New method developed to identify regions at high risk of compound flooding along the Spanish Mediterranean coast

Car sinking in a flood
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The study, published in Communications Earth & Environment, has identified three particularly vulnerable areas: central Valencia, northern Catalonia and western Andalusia

Alt and Baix Empordà, the areas at highest risk

In Catalonia, the flood-prone areas already identified in the Floods Directive that show the greatest potential for developing compound floods are concentrated along the coast of Alt and Baix Empordà, followed by the Maresme coast. "It should be noted that this work is a first step, which should be complemented with a detailed assessment of flood risk in each area for different probabilities of occurrence," adds the UPC researcher.

A joint research effort by the UPC and the UGR has developed an innovative method to detect and classify areas at high risk of compound flooding—flooding caused by a combination of intense rainfall, river overflows and coastal events such as storms and heavy waves. The study, published in Communications Earth & Environment, has identified three particularly vulnerable regions: central Valencia, northern Catalonia and western Andalusia.

May 09, 2025

A team of researchers from the University of Granada (UGR) and the Universitat Politècnica de Catalunya - BarcelonaTech (UPC), led by professor María Bermúdez (UGR) and professor José A. Jiménez, a researcher at the Maritime Engineering Laboratory and faculty member at the Barcelona School of Civil Engineering (ETSECCPB), has developed an innovative method to detect and classify areas at high risk of compound flooding—that is, flooding caused by the combination of intense rainfall, river overflows and coastal phenomena such as storms and heavy waves. These floods, increasingly frequent and damaging, pose a serious threat to regions like the Mediterranean basin. A recent example is Storm Gloria, which in January 2020 caused severe damage along the Spanish Mediterranean coast due to the combination of heavy rainfall and a powerful marine storm.

Currently, the European Union’s Floods Directive (FD) provides a common framework for managing flood risk. However, current assessments focus mainly on single-cause events, overlooking the combined risks posed by compound floods. The new approach allows for the efficient identification of what are known as areas of potential significant flood risk (APSFR), taking into account the intensity of individual hazards, their likelihood and how they interact. Based on a detailed analysis of 1,600 kilometres of the Spanish Mediterranean coastline, the study identified three especially vulnerable regions: central Valencia, northern Catalonia and western Andalusia. Of the 214 APSFRs analysed, 11% were classified as being at the highest level of risk.

The method stands out not only for its technical precision but also for its practical applicability. Its scalable design makes it an ideal tool for integration into the third planning cycle of the EU Floods Directive, helping authorities make more informed decisions and strengthen protection against increasingly complex natural disasters. With this initiative, the researchers aim to bridge the gap between science and public policy, offering real solutions to better anticipate and respond to the challenges of climate change in coastal areas.

The research, published in Communications Earth & Environment, part of the Nature portfolio, was carried out within the framework of three projects: C3RiskMed (UPC), EcoC2S (UGR)—funded through the 2023 Joint Transnational Call of the Water4All European Partnership—and MyFlood, a collaboration between the UPC and the UGR. All three projects are funded by the Spanish State Research Agency of the Ministry of Science, Innovation and Universities, with support from the EU’s Next Generation funds.

 

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