Canals in India are of two types:

♤ Inundation canals, which are taken out from the rivers without any regulating system like weirs etc. at their head. Such canals provide irrigation mainly in the rainy season when the river is in flood and there is excess water. When the rainy season is over, the flood in the river subsides, the level of water falls below the level of the canal head and the canal dries up. Some canals taken off from the Satluj in Punjab were of this type. Since irrigation from this type of canals is uncertain, they have been converted in perennial canals.

Barrage: An artificial obstruction placed in a river or water course to increase the depth of water.

♤ Perennial Canals are those which are taken off from perennial rivers by constructing a barrage across the river. Most of the canals in India today are perennial.