How can I measure flow through a dam or out a drain?

In a FEA seepage analysis, the flow rate can be determined using a series of discharge sections. 

The flow rate out of a drain can be measured by putting discharge sections around the drain, but a better way to do it is to compare the discharge before and after the drain. The difference in discharge values across the body of the dam will give you the discharge through the drain.

When drawing discharge sections, make sure that they are drawn across the elements and not on a material boundary.