 The southern part of the river's shores, near the estuary, was the site of the construction of industries during the 1960s (who used it as an open sewer) and that was girdled in concrete in the 1970s in order to regulate its flow.At this time, the river was among the most polluted (in great part due to the city's sewage system overflow) in Québec by its microbian pollution and its recreational use near the estuary was impossible.Since the mid-1990s, community and governmental efforts allowed an important renaturalisation project to take place, for over 100 million Canadian dollars.