I just checked out GooMaps satellite view to see how far this channel goes, as this direction is toward the upper reaches of the catchment. Less than a quarter mile.
You probably can’t pick her out, but just at the last visible bend is a lady mallard paddling away. I think she’s the same one who surprises me most days when I walk this way by jumping into flight while loudly quacking. As she did today. She sure is hanging around this spot for quite a while.