Author(s): C. H. Atkinson; T. W. Waters
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Keywords: No Keywords
Abstract: The reservoirs for the Churchill Falls project are located on the Labrador plateau, Canada at an elevation of approximately 470 m. At this latitude, approximately 54 degrees north, winters are severe with minimum temperatures ranging as low as -50 degrees C. Natural lakes are normally ice-covered from November to mid-June with ice thicknesses reaching a maximum of about 1 m. The Churchill Falls project is a 5,225-MW hydroelectric development which reached completion in 1975. The average annual flow is approximately 1,370 m3/s of which 98 percent is used for power generation. The project involves the creation of a vast reservoir (the Smallwood reservoir on the central Labrador plateau) to control and regulate the flow in the Churchill River for power production. This reservoir has a live storage volume of 28 x 10^9 m3 and receives runoff from an area of 45,200 km2. The Ossokmanuan reservoir controlling a drainage area of 22,400 km2 is a secondary reservoir of 2.8 x 10^9 m3 capacity which also forms part of the system. The conceptual design of the development required extensive field investigations of the natural ice conditions in the river and lake systems to derive criteria for the conception of a scheme which would allow an uninterrupted winter flow of up to 2,000 m3/s instead of the natural winter flow of 200 m3/s. Reliability of winter flow is essential because electrical demand peaks in winter. A description of the design procedure at a critical structure is presented in the paper together with results from operation and discussion of the comparison between the design expectations and the actual situation.
Year: 1978