On June 18, 2013, the Garonne River unleashed its force and devastated everything in its path. A dozen towns in the Pyrenees succumbed to the floods and almost 400 people had to be evacuated. An intense episode of rain, added to the melting of a large blanket of snow that had resisted since winter, overflowed its channel and flooded the Vall d’Aran region, in the province of Lleida, destroying bridges and roads and leaving thousands of people no supplies.
These floods are not something exceptional in the area. In fact, approximately every 30 years, one of the rivers in this Pyrenean region overflows. It happened in 1907, 1937, 1940 and in 1982. In total, more than 300 people have died because of the floods. The difference with the 2013 floods is that eleven years ago no one lost their lives. And it was thanks to some sensors that this area of Catalonia has installed in various river headwaters.
After the floods that have devastated the Valencian Community and some areas of Catalonia, and in view of the effectiveness of this system, the Camping Association and some Lleida City Councils have requested that the sensors be installed in all rivers. In this way, these tourist facilities – most of which are in a flood zone – would avoid having to close because they would have room to evacuate their facilities in the event of a flood. As already happened in 2013.
“Those floods were particular. We acted very quickly,” recalls Andreu Cortés, now mayor and then deputy mayor of Les, one of the towns that was most devastated. The bridge collapsed and the roads connecting this town – which is the third most important border access with France – were impassable for days. Furthermore, 49.5% of Les’ homes are built in a flood zone.
Source: Ministry of Ecological Transition, Cadastre
The City Council evacuated the 200 people who lived within 50 meters of the Garonne, a fifth of its total population, and relocated them to hotels away from the river just before it broke out and took everything with it. Thanks to that, only material damage was reported. “We knew what was going to happen for two days. The municipalities were warned,” recalls Jordi Gavaldà, geologist and technician at the Conselh Generau d’Aran (the autonomous governing body of the valley).
Prevention is key in this place where disasters like this periodically occur. For this reason, in addition to the sensors that the ACA (Catalan Water Agency) and the CHE (Ebro Hydrographic Confederation) place in some points of the rivers, the Conselh has had more complex and complete detectors in the rivers for nine years. headers. They were placed just three months before the 2013 floods. “They were decisive,” they say from the Conselh.
Eisharc Jaquet is an engineer and founder of Arantec, the local company that designed them. “The problem with most sensors is that they function as water information systems, not emergency ones,” he explains. On the other hand, those that have installed in the Vall d’Aran take into account the flow in real time, but the forecast of rain and temperatures that can affect the snow covers is also analyzed, as well as the inclination of the terrain, the width of the river, and the characteristics of the basins to determine when and where there is a risk of overflow.
“It is an ultra-personalized system that serves as an early warning of possible floods,” says Jaquet, who explains that “each basin is a world and has a different reaction time.” It depends on various factors such as, for example, the presence of vegetation. This acts as a sponge and gives more room to absorb than asphalt. It also depends on whether the river channel has been modified for development or not.
If the sensors detect that enough factors have been conspired, “the alarms go off” and an SMS is sent to those responsible for civil protection at the Conselh. Once here, politicians, technicians and security forces evaluate the situation and alert the municipalities. “It is better to always warn, even if it is a false alarm,” says Gavaldà. Jaquet backs him up. “The preventive technical tools are more than ready. What fails is human action, which sometimes does not react when it should.”
Incommunicado for days
The municipalities of the Vall d’Aran knew that June 18 would be complicated. But they didn’t know it would be so bad. They did expect that, in addition to the rainfall, a lot of water would come down from the thaw. What surprised them was that, as in Valencia with DANA, much more rain fell than expected and the accumulation became historic in cities like Vielha.
The river’s flow doubled at some points, causing hydraulic dams to become overfilled and burst. That caused “a domino effect” that multiplied the force of the water and washed away roads and bridges.
“We began to see that something was not right first thing in the morning, when we saw that the river was falling higher than it should, even for the alert they sent us,” he remembers from Les Andreu Cortés. It was at 2:00 p.m. when they decided to evacuate its inhabitants. And it was just in time, because shortly after the water flooded Les, filling its streets with mud, leaving residents without services and destroying road access.
“It was a surreal vision. Lucky for our culture of prevention,” explains the mayor, in reference to the existence of drinking water wells, gas reserves and electric batteries that allow the entire town to subsist for days. That was vital because, while other towns received help, they were completely cut off and could only be helped by some neighbors who acted as volunteer firefighters.
“The main accesses, which lead to France, were fixed in a few days, but the rest of the roads, like the bridge, took months to recover,” recalls Cortés. In fact, there are consequences that are still being paid today. “The town was filled with mud and the people, with all good intentions, took out the hoses. But the mud, when it dries, creates a clog worse than cement,” adds the mayor. That made most of the town’s sewer unusable and even today, ten years later, the City Council has yet to put out to tender the last repair work.
“We learned a lot from that episode,” they explain from the Conselh. All the sensors were torn off by the water but were replaced shortly after, with some improvements. In addition, they optimized the alert system and communication with the municipalities. “We have had a couple of alarms since then and we have been able to act quickly,” says Jaquet.
They have monitored all the rivers in the Valley for years and have also expanded to other communities such as Extremadura or Castilla y León, but it is a type of prevention that “is still very incipient,” he laments.
This engineer believes that administrations should “get their act together”, especially because the most basic measurement systems, which take into account the flow of the river on the one hand and the weather forecast on the other, will increasingly fail. And “the indicators are changing.”
Climate change is altering patterns and causing prediction methods, which are built with historical data, to be less accurate. For this reason, Jaquet now works with devices that incorporate artificial intelligence and learn on the fly, generating “much more concrete and reliable” predictions.
More citizen awareness
During the days after disasters such as those in the Vall d’Aran or Valencia, there is a lot of discussion about prevention. But experts in the field such as geologist Joan Manuel Vilaplana regret that, “although now everyone has prevention in their mouths, in a few months we will forget about it.” Note that between these types of events there are long periods of calm that should be used to work.
He points out that the development of technical warning tools is important, but “it must be accompanied by awareness.” Vilaplana lacks good coordination of civil protection with administrations and political leaders and training for the population in risk areas. “Let’s do more drills, like with fires, so that people know what to do and, above all, what not to do, in times of risk.”
It ensures that floods and floods cannot be avoided, but their impacts can be minimized. For this reason, the College of Geologists of Catalonia is committed to studying river basins and installing pools or containment tanks like those that already exist in cities like Barcelona.
But for Vilaplana the most important question is: “what do we do with urban planning?” The expert is committed to “deconstructing” certain buildings and relocating those that are most vulnerable, “even if people make a bad face.” The problem is that there are areas like Vall d’Aran in which many of its municipalities have a significant proportion of homes in flood zones. From Les (49.5%), to Esterri d’Àneu (89.5%), passing through Llavorsí or Rialp (38.2%).
“We live in a valley. The houses are where they can be. We cannot build on the slopes, so we live with a great culture of prevention and mutual aid,” says Cortés. The residents of this town of less than 1,000 inhabitants spent days shoveling mud, sharing food and rebuilding the streets. “Families that had not spoken for a long time gave each other a hand.”
They had a common objective, which was not only to recover their town. Less than 10 days after the tragedy, Les celebrates its major festivals and the municipality had to be ready. “They were strange celebrations, but we were able to do them. It was the first step towards normality,” recalls the mayor.
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