If control measures are delayed other game animals may be damaged as during the fall and winter they may take refuge in the groundhog burrow. Fumigation is one of the most affective methods of controlling groundhog population. However, around buildings or in a high fire hazard area trapping or shooting may be a better approach. It has also been noted that a well cleared and mowed dam discourages inhabitation. Muskrats - The muskrat is a small stocky rodent with rich dark brown fur.
Muskrats are chiefly nocturnal.
Muskrat dens are constructed by burrowing into the banks of lakes and streams. These burrows start from six to eighteen inches below the water surface and the tunnel then rises to above the phreatic surface. It can be seen that the burrow starting from the reservoir side offers a path for water flow, and can seriously weaken the embankment. It becomes even more hazardous when a muskrat den on the upstream side is close to a groundhog den on the downstream side. If the earth partition between these dens should fail there is a conduit completely through the dam.