Serious concerns less than a year from the Paris Olympics. The pollution of the Seine, which deprived triathletes of swimming on Saturday and Sunday, is undoubtedly due to the “malfunction of a valve” of the Parisian sanitation network, the town hall of Paris indicated on Tuesday August 22, confirming information from Le Canard chained to appear on Wednesday.

“At this stage the preferred hypothesis is that of the malfunction of a valve of the sewerage network located at the level of the Tolbiac bridge”, informed the town hall. It is this malfunction that probably led to degraded water quality, beyond the bacteriological thresholds required for diving and swimming in the river in complete safety. The para-triathlon events on Saturday and the mixed relay on Sunday have been transformed into a duathlon.

“Investigations are continuing to understand the sequence of events and determine the measures to be taken in order to guarantee the perfect quality of the water for the holding of the events in 2024”, added the town hall of Paris. “It’s regrettable, but it’s a situation that we will be able to better understand in the future”, commented to Agence France-Presse, the assistant to the Olympic Games and sport, Pierre Rabadan, who is still waiting for the details of exactly what happened.

He had not hidden “the absence of explanation” in the face of the degraded results and the presence beyond the threshold of the bacterium Escherichia coli (E. coli), fixed at 1000 CFU / 100 ml, in the absence of rains and thunderstorms over the French capital. Because ten days earlier, it was indeed the storms and exceptional rainfall on the Île-de-France which had derailed another pre-Olympic test, that of swimming in open water.

This scenario of heavy rains was feared by all the actors and, with a view to the Olympic Games, several projects are underway to try to counter this risk, such as the Austerlitz basin, still under construction, which will make it possible to store rainwater (50,000 m3), and will be operational in 2024.

On the side of the Olympic Games organizing committee (Cojo), apart from perhaps providing a greater amplitude to stagger the events, there is no plan B planned for swimming elsewhere than in the Seine. These competitions in the Seine are preludes to future swimming promised for 2025 by the mayor of Paris, Anne Hidalgo (PS), on three sites while swimming has been prohibited there since 1923.