A Super passage is a cross drainage work provided to carry a natural drain over a canal when
- Abed of the natural drain is at the same level as the canal bed.
- Bbed of the natural drain is well above the canal F.S.L.Correct
- Cbed of the natural drain is below the canal F.S.L.
- Dbed of the natural drain is below the canal bed.
Solution
Concept
Conditions for constructing a super passage
Formula
NONE
Step-by-step solution
1. Cross drainage works are required where a canal intersects a natural stream or drain. 2. In a super passage, the drain is passed above the canal, with canal water flowing under gravity beneath the drain trough. 3. This is provided when the bed level of the natural drain is well above the Full Supply Level (F.S.L.) of the canal. Answer: B
Explanation
A super passage is a hydraulic cross-drainage structure designed to carry a natural stream over an irrigation canal. It is constructed when the bed level of the natural drain is well above the full supply level of the underlying canal. This allows the canal water to flow under gravity beneath the stream trough without any obstruction.
Why the other options are wrong
A) Equal bed levels require a level crossing structure rather than a super passage. C) When the natural drain bed is below the canal F.S.L., an aqueduct or siphon aqueduct is used. D) When the drain bed is below the canal bed, an aqueduct is provided to carry the canal over the drain.
Shortcut
Super Passage = Drain OVER Canal (drain bed above canal F.S.L.).
Common mistake
Confusing a super passage, where the drain flows over the canal, with an aqueduct where the canal flows over the drain.
Correct answer: B) bed of the natural drain is well above the canal F.S.L.