this has been posted before, but annoyingly I'd got a few niggley things a little wrong (dust, dodgy cloud) so reworked it yesterday when bored. In the spirit of showing the humble RAW file, it will be attached...
This one's a little wider than the original, more space to the right, and the sky's a little more carefully honed... I think...
Well it's 3 conversions
1 for the sky (there is detail in that RAW)
1 for the colours - grass, valley etc.
1 for the water flow. I made sure it didn't burn out using CP1's highlights option.. though it does look a bit bright when resized BUT it's not burned!
I used the "colours" layer as the background and pasted in the other 2 layers on top, masked them both out completely. Then with a low opacity brush (6%) I painted white on to each layer to bring the sky out and the detail in the stream.