The impact of reservoirs on the water temperature of the Tobique River, Canada In Eastern Canada, water temperature is a crucial variable in lotic ecosystems due to the presence of cold-water species such as Atlantic salmon and Brook trout and the economic importance of these species. Impoundment of rivers to regulate flow and generate electricity can alter the thermal regime in river reaches downstream of dams. This research investigates the impact of the reservoirs on the temperature of the Tobique River located in New Brunswick, Canada. In this regard, CEQUEAU, a hydrological and water temperature model, was used to simulate the flow and water temperature of the Tobique River. First, the simulation was carried out without considering the effect of the reservoirs on the river. The Root Mean Square Error (RMSE) of 2.3°C for water temperature was obtained, and the simulated water temperatures in winter were lower than the observed temperatures. In the second simulation, reservoir water temperatures were imposed as a boundary condition. The RMSE decreased to 1.61°C, and winter temperatures were closer to the observed ones, which confirms the impact of the reservoirs on the water temperature. A statistical model that uses air temperature as a predictor was used to generate water temperature at different depths in the reservoir. Initial results show good agreement between observed reservoir temperatures and those simulated by the statistical model. This statistical model will be coupled to CEQUEAU to investigate the impact of drawing reservoir water at different depths on the downstream temperatures.
