Very nice river, Paul. I like the sweep of it and the water color is fantastic. I do have some comments; I would take a look at the trees; some are very translucent, others very dark. A more subtle mix, perhaps with added species would do the render good.
Also, some wisps of foam at the water's edge would be quite natural. Not much, just a few strands. Another thing you might try is increase patchiness of the water, like turbulence creating smooth areas and rougher areas.