Intake Structures and Conveyance Questions and Answers

Answer: D

The statement that submersible intake structures are normally used for lake-based water supply is the true one, as the key shows. A submerged intake sits below the water surface in the lake and draws water from there, so it works at every level of the lake. The other statements do not describe the usual practice: an intake tower is placed upstream of a dam (in the reservoir), not downstream, an underground chamber in the river bed is not the usual river intake, and a siphonic intake at the middle of the canal is not the way a canal supply is augmented.

Answer: C

Steel pipes are best for laying in ground that is liable to subsidence, since they are ductile and flexible and have long lengths with welded joints, so they can undergo some settlement and movement without breaking or leaking. Cast iron pipes are brittle, asbestos cement pipes are also brittle and break under the uneven settlement, and PVC pipes are not suited to heavy loads and soil movement in large water supply schemes.