The city of Longueuil will dump up to 150 million litres of raw sewage into the St. Lawrence River between Nov. 15 and Nov. 22.
In this case the untreated waste water will be dumped while the city is making repairs to its sewage system.
Opposition spokesperson Francis Dubreuil said the broken pipe lies at the bottom of the river between a South Shore pumping station and a water treatment plant on Ile Charron.
Government officials said this is the best time of year to dump sewage because fish are not spawning -- and because the rate of water flowing through the river remains high and unfrozen.
Booms and collector nets will be used to catch some debris.
Longueuil officials said crews will be working 24/7 during this discharge, and two teams will work simultaneously on the repair at times, including two divers.
The repair operation should be completed within six weeks, as they replace the conduit, which is 90 centimetres in diameter. Two sections of six metres will need to be replaced.
The sewage that will be released represents 7 per cent of all waste water treated by Longueuil.
Throughout the operation, officials will be monitoring the bacteria levels in the water to ensure there's no health risk.
“We will be doing thorough water quality tests at 20 sections of the river throughout the course of the work to make sure and monitor quality levels,” said Longueuil spokesperson Louis-Pascal Cyr.
Cyr said residents should stay away from the river during the sewage dump.
“We will be asking the population in that area not to have any contact with the river during those eight days. We will be sending out flyers to the residents living in the area plus posting up signs,” he said.
Sewage dumping extremely common in Canada
Three years ago the city of Montreal came under criticism for dumping 4.9 billion litres of sewage into the river while it repaired a collector system in four days.
The environmental effect was, however, determined to be minimal, limited to an area about 250 metres wide and 10 kilometres downstream.
Water tests showed that bacterial levels were back to normal just four days after the work was completed.
Fecal coliform tests in nearby Repentigny showed no change during and after the dump.
As gross as it might sound, Montreal's scheduled dump was barely a drop in the bucket compared to how much untreated wastewater is poured into waterways on a daily basis in Canada.
In 2017 alone, municipalities spilled, leaked, or dumped 215 billion litres of sewage into waterways; in 2013 towns in Quebec dumped raw sewage into the St. Lawrence on 45,000 separate occasions.
Throughout Canada more than one trillion litres of sewage was flushed into waterways over the past five years.
