1.The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is

2.The main disadvantage of cement concrete sewers is

3.If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be

4.The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is

5.The design discharge for the separate sewer system shall be taken as