The main occupation of the people in our country is farming. We depend on rainwater to grow
crops. It does not rain regularly throughout the year. We do not receive the same amount of
rainfall in all parts of the country. Thus we cannot depend only upon rainfall to grow our crops.
We must make other arrangements to water the fields at the proper time. Irrigation is one of the
important ways to do it. Canals, wells and tanks are three important means of irrigation. Today,
India has one of the largest irrigation systems in the world.
The canal is the most important source of irrigation in India. Channels are dug to build canals.
River-water is diverted into these canals. The canals can take river-water to the far-off fields,
where there is not enough water. At some places, the river-water has to be stored. We can build
a barrier of cement and steel to block the flow of river-water. This is called dam. A huge lake is
created behind the dam. The water from the lake can regulate the flow of water in the river. The
water from such lakes can also be diverted to the canals for irrigation. Punjab, Haryana, West
Bengal and Tamil Nadu have a good network of canals.Dams also help in the production of
electricity. When water from the lake behind the dam is made to fall from a high point, it is used
to turn turbines which produces electricity. The dam also helps to control floods in the river. A
project which helps to provide water for irrigation, produces electricity and controls floods in the
river is called a multipurpose project. Our government has build a number of multipurpose
projects.
Some of them are shown on the map.