The crest level of a canal diversion head work, depends upon A. F.S.L. of the canal B. Discharge perimeters C. Pond level D. All the above

The correct answer is D. All the above.

The crest level of a canal diversion head work is the highest level that water can reach in the canal. It is determined by the following factors:

• The F.S.L. of the canal: This is the full supply level of the canal, which is the level that the canal is designed to operate at.
• The discharge perimeters: This is the length of the canal that is in contact with the ground. The greater the discharge perimeter, the higher the crest level needs to be to prevent water from overflowing the canal.
• The pond level: This is the level of the water in the pond that the canal is diverting water from. The higher the pond level, the higher the crest level needs to be to prevent water from flowing back into the pond.

It is important to ensure that the crest level of a canal diversion head work is high enough to prevent water from overflowing the canal. If the crest level is too low, water can overflow the canal and cause flooding. This can damage property and infrastructure, and can also pose a risk to human life.