<P> A drainage basin or catchment area 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 . </P>
<P> A drainage basin or catchment area 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 . </P>
area of land drained by a single river
area of land drained by a single river
drainage basin
drainage basin