Hydro Quebec – lowering of levels above our dams

Bulletins posted on 2020-03-27 by Hydro Quebec

Starting this week, Hydro Quebec will progressively lower forebay (area just upstream of dams) levels at its run-of-the-river facilities on the Gatineau and Ottawa rivers. This operation is done every spring before expected flow increases as freshet begins.

Upstream impact: By lowering the water level upstream of its run-of-the-river facilities, Hydro Quebec allows the river to flow naturally during freshet, without being influenced by its forebay level. As flows increase during spring, water levels along the river will rise accordingly, except for the reach located near the dam, where the water level could appear abnormally low due to the lowered forebay.

Downstream impact: A slight flow increase will be held for a short period while the forebay level is lowered before freshet. This controlled flow change is imperceptible and will not cause any flooding. Once the targeted level in the forebay is reached, flows discharged through the facility will be equal to river flows entering the forebay area.

The forebay levels will be lowered at the following dams:
Paugan, Chelsea, Bryson et Carillon