Author(s): Octave Caron; Pierre Dupuis; Pierre Pelletier
Linked Author(s): Pierre Dupuis
Keywords: No Keywords
Abstract: The La Grande hydroelectric complex is located on the east side of James Bay, in Quebec. The LG2 reservoir and LG2 and LG2A powerhouses are part of this complex. When LG2A will be commissioned in November of 1992, the two powerhouses will have an installed capacity of 7 326 MW and will withdraw up to 5,950 m3/s During winter, discharge of this magnitude from the reservoir produces an appreciable influx of heat downstream of the site, which affects the thermal regime and thus has an impact on the hydraulic and ice regimes of La Grande Riviere downstream. Winter observations of both reservoir and river prove valuable in evaluating the hydraulic parameters controlling the nature of the ice cover and its stability. In order to better quantify the thermal regime evolution of the system, the Hydraulic department of la Societe d'energie de la Baie James installed electronic thermometers in the reservoir and in the river downstream of the powerhouses. Temperatures are measured by thermometers hourly, over a depth of 90 m, from the surface with strings of 11 thermistors attached and hanging from a buoy in the reservoir. They permit evaluation of the vertical distribution of temperature with resolution of less than 0.01C and accuracy of 0.05°C. Punctual measurements were taken at 20 sites in the winter of 1992, and covered much of the reservoir in less than a week to get a spatial image of the temperature field. This paper presents a brief review of the instrumentation and logistics required for their deployment, data acquired by electronic thermometers and analysis, with emphasis on the vertical thermal profile of the reservoir. Analysis is performed on time series and spatially distributed profiles to establish the reservoir thermal response during winter.
Year: 1992