Soil, vegetation and water are most important vital natural resources for the existence of the man and his animals. These three interdependent resources can bee managed collectively, conveniently, simultaneously and efficiently on watershed basis (unit of management.)
“Watershed can be defined as a unit of area covers all the land which contributes runoff to a common point or outlet and surrounded by a ridge line”. It is also known as ridge line.
Delineation procedure of watershed:
Watershed delineation is to describe or sketching out the area bounded by ridge line, contributing runoff at common point and dividing or separating it from the adjoining area.
The delineation of priority area can be performed to some extent by reconnaissance survey and study of topo -sheets. However, this technique is slow and also not provides very accurate information. Normally, the photographs of 1:15,000 can also be used for the purpose.
The demarcation of priority areas should be accomplished on watershed basis, because a comprehensive watershed management approach is essential for caring out for proper soil conservation measures. It is also necessary that, that the size of watershed to be delineated should be ranges from 10,000 to 20,000 ha, because for small watershed the formulation of soil conservation working plans and their execution over reasonable period is practically possible and easy, too.
The steps for demarcation of small size watershed are described as under:
1. Divide the entire watershed into different sub-watersheds following important tributaries.
2. Again, divide each sub watershed into small size, following distinct tributaries and streams passing through respective sub watershed.
3. further, sub-divided each small part of watershed [as obtained in step (2) in size ranges from 10,000 to 20,000 ha.]
Causes of watershed Deterioration:
Deterioration of watershed takes place due to faulty and bad management through the activity of man and his animals. These activities are:
Faulty agriculture, forestry and pasture management leading to degradation of land.
Unscientific mining and quarrying.
Faulty road alignment and construction.
Apathy of the people.
Results of watershed Deterioration:
Less production from agriculture, forests, grass lands etc.
Erosion increases and decreases biomass production
Rapid siltation of reservoirs, lakes and river beds.
Less storage of water and lowering of water table.
Poverty as a result of less food production.