PRESS RELEASE
SOURCE: FONDATION RIVIÈRES
Montréal, November 19th, 2024
Fondation Rivières publishes the ranking of municipalities based on the intensity of their untreated wastewater discharges into lakes and rivers in Quebec. There were 44,765 wastewater discharges into lakes and rivers in 2023, a decrease of nearly 8,400 compared to the previous year. However, this masks the fact that the intensity of discharges has increased by 25% between the two years. While the number of discharges is lower, they last longer and occur more frequently during the summer, when their impact is greatest.
The measurement of discharge intensity, which takes into account both the duration and the size of the overflow structures, highlights the impact of the heavy rains of the summer of 2023 on wastewater discharges. For example, in Montérégie, the summer 2023 rainfall is comparable to that of 2020 in terms of average precipitation (312 and 316 mm) and the number of discharges (4,369 and 4,171). However, in reality, the intensity of discharges increased by 41% between these two summers.
This analysis highlights the limitations of the frequency of discharges, the indicator used by the Ministry of the Environment to set specific discharge targets for each overflow structure in Quebec. No overall target is proposed by the Ministry of the Environment.
"The number of discharges does not allow us to capture the impact on aquatic life and the recovery of watercourse uses during the summer. In Beloeil, for example, the water quality at the whitewater pool took several days to recover after the Debby storm due to the major overflows that occurred upstream along the Richelieu River. We need an indicator that reflects the intensity and impact of discharges on the health of rivers, and we are asking the Ministry of the Environment to develop and make it available quickly."
Having a better indicator that reflects the impact of wastewater discharges on the natural environment and its uses (drinking water intake, water activities, swimming) will help prioritize interventions in municipalities for the allocation of funding for infrastructure upgrades. These upgrades must be accompanied by efforts to enforce municipal regulations on connections to pipelines (gutters, drainage, etc.), demineralize our cities, and implement green infrastructure, which will be particularly important during heavy summer rainfall, which is becoming increasingly frequent with climate change, as today's study by Fondation Rivières, backed by data, reveals.
"To achieve concrete results quickly, we need to implement planning at the watershed scale with support for municipalities and regional county municipalities (MRCs). We could draw inspiration from the regional project offices set up by the Ministry of Municipal Affairs for flood adaptation, where ministerial stakeholders align to facilitate decision-making and project monitoring," says André Bélanger.
Montérégie still at the top of the 2023 rankings
Montérégie remains the region with the poorest performance in Quebec in terms of wastewater discharges. The situation for all cities worsened in 2023, particularly for those served by the Régie d’assainissement des eaux usées de la Vallée du Richelieu (McMasterville, Beloeil, Otterburn Park, Mont-Saint-Hilaire) and those in the Longueuil agglomeration (Longueuil, Boucherville, Brossard, Saint-Lambert). Others, like Verchères, Acton Vale, and Beauharnois, were better able to absorb the impact of the heavy rains of the summer of 2023. The mild winter also led to more discharges than usual.
Elsewhere in Quebec, a few cities have improved, including Chibougamau, Mont-Tremblant, and Mascouche.
Diversions: discharges that go under the radar.
The 2023 rankings from the Fondation Rivières also highlight the high use of diversions by several cities, including L'Île-Perrot (545), Lévis (230), and Laval (251). A diversion involves redirecting some wastewater from treatment plants when their capacity is reached. Although these discharges may be partially treated, they represent significant volumes of wastewater and have a harmful impact on the environment.
In Laval, wastewater diverted from the Fabreville treatment plant ends up in the Auteuil drinking water intake, and the impact is much greater than all the wastewater overflows along the 10 km separating the two plants. We highlighted this specific issue in the rankings table.
About the Spill Intensity Index
The rankings are based on data from the MELCCFP available since 2017. The intensity index, developed by the Fondation Rivières, takes into account the duration of discharges and the size of the overflow structure. The per capita discharge index allows for comparisons of discharges relative to the population.
The data from 2017 to 2023 has been adjusted to align with the methodology used by the Ministry of the Environment, which excludes discharges lasting less than 13 minutes. The exclusion of these very short discharges has a negligible impact on the intensity calculation (0.02%).
Sewage discharges affect aquatic species and, more broadly, biodiversity. They harm aquatic species by exposing them to a range of contaminants and depriving them of oxygen. These discharges can impact water quality at drinking water intake points and complicate the treatment and disinfection processes required to eliminate harmful elements for health. Sewage discharges also limit the availability of swimming sites and hinder water-based activities.
About the Fondation Rivières
For over 20 years, the Fondation Rivières has worked to preserve, restore, and enhance the natural character of rivers. It contributes to ensuring water quality and access to water for the people of Quebec, taking into account social, environmental, and economic factors.
Check out the 2023 ranking: https://bit.ly/4eDTWq7
Interactive map : https://bit.ly/4fsiGTD
Evolution 2017-2023 : https://bit.ly/4hQLG9n
FAQ palmares : https://bit.ly/4fxXY4X
For further information:
Samuel Sauvageau-Audet
Digital Communications Officer
Fondation Rivières
514 272-2666, ext. 306
