There is NOTHING 'wrong' with the picture other than the foreground looks more like a mount/picture frame than part of/belonging to the background....an attached border.
To anchor/connect it to its background an intermediary element is needed..
Put simply....the difference between where it now is...and how I've described it should be [and how it almost was...at one stage] will be the difference between its straight acceptance as a wall submission or its rejection.
You 'may' not understand/accept the distinction/difference but it's one of the criteria by which people [mods] judge a submission....whether it looks/reads right.
The stand-out issue is that the grass is so dark immediately below the water....it doesn't so much separate the foreground from the background as separate the result into two totally unconnected images....like a cut-and-paste.
Now if THAT's because the foreground grass/trees is on a separate image layer to the background then that's a real problem with the use of layers.... splitting drawings into 'bits' that are actually unrelated....the result is disjointed.
You can have umpteen pictures without a shoreline...you can have umpteen photographs of real locations....if they don't read right they won't be approved, either.
I am not [trying to] help you with some 'other' picture of a lake scene...I'm responding to THIS one.
Maybe someone else will learn something from the advice, even if it's ignored here.