Olympic organisers are confident The Seine will be cleaned up in time for the Paris Olympics. GETTY IMAGES

Despite recent heavy rains, swimming in the River Seine is still the plan at the Paris Olympics after a $1.5 billion (€1.3 billion) investment to improve the water quality, according to a report Thursday by the Associated Press. Marathon swimmers and triathletes are scheduled to plunge into the cleaned-up waters after the Olympics open in July.

Heavy rains that overwhelmed old sewers in Paris have already prevented several test events for the Olympics from taking place last August and Olympic organisers also have not been lucky with the weather so far this summer. Just last week an open water swimming test event was cancelled due to heavy rainfall with officials saying it could lead to increased pollution in the Seine with Paris' overwhelmed sewerage system — despite recently inaugurating a huge reservoir next to Austerlitz train station to collect excess rainwater and prevent bacteria-laden waste from entering the river.

The huge new structure —buried 30 metres underground next to a railway station— is a key part of efforts to clean up the River Seine. The rainwater facility is due to be operational this month after being opened in May and will store rainwater in the event of heavy downpours, reducing the chances of pathogen-laden contents from being discharged directly into the Seine.

"Downpours have complicated the issue", International Olympic Committee executive Christophe Dubi said Thursday at an online briefing after hearing from city officials and Summer Games organisers.

"No reasons to doubt… We are confident that we will swim in the Seine this summer," he added.

Swimming in The Seine has long been the dream of Parisians. As far back as the 90s, the idea has been proposed by former French president Jacques Chirac and now the city’s current mayor, Anne Hidalgo, carries on the dream. Hidalgo has expressed her confidence that the river's water quality will be up to Olympic standards by this summer and that she too will prove it by swimming there, possibly joining French President Emmanuel Macron, who has repeatedly promised to take an Olympic swim in the Seine.