Canal Irrigation System in India
Canal irrigation is the most important form of irrigation in India. It is cheaper. It is of greatest advantage in the river valley regions. In canal irrigation, U.P. stands first in India, followed by Punjab and Haryana. Canal irrigation is of much use in the deltas of rivers, the Godavari, the Krishna, the Kaveri and the Mahanadi and the Ganga, and in the coastal plains of Kerala.
The role of Canal irrigation for modernization of irrigation in India is great. Modern Canal irrigation is now conducted, controlled and administered as a part and parcel of river valley projects.
They are planned to serve dual purpose effectively. They provide irrigation facilities and control flood. Many of these river valley projects are called multipurpose projects as they serve manifold benefits such as flood control, irrigation and generation of power, etc.
The canal irrigation is of two types, namely: Inundation Canal and Perennial Canal.
Inundation canals are taken out from the rivers. These canals do not have any kind of weir at their head to regulate the flow of water from the river. During rainy season, the river gets flooded and the flood water overflows into these canals. Many canals of these types are found on the Sutlej-Ganga plains and Brahmaputra valley. These canals constitute simple flood water drainage system. The supply of irrigation water through the inundation canal is dependent on the rainfall. Besides, irrigation is restricted to the land lying on a level lower than the river valleys. Moreover, during winter these canals are practically of no use. In modern India, attempts are being made to convert them into perennial canals with the help of river valley projects.
Perennial canals are those canals which maintain its flow of water throughout the year even during winter season. These canals draw their water either from rivers or from reservoir of the river projects. A weir is built below the intake of the canal, the intake itself being regulated by sluice gates.