The beave has been busy after a month of seemingly puttering around; the water level of his new domain has risen several inches, no doubt assisted by the increasing cold and slowly freezing waters. It also looks like he has added material to the highway culvert entrance. From the second image at left you can see it is now about 70-80% occluded.
A general location map (below) shows the general area of his home vs. our house and the former major beaver habitation that was abandoned perhaps 10 years ago or so (click to get a larger image):

Legend for the map: green icon is new beaver location; red is our property; yellow is location of previous beaver encampment; dotted line is snow machine route