Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for

Unexpected large scale infiltration of stream water

Unexpected increase in the population

Under estimates of maximum and average flows

Sewer pipes are designed for maximum discharge with 25% to 33% vacant

1.	Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for
A.	Unexpected large scale infiltration of stream water
B.	Unexpected increase in the population
C.	Under estimates of maximum and average flows
D.	All of the above
Answer» E.