Chop a large hole near the edge where it looks like the beaver comes out when there isn't any ice. Then put a stik with some beaver castor on it about 4 ft from the edge of the water and put a #4 or #5 leg hold trap on the bank. stake it down really really really good. Hopefully the beaver will stick his head out of the hole, smell the beaver castor, start to walk toward the scent and WHAM! he is caught.