Engineering Wonders of the World
Volume I

308 ENGINEERING WONDERS OF THE WORLD. the headworks of the Ontario and Canadian Niagara Power Companies. The general plan of development included at least two bold and original conceptions, both regarded at the time by the majority of engineers as impossible of execution. These were a wing dam, 785 feet long and 27 feet sunk in many places to a depth of 24 Arduous and hazardous though the wide, feet. work proved, but one life was lost during the operations. Now there extends into the river, 785 feet from the line of the power-house, a dam built of concrete and capped with cut granite, diverting to the penstocks an amount INTERIOR OF GENERATING STATION, ONTARIO POWER COMPANY, SHOWING SIX UNITS OF 10,000 HORSE-POWER EACH. TWO TURBINES TO A GENERATOR. in height, designed to gather the water from the Rapids into a fore-bay excavated in the river; and a tail-race tunnel, 3,160 feet long, including branches, excavated beneath the Rapids for the purpose of discharging “ dead ” water under the centre of the Horse-shoe Fall. Of all the many marvels of construction work to be found at Niagara, these, perhaps, are the most striking. To clear a place for the great gathering dam and wheel-pit, it was necessary to “ unwater ” twelve acres of the river-bed where the Rapids are deepest Wonderful an(j ^he greatest velocity. Engineering. . . To do this the engineers built a crib-work coffer-dam within which to carry on their operations. This dam was about 2,160 feet in length and from 20 to 46 feet of the river’s flow sufficient for the develop- ment of the maximum capacity of the plant. About 2,000 feet from the crest of the Falls there has been sunk into the solid rock an immense pit-shaft, 416 feet long, 150 feet deep, and 22 feet wide inside the brick lining, which is 2 feet thick. This pit is spanned at three levels by masonry arches carrying machinery, and at the bottom, resting on a heavy concrete foundation, are twenty-two Francis internal-discharge turbines, with wheels 5 feet 4 inches in diameter, each having a capacity of 13,000 horse-power. Eleven pen- stocks supply these turbines. Branching out from two sides of the wheel- pit are tunnels, 25 feet deep and from 66 to 30 feet wide, which eventually unite to form the “ tail-race.” This is a tunnel, the largest