Bas-Saint-Laurent

False. Témiscouata dam is used to supply water to NB Power, which, thanks to this input, can offer green energy to its population. NB Power is therefore constantly informed of any maneuvers that Hydro-Québec is required to carry out and adjusts its management accordingly. The Rivière Madawaska is also affected by the presence of several rapids. These rapids prevent the water from simply flowing back up to Québec.

True. However, doing so would deprive the residents of Témiscouata-sur-le-Lac of drinking water. The minimum lake level threshold has been set to protect the municipality’s drinking water supply. A lower threshold would entail the risk of frost forming in water intakes. Moreover, the volume of flooding is not known in advance. If the lake level were lowered further before the flood, it might not reach a high enough level during the summer in the event of very low flows.

True. Small numbers of zebra mussels were first observed on the dam in October 2022.

As this species proliferates very quickly and clings to surfaces, it could interfere with visual inspections to ensure the safety of the installation and with maneuvers. For this reason, we remove shellfish by hand.

In addition, employees are trained in the rigorous cleaning and drying of boats and nautical equipment to prevent contamination of other bodies of water. These activities take place in our warehouses. A training capsule has been produced in Témiscouata.

False. Lakes are a collective wealth. Several ministries and organizations have specific responsibilities for the management of watercourses, water bodies and their banks (municipalities, Ministère de l’environnement, etc.).

Hydro-Québec is responsible for managing the dam. Its mandate is to ensure the safety of the facility and, in this case, compliance with the agreements it has with NB Power and the community.

It fulfills this responsibility by constantly monitoring water levels, using measuring tools installed on the dam as well as in the reservoir and the Rivière Madawaska. It also keeps a close eye on the weather, using data collected at several weather stations located in and around the Lac Témiscouata watershed. These data, combined with field observations and weather forecasts, enable us to make the best decisions on the maneuvers to be carried out at the dam.

In emergency situations, Hydro-Québec shares this information with partners who have civil protection responsibilities, so that they can adopt the appropriate measures to ensure public safety.

As manager of the structure, it also carries out the necessary maintenance work.

False. Bank erosion is a natural, extremely complex phenomenon that affects all watercourses. The intensity of weather events causing waves and rapid variations in water levels, the presence or absence of vegetation on the banks, the formation or absence of ice cover, artificial modifications to the banks and the very nature of the soil are just some of the many factors that can influence the intensity of bank erosion. Each case is different. In most cases, erosion is caused by a combination of factors, and it is difficult to pinpoint one predominant reason.

False. Despite the presence of dams, Mistigougèche and Mitis lakes cannot absorb all the water that flows in from the watershed during flooding. However, the water flowing into the Mitis downstream of these structures represents only about 25% of the volume of water coming from the river’s many tributaries, and 75% of the volume of water passing through the municipality of Sainte-Angèle-de-Mérici comes from the Rivière Neigette and other tributaries, over which Hydro-Québec has no dam.

The intensity of the spring runoff depends entirely on weather conditions. Flooding is less severe if the snowpack melts gently and rain is scarce. On the other hand, warm, rainy springs accelerate snowmelt and increase flood-related risks.

When the spring runoff starts, Hydro-Québec closes the gates of its facilities to minimize the volume of water released into the Mitis, which in turn limits the impacts of the runoff. The amount of water released into the river only increases again after the runoff has slowed and flood risks for neighboring communities have declined.

False. Although these power plants no longer generate energy, Hydro-Québec ensures the safety of both the public and the facility, as well as compliance with the Environmental Quality Act, on a daily basis.

It fulfils these responsibilities by constantly monitoring water levels, using measuring devices installed in the watershed. It also keeps a close eye on the weather, using data collected by several weather stations. These data, combined with field observations and weather forecasts, enable us to make the best decisions on the maneuvers to be carried out at the dam.