Paris | Financial Times
Samuel ColinCanivez, chief engineer of the Paris water system, stood in a 100footdeep concrete cave as hundreds of construction workers rushed to complete the pharaonic project before next year’s Olympics.
Their mission: build a 700meterlong tunnel and a large storage tank to clean the Seine so athletes can compete in swimming and triathlon competitions.
“It’s been a marathon, but we’re in the home stretch,” ColinCanivez shouted over the noise of workers pounding hammers to install a final piece of barbed steel to reinforce the concrete beneath the tank floor. Construction began nearly four years ago and was scheduled to be completed this spring. The cost was 90 million euros (R473 million, at current prices).
Located between a 17thcentury hospital and the busy Austerlitz train station, the underground reservoir will have a capacity equivalent to 20 Olympicsized swimming pools and is designed to capture overflow from the French capital’s old sewage system during heavy rain.
“The goal is to prevent untreated water from entering the river,” ColinCanivez said.
Currently, the city’s underground sewage tunnels are overloaded about a dozen times a year, dumping wastewater into the river to prevent street flooding including dangerous E. coli bacteria found in toilet flushes.
The new storage tank is designed to help reduce such incidents to just twice a year by storing water during storms and releasing it gradually afterwards.
This is one of five engineering projects the Paris region is undertaking to clean up the Seine and Marne rivers so residents can swim in them again. New water treatment systems, pipes and pumps were also built.
Many local residents remain skeptical about swimming in the Seine, and there is no guarantee that the Olympic cleanup will be effective enough to reduce bacteria levels to levels safe for athletes.
Paris had to cancel several testing events this summer when laboratory monitoring tests showed there were too many E. coli in the Seine. The excessive pollution was caused by a period of heavy rain. The new tank is intended to help ensure that these natural phenomena do not damage the water.
But a second series of test events at the end of August were also canceled even though there had been little rain in the days before, leaving organizers irritated by the poor water quality. Further investigation revealed that a faulty valve had been left open, allowing wastewater to leak, and that an automatic monitoring system had failed.
“It was disappointing, but we are confident we can do it in time for the Games,” said Pierre Rabadan, deputy mayor of Paris in charge of sports.
If the water quality does not meet standards, the competitions could be postponed for a few days or a week, Rabadan said, to allow the water quality to improve but there is no plan B to hold the swimming competitions elsewhere.
That has increased pressure on ColinCanivez’s underground construction workers, as well as others working on other parts of the Seine redevelopment plan, such as trying to connect barges docked in the Seine to the sewage system.
Another challenge was convincing homeowners to make costly repairs to fix the approximately 20,000 homes and buildings in Paris and surrounding suburbs that are not properly connected to the sewage system.
“Anything we can do will help,” ColinCanivez said.
Swimming in the Seine was banned in 1923 because of pollution, but politicians have long promised to reintroduce it. Former President Jacques Chirac promised this when he was mayor of Paris in the 1990s, but failed. Heavy rains regularly brought streams of trash and plastic into the Seine, damaging Paris’s historic artery.
Paris Mayor Anne Hidalgo has called the Olympics a catalyst for the opening of 20 swimming spots by 2025 in the capital, where summers have become hotter due to global warming.
“Without the additional boost and budget from the Olympics, it would have taken us 20 years to clean up,” Rabadan said.
In addition to the swimming competitions, the Seine will take center stage at the Paris Games in a way that critics say could be overly ambitious and risky.
The plan to hold the opening ceremony on the river has raised safety concerns. Police and military authorities expressed concerns about the safety of a parade of around 150 boats with 10,000 athletes as well as the crowds of spectators on the riverbank.
Organizers dismiss those fears, arguing that the unique ceremony will showcase the beauty of the capital’s riverside buildings such as the Eiffel Tower, Notre Dame Cathedral and the Invalides.
Rabadan defended both the parade and the Sena’s cleanup efforts: “There is no Plan B as implementing Plan A will be complicated enough.”