The Niagara River

by Archer Butler Hulbert

With this general picture of these great power companies in mind, it is proper to survey some of the more interesting details of construction which may appeal to individual taste and curiosity. Space forbids entering into the minutia either of construction or machinery used. Only the main principles of interest to the general reader can be touched upon.

Let us descend first into the tunnel under the bed of the river, which discharges the tail water from the power-house of the Toronto Company, hurling it with almost inconceivable fury against the mass of foaming water plunging over the Horseshoe precipice. Here is a sight to thrill even the most jaded traveller hunting for new wonders. A trip through this underground passage which American genius has shot through a mass of solid shale and limestone, beneath the bed of the river, will in itself more than compensate for a trip to Niagara Falls. Some idea of the size of this tunnel is indicated by the fact that two lines of railways were maintained in it to dispose of the rock and shale excavated by the workmen. Clad in rubber coat and boots the visitor to the Falls may wend his way down along the visitors' gallery which is suspended from the roof of the tunnel, one hundred and fifty-eight feet below the river bed, to where the outrushing waters join the great volume of the river in its headlong plunge over Horseshoe Falls. Here standing behind that mighty veil of rushing water, with the spray swept into the opening by furious storms of howling winds, one beholds a spectacle, almost terrifying in its grandeur, the equal of which perhaps can not be found in any of the numerous attractions of the Falls.

American Falls from Below.

Before work on the main tunnel was begun, a shaft was sunk on the river bank just opposite the crest of Horseshoe Falls. From this shaft a tunnel was dug to the point where the lower end of the main tunnel would terminate. No difficulties were experienced in the driving of this opening until near the face of the cliff behind Horseshoe Falls. Here, with only fifteen feet to go, water began to rush into the cavern through a fissure in the rocks. The engineers fought against the water for several days but could not stop its flow. Finally eighteen holes were drilled into the cliff between the end of the tunnel and where the final opening was to be made; these holes were loaded with dynamite, which, together with a large charge placed against the end of the passage, was exploded, after the tunnel had been flooded. This only accomplished a part of what was desired. An opening was made in the cliff but too near the roof of the tunnel to allow of any work. What to do now was a difficult problem, but American daring accomplished the work. Volunteers were called for to crawl along the ledge of rock running along the cliff behind the Falls to where the opening had been made. Several men offered to make this almost impossible trip. Lashed together with cords, with the thunder of the Falls in their ears, blinded by spray which was driven into their faces with cyclonic fury, the men at last reached the opening and placed a heavy charge of dynamite against the opposing wall. This was discharged, making a sufficiently large opening for the water to run out, and the work was continued.

In the design of the main tunnel, ingenious provision was made for recession of the Falls. From the opening in the cliff for three hundred feet the lining will be put in in rings six feet long; this arrangement will allow a joint to drop out whenever the Falls recede so that it is exposed, thus leaving a smooth section always at the end of the tunnel. Through this main tunnel and through the branch races, the water, after having left the turbines, will whirl along at the rate of twenty-six feet per second, having generated a total of 125,000 electric horse-power. In engineering problems connected with the tunnel and the construction of the plant, the work of this company far surpasses that of any of the others. In order to secure a place for the wheel-pit and gathering dam, an area of about twelve acres in the bed of the river was converted into dry land. To do this a coffer dam was constructed 2153 feet in length and from twenty feet to forty-six feet wide in water varying in depth from seven feet to twenty-four feet, besides being very swift in most places. About two thousand feet above the Falls, in the space thus deprived of its water, an immense wheel-pit was sunk into the solid rock. On the bottom of this pit, 150 feet below the surface rest the monster turbines, from which two tail-races conduct the water to the main tunnel. A large gathering dam sufficient to supply the maximum capacity of this plant runs obliquely across the river for a distance of 750 feet. The height of this dam varies from ten to twenty-three feet; it is constructed of concrete, the top being protected by a course of cut granite. The power plant is located on the original shore line and parallel to it in Queen Victoria Park. In the power room are to be found eleven monster generators capable of developing 12,500 horse-power each.

A short distance farther up the river at the Dufferin Islands is the beginning of the mammoth steel conduits of the Ontario Power Company. These pass about a hundred yards from the shore and conduct the water to the power-house situated in the canyon below the Falls. This contrivance for water transmission consists of three steel pipes, the largest in the world, eighteen feet in diameter, and a little over six thousand feet long. This plant has the advantage of the others in several respects. While it draws its water from farther up the river, it preserves it for a longer time from the recession of the Falls, besides securing to it the greater amount of power per volume by obtaining the additional advantage of the descent of the rapids which amounts to about fifty-five feet. The power plant located as it is in the Gorge discharges its waste waters directly into the lower river without the necessity of an intervening tunnel. Lastly, the plan of applying the power to the turbines is slightly different in this case from the others, being made possible by its different plan. Here the turbines are placed vertical instead of horizontal, and are directly connected with the main generators, which are the only machines located on the floor of the station.

A departure from the ordinary construction of the dynamo is noticed in those for use at Niagara. The ordinary one is built with the field-magnets so placed that the armature revolves between them, the field-magnets being stationary. In these monster dynamos, developing thousands of horse-power, and weighing many tons, the field-magnets revolve around the armature which remains stationary. With such an enormous weight of swiftly revolving parts, it became necessary to lessen the immense centrifugal force tending to tear the machine to pieces. Engineering skill surmounted this problem as it did all others in what might be called this mighty scientific drama, and, by reversing the parts of the dynamo, secured the desired result. The field-magnets, being placed on the outside and being made the revolving part, by their mutual attraction for its armature within their ring are pulled, as it were, toward the centre, thus lessening the great strain produced by the centrifugal force upon the large steel ring upon whose inner circumference they are mounted.

The currents furnished by the power-houses at Niagara are all alternating. This kind of current being decided upon for various reasons. It can be used for driving dynamos as well as any, and as nearly all the power developed at the Falls is used in this way no provision is made for a direct current. Where a direct current is desired the electricity is made to drive a dynamo of the alternating type which in turn is made to drive another of the kind of current desired. Establishments on or near the grounds use the power furnished them direct from the power-house. When the power must be transmitted to a distance, it becomes necessary to use a step-up transformer for the purpose of losing as little power as necessary in the transmission, this to produce a higher voltage. When the current reaches those places where it is to be used a low voltage is again obtained by the step-down transformer.