The Arboretum knew nothing about it, either. The Seattle Parks Department knew nothing of a missing beaver lodge, either, but I did learn a lot about the jurisdiction of the area in question from John Candy, senior gardener for Seattle Parks. He knew well of that particular lodge, and was sincerely horrified that anything so final could've befallen it. Mr. Candy told me that the University of Washington had title of the land down to the original shoreline. Land that was reclaimed when the U.S. Army Corps of Engineers dropped the level of Lake Washington in 1916 at the completion of the Ship Canal had been granted to the Seattle Parks Department.
Country clubs are notorious for disregarding local wildlife laws to protect their properties.
I considered putting up notices at all the local rowing clubs and collegiate rowing programs, as they're out at the crack of dawn in the general vicinity, and so might've heard or seen something. Decided to return to the site the next day to look for clues. Didn't pack a magnifying glass, but did take camera and a couple Zip-loc bags. Found the beaver lodge. To my utter mortification and chagrin.