Water Supply and Sanitation Questions and Answers

Answer: B

Water drawn directly from natural lakes, along with rivers, streams, ponds and reservoirs, is a surface water source. Rainwater is collected from the roofs or the ground as precipitation, groundwater is taken from wells and tube wells below the ground, and desalinated water is produced by treating sea or brackish water. None of those is taken by a direct intake from a lake.

Answer: B

S1 is false and S2 is true. Infiltration galleries (horizontal, porous conduits laid in water-bearing ground near a river or lake) collect water from the unconfined aquifer or by seepage from a surface source. They are not used for confined aquifers, which are tapped by wells. S2 is true: water that has filtered through the soil is usually clear and of low turbidity and bacterial count, so groundwater from tube wells needs less treatment than the water of a river, though it may need softening or removal of iron.