The canal fall with a combination of a convex curve and a concave curve, which is provided for carrying the canal water from a higher level to a lower level, is known as:
- Aogee fallCorrect
- Bsarda fall
- Cstepped fall
- Drapid fall
Solution
Concept
An ogee fall uses a convex curve followed by a concave curve to carry canal water smoothly from a higher bed level to a lower bed level.
Step-by-step solution
1. Water must drop from a higher canal bed to a lower canal bed. 2. A fall shaped like the letter S (convex curve first, then concave curve) is called an ogee. 3. So the fall is an ogee fall.
Explanation
In an ogee fall, the water first flows over a convex curve and then over a concave curve. This gives a smooth S-shaped (ogee) profile from the upper bed to the lower bed. The shape reduces sudden impact, but energy dissipation is poor.
Why the other options are wrong
B: Sarda fall is a vertical drop fall with a raised crest, not a curved profile. C: Stepped fall has a series of steps, not convex and concave curves. D: Rapid fall is a long, gentle sloping glacis, not an S-shaped curve.
Shortcut
Convex + concave = S shape = ogee.
Common mistake
Confusing the ogee fall with the rapid fall because both give a smooth flow path.
Correct answer: A) ogee fall