Because of the poor quality, shakiness, and brevity of the footage, it's not even clear that the would-be monster is actually moving. It seems to be heading upstream, but that could just be an illusion created by the water moving past it. It could be making progress toward the shore-or its head might be simply sitting there, more or less stationary in the water while the "body" contorts with the current. To really know, we'd need to see more than a short clip; if it's still in the same spot after a minute or two, then it's not making forward progress and therefore not a living creature.
There's something else very suspicious about this video: It seems to have been shot by two different people with two cameras-or at least from two different angles.
It begins with a wide shot, and then cuts to a closer-up one, but the closer-up one seems to be much lower and head-on, instead of from above and to the right. The final video intercuts the two different clips, raising the question of why. If there are two different, genuine videos of the "animal," why not just show both of them in their entirety, instead of editing and manipulating the footage?