A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely at the end of its course, and does not reach another body of water. Small rivers may be called by several other names, including stream, creek, brook, rivulet, and rill. There are no official definitions for generic terms, such as river, as applied to geographic features, although in some countries or communities a stream may be defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.
Rivers are part of the hydrological cycle. Water generally collects in a river from precipitation through a drainage basin from surface runoff and other sources such as groundwater recharge, springs, and the release of stored water in natural ice and snowpacks (e.g. from glaciers). Potamology is the scientific study of rivers while limnology is the study of inland waters in general.
No extraterrestrial rivers are currently known, though large flows of hydrocarbons described as rivers have recently been found on Titan. Channels may indicate past rivers on other planets, specifically outflow channels on Mars and are theorised to exist on planets and moons in habitable zones of stars.
Famous quotes containing the word river:
“The Xanthus or Scamander is not a mere dry channel and bed of a mountain torrent, but fed by the ever-flowing springs of fame ... and I trust that I may be allowed to associate our muddy but much abused Concord River with the most famous in history.”
—Henry David Thoreau (18171862)
“Ask me no more: thy fate and mine are sealed;
I strove against the stream and all in vain;
Let the great river take me to the main.
No more, dear love, for at a touch I yield;
Ask me no more.”
—Alfred Tennyson (18091892)
“It is from quiet places like this all over the world that the forces accumulate which presently will overbear any attempt to accomplish evil on a large scale. Like the rivulets gathering into the river, and the river into the seas, there come from communities like this streams that fertilize the consciences of men, and it is the conscience of the world that we are trying to place upon the throne which others would usurp.”
—Woodrow Wilson (18561924)