Head regulator; outlets and escapes

Head regulator (4 marks)

A head regulator is a gated structure constructed at the head of an off-taking canal, distributary or minor from a parent canal or river. It admits the required discharge into the off-take and shuts it off when needed.

Functions:

1. Regulates the discharge entering the off-take channel.
2. Controls silt entering the off-take (high crest, silt excluder).
3. Measures the discharge.
4. Closes the supply for repair, flood or when the water is not required.

Importance of outlets (2 marks)

An outlet delivers the water from the distributary to the water course (or field channel).

1. It gives the farmers a fixed and equitable share of water.
2. It allows measurement and control of the discharge to each chak (command area).
3. It makes the best use of the available supply and gives equitable distribution.

Importance of escape structures (2 marks)

An escape is a structure that disposes of the surplus water of a canal into a natural drain or river.

1. Protects the canal against overtopping and breach from sudden excess flow (heavy rainfall or sudden closure of gates).
2. Provides a means to empty the canal quickly for repairs or in an emergency.
3. Removes silt (scouring escape) and disposes of flood water that enters through cross-drainage works.
4. Escapes are placed near the canal head, upstream of major structures and upstream of cross regulators.