If there is insufficient rainfall throughout the year then the crop production is greatly affected. For overcoming this problem, irrigation canal system are created for supplying water to commanded area.
Irrigation Canal generally comprise of a source being river, lake,etc which then passes water to commanded area through a system of main canal,branch canal and dis-tributary canal.
Human made channel for purpose of irrigation through which water flows is called irrigation canal.
Main Canal is constructed with head regulator at entry on either side of river to pass the water.The discharge of water is smaller than that of river.During flooding the gates are closed.If excess silt is present then silt ejector can be created in downstream to preserve the crops.
A cross regulator is constructed at upstream of main canal and a head regulator is constructed near it in downstream passing the water to branch canal.If the level difference from upstream to downstream is high then fall is created to reduce the level of water flow.
Dis-tributary Canal traps water from the branch canal and passes on to the command area for irrigation.The discharge of water is minimum than other canals.
If the canals are in filling then lining should be done on either side to prevent seepage of water.
The canals structure also serve to connect varied topography acting as a bridge.