After wildfires destroyed 42,000 hectares of forest in the Bassin d'Arcachon region, local officials are now worried about a new threat: flooding. Trees in the area, especially pines, help absorb and move water, acting like natural pumps. With so many trees burned, there is concern that the region could collect significantly more water during the winter, increasing the risk of flooding, especially if heavy rains occur. To prepare, the intermunicipal syndicate (SIBA), which manages the region, has begun emergency work, including cleaning ditches and improving drainage systems, to protect nearby towns and infrastructure. Bruno Lafon, president of SIBA and head of the Forest Defense against Fires, explained that large areas of the region—particularly in the north—have been severely affected by the fires. Adult pine trees, which can absorb up to 150 liters of water per day, are no longer available to help manage water flow. This has left the region vulnerable, and officials are working to model the impact of the fires on water movement. Three major projects are underway, including one in the commune of Lanton, where ditches are being cleaned to prepare for the upcoming rainy season and prevent overflow. In Lanton, SIBA has enlisted companies to carry out urgent work on drainage systems. Sabine Jeandenand, the general director of services for SIBA, explained that they are digging a ditch near a river to help drain an urban area. This is crucial because the Bassin d'Arcachon acts as the outlet for a large watershed, and urban areas lie between the forest and agricultural land to the north and the basin to the south. This positioning makes the region especially vulnerable to flooding if water cannot be drained efficiently. The challenge is even greater because the Bassin d'Arcachon already faced major flooding in 2023, which caused sewage systems to overflow and severely impacted the local oyster industry. To avoid a repeat, SIBA is working to improve drainage and slow water flow upstream of urban areas so that the cities can handle the water more effectively. Bruno Lafon emphasized that the goal is to keep water in surrounding areas like firebreaks and wetlands, rather than letting it accumulate in the forest massif, which is difficult to manage. Meanwhile, authorities are also dealing with the enormous task of removing 4.3 million tons of burned wood from the area, while trying to minimize the impact of water on local communities.