4.  A cross drainage work is a structure carrying the
discharge from a canal across a natural stream
intercepting the canal.
 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
are called cross drainage works.

11. Canal over • aqueduct
• Siphon
the drainage
aqueduct
Canal below • Super passage
the drainage • Canal siphon
Drain through • Level crossing
• Inlets and
the canal
outlets

21. TYPES OF AQUEDUCTS
Type Type Type
1
2
3

25. How does an aqueduct work?
The water was transported in concrete tunnels.
The tunnels were underground if possible.
Sometimes the tunnel had to go above
ground. Tunnels could be build with a shaft. This
shaft allowed them to take out dirt and lower
supplies to the workers.
tunnel

26. PROPER SITE FOR DRAINGE CROSSING:
The site selected for the cross drainage works should have
the following main characteristics,
1. It should be such that it requires minimum disturbance
regarding the approach and tail reaches of the drainage
channel.
2. Suitable foundation soil should be available at reasonable
depth.
3. Sufficient headway is available for the super structure of
the aqueduct over the H.F.L of the natural stream.
4. Suitable existing topography, geological and hydraulic
conditions for the cross drainage works at reasonable costs

27. LICHFIELD CANAL AQUEDUCT
Birmingham, England.

29. This aqueduct consist of the centre support and the
parts of the 2 abutments located adjacent to the hard
shoulders.