Waterfall

A waterfall is usually a geological formation resulting from water, often in the form of a stream, flowing over an erosion-resistant rock formation that forms a sudden break in elevation or nickpoint.

Some waterfalls form in mountain environments where the erosive water force is high and stream courses may be subject to sudden and catastrophic change. In such cases, the waterfall may not be the end product of many years of water action over a region, but rather the result of relatively sudden geological processes such as landslides, faults or volcanic action.

Waterfalls may also be artificial, and they are sometimes created as garden and landscape ornaments.

Formation


Typically, a river flows over a large step in the rocks which may have been formed by a fault line. Over a period of years, the edges of this shelf will gradually break away and the waterfall will steadily retreat upstream, creating a gorge of recession. Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning 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.

Streams become wider and more shallow 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 can occur along the edge of 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.

World Largest Waterfall

1 .	Inga Falls	1,500,000 cfs	? ft / ? m	Congo River	Congo
2 .	Livingstone, Chutes de	1,240,000 cfs	15,840 ft / 4,828 m	Congo River	Congo
3 .	Boyoma Falls	600,000 cfs	4,500 ft / 1,372 m	Lualaba River	Congo
4 .	Guaíra, Salto del	470,000 cfs	15,840 ft / 4,828 m	Rio Paran	Brazil
5 .	Khone, Chutes de	410,000 cfs	35,376 ft / 10,783 m	Mekong River	Laos
6 .	Celilo Falls	191,215 cfs	10,560 ft / 3,219 m	Columbia River	USA
7 .	Par?, Salto	125,000 cfs	18,400 ft / 5,608 m	Rio Caura	Venezuela
8 .	Paulo Afonso, Cachoeira de	100,000 cfs	60 ft / 18 m	Rio S?o Francisco	Brazil
9 .	Urubupunga, Salto do	97,000 cfs	6,600 ft / 2,012 m	Rio Paran	Brazil
10 .	Niagara Falls	85,000 cfs	3,948 ft / 1,203 m	Niagara River	USA / Canada
11 .	Iguacu, Salto de	61,660 cfs	8,858 ft / 2,700 m	Rio Igua	Argentina / Brazil
12 .	Patos e Maribondo, Saltos dos	53,000 cfs	6,600 ft / 2,012 m	Rio Grande	Brazil
13 .	Victoria Falls	38,430 cfs	5,700 ft / 1,737 m	Zambezi River	Zimbabwe / Zambia
14 .	Virginia Falls	35,300 cfs	850 ft / 259 m	South Nahanni River	Canada
15 .	Grand Falls	35,000 cfs	150 ft / 46 m	Hamilton River	Canada
16 .	Cauvery Falls	33,000 cfs	2,784 ft / 849 m	Cauvery River	India
17 .	Kongou Falls	31,783 cfs	10,500 ft / 3,200 m	Ivindo River	Gabon
18 .	Williamette Falls	30,849 cfs	1,550 ft / 472 m	Willamette River	USA
19 .	Kaieteur Falls	23,400 cfs	370 ft / 113 m	Potaro River	Guyana
20 .	Epupa Falls	17,657 cfs	? ft / ? m	Kunene River	Namibia
21 .	Hidden Falls	15,000 cfs	? ft / ? m	Yarlung Tsangpo	Tibet
22 .	San Rafael, Cascada de	14,125 cfs	? ft / ? m	Rio Coca	Ecuador
23 .	Rheinfall	13,066 cfs	370 ft / 113 m	Rhein River	Switzerland
24 .	Great Falls	11,406 cfs	150 ft / 46 m	Potomac River	USA
25 .	Augrabies Falls	11,050 cfs	80 ft / 24 m	Orange River	South Africa
26 .	Kootenai Falls	10,941 cfs	845 ft / 258 m	Kootenay River	USA
27 .	Murchison Falls	10,594 cfs	23 ft / 7 m	Victoria Nile	Uganda
28 .	Ruacana Falls	10,000 cfs	2,280 ft / 695 m	Cunene River	Namibia / Angola
29 .	Shoshone Falls	10,000 cfs	1,000 ft / 305 m	Snake River	USA
30 .	Sandstone Falls	7,847 cfs	1,500 ft / 457 m	New River	USA
31 .	Great Falls	7,558 cfs	? ft / ? m	Missouri River	USA
32 .	Dettifoss	7,062 cfs	328 ft / 100 m	J?kuls? ? Fj?llum	Iceland
33 .	Hafragilsfoss	7,062 cfs	300 ft / 91 m	J?kuls? ? Fj?llum	Iceland
34 .	Selfoss	7,062 cfs	600 ft / 183 m	J?kuls? ? Fj?llum	Iceland
35 .	Spokane Falls	6,731 cfs	400 ft / 122 m	Spokane River	USA