Outaouais

Reality: The emptying of the Baskatong reservoir begins in December each year in anticipation of spring flooding. After the few months it takes to empty it, the reservoir is at its minimum level. Reservoir level data during the past 34 years are available to the public. Hydro-Québec has no financial interest in keeping water in its reservoirs in spring, since energy demand in Québec, Canada and the United States is at its lowest at this time of year.

Reality: Bryson, Paugan, Chelsea and Rapides-Farmer are run-of-river generating stations, which means they do not have reservoirs to retain water. If we tried to use these stations to retain water, the water would overflow within a few hours and escape around the sides of the structure. This would damage the generating station and would not reduce the impacts of spring runoff in any way.

Reality: Hydro-Québec cannot hold back water at Carillon, because it is a run-of-river generating station, which means it does not have a reservoir to retain water from spring flooding. During periods of high water, the generating station’s spillway allows surplus water to pass through without being fed to the turbines. If the spillway gates were closed at the peak of spring flooding, the water would spill over the facility within a few hours!

Reality: Unfortunately, floods cannot be entirely avoided when water inflows are very high, since the reservoirs only drain 40% of the Rivière des Outaouais watershed and have limited capacity. The main way to limit the impact of spring runoff is to make as much room as possible in the reservoir (emptying) before the flooding begins and to let water accumulate in it during runoff. This is what Hydro-Québec does. This means the flow leaving the reservoir will be as low as possible when the water level in the river downstream is highest. This management approach is the best way to reduce the magnitude of spring flooding. It should also be noted that the management of Baskatong reservoir is directly linked to the amount of water received and the time of year when the water arrives.

Reality: On the contrary, Hydro-Québec reservoirs reduce the impact of flooding. In winter, the reservoirs are emptied so they can retain large amounts of water come spring. Without these facilities, spring floodwater levels would be much higher.