SALTWATER INTRUSION IN THE BAIE DE RUPERT, JAMES BAY, CANADA

After commissioning the Rupert diversion-Eastmain-1-A and Sarcelle powerhouses, Hydro-Québec had validate the changes anticipated during Environmental Impact Assessment (EIA) covering salinity and water levels in the Baie de Rupert as well as the mouth of Pontax and Rupert rivers estuaries. The follow-up was carried out during winter and summer 2010 and 2013. Fixed instruments were put in place to continuously record salinity, current on the bottom and at the surface at four locations. Vertical profiles of temperature, salinity and current were also measured. Our results demonstrate that after diversion, limits of the freshwater-saltwater interface in open water moved about 3-5 km upstream, this change was predicted in the EIA. In the presence of ice cover, saltwater penetration is very limited and is similar to baseline conditions. In open water, levels in the Baie de Rupert were similar before and after diversion. There is no evidence of the Rupert diversion having any effect on water levels in the bay. At the mouth of the Rupert River estuary, we observed a mean lower water level of about 0.10 m to 0.15 m and about 0.30 m at low tide in comparison to the two baseline years. These results correspond to predictions made in the EIA.