- A structure whose main purpose is to supply water to the off taking canal is know as head works.
- When the off taking canal is to supply water for irrigation purpose, its headworks is call irrigation head works.
- Irrigation headworks may be divid into two categories.
1. Diversion headworks or simply head works.
2. Storage headwork.
1. Diversion head works.
- The purpose of this head work is to divert river water into the off taking canal.
- It is located across the river near the point of the take-off of the canal.
A diversion headwork performs the following functions:
- It regulates the flow in the off-taking canal.
- Silt entrance into the canal is controlled.
- It raises the level of water in the river.
- This causes diversion of the river water into the off taking canal, under gravity flow.
- By raising the level of water in the river with the help of diversion work.
- Consequently raising the off-take level of the canal, more area may be brought into the command of the propose canal system.
- The level of water in the rivers remains fluctuating due to changing flow.
- Diversion works reduce such fluctuations in river water level.
- Although the purpose of diversion head work is not to store water but still some water definitely gets store.
- This stored water can be use to augment the short supplies of the river.
- This type of augmentation is possible for few days only, because stored water is not much in amount.
2. Storage head works.
- Storage works the works which store surplus water when available in the river.
- This store water is use to supplement the available flow when flow in the river falls short of the deman.
- Storage head work comprises the construction of dams across the river.
- Various aspects of storage of water have already been discusse in chapter on Reservoir Planning Construction Aspects.
- Various types of days also have been discusse in earlier chapters.
- In this chapter, only diversion headwork will be dealt with.