Types of Canal Head Regulators

Canal Head Regulator

Structure at the head of canal taking off from a reservoir may consist of number of spans separated by piers and operated by gates. Regulators are normally aligned at 90° to the weir. Up to 10" are considered preferable for smooth entry into canal. The functions of canal head regulator are:

To admit water into the off taking canal.
To regulate the supplies into the canal.
To indicate the discharge passed into the canal from design discharge formula and observed head of water on the crest.
To control the silt entry into the canal. During heavy floods, it should be closed otherwise high silt quantity will leave to the canal.

Types of Canal Head Regulator

Following are the common types of Canal Head Regulator:

Still pond regulation:
Open flow regulation
Silt control devices

1. Still pond regulation:

Canal draws water from still pond
Water in excess of canal requirements is not allowed to escape under the sluice gates.
Velocity of water in the pocket is very much reduced; silt is deposited in the pocket
When the silt has a level about 1/2 to 1m below the crest level of Head Regulator, supply in the canal is shut off and sluice gates are opened to scour the deposited silt.

2. Open flow regulation

Sluice gates are opened and allow excess of the canal requirement
Top water passes into the canal
Bottom water maintain certain velocity in the pocket to keep the silt to remain in suspension
Canal is not closed for scouring the silt.

3. Silt control devices

Another type of Canal Head Regulator is the silt control device

Silt control at head works can be controlled by Providing a divide wall to Create a trap or pocket
Create scouring capacity of under sluices By concentrating the currents towards them
Paving the bottom the approach channel to reduce disturbance because due to disturbance sediment remains in suspension