Nutria and muskrats share a lot of traits in common, including a very prolific nature. Here's an example of what nutria can do to an urban pond with a steep embankment (similar to a dam).
And here's my covert, pet-safe, non-patented nutria "snare-barrel", complete with a one-way drowning-wire harness - shown in the red circle (keeps the dead rats out of sight from squeamish city-folk). Two 5-inch, capped PVC pipes are secured midway inside the drum (length-wise) for flotation purposes. Sweet potatoes for bait. Rats have to pass through the submerged opening - and engage the snare - to gain access to the bait. Not sure if this concept would also work for muskrats, but it might.
