<<Edit>> (Was made more readable, good luck with your wall!)
Well I'm not well versed in wall creation, so I can't really help you there. I do hope someone can help you
with that though. What I can do is be an objective pair of eyes. And from what I can tell, your problem stems from these
things.
Standing in water:
A water line across the body makes the person in question appear to be standing behind the water, unless you can see
water around her, especially between gaps in arms, legs, etc.
If you put the water line around her (not allowing it to cross her body) then she will seem as if she's in front of
it.
To make it appear like she's standing in it, you'll need to have a line across her like you do now, and then
water behind her with a line NOT touching her.
Since she doesn't appear to have any useable gaps untill around her neck, and that would raise the water too high,
my suggestion is to add foam to the line in front when it crosses her body. Round the line around her at the edges of
when it reaches/leaves her. This foam should suggest movement, and may also help fix your problem. Also lighten up on
the ripples in the water. As you have it now, it's more detailed than the rest of the pic, (it looks like 3D on 2D)
and throws it off a bit.
A reflection may not be needed, but I'm not sure.
Additional:
I also think if you add some background, like trees or something else indicating a location, like a bath house, it will
make the whole thing more believeable. Another part of why the background may look odd is if there is water, there is a
reason for the water. Water doesn't just come out of nowhere. It happens in a location. And bathing doesn't
take place in a void unless your swimming under the water.
And when I look at it some more, her hand seems odd the way it's coming out of the water.. it may need some more
wrist or something to make it appear more natural. On first glance you don't associate it with her arm. It takes
you a bit to realize that she has it across her chest.
Anyway, I hope that helps some, and I think your idea is a good one. :)