Silt excluders are constructed ________ while silt ejectors are constructed ________.

Concept:

Silt Control Devices: The entry of silt into a canal, which takes off from a diversion head works, can be reduced by constructing certain special works which are called silt control works or silt control devices. These works may be classified into the following two types:

Silt Excluders:

• Silt excluders are those works which are constructed on the bed of the river at upstream of the head regulator.
• The clearer water enters the head regulator and consequently the silted water enters the silt excluder. In this type of works, the silt is, therefore, removed from the water before it enters the canal.

Silt Ejectors:

• Silt ejectors, also called silt extractors, are those devices that extract the silt from the canal water after the silted water has travelled a certain distance in the off-take canal.
• These works are, therefore, constructed on the bed of the canal, and a little distance downstream from the head regulator.