In places a river may descend verti

In places a river may descend vertically giving rise to a waterfall. The term cataract, usually designating a series of rapids in a large river, is often applied to waterfalls of large volume. Waterfalls develop due to many causes. The most common one is the presence in the river's course of rocks of unequal hardness or resistance.
The beautiful Lower Falls in the Yellowstone National Park appeared due to a body of resistant, igneous rock which here extends across the Yellowstone River. The rocks on either side of the river are of a rich yellow color, giving the river its name.
Some waterfalls appear as a result of different rates of erosion where a resistant layer of rock in a streambed lies over a less resistant rock. Subsequent erosion of the softer rock by the falling water periodically breaks off portions of the harder cap rock. Some of the largest cataracts in the world, Niagara Falls in North America and Victoria Falls in Zimbabwe, Africa, originated in this way.
Niagara Falls. Between Lake Erie and Lake Ontario the Niagara forms the famous Niagara Falls. The Niagara River was born near the end of the Glacial Period; it flowed northward as now, and about 10 km below the present falls it plunged over the edge of a limestone, which there forms an escarpment, or steep rock-slope. The limestone is resistant, but the swirling water at the base of the fall gradually undercuts the softer rocks below and the heavy limestone, robbed of its support, breaks off in huge blocks. Each time this occurs the crest of the cataract recedes a few feet father upstream. Century by century the fall has worked its way upstream, leaving a deep gorge. At the present time the cataract is divided into two parts. The lesser falls is on the American side and the great horse-shoe fall is on the Canadian side. So much more water pours over the latter that its crest is receding faster than that of the American fall. Millions of people come each year to see this spectacular natural wonder.
Victoria Falls. One of the world's largest and most magnificent waterfalls Victoria Falls lies on the border between Zambia and Zimbabwe in South Africa. These falls of the Zambezi River are said to be more imposing than Niagara. Beautiful Victoria Falls lies at the southern end of the Great Rift Valley. They are formed due to inequalities in a vast body of solidified lava in which the river is cutting this portion of its channel. The mist and noise produced by the 122-m drop of the Zambezi River inspired the waterfall's alternate name "smoke that thunders". Many tourists visit the falls each year.
Iguagu Falls. Igua9u Falls on the border between Argentina and Brazil is one of South America's great natural wonders. The falls range between 60 and 80 m high. In the dry season the river drops in two crescent-shaped falls, but in the wet season the water merges into one large fall more than 4 km wide.
Summarizing, we may say that waterfalls belong to the youthful stage of a river, are usually due to the presence of unequally resistant rocks in the stream channel. Waterfalls are often of imposing grandeur, but in time disappear by erosion.

Результаты (баскский) 1:

Leku ibai bat jaitsi daiteke bertikalean emanez jauzi bat sorrarazten. Epe katarata, normalean sorta bat izendatzeko ibai handi batean rapids, askotan bolumen handien urjauzien aplikatu. Waterfalls arrazoiak asko garatu. Are ohikoena en inork guztiak ibai ikastaroa desorekatua gogortasuna partiturak edo erresistentzia arroka en presentzia da.
Eder Lower Yellowstone ere jaitsierak Parke Nazionalaren ondoren ondorioz agertu erresistentzia, igneo gorputz bat hemen aurki zein izango du Yellowstone ibaian zehar hedatzen da. baten ibaiaz bai harkaitzak kolore horia aberats baten dira, eszena ibaia bere 'izena emanez.
urjauzien batzuk informazio Tarifak emaitza of batekin gisa agertzen higaduraren Different bat non streambed ere erresistenteak rock geruza klausula gutxiago erresistenteak rock bat ikusten baino gehiago dago. the rock higaduraren leunagoak Ondorengo arabera erortzen ur aldian behin hautsi gogorragoa txano rock zatiak. Munduko Victoria-handiena kataratak batzuk, Niagara Falls Of North America eta Falls Zimbabwe, Afrika da, modu horretan jatorria.
Niagara Falls Of. Lake Erie eta Ontario lakua Between the Niagara ospetsua Niagara Falls osatzen. Niagara ibaia amaiera gertu jaio zen Glaziaraldiaren; iparralderantz zihoan, gaur egun bezala, eta gaur azpian 10 km jaitsierak murgildu baino gehiago da kare-a, eta horrek ez malkar bat, edo aldapatsuak rock-malda eratzen ertzean. Kararria erresistentea da, baina swirling du udazkenean oinarrian ura pixkanaka nahierara arroka leunagoak behean eta heavy kareharria, bere laguntza lapurtu, hautsi bloke handi batean. Aldi bakoitzean hau gertatzen gandorra katarata oinak aita gutxi batzuk atzera ibaian gora. Century mendearen arabera udazkenean bere egin du lan modu upstream, arroila sakona utzita. Gaur egun jauziena dago banatuta , bi zatitan. txikiagoan jaitsierak American alde da, eta handia zaldi-zapata jaitsiera Kanadako alde. Beraz, askoz ur gehiago bigarrenak baino gehiago isurtzen bere gandorra American jaitsiera baino azkarrago kantitatea jaisten da. Of jendea etorri Milioi, urte bakoitzeko hamarkadan hau Wonder natural ikusgarria ikusteko.
Victoria Falls da. munduko handiena eta gehien bat ur-jauzi zoragarriak Victoria Falls Zambia eta Zimbabwe arteko muga Hegoafrikan datza. Zambezi ibaiaren jaitsierak Hauek dira, esan zuen Niagara baino gehiago inposatu izan. Beautiful Victoria Falls hegoaldeko muturrean dago Handia Rift Valley. ra batean desberdintasunen ondorioz ez dute kontzepturik solidotuz laba gorputz izugarri bertan ibaia bere kanalaren zati hau ebaketa. lainoa eta zarata 122 m-Zambezi ibaiaren jaitsiera sortutako inspiratutako waterfall ordezko izena "ke trumoia". Turistak erorikoak askok ekitaldi bakoitzeko. Bisitatu
Iguagu Falls. Igua9u Argentina arteko mugan erorketak eta Brasilen Hego Amerikan mirari natural handi bat da. Jaitsierak bitartekoa 60 eta 80 m arteko altuera dute. Lehor denboraldian ibaian behera bi Ilargierdi-itxurako jaitsierak, baina garai hezean ur jaitsiera handi bat sartu batzen baino gehiago 4 km orokortu.
Laburbilduz, esan genezake ur-jauziak gazteentzako ibai bat etapa egileenak, dira Normalean arroka desorekatuan erresistenteak presentzia ondorioz korronte kanalean. Waterfalls handitasuna inposatu ohi dira, baina denbora batean higaduraren ondorioz desagertuko.