Debris in Sewers

[haghanian]

Is there any basic formula to use to estimate debris deposits in a sewer? I'm concerned about a location where there is a change in slope from a very steep slope to a mild slope. I have values for seddimentation in the same line (with a different slope) at an upstream location.

 

[BobPE]

There are formulas for solids deposition, thay are called siltation formulas. These formulas are the basis of the minimum 2 fps velocity that is recommended in sewers. If you follow this rule, you typicall should have no problem. I say typically because I have found such things as VW Bettles in sewers, and 2 fps would just not keep the bug is suspension.

BobPE

 

[haghanian]

The line is already in place and its velocity is significantly less than 2 feet per second. This effect is increased by the change in slope since all the debris coming down the steep slope accumulates right there.