CANAL - definition and classification

    A canal is an artificial channel constructed to carry water from a river, water tank or reservoir for different purposes like hydropower generation, irrigation, navigation etc.

  An irrigation canal is the one which carries water from the source to the agricultural fields for the purpose of irrigation.

Classification of irrigation canal based on discharge 

1. Main canal -
• It is the leading canal of a network of irrigation channels.
• Its discharge capacity is very high.
• It is used to supply water to branch canals and major distributaries.
• It is mostly not used for direct irrigation. 
2. Branch canal -
• It takes off from the main canal to either side.
• It carries a discharge of about 5 cumecs.
• Its main function is to supply water to major and minor distributaries.
3. Major distributaries -
• They take off from the branch canals and sometimes from the main canal.
• They carry a discharge varying from 0.25 to 5 cumecs.
• They are mostly used for direct irrigation and supply water through outlets to water courses.
• They also supply water to the minor distributaries taking off from them.
4. Minor distributaries -
• They take off from major distributaries and branch canals.
• They carry discharge less than 0.25 cumec.
• They supply water through outlets to water courses for irrigation.
5. Water courses or field canals -
• They are small irrigation channels which carry water from the outlets of a major or minor distributaries or a branch canal to the field to be irrigated.
• These are owned, constructed, controlled and maintained by the cultivators.

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Quora space - civil engineering