Aha some of that looks perfect, thanks!

There's also these cobble like floor bits you see where the water flows over them. There's a really impressive outdoor example of this at the top of this series of waterfalls in the river beforehand which is located north east of Ivarstead. I've definitely seen the same thing in caves too.
Oh also, what do you reckon this river is made up of?
http://i3.photobucket.com/albums/y58/round3/In%20game%20screenshots/TESV2011-11-1113-45-52-64.jpg
EDIT: Ah this is what I was on about, I saw a more condensed version of this in a cave (yay I can post links now

)
http://i3.photobucket.com/albums/y58/round3/In%20game%20screenshots/2012-02-22_00001.jpg