Flooding and heavy rains are becoming more and more frequent in France. The town of Bolbec, near Le Havre (Seine-Maritime) has installed a hydraulic structure to combat this phenomenon.
Located in a basin, Bolbec (Seine-Maritime) suffers from major flooding every year. To de-impermeabilize the city and allow water to circulate, the town hall has launched numerous projects costing seven million euros.
Everything is happening four meters underground… The water from the next storms will be collected in the heart of a residence in Bolbec (Seine-Maritime).
“It is a stack of plastic modules which allows, a bit like a honeycomb or a sponge, to fill with water and reach 1,000 m3 storage”, explains Arnaud Dacar, project manager.
Find the report by Mélissa Genevois and Elodie Do Nascimiento:
The technician gives us the image of a large bathtub that fills up at a certain speed: “At the end of the bathtub, we will plug the hole and we will let the water pass less quickly. It will flow more slowly towards the river and towards the Place du Genetey“.
Increasingly faced with flooding problems, cities must innovate. If it is possible to dig water retention basins of 3,500 m3 on the outskirts of cities, in the city center, the solution would be to reinvent basements.
In 2022, the municipality played another card: the accentuation of the curves of the Bolbec in order to slow its flow, as well as the deconcreting of its banks. A gamble, which proved to be a lifesaver during the heavy rains of December 2023.
“We saw this floodable garden of 10,000 m3 fill up well, it was full. That means that this work was important and we were able to measure, at the river level, that this work that was done on this floodable garden was substantial and avoided flooding points”, explains Christophe Doré, mayor (SE) of Bolbec.
Another project is planned in his commune with the construction of a 15,000 m2 pool3 on the SNCF wasteland site. Work is scheduled to begin at the end of 2025.
