Went to a city park here in Seattle, one that abuts the elementary/middle school my kids went to. I hadn't been there in several years, but my daughter goes there often (a friend lives nearby). It seems a beaver or two has taken up residence there, no more than 20 yards from where a creek flows through a culvert and under the railroad into the Sound. They've got a dam in place which we saw (though we saw no beavers), a pond building up behind it, and the area around is transforming into more of a meadow. Would be a fascinating place to do ecological monitoring as the invertebrate species shift with the changing environment.