The opening ceremony for the Summer Olympics in Paris next year will be an unusual one. Rather than taking to an Olympic stadium for the festivities, a flotilla of boats will ferry the athletes down the river Seine past landmarks like the Eiffel Tower and the recovering Notre-Dame Cathedral. Even more unusual, soon after, some of those athletes will be competing in the very same waters.
That is, as long as the city succeeds in its ambitious cleanup plan to make the water safe to swim in.
When Paris hosted the Olympics in 1900, multiple swimming events took place in the river. Since 1923, however, swimming in Paris’ Seine river has been banned to protect swimmers from currents, river traffic and water pollution. Now, the city is hoping to return the river to its former state as an Olympic venue and public swimming hole.
“Swimming at the foot of the Eiffel Tower will be very romantic,” says Emmanuel Grégoire, deputy mayor of Paris in charge of urban planning, to Time’s Vivienne Walt.
The $1.5 billion project involves a significant overhaul of infrastructure, adding new underground pipes, tanks and pumps to prevent harmful bacteria from joining swimmers in the river. One storage tank near Paris’ Austerlitz train station will hold the equivalent of 20 Olympic swimming pools worth of water, reports John Leicester of the Associated Press (AP).
These storage tanks and other additions are to prevent rainwater from overwhelming Paris’ sanitation system and causing untreated wastewater to flow into the river, one of the main sources of pollution in the Seine.
“We are not purifying the Seine,” says Samuel Colin-Canivez, the city’s lead engineer in charge of sewage projects, to the New York Times’ Catherine Porter. “Our approach is to keep untreated water from being dumped into the Seine.”
The city also recently changed its laws to require moored boots to use Paris’ sewage networks, rather than emptying sewage and wastewater directly into the river. It is also improving sewage treatment plants on the Seine and the Marne, a tributary of the Seine, reports the AP.
While the plan is an exciting one, it isn’t bulletproof, says Pierre Rabadan, the deputy mayor who is directing the city’s Olympic planning.
“Do we have a 100 percent guarantee? The answer is no,” Rabadan tells the Times. “If it rains for a week continually before the races, we know the quality of water—even with all the work that has been done—probably won’t be excellent.”
Still, thanks to the city’s work so far, the water is already improving. Last summer, hydrologists measuring fecal bacteria in the planned swimming courses of the river found that 90 percent of samples were clean enough for swimming, according to Time.
After the Olympians swim their laps, the public will have the chance to take a dip in 26 new swimming pools in the river starting in 2025, four of which will be in the city center. Like the first public pools that opened on the river in 2017, these new swimming holes will be “walled off from heavy boat traffic that carries cargo, garbage and about seven million tourists a year,” according to Time.
Officials hope the project will be a source of inspiration for other cities looking to clean up their waterways.
“It will create waves, so to speak, across the world because a lot of cities are watching Paris. It’s the beginning of a movement,” says Dan Angelescu, a scientist who is tracking the Seine’s water quality for City Hall, to the AP. “We hope so, at least.”