As sated above, trapping and hunting (since you dont like the idea of setting the dam on fire I dont guess you would like the idea of a slow drip of diesel into the pond either. Not that I would do it)
Really just some evening hunts will take the toil quickly. You dont have to sit out all night. Or, deer season is about to start. Maybe you will have to change your stand placement. Set up on the pond so you can pick off beavers while you deer hunt. Might not be the best place on your property to deer hunt but if you want the things gone with out spending money or any extra time your going to have to multi task.
Really just some evening hunts will take the toil quickly. You dont have to sit out all night. Or, deer season is about to start. Maybe you will have to change your stand placement. Set up on the pond so you can pick off beavers while you deer hunt. Might not be the best place on your property to deer hunt but if you want the things gone with out spending money or any extra time your going to have to multi task.