Oh, is that one on the left an older version that you have available? You could flatten it if need be and put that above the problem layer, then add a new mask, invert it so it's black, then paint over with white on the mask just the side of the river with the shadow, and once done add a hue or color balance layer adjustment with a clipping mask to get the colors of the new old layer more in line with the post lighting effects layer.