Could Seine-et-Marne be affected by floods of the same intensity?

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On the night of October 29 in the Valencia region, Spain, a “dana” (isolated high altitude depression) poured into the territory, where it was counted around 80 liters of water per square meter. The red alert was quickly issued to warn of the risk of flooding but residents and emergency services found themselves helpless in the face of the downpours which swept away cars, trees and houses and cost the lives of lives of more than 200 people. If the scale of such a phenomenon could not be the same in Seine-et-Marne due to the lower density of large cities than in Valence, it cannot entirely be ruled out that a flood similar happened one day in the 77.

The direct consequences of global warming

Questioned by the newspaper Le Monde on the tragedy in Valencia, the geologist and natural disaster expert Antonio Aretxabala affirmed that recent meteorological phenomena which could have caused floods such as the intense rains which hit eastern Spain (or even those, less intense, which affected Seine-et-Marne at the beginning of October) were directly linked to global warming: “The more temperatures increase, the more the atmosphere becomes charged with water vapor. »

Unlike Seine-et-Marne, the Mediterranean rim is where the atmospheric depressions from the north and the south meet. When the air is heavy with moisture, it can create intense precipitation, which explains why floods in the south always seem more impressive than in the north in terms of damage and intensity. However, the latest floods in Seine-et-Marne have clearly shown that intense rains (but less heavy than in Valence) could also occur in the region: with global warming, phenomena of this type are likely to multiply , specified scientist Antonio Aretxabala.

Less permeable soils

One of the points raised by the Spanish disaster is the excessive concreting in the Valencia region, which has led to a loss of permeability of the soils, which then absorb much less water. Seine-et-Marne being a fairly rural area, concreting quickly finds its limits, even if the lack of work to retain water during the heavy rains which cause the Grand Morin to rise from its bed is pointed out. If what is necessary is done in the coming years, it will also be necessary to take care of the territory's soils to avoid rendering the tanks and other infrastructures obsolete in the event of prolonged or too intense flooding, because we must not forget that Valencia has numerous dams. and ramblas which were nevertheless not enough, the majority of inhabited areas being located in flood-prone areas.

Territories already condemned?

If we can always ensure, on a local scale, to limit the damage linked to floods with a lot of work, prevention and solidarity, it is still difficult to fight against the vagaries of nature. A flood zone is likely to suffer bad weather and if floods of an intensity similar to those of Valence are not likely to affect Seine-et-Marne tomorrow (for all the reasons cited above: not the same population density nor the same atmospheric conditions), it is appropriate to question the future of certain urban areas constantly affected which, in the long term, risk being completely deserted by the population.

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