Water Regime Characterization – Opaskwayak Cree Nation

DAL Projects was contracted by Opaskwayak Cree Nation (OCN) to provide hydrotechnical engineering services associated with water flows and levels on the Saskatchewan River and investigate the influence of the downstream Grand Rapids generating station on the water regime within their traditional territory.

Between 1960 and 1968, Manitoba Hydro constructed the Grand Rapids generating station on the Saskatchewan River at Cedar Lake approximately 80 km downstream of The Pas. This generating station utilizes Cedar Lake as a reservoir to store water for hydro electric generation. DAL Projects performed hydrologic and hydraulic analyses of Saskatchewan River flows and water levels to establish the effect that Grand Rapids regulation has on the Saskatchewan River within the OCN traditional territory.

Upon completion of the study, DAL Projects found that the water regime between The Pas and Cedar Lake has experienced significant changes since construction of the Grand Rapids generating station. It was found that a backwater condition existed along the reach during low flow events coupled with high Cedar Lake water levels. The increased water levels along this reach due to a backwater, results in lower velocities and sedimentation, which ultimately affects the eco-system and navigation.

This assessment, completed by DAL Projects, ultimately  led to an agreement between Manitoba Hydro and OCN for the ongoing operation of the Grand Rapids Generating Station.