Paris Olympic organisers are confident that improvements to the water quality of the River Seine will be sufficient for the open-water swimming competitions to take place there as scheduled in four months. The prefect of the Île-de-France capital region, Marc Guillaume, said on Wednesday that €1.4 billion ($1.5 billion) has already been spent on better water quality after complaints from swimmers in warm-up events over potential sewage in the river. Persistent heavy rainfall caused canals to overflow, resulting in waste water entering the river and a concentration of bacteria. Catch basins and…