Lovnlivin, sorry I didn't answer quicker, but I was spending the Powerball money in my head last night. I'm obviously over that now.
First, no hijack, a hole's a hole. My beaver dens went horizontally from the bank, not down. After 3-5', they traveled up where I assume they built the dens above the water table. All the entrances, and I had as many as 9 at one point scattered around the lake, where all built on the steeper slopes like yours. I'm not sure what would burrow straight down, but maybe guys who have muskrats would know.
I've never used any bait, I've just found the entrances to the shore, and set the Conibear 330's in that path. I covered them with grass and twigs, and they seem to work OK. I have had several instances where you could actually see the trails go around the traps, and the beaver continue on the same path, so they were careful to avoid a uncovered trap.
I've also caught 3 with a double doored trap set at a den entrance. I packed loose limbs around the trap, and trapped them as they left the den at night. I've had good luck using the Advanced Trap large double door model.
As said, I would fill and pack the holes, and spread a winter cover crop like rye grass as soon as possible. Erosion will eat away the holes, and they will continue to grow.
Hope this helps.
