Although many rainwater reservoirs have been created, such as the Bassin d’Austerlitz, which collect rainwater and slowly release it after bad weather has passed, if enough rain is concentrated in a small enough period of time, not everything that falls from the sky can be captured. In such a situation, the runoff water has to be released into rivers, increasing bacteria levels.
“[Weather] “Climate change is a big problem and this will only make things more difficult,” Dan Angelescu, CEO of water monitoring startup Fluidion, said at a July 31 press conference at the company’s offices in Alfortville, just outside Paris. The company makes remote water sampling devices that transmit data to a central base and has been working with Paris authorities since 2016 to provide water analysis services at the Bassin de la Villette reservoir, a separate swimming spot north of Paris that is now open to the public for swimming.
“If new projects to capture runoff from waterways are not implemented in the coming years, the ability to swim on the Seine and the opening of leisure and sports areas will likely depend on weather events, with swimming bans imposed after rainy days,” said Loïs Mougin, a PhD student in exercise and environmental physiology at Loughborough University’s School of Sport, Exercise and Health Sciences.
Even without an increase in extreme weather, keeping the Seine clean enough to swim in amid normal weather events—like regular summer rains—is a major challenge, says Jean-Marie Mouchel, a hydrology professor at Sorbonne University. “There are also a lot of non-specific weather events that impact water quality. We need to make the system more efficient at improving water quality when faced with these.” Water quality data from last summer bears this out. The Seine was unswimmable about 30 percent of the time—but Paris did not experience extreme rainfall a third of the time.
Experts say the way water is monitored, what information is shared with the public, and when, also needs to be improved. “It is important that bacteriological data is published daily, along with information about the associated risks,” Mougin said. Those risks include the potential to cause gastrointestinal problems and eye and skin infections.
“Monitoring is going to be critical,” Angelescu says. “Having technology that can properly monitor risk, measure the actual risk from all the microbes, and provide results quickly is going to be incredibly important.” Conventional monitoring methods, the ones used to make decisions for the triathlon (and unrelated to Fluidon), involve taking samples from the river and sending them to a lab—a much slower process than real-time monitoring.
So Fluidon specifically tested its technology at the triathlon venue near the Alexandre III bridge during the Games, focusing on levels E coli bacteria, to show how a faster system involving on-site treatment could work in rivers. It published its results in near real time on a open data pageand said their technology provides a more accurate and up-to-date picture of water conditions.
