Correct Answer - Option 4 : Trapezoidal
Lining of canal:
(i) By lining of canal we mean that the earthen surface of the canal is lined with a stable lining surface (such as concrete, tiles, asphalt etc.)
(ii) In general, We adopt two types of lined canal section:
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Triangular shaped channel with circular bottom (for smaller discharge)
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Trapezoidal shaped channel with rounded corner (for larger discharge)
Advantage of lining of the canal:
(i) Prevents seepage loss and hence more area can be employed for irrigation.
(ii) Helps in the prevention of water-logging.
(iii) Increased velocity in a canal prevents silting of the canal.
Disadvantage of lining canal:
(i) It requires heavy initial investment.
(ii) It is difficult to repair initial investment.
