This week, 20 departments were affected by the orange flood vigilance. On Wednesday, the Lot-et-Garonne was even placed in red vigilance by Météo France. Among the other areas most affected: Dordogne and Deux-Sèvres. The Garonne in particular overflowed for 60 km on both sides of the river.
In recent years, around twenty departments have been regularly affected by significant floods which systematically leave considerable damage.
In 1910, Paris had been confronted with a so-called centennial flood, which therefore occurs only once every 100 years. Deputies even arrived by boat at the National Assembly. Now floods of this magnitude appear to occur every decade, and soon every year.
Several reasons can explain this phenomenon. Global warming and the drying up of wetlands are only part of the problem. Indeed, wetlands are real tools in the fight against floods. Home to many species, they also have a great water retention capacity. But the artificialization of soils and urban sprawl are in reality the main cause. In France, every 9 years, the area of a department is concreted. Water is no longer absorbed by the earth, quite simply.
There are several tools to prepare for the approach of a flood. The first of them: Vigicrue. This website provides real-time information on rising water levels.
In anticipation of flooding, France’s Waterways lower dams to better evacuate water, and monitor retention basins that can mitigate the effects of flooding.
This anticipation is essential in view of the human and economic consequences of a flood.
We have reached the height of 4.30m. This is the level of the Seine from which navigation in Paris is prohibited because the bridges are too low. However, it is 9 or 10 million tonnes per year that pass through Paris. If everything had to go by road, it would be in the order of 500,000 trucks.
François Landais, deputy director of the Seine basin
Listen to the interview with François Landais, deputy director of the Seine basin with Gérard Feldzer.
Faced with the increased frequency of flooding, experts are working on solutions. “Maintain wet areas, provide effective protection. The third point will be to design elevated constructions, naturally or artificially. And finally, the most serious would be to consider scenarios of partial or total relocation of certain places of life or of urban work “; explains Jean-Louis Janeau, researcher specializing in hydrology and soil sciences at the Institute for Research for Development.
This means considering moving millions of people, like to Bangkok, Jakarta or Manila. In these cities affected by the rising waters, such population movements would be a nightmare, a question which is nevertheless taken seriously today. Scientists estimate that, per year, floods could impact more than 300 million people in the world by 2050. Beyond taking this threat seriously, concrete action is necessary to curb this phenomenon.
Listen to the full interview with Jean-Louis Janeau With Gérard Feldzer
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