Let me start by talking about some of the highlights of this photograph. For starters, the composition is clean, you’ve managed to limit your photographs color pallet and you’ve played heavily with depth and shape.
In fact, the depth is the feature I like most about this photograph. I love photographs were I feel like I’m in the image. This requires great use of lines, depth and textures that help add to the three dimensionality of the shot. You have all of those things in this photograph. For example, the pattern on the dock along with the texture of the water help provide texture and context without upstaging the main idea of the photograph.
The way you’ve positioned yourself above your subject allows the viewers to use the shapes created by the subject’s body to lead their eye into the photograph through the upper right corner of the shot. Similarly, the lines and colors all help draw our attention towards the girls feet. It seems that is what she is looking at, and this photograph allows us to see things from her perspective for a moment. It’s quite an emotional photograph. It doesn’t appear staged at all (even though you mentioned you did provide direction). It seems very natural and relaxed.