I like to go out and shoot vintage bridges. Near this is a low water bridge and a very nice railroad bridge. This is kinda up in the woods. There is a cable coming off the right side and is anchored in the ground. This is a pier for something, but I cannot figure out what. There is no evidence on the bank on the other side of the river.
In Austin, Texas on the north bank of the Colorado River there is a similar structure that was used to support equipment to dredge gravel from the river. Perhaps that is what this is. Whatever it is this one is a very beautiful object.
Down in Alabama this would be a pier to attach a cable crossing the river to control the movements of a water current propelled ferry boat. The matching one for the other side may have been removed by now.