Tunnels

• The common muskrat burrow has an opening below the waterline with a tunnel rising to an above-water living chamber. The burrow structure can sometimes lead nearly all the way through the pond levy or dam. Rising water can fill the entire chamber, which can lead to leaks through the levy or dam. In some cases, the burrows weaken the levy to the point of collapse, leading to catastrophic failure of the pond.
  
  

Plant Destruction

• Muskrats consume roots and plants found in the water and along the shores of ponds. The roots of these plants serve to stabilize the soil of the pond shore. If the plants are consumed, the bank is prone to erosion which can damage the pond.
  
  

Prevention

• It's easier to prevent muskrats from burrowing than to eradicate them after they have already done damage. Rock riprapping -- an armor of large stones placed next to each other on the wet slopes of the levy or pond shore -- can prevent the muskrats from digging into the shore. Fastening a galvanized mesh wire along the waterline also prevents muskrat burrows. Use 2-inch-square wire mesh, placed from about 1 foot above the waterline to 3 feet below.
  
  

Pond Protection

• Adding cement to the pond shore or levy structure provides a barrier to burrowing muskrats. This allows the muskrats to exist without damage to the pond. Use a trencher -- a tool commonly used to bury electrical cables -- to dig a trench in the middle of the levy or a few feet away from the shore. Fill the trench with concrete and vibrate into place.