Relationship between canal systems and drainage systems in an irrigated command: choose the correct comprehensive statement.
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ACanal and drainage systems are complementary networks
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BCanal system generally runs along ridges and distributes water into fields
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CDrainage system follows the lowest lines, collecting runoff to outfalls
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DAll of the above
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ENone of the above
Answer
Correct Answer: All of the above
Explanation
Introduction / Context:Sustainable irrigation requires not only conveyance of water but also safe removal of excess. Hence, canal (supply) and drainage (disposal) systems must be planned together to avoid waterlogging and salinity, and to maintain infrastructure integrity.
Given Data / Assumptions:
- Irrigated command area with relief features (ridges and valleys).
- Separate channels convey supply vs. drainage.
- Hydraulic gradient and gravity dictate alignments.
Concept / Approach:
Canal systems commonly take ridge alignments to maximize command by gravity; water is then distributed via minors and watercourses. Drainage systems occupy the thalwegs (lowest lines) to collect surface and subsurface flows and discharge to natural streams. Proper integration makes the two systems complementary.
Step-by-Step Solution:
Check statement (a): Complementarity is fundamental—true.Check statement (b): Ridge alignment enhances gravity command—true.Check statement (c): Drains follow low lines to outfalls—true.Hence, (d) All of the above is correct.Verification / Alternative check:
Command design guidelines show paired maps for canals and drains; failures to coordinate cause chronic waterlogging.
Why Other Options Are Wrong:
Any single statement alone is incomplete; “None” contradicts well-established planning practice.
Common Pitfalls:
Using canals for dual drainage in flat terrain without checks; underestimating subsurface drainage needs.
Final Answer:
All of the above