Correct Answer : 1 to 3 months
Explanation : For the purpose of cleaning the top layer of sand is removed to a depth of 15 mm to 25 mm. The water is admitted to the filter the cleaning interval varies from 1 to 3 months.
Correct Answer : Option (B) : Outlets
Explanation : An outlet is a simple and small irrigation structure which is constructed along the distributaries. The amount of water that is withdrawn through the outlet is in proportion to the area that is irrigated below respective point.
Correct Answer : Option (A) : 2.5:1
Explanation : According to Terazghi, the following upstream slopes should be recommended.1. Homogeneous well graded – 2.5 : 12. Homogeneous coarse silt – 3 : 13. Sand and gravel with RCC core wall – 2.5 : 1.
Correct Answer : Option (A) : 0.25 to 5 cumecs
Explanation : The major distributary takes off from a branch canal to distribute the water to various parts of the field. The supply of the water varies from 0.25 to 5 cumecs.