Question

difference between doab and basin

Answer 1

Drainage basin: A drainage basin is an extent of land where water from rain or snow melt drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea orocean. 
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 like a funnel, collecting all the water within the area covered by the basin and channelling it into a waterway. 
Each drainage basin is separated topographically from adjacent basins by a geographical bar Watershed: In the technical sense, a watershed refers to a divide that separates one drainage area from another drainage area. 
However, in the United States andCanada, the term is often used to mean a drainage basin or catchment area itself. 
Drainage basins drain into other drainage basins in a hierarchical pattern, with smallersub-drainage basins combining into larger drainage basins.