Was there fresh mud on the dam? was there a wet spot or area on the cross over?
I do not break a dam when doing beaver,first off its illegal here,but even when I am doing adc work--I dont break the dam, I want the water levels to stay where they are--its just easier with stable water levels, than with dropping levels.
If the cuts you saw are old,and you find no fresh cuttings --no new feed bed or no new chews,and no new mud on the dam--look elsewhere.How long is the ditch?
Tom