River Seine closed to swimmers one day after historic opening

Telegraph

a day ago

Parts of the River Seine have been closed to swimmers less than 24 hours after its historic reopening because of heavy rain.
Three areas of the river that run through the capital were opened to excited Parisians on Saturday after a £1.2 billion clean-up operation.
The zones, within view of the Eiffel Tower and the bras-Marie on the right bank of the île Saint-Louis, were set to be open every day from July 5 to Aug 31 2025, 'as long as safety conditions are met: moderate current, water quality'.
But red flags at all three designated zones on Sunday indicated the Seine was temporarily off-limits because of water quality concerns caused by wet weather.
On rainy days, the mid-19th-century Parisian sewage system often overflows, causing rain and waste water to pour into the river.
Authorities built a vast run-off reservoir, which can hold 20 Olympic swimming pools' worth of water, in order to prevent this problem.
The river is also assessed 'every 15 minutes' for the presence of faecal bacteria E. coli and enterococci.
Eve Plenel, the head of public health Paris City Hall, told The Telegraph: 'The water goes through a circuit…and if it is not swimmable, we will not open it for the day or until it gets better. So it's impossible to open the swim station without being sure the water is absolutely clear and OK and no risk for public health.'
When asked whether that would happen often, she said: 'It obviously depends on the weather.'
'If it rains a lot or there is any localised pollution anywhere on the Seine then it can affect quality, of course that can happen. It's just like any beach in the summer. Sometimes beaches are polluted or closed and this is exactly the same.'
Paris banned swimming in the Seine in 1923 due to pollution.
Jacques Chirac, the then mayor and future president, promised to clean it up in 1988 within six years but it took far longer than expected.