Bed level of Canal = + 171 m;

Full Supply depth of Canal = 1.6 m;

Bed level of Drain = + 169.2 m;

High flood level of drain: = 169.2 + 2.5= 171.7 m

From the given data,

We can conclude that the HFL of the drain is higher than the bed level of the canal and the bed level of the canal is higher than the bed level of the drain, so the suitable type of cross drainage structure is syphon aqueduct.

There are mainly two conditions for syphon aqueduct-

• The canal passes over the drainage system
• HFL of the drain is much higher than above the canal bed (on canal bottom).

Full Supply Level (FSL): It is the elevation of the water surface when then the channel is carrying the discharge at its peak capacity.

High flood level (HFL): It is the maximum elevation of the water surface in the river when it is carrying maximum discharge during high flood time.