Niagara Falls

Niagara Falls, great waterfall, east central North America, on the Niagara River, in western New York and south-eastern Ontario. One of the world's most scenic sights, it consists of two cataracts: the Canadian, or Horseshoe, Falls (49 m/161 ft high), on the Canadian side of the river, and the American Falls (51 m/167 ft high), on the United States side. The waterfalls are separated by Goat Island, New York. The crestline of the crescent-shaped Canadian Falls, which carries about nine times more water than the US cataract, is about 790 m (2,592 ft) long, and the fairly straight crest of the narrower and slightly steeper American Falls measures about 305 m (1,001 ft). A small section of the American Falls near Goat Island is also known as Bridal Veil Falls.

Niagara Falls is a great tourist attraction, luring millions of visitors each year. The falls may be viewed from parks located on either side of the river, from observation towers, from boats, from Goat Island, and from the Rainbow Bridge, located a short distance downstream. The bridge connects the town of Niagara Falls in Canada with the town of the same name in the United States. Visitors may also enter the Cave of the Winds, a natural cavern situated behind a curtain of falling water near the base of the American Falls.

Samuel de Champlain, a French explorer, probably visited Niagara Falls in 1613. Father Louis Hennepin, a Flemish (see Flanders) monk, is known to have visited the waterfall in 1678; he later published an eyewitness description of it.

Niagara Falls was formed about 12,000 years ago, when glaciers retreated north, allowing water from Lake Erie to flow over the Niagara Escarpment, a ridge that extends from southern Ontario to Rochester, New York. Since that time, erosion has slowly pushed the waterfall about 11 km (7 mi) upstream, forming the Niagara Gorge. At present the Canadian Falls is receding at an average yearly rate of about 1.5 m (5 ft), and the American Falls is being cut away at an annual pace of about 15 cm (6 in). The Canadian Falls erodes at a faster rate mainly because it carries more water.

In 1954 a considerable portion of the American Falls broke off, creating a large talus, or rock slope, at the base of the cataract. In order to study ways of preventing further rockfalls and to remove some of the talus, the American Falls was successfully “shut off” for several months in 1969 by a dam that was constructed between the US mainland and Goat Island.

The Niagara's large volume of flow, averaging about 5.5 million litres (1.2 million gallons) per second, plus its steep drop, give the river great power potential. The water-power was probably tapped first in 1757, when Daniel Chabert Joncaire built a sawmill on the upper river. In 1853 work started on a hydraulic canal to divert the waters of the upper river to drive machinery in mills and factories situated below Niagara Falls. In 1875 the first flour mill powered by the canal water was opened, and in 1881 the first hydroelectric generator was installed along the waterway. The first large-scale hydroelectric facility, the Edward Dean Adams Power Plant, was opened on the US side in 1896.

In 1950 the United States and Canada signed a treaty fixing the amount of water that could be diverted from the river for power generation, and soon thereafter two major hydroelectric projects were constructed. The Canadians built the twin Sir Adam Beck-Niagara generating stations (completed 1958; capacity, with associated pumped-storage facility, 1,815,000 kW) at Queenston, Ontario. The Power Authority of the State of New York constructed the Robert Moses-Niagara Power Plant (completed 1963; capacity, with associated pumped-storage facility, 2,400,000 kW) near Lewiston, New York. Both projects, each located about 6 km (4 mi) below Niagara Falls, are driven by water diverted just above the falls and conveyed by underground conduits and canals to turbines. Much of the hydroelectricity is consumed by industries in the nearby cities of Niagara Falls, New York, and Niagara Falls, Ontario.