If you haven’t already, Shadowmap is much better for nature themed map like these so I suggest you switch to it. You can also play around with how the water looks with the terrain settings. Normally people goes for a clear and realistic water texture in these maps unless you planned to have the map looks cartoony then you can keep the water as is. I also suggest you add ColorCorrection, SunRays and use the celestial dragger plugin to make the forest pops out a lot more with Shadowmap. Good luck on your build 
Great map! Maybe a little dull, also your graphics cuts off the rest of the map so we can’t see into the distance! Overall great job on the detail and the trees!