“Strong odor,” “dirty water”: an association denounces pollution in the Cazaux-Sanguinet pond

Since the end of 2024, the Campéole Navarrosse Plage campsite in Biscarrosse has been discharging water from the construction of a swimming pool into the Canalot port. An environmental protection association is highlighting the consequences of this discharge in a Natura 2000 listed site.

Just a few kilometers from the city center of Biscarrosse, the Cazaux-Sanguinet pond is a small natural paradise surrounded by greenery and pine trees. It is the second largest lake in France.

Not far from this natural setting, aboard a small boat, three members of the Société des amis de Navarrosse (SAN), an environmental protection association created in 1997, are sailing along the waters of Port Canalot, opposite Chemin de Navarrosse. And while these "nature protectors," as they like to call themselves, also enjoy recreational fishing, their daytime occupation is quite different: "Normally, the water here is much clearer than it is right now," laments Gérard Roux.

The boat continues its journey, stopping abruptly in front of the Campéole Navarrosse Plage campsite. There, a few rows of concrete blocks form a settling basin into which water from the construction of a swimming pool flows, then discharged into the Canalot port.

"It's pestilential! This strong odor of excrement or rotten eggs is characteristic of hydrogen sulfide, a gas toxic to aquatic organisms. On November 23, 2024, a bailiff noted the turbidity of the water and demonstrated the high concentration of organic matter in this discharged water. The closer you get to the discharge, the more contaminated the water becomes. This polluted water flows into the Canalot port and then into the Trans-Aquitaine Canal, even though the entire site is classified as Natura 2000," said Pierre Bonnet, president of the SAN.

In May 2024, the campsite declared the discharge of this groundwater drawdown to the Departmental Directorate of Territories and the Sea (DDTM). "In this declaration, the campsite stated that it was not affected by the discharge of polluted water. We relied on this declaration and the analyses provided by the City, which showed that there was no pollution problem in the Canalot port, to issue a permit in August 2024," the DDTM stated.

"We did, however, question the color of the water. The hypothesis is that most of the sand layer is ferruginous. When this water was discharged into the Canalot, it oxidized and created iron-related bacteria. We have no explanation for the odor. We have asked the campsite to draw up a report on these discharges; we are waiting," said the water and aquatic environment police service.

For SAN members, this is the first pitfall: "Instead of submitting an authorization application, they submitted a simple declaration. So there was no impact study." On April 15, 2025, following an online petition launched by the association , the City of Biscarrosse published a press release. It partially indicates the results of the analyses.

Contacted about this matter, Nathalie Benquet, Deputy Minister for the Environment, offered reassurance. "We have implemented, as of November 29, 2024, an initial analysis of the water at various points in the Canalot port. The results were forwarded to the DDTM. We then conducted additional analyses. They are compliant and are not alarming, contrary to what this association claims. In early April, agents from the French Office for Biodiversity visited the site to make observations. They did not make any more in-depth comments. If there had been a real risk to the environment, they would have written a very detailed analysis report."

The association's members are unwavering. On February 20, 2025, a complaint was filed with the public prosecutor. "We want a full analysis," says Pierre Bonnet. The Campéole Navarrosse Plage campsite belongs to the MS Vacances group. The land occupied by the campsite belongs to the Biscarrosse town hall. When contacted, the MS Vacances group did not respond to our requests.