With the recent summer floods, I could see where the water level was much higher at one point. It has since settled down to it's normal level, I'm guessing. Cachers are likely to find lots of ducks and nutria at this location. The adjacent building seems to have adopted the critters.
UPDATE: The tree that originally held the cache slumped into the water, and I lost the ammo can. Replacing it with a small tube that is tied (nylon) and zipped secure. The lid unscrews. I've corrected the coordinates.