Environmental Engineering
The most commonly used sewer under culverts is

Circular cast iron sewer
Semi-elliptical sewer
Horseshoe type sewer
Circular brick sewer

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Environmental Engineering
Scour valves are provided

At every depression and dead ends to drain out the waste water that may collect there
At street corners to control the flow of water
At the foot of rising main along the slope to prevent back running of water
At every summit of rising mains

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