As the Olympics in Paris approach, the city is undergoing a remarkable transformation with a historic clean-up initiative. After being banned for a century due to the polluted water, swimmers and divers are soon to return to the River Seine.
The regeneration project, which has been universally praised as a success, comes with a substantial investment of €1.4 billion. This project is expected to leave a lasting legacy for the Games by making city swimming a significant attraction.
The River Seine, once considered too polluted for recreational activities, will now host three Olympic and Paralympic events: triathlon, marathon swimming, and Para-triathlon, all scheduled to take place in central Paris.
Beyond the Olympic Games, the transformation will continue to benefit Parisians and visitors alike. By 2025, three open-air swimming areas will be accessible from the quayside, providing people with safe and enjoyable opportunities to swim in the heart of the city.
The return of swimmers and divers to the River Seine signifies a momentous step forward in the city’s efforts to reclaim its historic waterway and make it a vibrant hub for recreational activities.
The clean-up and regeneration project demonstrates Paris’s commitment to both preserving its cultural heritage and embracing a sustainable future, providing a cleaner and more inviting environment for its residents and visitors.
Decline in quality of river water
Like many Western cities, Paris experienced a significant decline in the quality of its river due to various factors such as upstream industrial sewage and the increasing sanitation needs of a growing population.
The impact on aquatic life was severe, and by the 1960s, only three species of fish were found in the city’s river. In response to the deteriorating water quality, swimming was officially banned in 1923, although a yearly Christmas cross-river competition persisted until World War II.
One of the significant contributors to the river’s pollution has been the 19th-century “single-system” drainage infrastructure. This system combines wastewater from kitchens and bathrooms with sewage from toilets.
Under normal circumstances, this mixture flows through a network of underground tunnels to treatment centers on the city’s outskirts. However, during periods of heavy rain, the drainage system becomes overwhelmed, and excess wastewater is discharged directly into the Seine.
This outdated drainage system, unable to cope with the demands of a modern city, has been a significant cause of pollution in the River Seine.
Addressing this issue has been a crucial aspect of the €1.4 billion regeneration project aimed at restoring the waterway’s health and making it suitable for recreational activities like swimming and diving once again.
By investing in modernizing the drainage infrastructure and implementing better wastewater management practices, Paris is taking essential steps toward creating a cleaner and more sustainable urban environment for its citizens and visitors.
The success of this initiative will not only be felt during the Olympics but will leave a lasting legacy for the city, benefiting the community and the environment for years to come.
Comprehensive strategy for clean rivers
Over the past two decades, significant improvements have been made to reduce the number of fecal bacteria entering the River Seine in Paris.
However, achieving the official classification of “clean” has proven to be challenging, as there are still a few remaining percentage points to address, according to Samuel Colin-Canivez, the chief engineer for sanitation at Paris city hall.
To tackle this issue, a comprehensive solution has been implemented involving the construction of a vast underground reservoir.
Located near Austerlitz station and in front of the Pitié-Salpetrière hospital, where Princess Diana tragically passed away in a car crash in 1997, the construction site appears like a typical building project from the surface.
But underneath lies a massive cylindrical space, 34 meters (112 feet) deep and 50 meters wide, capable of storing runoff water during periods of heavy rainfall. This reservoir has an impressive capacity to hold water equivalent to that of 20 Olympic swimming pools.
By creating this underground reservoir, the city of Paris aims to manage the excess water during heavy rain events, which would otherwise overwhelm the outdated drainage system and lead to sewage and wastewater discharge into the river.
The reservoir will act as a buffer, providing a means to store and treat the excess water, thus preventing further pollution of the River Seine and helping in the final steps toward achieving the official “clean” classification.
The construction of such a reservoir demonstrates the city’s commitment to improving the water quality of the River Seine and ensuring a healthier environment for its residents and visitors.
With this innovative infrastructure in place, Paris is taking significant strides towards achieving its goal of making the river suitable for various recreational activities, including swimming and other aquatic sports.
Construction site for the underground reservoir
The construction site for the underground reservoir is a hub of activity, with machines diligently digging and scraping in the depths. An excavator equipped with a long telescopic arm extends from the surface to remove the excavated earth.
Samuel Colin-Canivez says, “Up to now the Seine has been the safety valve for the sewage system. If we didn’t occasionally allow wastewater into the river, it would have backed up into people’s homes.”
However, with the construction of the reservoir, this approach will change. Instead of discharging excess wastewater directly into the Seine, a tunnel will divert the overflow to the underground reservoir.
There, the water can be stored for a day or two, giving the system enough time to settle down. Subsequently, the stored water will be drained to the treatment centers, where it can undergo proper treatment before being released back into the environment.
Revitalization of River Seine
The mega basin, scheduled to be operational by next year’s Games in late July, will showcase the revitalized River Seine as a sporting venue and as the centerpiece for the Olympic opening ceremony.
During the ceremony, 160 boats will carry 10,000 athletes down a 6km (3.7 miles) stretch of the river, culminating at the iconic Eiffel Tower.
When Paris hosted the Olympics in 1900, seven events were held on the river Seine.
Now that sounds mad as since 1923, swimming in the capital's river has been banned due to sewage.🤢
But with a budget of €1.4B, the French are on a massive clean-up before the 2024 games.🙄😂 pic.twitter.com/PwsReb4LFx
— Mr Pål Christiansen 🇳🇴🇬🇧 (@TheNorskaPaul) July 17, 2023
While the River Seine is undergoing a remarkable transformation, one event that won’t be part of the Games or any longer exist in the river is angling. Interestingly, the first Paris Olympic Games in 1900 did feature a fishing competition, alongside other unconventional sports such as cannon-firing and hot-air ballooning.
Bill François, representing the Paris fishing federation, reminisces about the fishing competition, saying, “Back in 1900, they measured the fish they caught in the competition, and none was bigger than the size of your hand.”
“Today, we have between 30 and 35 species of fish in the city center, and we get catfish measuring 2m long. It has been a transformation.”
Fish populations have rebounded, and the Seine has also seen a resurgence of other aquatic life, including molluscs, insects, sponges, and crayfish.
Return of fish and humans to River Seine
Paul Kennouche, the head of water quality at Paris city hall, reassures that studies have shown that the amount of leptospirosis bacteria in the canal at La Villette, where swimming is already allowed, is not abnormally high.
He mentions that there have been no reported cases of leptospirosis there, despite it being a similar urban environment. The city will closely monitor the situation and take necessary measures to address the rat population to ensure public safety and a pleasant swimming experience.
Now, with the improvements in water quality and the completion of the mega basin, Mayor Anne Hidalgo has revealed three spots on the Seine that will be open for public bathing starting in the summer of 2025.
These locations are in central Paris near the Île Saint-Louis, and at the eastern and western ends of the city. The transformation of the River Seine is not just benefiting aquatic life, as humans are also returning to enjoy the revitalized river.