Irrigation may be defined as the process of artificially supplying water to soil for raising crops.

The engineering of controlling and harnessing the various natural sources of water, by construction of dam and reservoirs, canals and headwork and finally distributing the water to the agriculture fields is called as irrigation engineering.

1. India is basically an agricultural country, and all its resources depend on the agriculture output. Water is evidently the most vital elements in the plants life.
2. Water is normally supplied to the plants by nature through rains. However, the total rainfall in a particular area may be either insufficient, or ill-timed.
3. In order to get maximum yield, it is essential to supply the optimum quantity of water, and to maintain correct timing of water.
4. This is possible only through a systematic irrigation system by collecting water during the period of excess rainfall and releasing it to the crop as and when it is needed.

5. Thus the necessity of irrigation depends upon following points:

   a) Less Rainfall

   b) Non-uniform Rainfall

   c) Growing a number of crops during a year

   d) Growing perennial crops

   e) Commercial Crops with additional water

   f) Controlled water supply