Question

The area drained by a single river system is called _________.

• A. Water Divide
• B. Drainage Basin
• C. River System
• D. Perennial River
• E. None of these

Answer 1

The correct option is B Drainage Basin

A drainage basin is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. The drainage basin includes all the surface water from rain runoff, snowmelt, and nearby streams that run downslope towards the shared outlet, as well as the groundwater underneath the earth's surface. Drainage basins connect into other drainage basins at lower elevations in a hierarchical pattern, with smaller sub-drainage basins, which in turn drain into another common outlet.

Other terms used interchangeably with drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. 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, that of a drainage divide.

In a closed drainage basin, or endorheic basin, the water converges to a single point inside the basin, known as a sink, which may be a permanent lake, a dry lake, or a point where surface water is lost underground.