A canal headwork is an assemblage of various hydraulic structures constructed at the head of a canal to divert clear water to the canal.

PARTS OF CANAL HEADWORK

• DIVIDE WALL: A long solid wall constructed at right angles to weir. It divides the river channel into two compartments.

• HEAD REGULATOR: Structure constructed at the entrance of canal to regulate the supply of water to canal.

• UNDER SLUICES / SCOURING SLUICES: These are the transverse openings in the weir body, used to remove the deposited silt.

• FISH LADDER: Structure is provided for the movement of fish from one side to other.

• SILT EXCLUDER: Structure constructed to control entry of silt into the canal

• SILT EXTRACTOR / SILT EJECTOR : Structure constructed within the canal to eject silt entered in the canal.

• WEIR / BARRAGE: A barrier constructed across the river to raise water level. They are constructed with the crest at pond level. The difference between weir and barrage is that gates are provided at the crest of barrier in barrage. The flow is perfectly controlled by gates in a barrage.