What is River?
{{for|the other uses|River (disambiguation)}} [[File:River Thames - Isle of Dogs to Thurrock.jpg|thumb|300px|[[River Thames]] in [[London, England]]. People have lived along the banks of this river for thousands of years.]] A '''river''' is a [[stream]] of [[water]] that flows through a channel on the surface of the ground. The passage where the river flows is called the riverbed and the earth on each side is called a riverbank. A river begins on high ground or in hills or mountains and flows down from the high ground to the lower ground, because of [[gravity]]. A river begins as a small stream and gets bigger the farther it flows. == River parts == === The beginning of a river === The start of a river is called the ''source'' or ''head water''. The part of the river that is near the source is called a 'young' river.<ref name=camilla>{{cite book | last = | first = | title = Earth Science| url =https://archive.org/details/holtsciencetechn00na_0| publisher = Austin, [[Texas]]: Holt, Rinehart and Winston| date = 2001| isbn = 0-03-055667-8}}</ref> A young river is often in a V-shaped river bed, and flows quickly downhill over stones, and around big rocks. Young rivers often have lots of small [[waterfall]]s and [[rapids]]. As the rivers travel downhill they begin to erode the ground taking small bits of soft rock and soil. * The source of a river may be a [[spring (water)|spring]], often on a [[hill]], [[mountain]], [[glacier]], or another high place. A spring is water that flows out from under the ground. * The source of a river may be a lake where lots of water from small streams gathers when it rains or snows. * A river may begin in mountains where there is snow. The melting snow runs together to form a small stream that runs down the mountain. As more little streams run in, the main stream gets bigger, until it forms a river. * Some rivers flow from hills where there is no snow, but lots of rain. * Some rivers only flow after there has been rain near the head water. <gallery> File:Arkansas head waters.jpg|Th