The time of concentration is defined as_______________?

The time of concentration is defined as_______________?

A. the time taken by rainfall water to run from most distant point of water shed to the inlet of sewer
B. the time required for flow of water in sewer to the point under consideration
C. sum of (A) and (B)
D. difference of (A) and (B)

Scour valves are provided ______________?

Scour valves are provided ______________?

A. at street corners to control the flow of water
B. at every depression and dead ends to drain out the waste water that may collect there(Correct)
C. at the foot of rising main along the slope to prevent back running of water
D. at every summit of rising mains