Watershed
Also called: Water divide · Topic: Drainage System of India: Rivers, Basins and Patterns · NCERT: Class 11, Ch 3 "Drainage System"; Class 12, Ch 4 "Water Resources"
Meaning
A watershed has two meanings. First, it is the boundary line, usually a ridge of high ground, that separates one drainage basin from the next. Rain on one side flows to one river and rain on the other side flows to another. Second, it means the small catchment of a stream or rivulet. In that sense it is the basic unit of watershed management: saving soil and water by building check dams, planting trees and making contour bunds (low earth banks built across a slope).
Example
The Delhi ridge and the low ground through Haryana form the watershed between the Indus and Ganga systems. Rivers west of it drain to the Indus and rivers east of it drain to the Ganga.
Don't confuse with
- Drainage basin: the whole area drained by a large river. A watershed is either the line between basins or a small stream's catchment.
Related concepts
- Drainage basin
- Catchment area
- Arabian Sea and Bay of Bengal drainage
- Classification of river basins by size