Blue stream

All the rivers are blue in the sunshine.
Something to do with superfine particulates, short wavelength light (blue) and refraction.
Don’t ask me to explain because A level physics was 60 years ago and I struggle to remember now what I did yesterday!
Anyway the rivers look amazing in the sunshine. Another 10 miler, however we had a lift up and just walked back! 6 hours including two coffees and a picnic lunch.