to this Portugal’s extensive coastline along the west of the country is vulnerable to coastal floods which are driven by low pressure systems developing within the Atlantic Ocean.

Ambiental’s FloodMap  and FloodScore products are designed to support insurers, banks and lenders in making faster, more accurate decisions around flood risk and climate change.  According to PreventionWeb flooding constitutes 95% of the Annual Average Losses from natural disasters, 141 Million US$ per year. Ambiental flood data is used to visualise, assess and understand potential flood risks so that mitigations can be made in order to reduce losses.

A flood event verification showing the Mondego River Basin flood of 19th December 2019 in red. Displayed underneath this is the Ambiental 1 in 100 year flood data which shows good alignment with the historic event footprint.

A flood event verification showing the Mondego River Basin flood of 19th December 2019 in red. Displayed underneath this is the Ambiental 1 in 100 year flood data which shows good alignment with the historic event footprint.

Proven accuracy against historic flood events

Major flooding has occurred in Portugal in recent years. Notable events have occurred, including in October 2020 Storm Barbara where houses were destroyed and damaged when heavy rains resulted in flood induced landslides.

In October 2020 Storm Barbara, combined with a high tide, caused flooding in coastal areas and surface water flooding in Portalegre, Fronteira, Braga, Coimbra, Bragança, Mogadouro, Loulé and Ovar.

At Montemor-o-Velho in December 2019 high flows occurred on the Mondego River where flood control levees were overwhelmed, resulting in restricted road and rail traffic, as well as damage to the electricity network affecting energy distribution to thousands of people, especially in the Centro region.

The Mondego River

The Mondego River

The accuracy of our Portugal flood models is verified against historic events and local government flood maps. FloodMap is built at high resolution (5m) using the latest hydrological input data. FloodScore extracts flood depth information from FloodMap to provide a convenient property-level flood risk scoring database for all addressable properties in Portugal.

Accounting for the impacts of climate change

Today approximately 2% of mainland Portugal displays high or very high vulnerability to risk of flooding. In the future this is expected to increase as coastal inundation and erosion, plus tidal encroachment into lagoons and estuaries, represents a significant climate change-induced risk.

Ambiental’s future facing climate change flood risk data for Portugal considers the full range of emissions scenarios and climate outcomes across a range of time epochs. FloodScore Climate is designed to simplify the process of determining sensitivity to change and achieving regulatory compliance by removing the challenges of working with highly dimensional large datasets.

Our Portugal data is formed from under a consistent modelling methodology to our flood data for Spain and our forthcoming product launches for multiple countries across Europe. Sample Data for Spain is available to download for evaluation purposes with other locations available on request.

If you are interested in how Ambiental data can help you to better understand flood risk in Portugal, Europe and throughout the world contact us to discuss your needs. Our team of flood risk experts are standing by to advise you.

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