25-02-2013, 11:43 AM
Cross Drainage Works
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Definition:
A cross drainage work is a structure carrying the discharge from a natural stream across a canal intercepting the stream.
Canal comes across obstructions like rivers, natural drains and other canals.
The various types of structures that are built to carry the canal water across the above mentioned obstructions or vice versa are called cross drainage works.
It is generally a very costly item and should be avoided by
Diverting one stream into another.
Changing the alignment of the canal so that it crosses below the junction of two streams.
Cross drainage works carrying canal across the drainage:
the structures that fall under this type are:
1. An Aqueduct
2. Siphon Aqueduct
Aqueduct:
When the HFL of the drain is sufficiently below the bottom of the canal such that the drainage water flows freely under gravity, the structure is known asAqueduct.
In this, canal water is carried across the drainage in a trough supported on piers.
Bridge carrying water
Provided when sufficient level difference is available between the canal and natural and canal bed is sufficiently higher than HFL.