4.1. Headworks: Definition and Types

• The hydraulic structure which is constructed at the head of irrigation canal and supplies water to the irrigation canal continuously without disturbance is called headworks.
• Headworks are constructed for storage, raise, diversion and supply of water from natural river/stream to the canal.

Function of headworks:

• Raise water level.
• Regulate intake of water.
• Control silt entry to canal.
• Store water for certain period.
• Reduce fluctuation in level of water supply.

Types of headworks:

1. Storage headworks
2. Diversion headworks

i. Storage headworks

• When dam/weir/barrage is constructed across a river to form a storage reservoir, such a headwork is called storage headwork.
• It is constructed at the head of the canal.
• It stores the river/stream water in reservoir.
• It ensures regulated continuous supply of silt-free water.
• It raises the head of source (water level of river/stream).

ii. Diversion Headworks

• When a weir or barrage is constructed across a river to raise the water level and divert the water to canal, such a headwork is called diversion headwork.
• It is constructed at the head of the canal.
• It raises the water level in river.
• It regulates the flow of water.
• It diverts the river water towards the irrigation canal.
• It ensures silt-free water.