waterfall | National Geographic Society (2023)

Awaterfallis the abrupt drop of a river or other body of water over a rocky outcrop in aplunge poolunder. Waterfalls are also calledwater falls. The process ofErosion, the erosion of the earth, plays an important role in the formation of waterfalls. The falls themselves also contribute to erosion. Waterfalls often form when streams flow from soft rock to hard rock. This occurs both laterally (when a stream flows across land) and vertically (when the stream falls into a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the creek falls. Afall lineis the imaginary line along whichparallelRivers tumble as they flow from the highlands to the lowlands. Lots of waterfalls in one area helpgeologistsehydrologistsdetermine the slope of a region and the underlying rock structure. When a current flows, it carriesSediment. The sediment can be microscopicofficially,pebble, or even boulders. Sediments can erode river beds made of soft rock such as sandstone or limestone. Finally the flowChannelIt cuts so deep into the river bed that only the hardest rock like granite remains. Waterfalls develop when these granite formations form cliffs and overhangs. a stream ofspeedincreases as you approach a waterfall, increasing erosion. The water movement at the top of a waterfall can erode the rocks, making them very flat and smooth. Flowing water and silt fall over the waterfall and erode the plunge pool in theBase. The violent water flow can also generate powerfulswirlseroding the pond rock below them. The resulting erosion at the base of a waterfall can be very dramatic, causing the waterfall to "retreat." The area behind the waterfall has been eroded, creating a hollow, cave-like structure called the "rock shelter."outcrop) can fall down and send boulders into the creek bed and into the pool below. As a result, the waterfall "recedes" many meters upstream. The erosion process of the waterfall begins again, breaking the boulders of the old outcrop. Erosion is just one process that can form waterfalls. A waterfall can form through aLack, or crack in the earth's surface. Oneearthquake,landslide,glacier, orVulkanIt can also disturb stream beds and contribute to the creation of waterfalls.classifywater fallsThere is no standard way to classify waterfalls. Some scientists classify waterfalls according to the averageVolumewater in the waterfall. A Class 10 waterfall on this scale is Inga Falls, Democratic Republic of the Congo, where the Congo River meanders in a series of meandersrapids. The estimated volume of water discharged from Inga Falls is 25,768 cubic meters per second (910,000 cu ft per second). Another popular way to classify waterfalls is by width. One of the widest falls is the Khone Phapheng Falls, Laos. At Khone Phapheng Falls, the Mekong flows through a series of relatively shallow rapids. The width of Khone Phapheng Falls is about 10,783 meters (35,376 feet). Waterfalls are also sorted by height. Angel Falls, the highest waterfall in the world,crashes979 meters (3,212 feet) on a remote controlcanyonin a tropical forest in Venezuela. The water of the Gauja River often does not reach the bottom. The fall is so long and so steep thatair pressureit is often stronger than the water pressure of the falls. The water is rotatedFogbefore reaching the little onewealthyunder.types of waterfallsOne of the most popular, albeit less scientific, ways of classifying waterfalls is by type. The nature of the waterfall is simply the way it goes down. Most waterfalls fit into more than one category. Ablock waterfallcomes from a broad stream. Niagara Falls in the United States and Canada is a block waterfall on the Niagara River. AwaterfallIt is a waterfall descending a series of stone steps. Monkey Falls in the Indira Gandhi Wildlife Sanctuary and National Park in Tamil Nadu, India is a gently sloping waterfall. The waterfall is safe enough for children to play in the water. ACataractit is a powerful, even dangerous waterfall. Among the widest and wildest falls are the roaring waters of the Iguazu River on the border of Brazil and Argentina. ATrogIt is a waterfall where the passage of the creek is very narrow, due to which the water flows with an unusually high pressure. Three Chute Falls is named for the three "chutes" through which Tenaya Creek falls in Yosemite National Park, California.fan waterfallsare named for their shape. As it sinks, the water spreads out horizontally. Virgin Falls is an impressive waterfall on Tofino Creek on Vancouver Island, British Columbia, Canada.frozen waterfalls are exactly what they seem. During at least part of the year the waterfall freezes over.climberThey often scale frozen waterfalls as a challenging test of their skills. The catch is a single column of ice in Vail, Colorado, falling vertically over 30 meters (100 feet).Horsetail FallsStay in touch with the hard rock that supports them. The Reichenbach Falls, a waterfall in the Reichenbachbach River in Switzerland, is a waterfall where legendary detective Sherlock Holmes is said to have fallen to his doom.multi-level waterfallsare a series of interconnected waterfalls, each with its own pool. The breathtaking "falling lakes" of Croatia's Plitvice Lakes National Park are a series of cascading waterfalls.diving waterfallsUnlike field horsetails, they lose contact with the hard rock. Japan's highest waterfall, the Hannoki Falls is a 497 meter high waterfall. The Hannoki Falls are seasonally fed by melting ice from the Tateyama Mountains.hitThe falls are characterized by wide pools at their base. Wailua Falls is a punchbowl waterfall on the island of Kauai in Hawaii. Although the pool isquietand popular for swimming, the Wailua Falls area itself is dangerous. the flowing watersegmented waterfallsseparated as separate streams. Huge rocky outcrops separate the streams of Nigretta Falls, a segmented waterfall in Victoria, Australia, before meeting in a large pool.Case Study: Niagara FallsThe Niagara River has two falls, one in upstate New York and the other in the province of Ontario, Canada. Each waterfall is less than 60 meters (200 feet) high, but together they are over a kilometer (0.62 miles) wide. Niagara and many other falls with large amounts of water are used for generationHydropower. A tremendous amount of water flows over Niagara Falls, reaching 5,525 cubic meters (195,000 cu ft) per second. Convert the power plants upstream of the fallsHydropoweremelectricityfor residential uAdvertisinguse. The US and Canadian governments manage the Niagara River so carefully that it is possible for both countries to "turn off" the falls. This is done at night so as not to disturb thattourismIndustry and burglaries are never really eliminated, only reduced. water andredirectedforchannelsereservoirs, it's atreducedflow allowsengineersto check for erosion and other damage to the falls. US and Canadian authorities are also working together to ensure Niagara Falls doesn't freeze over in the winter, which would jeopardize energy production. Because waterfalls are obstaclesNavigation, canals are sometimes constructed to bypass them. Niagara Falls blocks the passage between Lake Erie and Lake Ontario on the Niagara River. In the 19th century the Welland Canal was built to bridge the twobig lakespossible.