Cody,

Put the trap parallel with the dan and break the day to let water run under the trap.
Stick a couple of sticks (1" or larger) on the water side.
The beaver can't get to the broken dam, so he has to walk the dam to see how to fix it.
At this point he would have to walk into your trap. Let hope he doesn't bring in any repair material with him.
Good Luck, I have caught them this way.
If this doesn't work, I would wait, find where it is crossing over and set the trap on the downstream side. You should catch him here.
JC
