Freshwater contents and heat budgets of James Bay and Hudson Bay

The freshwater and heat budgets of James Bay and Hudson Bay showed that for a yearly cycle the annual ice cover and runoff are major and equal components of the freshwater budgets. James Bay has a baywide freshwater layer thickness of 6.25 m, while Hudson Bay has a 4.7 m layer; these represent summer residence times of 10 months and 4.1 years, respectively.The heat budget results indicated that the incoming surface heat flux is mainly balanced by the heat required to melt the seasonal ice cover and bring the water temperature up to the observed summer values. Thus, an assessment of hydroelectric developments in the surrounding watersheds should not only investigate the changes that will occur in the marine environment, but also in the seasonal ice cover, as they together determine the oceanic climate pattern of the two bays.