Waterfall (redirected from Plunge waterfall)

waterfall, a sudden unsupported drop in a stream. It is formed when the stream course is interrupted as when a stream passes over a layer of harder rock—often igneous—to an area of softer and therefore more easily eroded rock; the edge of a cliff or plateau; or the edge of a hanging valley formed under glacial conditions (see glacial periods). Normally, as a stream grows older, the waterfall, by undercutting and erosion of the waterfall edge and stream bed above the fall, moves upstream and loses height until it eventually becomes a series of rapids and finally disappears. Waterfalls are often a source of waterpower for cities such as the string of cities in the United States that grew up along the waterfall line where streams from the Appalachians descend suddenly to the coastal plain and early textile and flour mills used power from waterfalls. Angel Falls in Venezuela is the world's highest waterfall.

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waterfall

Area where flowing river water drops abruptly and nearly vertically. A waterfall may also be termed a falls, or, when large volumes of water are involved, a cataract. Waterfalls of small height and less steepness or a series of small falls are called cascades. Still gentler stretches of river that exhibit turbulent flow and white water are called rapids.

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waterfall

a cascade of falling water where there is a vertical or almost vertical step in a river

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waterfall [′wȯd·ər‚fȯl]

(hydrology)

A perpendicular or nearly perpendicular descent of water in a stream.

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Waterfall 

the falling of water in a river in places where its height changes abruptly, forming an almost sheer drop. When a river flows through an area composed alternately of solid and loose rock, it cuts into the erodable rock much

Table 1. The largest and best known waterfalls in the world
Name	Location	Height(in m)
Eurasia
Utigard...............	Norway	610
Kile...............	Norway	561
Gavarnie...............	Gave de Pau River, central Pyrenees, France	422
Krimml...............	Krimml-Ache River, Austria	380
Serio...............	Serio River (Po basin), Italy	315
Gisbach...............	Gisbach River, Switzerland	300
Il’ia Muromets...............	Iturup Lake (Kuril Islands), USSR	141
Imatra...............	Vuoksi River, Finland	18
Africa
Tugela...............	Tugela River, Union of South Africa	933
Kalambo...............	Kalambo River, border of Tanzania and Zambia	427
Augrabies...............	Orange River, Union of South Africa	146
Victoria...............	Zambezi River, border of Zambia and Rhodesia	120
Murchison...............	Victoria Nile River, Uganda	120
Stanley...............	Congo River, Zaïre	60
North America
Yosemite...............	Merced River, USA	727.5
Ribbon...............	Merced River, USA	484
Upper Yosemite...............	Yosemite Creek, USA	435
Nevada...............	Merced River, USA	178
Grand...............	Churchill River,Canada	74
American...............	Snake River, USA	55
Niagara...............	Niagara River, border of USA and Canada	51
South America
Angel...............	Churun River (Caroni River system), Venezuela	1,054
Kukenaam...............	Kukenaam River (Orinoco basin), Venezuela	610
Roraima...............	Potaro River, Guyana	457
Cayetur...............	Potaro River, Guyana	225
Paolo Afonso...............	San Francisco River, Brazil	84
Iguassu...............	Iguassu River, border of Brazil and Argentina	72
Australia and Oceania
Sutherland...............	Arthur River, New Zealand (South Island)	580
Wollomombi...............	Mackleay River,Australian Commonwealth	519

more quickly than into the stable rock. As a result, the riverbed develops ledges from which the flow of water drops. The water can fall along several ledges, forming a series of waterfalls (cascades). The waterfall ledge is constantly being destroyed, especially at its base; thus, the waterfall retreats upstream. For example, Niagara Falls (North America), which has a bed composed of hard limestone underlaid by softer shale, moves back 0.7-0.9 m per year.

When the ledge of a waterfall is sufficiently destroyed, rapids often form. A waterfall can also form as a result of the partitioning of mountain ravines by avalanches, as well as in plain areas where a river crosses a section with uneroded rock—for example, a trap. There are also waterfalls with less steep descents (called vodoskat, as opposed to vodopad). In the northern USSR small waterfalls are often called paduny.

Angel Fall is the highest waterfall in the world (1,054 m). Yosemite Falls, in the Yosemite Valley of the Sierra Nevada Mountains (California), has a drop of 727.5 m. Victoria Falls on the Zambezi River (southern Africa) is 120 m high and 1,800 m wide. Niagara Falls has the most water flowing over it; it is 1,100 m wide and about 51 m high. There are waterfalls in the USSR in the Karelian ASSR, Kola Peninsula, the Caucasus, Altai, Sayan Mountains, and other mountain regions of Siberia.

The presence of waterfalls on rivers blocks lumbering and navigation, but rivers with great water drops within short distances are suitable for the construction of hydro-electric power plants. This is the case with the energy from Narva Falls on the Narva River and Kivach Falls on the Suna River, among others.

A. I. CHEBOTAREV