You might want to make sure that the contractor you choose has an excavator with a thumb. He will be able to grab much of the material and transfer it out of the pond. Often the beaver huts provide great fish habitat, so think about how much you want removed. Maybe just remove enough material so that the huts are a foot or so below the water line. We have had a lot of rain in the Richmond area, so you might think of the water line during dryer times!