waterfall
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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 periodsglacial periods,times during which large portions of the earth's surface were covered with thick glacial ice sheets. In the Pleistocene epoch, in the Carboniferous and Permian periods of the Paleozoic era era, and in Huronian time of the Precambrian, the earth experienced an
..... Click the link for more information. ). 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 FallsAngel Falls,
waterfall, Sp. Salto Ángel, 3,212 ft (979 m) high, SE Venezuela, in the Guiana Highlands. Springing from Auyán-Tepuí Mesa, it is the highest uninterrupted waterfall in the world.
..... Click the link for more information. in Venezuela is the world's highest waterfall.
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