The growing exposure of cities to the impact of climate-related disasters is driving the search for new strategies and engineering technologies that protect the population and improve infrastructural resilience against extreme phenomena. Of the main scourges of nature, intense rainfall and flooding pose the most serious threat to essential infrastructure in Spain. According to a study published in Geomatics, Natural Hazards and Risk magazine, in which the University of Malaga participated, more than three million inhabitants across Spain are exposed to the effects of flooding, and the potential economic loss amounts to more than 120 billion euros.
To address the fundamental role played by civil protection in damage prevention, we spoke with Luis Mediero, a professor in hydraulic engineering at the Polytechnic University of Madrid: “Flooding causes the greatest economic damage, at both European and national level. In Spain, around 70% of the compensation paid out by the Insurance Compensation Consortium is related to flooding”, he says. These phenomena particularly affect critical infrastructure elements like dams, bridges and transport systems.
A challenge for essential infrastructure
In addition to climate factors, regional planning has been a determining factor in increasing exposure and vulnerability to flood risks. Land use, especially in response to unplanned urbanization, has resulted in the loss of permeable surfaces and natural absorption areas, river channels have been modified and spaces for controlled overflow have been reduced. Consequently, growth is responsible for significant damage to infrastructure such as dams and bridges: “Overtopping due to cresting water levels is the biggest cause of dam failure,” explains Mediero.
Proper territory management is therefore essential to mitigating the effects of these natural phenomena. Civil engineering solutions like dams, riverbanks and river diversions play a crucial role in this. Luis Mediero cites the Forata dam in Valencia (Spain) as an example. During the flash floods of October 2024, the dam reduced considerably the peak flow of the Magro River, avoiding serious damage further downstream. “With extreme water surges like this, the only really effective measures are those that offer structural protection,” he asserts.
Using urban planning to reduce risks
Adapted zoning and urban planning are fundamental factors in managing exposure to risks deriving from flooding. In Spain, a recent study shows that more than 3 million homes are located in areas prone to some type of flood risk, and after the devastating rains and flash floods in Valencia, experts and citizen associations are demanding stricter urban planning policies. “The National Cartography System for Flood-prone Zones and the limitations on urban development in higher risk areas are important steps in the right direction,” says Mediero. He also adds that “the last amendment to the Regulations on Public Hydraulics has put a stop to constructing new buildings in areas prone to flooding”, effectively establishing limitations to land use in vulnerable areas. These measures complement and underpin action plans at autonomous community level in the event of an emergency.
There are also initiatives in place to mitigate the impact of disasters in collaboration with neighboring countries. The European Union coordinates regional regulations to structure a global shield. “Every six years, the different Hydrographic Confederations have to approve a flood risk management plan”, he explains. In addition to these regulatory solutions, the use of innovative technologies is essential to reinforce infrastructure protection.
New solutions to boost resilience
One of the main priorities during and after an extreme climate event is the maintenance of essential services like transport lines and electricity supply. To boost resilience, it’s more effective to integrate this into the planning phase: “It’s easier to design an infrastructure that is already prepared to deal with these risks than to adapt it to them later, on” the expert warns. In this regard, new regulations on the design of dams already include the need to consider climate change, and in the near future, similar advances will be implemented for roads and railroads.
Innovative technologies and materials have also been incorporated that are changing the way civil engineering addresses disaster prevention: “In the case of buildings in flood-prone areas, waterproof parameters like asphalt laminates or the direct application of isolating fluids can be used. Anti-flood barriers that prevent water flow and no-return valves that prevent the passage of water through sewerage and sewage pipes,” he explained.
New trends such as sponge cities (which aim to increase soil permeability and reduce flooding) and the “room for the river” philosophy (which involves giving over more space to rivers to facilitate controlled overflows) are gaining traction as strategies to follow in the coming years, together with the optimization of detection and alert systems. “In our case, we now have the Flood2Now research project underway, which aims to develop a tool that allows everyone in the affected population to play an active part in the alert system by uploading real-time photos to a mobile application,” he concluded.
Article collaborators:
Luis Mediero is Professor of Hydraulic Engineering in Roads, Channels and Ports at the European Telecommunications Standards Institute at the Polytechnic University of Madrid. He is an expert in the subject of flooding and has participated in, and led, several research projects, both in Spain and at European level.
