Structure at the head of canal taking off from a reservoir may consist of nu ber of spans separated by piers and operated by gates.
Regulators are normally aligned at 90° to the weir. upto 10″ are considered preferable for smooth entry into canal. These are used for diversion of flow. Silt reduces carriage capacity of flow.
Types of regulators in canals
- Still pond regulation
- Open flow regulation
- Silt control devices
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.
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.
Silt control devices:
- Silt control at head works
- Entry of silt to canal 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