A watershed is the entire area of land that drains into a common stream, river, or water body; watershed management is the planned use and conservation of land, water, and vegetation within that drainage unit to maximise water retention and soil health.
- The watershed (also called a drainage basin or catchment) is bounded by a water divide (a ridge) that separates it from neighbouring basins.
- The aim is to harvest and store rainwater where it falls, recharge groundwater, control runoff and soil erosion, and improve farm productivity, treating the whole basin as one unit.
- Common structures and practices include contour and gully plugging, check dams, percolation tanks, farm ponds, nala bunds, afforestation, and ridge-to-valley treatment.
- Watershed treatment follows a ridge-to-valley approach: work begins on the upper ridges to slow water early, then moves down the slope.
- In India watershed programmes are delivered through the Watershed Development Component of the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY), with community participation; the Hivare Bazar and Ralegan Siddhi villages in Maharashtra are model success stories.
The definition of a watershed and water divide, the ridge-to-valley principle, check dams and percolation tanks, and PMKSY watershed programmes appear in agriculture and environment sections.
Watershed (the drainage area) versus water divide (the boundary ridge); watershed management treats land and water together over a whole basin, not a single field; ridge-to-valley means starting work uphill, not downhill.
Treating a whole drainage basin (catchment) as one unit, ridge to valley, to store rain, recharge groundwater, and check erosion.