Ibiza proves that flood zones are not just a plan

Palm"Flood zones have a bad habit of flooding." Alfredo Barón, former head of the Government's Water Resources Studies and Planning Service and an authority on the subject, has been saying this for years. His judgment was directed at the public authorities, who for decades allowed construction in areas considered prone to flooding, even long after the studies and initial regulations began to come into effect. Last week, the force of nature struck Ibiza again, and luckily, only material damage was reported. The most significant lesson from this episode can be learned by superimposing the flooded area with the flood zone maps (see main photographs): they are a carbon copy.

"It's become clear that floods can take years, decades, or centuries, but they happen. If an area is mapped as prone to flooding, it's for a reason," explains Ibizan geologist Inès Roig. This is also confirmed by Joan Estrany, geographer and director of the Balearic Risk Observatory (RiscBal), who wants to emphasize "the importance of having studies that show us where the danger lies in the event of severe rainfall." "Flood zone maps are essential. There are places where the infrastructure is already in place, but they can be adapted, making them less rigid and more permeable, because when an area is considered prone to flooding, it's for a technical reason," he asserts.

The Ibiza floods were caused by very intense rainfall, with an estimated 254 l/m2 (Aemet figure), which some unofficial sources put at 261 l/m2. These amounts shattered the record from the 1977 floods. This enormous amount of water fell mainly on the city itself, causing severe flooding of low-rise buildings and commercial premises, and the rescue of more than 150 people. Emergency telephone lines and services were overwhelmed for hours, and everyone fled as best they could from the areas with the most water. Fortunately, everything remained a scare.

According to the maps and simulations generated by the Ministry for Ecological Transition's floodplain viewer on its floodplain platform, some 2,500 people live in a risk zone in Ibiza. But the reality is that a precise figure cannot be confirmed. "We are still working to provide a precise estimate," notes Joan Estrany. However, on September 30th, it became clear that a large part of the city could be flooded if there are torrential rains.

A few kilometers further upstream

The question experts are asking is what could have happened if, instead of raining on the city of Ibiza, the torrential downpour had been a little further north, at the headwaters of the torrents. "If only the same amount of water had been recorded two or three kilometers further upstream, a disaster could have happened. Fortunately, that wasn't the case, but we must take note because all precautions are insufficient," Estrany emphasizes. Experts agree that, despite this, the impact was lessened thanks to the water discharging so close to the sea. "There was no torrent, because it could have been much worse," says UIBC Geography professor los García.

The most tense moment came at noon on Tuesday the 30th, when it seemed the storm was finally easing. It intensified again and exceeded 180 l/m2 (180 liters per square meter). This led to the declaration of a red alert. "We all crossed our fingers that it wouldn't get worse and, above all, that it wouldn't rain any higher up. We were aware of the danger that would pose. I didn't take my eyes off the phone," recalls Miguel Fernández, a retired shopkeeper who says he was "pretty scared."

Professor Cels Garcia asserts that "emergency coordination and the warning system worked." "There's nothing to be said about this. However, there were still people who drove to pick up their children, even though they had been asked not to," he laments.

These behaviors, in Joan Estrany's opinion, confirm that "we lack an emergency culture." Nor did the government decree the day before, with a clear weather forecast, that classes were suspended. "It's very difficult to take preventive measures. In other places like the United States, adverse weather has led to the development of a very important respect and prevention," explains the director of Riscbal.

The lack of awareness regarding the importance and risks of torrential rains today is not only evident in the people who ignore warnings and drive. "It also happens with infrastructure and facilities. There are already cities, even in Africa, that are investing money to make them more permeable, so they absorb water. This reduces the effect of heavy rainfall in a short period of time, a situation we must get used to," warns Estrany. Along the same lines, geologist Inès Roig points out that "fairly recent constructions have been built very close to the Llavanera stream, where there is even an industrial estate, for example." "Asphalt and cement accelerate the flow of water when it rains a lot. As if that weren't enough, there is an awareness of cementing the stream beds and removing vegetation, which actually slows down the water. It's incredible, but we still prioritize the need to build an industrial warehouse instead of thinking about how to protect the population."

Climate change is here

Researchers at the UIB's Interdisciplinary Laboratory on Climate Change (LINCC) have identified that climate change is causing a decrease in average rainfall in the Balearic Islands—and is expected to increase further—along with an increase in seawater evaporation, which increases water stress. The forecast is for episodes of intense rainfall to become more frequent and violent. Given this scenario, "we have no alternative but to apply two maxims: never build on flood-prone areas, and protect cities and towns, instead of just thinking about continuing to lay concrete," warns Neus Prats, spokesperson for GEN-GOB.

"If we take a look around the outskirts of Ibiza, as is the case in other towns, we can see how priority is being given to further growth. There are more parking lots, roads, and commercial spaces, which in the event of torrential rain cause a multiplying effect of the force of the water. It seems that the warnings of the most experienced are not the warnings of the experts. They are more concerned with business than with the territory and the safety of people," Prats says.

On the other hand, wetlands like the Feixes "have acted as a sponge, slowing the water's speed and absorbing it." "In cities, we haven't built friendly structures; we've paved and concreted everything. It's never too late to change course. We have to renaturalize torrents, create earthen culverts, green areas... and be aware that water will reclaim its spaces again. The more prepared we are, the better off we will be," he warns.

These reflections aren't just for Ibiza. More than 150,000 people live in areas classified as at risk of flooding in the Balearic Islands. Although this is not an official figure, it comes from calculations by the Balearic Risk Observatory (RiscBal) and cross-referencing data with the cartography of the Ministry for Ecological Transition. The data is surprising: between Palma and Marratxí alone, there are nearly 123,000 residents in these risk areas. In Alcudia, for example, it is estimated that almost 80% of the population lives in these areas. In Santa Ponça (Calvià), almost the entire population of the town lives in a risk zone.

In the case of Palma, in 1956 only seven hectares had been developed in flood zones, while in 2018 this area increased to more than 250 hectares. Regulations are increasingly strict, although the PP and Vox narrowly avoided allowing rural development in flood zones.