Which one of the following is not correct with respect to the provision of freeboard in sewers? The freeboard will act as factor of safety against the
- AError in estimating the average, maximum sewage flow
- BLarge scale infiltration of storm water
- CUnforeseen increase in population or water consumption
- Dminimum flow velocity necessary for self-cleansing of the sewersCorrect
Solution
Concept
Freeboard in sewers
Step-by-step solution
1. Freeboard in sewers gives a margin against errors in flow estimation, storm-water infiltration and population growth. 2. It has no relation to the minimum self-cleansing velocity.
Explanation
Freeboard relates to capacity, not velocity.
Why the other options are wrong
A, B and C are the purposes of freeboard.
Correct answer: D) minimum flow velocity necessary for self-cleansing of the sewers