Power from Labrador: the Churchill Falls development

The Labrador Plateau of northeastern Canada, which is more than 460 meters above sea level, forms a shallow ``saucer´´Â¿with a few chips missing in the rim. Thus some water escapes through these low points to other streams; but most of the drainage is through the Churchill River, whose most dramatic feature is the 75-meter-high Churchill Falls. Long reaches of rapids precede and follow the falls so that the river drops more than 300 meters over a course of 30 km through a deep cut in the edge of the plateau. By means of man-made diversions, the water that would normally cascade over the rapids and falls will be retained on the plateau and directed into a new channel leading to the forebay intake of the power plant. The dents in the saucer will be ``plugged´´ by 64 km of low dikes. The impounded water will back up to fill a reservoir area that will be about 40 percent of the area of Lake Ontario. At a newly constructed outlet, the water will funnel down 11 penstocks to a huge underground powerhouse, through 11 turbines, each driving a generator; thence it will flow into a surge chamber, follow two tailrace tunnels, and emerge finally into the Lower Churchill River. An unusual feature of the huge powerhouse complex will be a central computer capable of monitoring hundreds of plant functions. Under normal circumstances, two operators in the central control room will be sufficient for station operation.