Canal Head Regulator

A share of water is given to a canal from a pool that is behind the barrage using a particular structure which is referred to as canal head regulator. This regulation helps in controlling the amount of water that would pass through the canal. There are a number of spans which are operated by different gates and separated by different piers. There are three major types of canal head regulators which are mostly aligned at 90° to that of the weir. These regulators help creating a diversion in the flow of the water. The three types of regulators are the open flow regulation, still pond regulation, and the silt control devices.

Still pond regulation:

In the still pond regulation the water will be drawn from the still pond. In this setup the water that is in excess of the requirements of the canal will not be allowed to escape through the sluice gates. Since the velocity of the water is reduced, the silt will be allowed to deposit in the pocket. The sluice gates will be opened only when the level of the silt is raised about ½ to 1 m below the crest level of the main regulator.

Open flow regulation:

The next regulation to be concentrated is the open flow regulation. In this flow regulation the sluice gates are opened always to allow the excess of water more than the requirement of the canal. In order to keep the silt in suspension the bottom water tries to keep a certain amount of velocity. No scouring of the silt is allowed in this type of regulation, even the canal won’t be closed for the scouring of the silt. The next important regulators are the silt control devices. The silt control devices works by creating a trap or pocket. It provides a divide in the wall. Since the disturbance makes the sediment to remain in suspension, the silt control devices concentrates the currents towards the capacity of under sluices and paves the bottom a particular approach channel in order to reduce disturbance. The wide canal head regulator plays a vital role in reducing the velocity of the water during the intake.

Purpose of the regulation:

The two main purposes of the canal head regulator are regulating the discharge into the off taking canal and the next thing is to control the entry of the sediments into the canal. Care should be taken to maintain the width of the water way in such a way that the canal should be capable to hold even if the full supply is given. With the working head provided at about fifty percent. 

Questions:

• What is open flow regulation?
• What are the two main purpose of the canal head regulator?