Mike Callahan and the folks on Facebook's Beaver Management Forum, we were able to build a culvert protection fence. That was one year ago. This video documents the results of that effort and the effort of the beavers. Unable to reach the inflow side, their only option was to try to block the outflow. Working against the flow proved difficult for them as the daytime flow, always washed some of their work away.
While our efforts were not 100% effective, it makes annual maintenance simple. Unfortunately, we may have some bad news along with the good news.
Last year we had five beavers on the pond, representing three generations. I suspect the parents told the oldest sibline to move on last season. However, there have been no sightings of the mother or two youngsters born last year, and during the winter, I saw beaver tracks and fox tracks in the same vicinity. I fear the worst for the two youngsters and mom. It's possible mom is still in the lodge with a new crop of kits, but only time will tell.