Beavers were released back into the wild a few years ago in Scotland. The farmers were firmly against it. Last year 87 were killed "legally" though I'm not too sure exactly what that means as I thought they were protected.
This is no reason for killing the beavers, but their dams actually cause flooding damage in some urban and rural areas because the dams re-direct the flow of the water of the streams and small rivers especially in the Spring run-offs. Here in Ontario, neighbours get together and dismantle the dams without killing the animals...The animals just mosey off somewhere else.