Good start. I think your image looks more graphical than a photoreal matte. It is more like a fantasy poster then a real landscape that could be used in a shot. That's fine if you are going for that but if you are going for a photoreal matte painting here are a few suggestions to start with.
1. The Sky should be reflected in the water. A sky that bight and dramatic would be also seen in the water. I have taken many pictures near the water at that time of day and most of the time the water is just about the same color as the water. It would not be a glassy reflection because your water is rough but it would definitely inherit the color of the sky
2. The highlight in the water seems out of place. You have the light reflected part of the water is sitting directly behind a cliff where the should be shadow. The highlight should begin at the edge of the cliff.
3. Your dark (black) values are the same throughout the image. Your blacks should not be nearly as dark the further into the distance you go. So the shadows of the statues should be lighter than the shadows on your foreground cliff.
I think these things would be a good start. Hope that helps.
thank you so much, i realy read ur 3 golden suggestions with a big attention and find them all right and very helpful for my final version, thanks for the time u give to this post and ur pro tips. wish to get ur helpe in my feature posts.