The land area drained by a river is known as the river basin. The watershed is defined as the land area from which water drains under gravity to a common drainage channel. Thus watershed is a delineated area with a well defined topographic boundary and one water outlet. The watershed can range from a few square kilometers to few thousand square kilometers in size. In the watershed
The hydrological conditions are such that water becomes concentrated within a particular location like a river or a reservoir, by which the watershed is drained.
The watershed comprises complex interactions of soil, landform, vegetation, land use activities and water. People and animals are an integral part of a watershed having mutual impacts on each other. We may live anywhere we would be living in some watershed.
A watershed affects as it is directly involved in sustained food production, water supply for irrigation, power generation, transportation as well as for influencing sedimentation and erosion, vegetation growth, floods and droughts.
Thus management of watersheds treating them as a basic functional unit is extremely important and the first such Integrated Watershed Management was adopted in 1949 by the Damodar Valley Corporation.
Watershed degradation: The watersheds are very often found to be degraded due to uncontrolled, unplanned and unscientific land use activities. Organizing, deforestation, mining, construction activities, industrialization, shifting cultivation, natural and artificial fires, soil erosion and ignorance of local people have been responsible for degradation of various watersheds.