If you're able to go back to the location I might try shooting from the opposite direction. I think using the tree as a subject can be interesting, but having the people, grass and other things in the background takes away from the image. I think the less you have in the frame (besides the water and branches) the better the composition will be. Try framing the branches (if that's what you call them) against the water (backlight if possible) and that could make a very simple but interesting frame.