Drainage Basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean.

In closed drainage basins the water converges to a single point inside the basin, known as a sink, which may be a permanent lake, dry lake, or a point where surface water is lost underground. The drainage basin includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels, and is separated from adjacent basins by a drainage divide.

The drainage basin acts as a funnel by collecting all the water within the area covered by the basin and channelling it to a single point. Each drainage basin is separated topographically from adjacent basins by a geographical barrier such as a ridge, hill or mountain.

Other terms that are used to describe a drainage basin are catchment, catchment area, catchment basin, drainage area, river basin and water basin. In North America, the term watershed is commonly used to mean a drainage basin (though in other English-speaking countries, it is used only in its original sense, to mean a drainage divide). Drainage basins drain into other drainage basins in a hierarchical pattern, with smaller sub-drainage basins combining into larger drainage basins.

Drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are designed to allow multiple inlets, outlets, or sinks. In a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins.

The United States Environmental Protection Agency launched the website Watershed Central for the US public to exchange information and locate resources needed to restore local drainage basins in that country.

Read more about Drainage Basin:  Catchment Factors

Other articles related to "drainage basin, basin, basins":

Columbia River Geobox - Course
... Its drainage basin covers nearly all of Idaho, large portions of British Columbia, Oregon, and Washington, ultimately all of Montana west of the Continental Divide, and small ... miles (1,200 km) of the river's length and 85 percent of its drainage basin are in the U.S ... The Columbia is the twelfth-longest river and has the sixth-largest drainage basin in the United States ...
Columbia River Geobox - Watershed
... Most of the Columbia's drainage basin (which, at 258,000 square miles or 670,000 square kilometres, is about the size of France) lies roughly between the Rocky Mountains on the east and the Cascade Mountains on the west ... In the United States and Canada the term watershed is often used to mean drainage basin ... The term Columbia Basin is used to refer not only to the entire drainage basin but also to subsets of the river's full watershed, such as the ...
Central Asian Internal Drainage Basin
... The Central Asian Inland Basin is the largest of 3 major hydrological basins that cover Mongolia (cf ... Arctic Drainage Basin Pacific Drainage Basin) ... The basin further includes the watersheds of the Great Lakes Depression, the Valley of Lakes, and the lowlands of the Gobi Desert ...
Canada Hudson Bay Drainage
... The Hudson Bay drainage basin is the drainage basin in northern North America where surface water empties into Hudson Bay and adjoining waters ... an area of about 3,861,400 square kilometres (1,490,900 sq mi), the basin is almost totally in Canada (spanning parts of the Prairies, central and northern Canada ... On the Continental Divide the basin is bounded at Triple Divide Peak to the south, and Snow Dome to the north ...