Prévision des températures de l'eau en rivières à l'aide d'un modèle conceptuel : le cas de la rivière Moisie

Abstract

Hydro-Québec is projecting to increase the hydroelectric production capacity of the St. Marguerite River by diversion of the tributaries Pékans and Carheil rivers of the Moisie River, the most productive salmon river of the whole Quebec. Along with substantial changes in hydrological regimes, this hydroelectric development is most likely to affect some physical environment factors such as the water temperature, which is of prime importance for the biotope and, in particular, for the salmon productivity. The objective of the present study is to simulate, over a long period of time, the river water temperatures under natural conditions as compare to those after the impoundment, to assess the consequences of the tributary diversion. We used the hydrological CEQUEAU model coupled with a temperature model.The temperature model developed is applicable to the ice-free period and calculates daily water temperatures in rivers by computing an energy budget to each element of the watershed. The energy budget considers the short-wave solar radiation, long-wave radiation, evaporation, and convection in the air as well as the advective heat of various inflows from surface runoff, interflow, and groundwaters. The estimation of the atmospheric thermal exchanges is based on the equations usually found in literature. The volumes of the various inflows are given by the hydrological model. The temperature model uses daily data for air temperature and monthly data for solar radiation, cloudiness, wind speed, and vapour pressure.The model has been applied to the Moisie River (Québec), using the measured values for the calibration. Both observed and calculated values show good agreement. The model was also used to simulate, over the whole watershed, the water temperatures for the 1961–1989 period and after the diversion. The results show that the tributary diversion contributed to increase the water temperature of the Moisie River and that this increase is gradually attenuated as we progress downstream. Key words: temperature, impacts, model, Moisie, Québec, diversion, hydrology.

The Influence of Air Temperature on Water Temperature and the Concentration of Dissolved Oxygen in Newfoundland Rivers

“…The deterministic models (Raphael, 1962;Morin et al, 1994;Taylor, 1998) are based on thermal budget calculations that take into consideration a wide range of heat inputs and outputs (e.g. solar radiation, convection from air, conduction from soil, and net long wave radiation from the local environment to the river system).…”

Predicting water temperatures using a deterministic model: Application on Miramichi River catchments (New Brunswick, Canada)

“…For example, deterministic models have been used to understand/ predict forestry impacts on temperatures due to deforestation or the removal of streamside vegetation (Brown, 1970). Deterministic models are also well adapted to study the impacts of flow reduction and/or flow alteration on the river thermal regime (Morin et al, 1994;Sinokrot and Gulliver, 2000). In recent years, climate change has been identified as an important source of aquatic disturbance on a large or global scale.…”

Predicting river water temperatures using the equilibrium temperature concept with application on Miramichi River catchments (New Brunswick, Canada)

“…For instance, deforestation has been identified as an important source of perturbation to the river thermal regime (Brown, 1970;Brown and Krygier, 1970;Holtby, 1988;Beschta et al, 1987;Johnson and Jones, 2000). Flow reduction and/or flow alteration can also be responsible for changes in river water temperature (Morse, 1972;Morin et al, 1994;Sinokrot and Gulliver, 2000). In recent years, climate change has been identified as an important source of aquatic disturbance on a large or global scale (Sinokrot et al, 1995).…”