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GATE 2022 CE (CE1) – Question 47

Irrigation · Canals, design of weirs on permeable foundation, cross drainage structures · 2 marks · Multiple select

In the context of cross-drainage structures, the correct statement(s) regarding the relative positions of a natural drain (stream/river) and an irrigation canal, is/are

  1. In an aqueduct, natural drain water goes under the irrigation canal, whereas in a super-passage, natural drain water goes over the irrigation canal.
  2. In a level crossing, natural drain water goes through the irrigation canal.
  3. In an aqueduct, natural drain water goes over the irrigation canal, whereas in a super-passage, natural drain water goes under the irrigation canal.
  4. In a canal syphon, natural drain water goes through the irrigation canal.

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Show answer and explanation

Correct answer: (A) In an aqueduct, natural drain water goes under the irrigation canal, whereas in a super-passage, natural drain water goes over the irrigation canal.; (B) In a level crossing, natural drain water goes through the irrigation canal.

Explanation

An **aqueduct** carries the canal above the natural drain; a **super-passage** carries the natural drain above the canal. A **level crossing** lets the two waters meet at approximately the same level.

A canal siphon carries the canal below the drain under pressure, rather than letting drain water flow through the canal. **Answer: A and B**.