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Angel Falls in Venezuela is the world's tallest waterfall at 979 m (3,212 ft).

A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.

Contents

Formation

Formation of a waterfall

Typically, a river flows over a large step in the rocks that may have been formed by a fault line. As it increases its velocity at the edge of the waterfall, it plucks material from the riverbed. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it.

Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning that undercutting due to splashback will occur here to form a shallow cave-like formation known as a rock shelter or plunge pool under and behind the waterfall. Eventually, the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they collide with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool or gorge.

Baatara gorge waterfall near Tannurin, Lebanon.

Streams become wider and shallower just above waterfalls due to flowing over the rock shelf, and there is usually a deep pool just below the waterfall because of the kinetic energy of the water hitting the bottom. Waterfalls normally form in a rocky area due to erosion. After a long period of being fully formed, the water falling off the ledge will retreat, causing a horizontal pit parallel to the waterfall wall. Eventually, as the pit grows deeper, the waterfall collapses.

Waterfalls can occur along the edge of a glacial trough, whereby a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon. The rivers are flowing from hanging valleys.

Classifying Waterfalls

Waterfalls are grouped into ten broad classes based on the average volume of water present on the fall using a logarithmic scale. Class 10 waterfalls include Niagara Falls, Paulo Afonso Falls and Khone Falls.

Classes of other well-known waterfalls include Victoria Falls and Kaieteur Falls (Class 9); Rhine Falls, Gullfoss and Sutherland Falls (Class 8); Angel Falls and Dettifoss (Class 7); Yosemite Falls, Lower Yellowstone Falls and Umphang Thee Lor Sue Waterfall (Class 6).[1]

Types of waterfalls

Dark Hollow Falls, near Skyline Drive, Virginia, is an example of a cascade waterfall
  • Block: Water descends from a relatively wide stream or river.
  • Cascade: Water descends a series of rock steps.
  • Cataract: A large, powerful waterfall.
  • Fan: Water spreads horizontally as it descends while remaining in contact with bedrock.
  • Horsetail: Descending water maintains some contact with bedrock.
  • Plunge: Water descends vertically, losing contact with the bedrock surface.
Frozen waterfall in southeast New York
  • Punchbowl: Water descends in a constricted form and then spreads out in a wider pool.
  • Segmented: Distinctly separate flows of water form as it descends.
  • Tiered: Water drops in a series of distinct steps or falls.
  • Multi-step: A series of waterfalls one after another of roughly the same size each with its own sunken plunge pool.

Examples of large waterfalls[2]

Havasu Falls, near Supai, Arizona, is an example of a plunge waterfall
Powerscourt Waterfall, near Enniskerry, Wicklow County, Ireland, is an example of a horsetail waterfall
Aerial view of Niagara Falls in the state of New York, USA, and province of Ontario, Canada

Significant waterfalls are listed alphabetically:

See also

Duruitoarea waterfall in Ceahlău,Romania
Plitvice lakes, Croatia

External links

References

  1. ^ Richard H. Beisel Jr., International Waterfall Classification System, Outskirts Press, 2006 ISBN 1598003402
  2. ^ http://www.world-waterfalls.com/ World Waterfall Database

Travel guide

Up to date as of January 14, 2010
(Redirected to Waterfalls article)

From Wikitravel

This article is a travel topic.

Waterfalls are some of the most spectacular sights that nature has to offer, and are the frequent goal of many travellers.

The Iguaçu Falls Waterfall
The Iguaçu Falls Waterfall

Stay safe

A liter of water weighs a kilogram; a gallon weighs ten pounds. When large amounts of water fall long distances, the forces involved are enormous, easily enough to kill a person or sink a boat.

