What is the name of this animal?

There are these creatures... they look like a cross between a beaver and a rat and a groundhog. People call them moreels or moreals or something like that but when I type that into google, they don't show up. I think they live in the water like a beaver cuz they are usually around streams and I mostly see them running around on slightly rainy days. They are smaller than beavers or groundhogs and have tails sorta like a rat. I used to see them all the time when I lived in Portland, Oregon. I see them occasionally back here in the Ozarks. Just wondering what their actual official name is, perhaps I just don't know how to spell it right.