NIAGARA RIVER flows in a northerly direction from Lake Erie to Lake Ontario, a distance of about 34 miles. It constitutes part of the boundary between the United States and Canada, separating the State of New York from the Province of Ontario. It is the principal drainage outlet of the four upper Great Lakes, whose aggregate basin area is about 248,500 sq. miles. Its dis charges at standard low water and standard high water of Lake Erie (57o and 575.11 ft. above mean tide at New York) are about 153,000 and 267,000 second-feet, respectively. The river is navi gable from its source to the upper rapids, 20 m., and from Lewis ton to the mouth, 7 miles. The current is rapid for the upper navi gable portion, where the average fall is about o.5 ft. per mile. The total fall of the lower 7 m. is 0.5 foot. The intermediate sec tion of the river, consisting of 7 m., includes a series of rapids and Niagara Falls, and has a total fall of 315 feet. The average width is about 3,500 feet.
The falls of Niagara are justly celebrated for their grandeur and beauty, and are viewed every year by over 2,000,000 visitors. They are in two principal parts, separated by an island. The greater division, adjoining the left bank, is called the Horseshoe Fall; its height is 155 ft., and the length of its curving crest line is about 2,600 feet. The American Fall, adjoining the right bank, is 165 ft. high and about 1,400 ft. broad. The water is free from sediment, and its clearness contributes to the beauty of the cataract. In recognition of the importance of the waterfall as a great natural spectacle, the Province of Ontario and the State of New York have retained or acquired title to the adjacent lands and converted them into parks, which are main tained at public expense for the convenience of visitors.
The scenic grandeur of Niagara Falls depends upon the volume of water flowing over the falls, but also on its distribution as it approaches the crest. The statement that the Horseshoe Fall is in danger of destroying itself as a spectacle by cutting a narrow "notch," destroying the symmetry of the horseshoe, possibly degenerating into a cascade and eventually draining the American Falls, has unfortunately been widely circulated. The mean annual rate of recession of the crest at the central part of the Horseshoe has been determined as being about 5 ft. since 1764, 3.7 ft. since 1842 and 2.3 ft. per year since 1906. The Horseshoe is now cutting back at a decreasing rate and the rate will continue to decrease. The recession of the American Falls is negligible. By proper action, supervision and control by the two Governments con cerned, the scenic beauty of the Falls can be preserved, the tendency toward erosion in the Horseshoe can be checked, water can be distributed over the at present bared flanks of the Canadian Fall and a more dependable flow over the American Fall ensured.
The problem of the river's age is of much interest to geologists, because its solution would aid in establishing a relation between the periods and ages of geologic time and the centuries of human chronology. The great Canadian glacier, which in the glacial period alternately crowded forward over the Great Lakes region and melted back again, so modified the face of the land by erosion and by the deposit of drift that the waters afterwards had to find new courses. The Niagara river came into
existence when the waning of the glacier laid bare the western part of the Ontario basin, and the making of the gorge was then begun. If it were supposable that the lengthening of the gorge proceeded at a uniform rate, the computation of the time would be easy, but there are various modifying conditions. A weighing of the evidence now available indicates 25,00o years as a lower limit for plausible estimates of the age of the river, but yields no suggestion of an upper limit.
Between Lake Erie and Lake Ontario, naviga tion passes through the Canadian Welland canal. The old canal had 25 lift locks, with a total lift of
feet. These locks were each 27o ft. long (usable length about 255 ft.) by 45 ft. wide, and were designed to have 14 feet depth on the sills. A new canal, constructed by the Dominion of Canada and opened to navigation. on April 20, 1931, was formally opened, August 6, 1932. Calcu lated to admit the largest existing lake freighters, its southern portion is for the most part an enlargement of the old canal. The northern portion follows a new course, entering Lake Ontario at Port Weller, about three miles east of the terminus of the old canal. The new canal is twenty-five miles long and has a total lockage of 3251 feet. It has four single locks, one flight of three double locks and one guard lock. The locks have a usable length of 82o feet, a clear width of 8o feet, and 3o feet depth of water on the sill at lowest lake stages. All locks have a lift of about 46 feet. The gates are of the mitering type. The prism is 200 feet wide at the bottom, 310 feet wide at the water line, and from 25 to 261 feet deep at low water. All masonry structures are so designed as to allow an ultimate deepening to 3o feet at low water. The construction of this canal was commenced in 1913, it was largely suspended during the World War but was later re sumed.
By treaty stipulation the amount of water that may be diverted from the Niagara river for power purposes has been limited to 36,000 cu.ft. per second on the Canadian side and 20,000 cu.ft. per second on the United States side. Of the Canadian diversion all but about Io,000 cu.ft. per second is used by the Hydroelectric Power Com mission of Ontario, in three plants, the largest of which, near Queenstown, has a gross head of over 30o ft. and develops about 450,000 h.p. from the nine turbo-generators installed. Of the American diversion practically all the water is utilized by one concern with an installation of 56o,000 horsepower. Three of the units of the latter company are rated at 70,000 h.p. each and are the largest hydro-electric units in existence. At all the plants electricity is generated at I i,000 volts, 25 cycles. Much is used in nearby electrochemical industries for the manufacture of aluminium, ferro-silicon, carborundum, artificial graphite, liquid chlorine, calcium carbide, cyanamide and other products. The remainder is transmitted to various cities for miscellaneous uses. The maximum distance to which this power is transmitted is somewhat in excess of 200 miles. (E. JA.)
see AZANDE.