Notable Waterfalls

Some of the most noteworthy waterfalls are:

  • Victoria Falls, on the border between Zambia and Zimbabwe, forms the largest single face of falling water in the world, with a width of 1.7 kilometers and height of 108 meters.
  • Angel Falls in Venezuela is the world's highest waterfall with one uninterrupted drop of 807 m (2,647 ft), from a total height of 978 m (3,212 ft)
  • Boyoma Falls (formerly, Stanley Falls) on the Congo River in the Democratic Republic of the Congo are the falls with the greatest volume of flow - 17 million litres per second over a drop of 60 m
  • Niagara Falls, the most-visited waterfall in the world, on the border between Canada and the United States of America

Africa

Congo

  • Boyoma Falls (formerly, Stanley Falls) on the Congo River are the falls with the greatest volume of flow - 17 million litres per second over a drop of 60 m

South Africa

  • Tugela Falls in the Drakensberg is the worlds second highest waterfall with a total drop of 947m in 5 leaps. The highest single drop is 411m.

Uganda

  • Murchison Falls where the Nile River passes through a narrow cleft in the rocks and crashes over a 30 m precipice

Zambia and Zimbabwe

Shevi Waterfall in Iran
Shevi Waterfall in Iran

China

China's largest waterfall, the Huangguoshu Waterfall is one of few waterfalls that can be viewed from above, below, front, back, left and right in the world. It is near Anshun in Guizhou.

Iran

  • Shevi waterfall is one of the most beautiful waterfalls in Iran with a height of about 85 m.
  • Rhine Falls in Switzerland, Europe's largest falls (by volume of water)
  • Savica Waterfall in Slovenia has two strands and is 78 meters high. France Prešeren's epic poem “Baptism by the Savica” is one of the great works of Slovene literature.

Iceland

  • Dettifoss, Europe's most powerful falls
  • Gullfoss, a two-level cascade
  • Godafoss in northern Iceland
  • Angel Falls in Venezuela, the highest single-drop falls in the world (nearly a kilometer)
  • Iguaçu Falls on the border of Brazil and Argentina, are one of the largest and most impressive in the world.
  • Kaieteur Falls in Guyana is said to be one of the most powerful waterfalls in the world with 663 cubic meters per second, it also carries the claim to be the highest single drop water fall in the world.

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

WATERFALL, a point in the course of a stream or river where the water descends perpendicularly or nearly so. Even a very small stream of water falling from any considerable height is a striking object in scenery. Such falls, of small volume though often of immense depth, are common, for a small stream has not the power to erode a steady slope, and thus at any considerable irregularity of level in its course it forms a fall. In many mountainous districts a stream may descend into the valley of the larger river to which it is tributary by way of a fall, its own valley having been eroded more slowly and less deeply than the main valley. Mechanical considerations apart, the usual cause of the occurrence of a waterfall is a sudden change in geological structure. For example, if there be three horizontal strata, so laid down that a hard stratum occurs between two soft ones, a river will be able to grade its course through the upper or lower soft strata, but not at the same rate through the intermediate hard stratum, over a ledge of which it will consequently fall. The same will occur if the course of the river has been interrupted by a hard barrier, such as an intrusive dyke of basalt, or by glacial or other deposits. Where a river falls over an escarpment of hard rock overlying softer strata, it powerfully erodes the soft rock at the base of the fall and may undermine the hard rock above so that this is broken away. In this way the river gradually cuts back the point of fall, and a gorge is left below the fall. The classic example of this process is provided by the most famous falls in the world - Niagara.


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Simple English

File:Fulmer Falls Closeup
A picture of the Fulmer Falls waterfall in the Childs Recreation Area in the Pocono Mountains

A waterfall is where there is a sharp fall of water found on a river or stream. The water flows from higher land, then it falls down a big step of rock to lower land where it will continue on its journey. Waterfalls are usually made when a river is young.[1]

Many people choose them as sacred spots. The roar from the falling water is very loud and the sound makes beautiful music. Many people think they are one of the most beautiful things in nature.[1]

The highest waterfall in the world is Angel Falls in Venezuela where the water falls 979 m (3,212 ft).[2]

References

  1. 1.0 1.1 Carreck, Rosalind, ed (1982). The Family Encyclopedia of Natural History. The Hamlyn Publishing Group. pp. 246–248. ISBN 011202257.
  2. "Angel, Salto". www.world-waterfalls.com. http://www.world-waterfalls.com/waterfall.php?num=1/. Retrieved 2009-02-25. 
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