Correct Answer : 99 %
Explanation : The slow sand filters remove suspended and bacterial impurities to an extent of 98 to 99%. It requires a large area and unsuitable for treating high turbid water.
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 The amount of water that is withdrawn through the outlet is in proportion to the area that is irrigated below respective point.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.