Question

The structure constructed at the head of a canal taking off from a reservoir behind a weir or dam is called as

• A. Sluice regulator
• B. Head regulator
• C. Silt excluder
• D. Silt extractor

Hint:

Remember the location and function of canal headworks components:
- Weir/Barrage: Across the main river to raise the water level.
- Head Regulator: At the entrance of the canal to control flow into it.
- Silt Excluder: In the river, just before the head regulator, to keep silt out.
- Silt Ejector: In the canal, after the head regulator, to remove silt that got in.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the name of the structure built at the starting point (head) of a canal where it takes off from a river or reservoir.

Step 2: Detailed Explanation:
Let's define the structures listed:

• (B) Head Regulator (or Canal Head Regulator): This is a structure constructed at the head of an off-taking canal. It has several functions: to regulate the supply of water entering the canal, to control the entry of silt into the canal, and to measure the discharge entering the canal. It is essentially the main gate or control structure for the canal. This perfectly matches the description.

• (A) Sluice Regulator: This is a more general term for a gate or sluice used to control water flow. A cross regulator on the main river could also be a type of sluice regulator. "Head Regulator" is the specific term for the structure at the canal head.

• (C) Silt Excluder: This is a structure constructed on the river bed just upstream of the head regulator. Its function is to prevent the heavier, bed-load silt from entering the canal.

• (D) Silt Extractor (or Ejector): This is a structure built within the canal itself, some distance downstream from the head regulator, to remove the finer silt that has already entered the canal.



Step 3: Final Answer:
The structure constructed at the head of a canal is called a Head regulator.