What is the optimal slope for a storm sewer pipe between the junction box and the drop inlet?

Answer 1

The optimum slope is approximately 1/2"per linear foot. Aside from creating too much velocity, piping at steeper inclines becomes difficult to connect into a vertical structure because it creates an acute angle. When designing storm systems, if you need to move more water, you do it by increasing pipe volume, not by trying to move water faster. Anything over 1/2" per foot is really unnecessary.

Answer 2

There is an optimal slope.....
Try to maintain 3-4 feet per second for the velocity of the storm water. Faster flow causes more expensive installation because you have to dig deeper. If you're going down hill, the installation might not be more but then you may create another problem of building velocity pressure and overfilling a downstream manhole.

Slower velocity allows solids to settle out and eventually clogs up the system.

So, in summary, not too fast and not too slow.

Answer 3

Optimal slope? No such thing. You have to provide enough slope to convey the necessary flow for a given pipe diameter.

Answer 4

90 DEGREES