I thought I'd already left a comment on this but it hasn't shown up for some reason - good job I came back to have another look! Can I ask what exposure you used? I'm beginning to experiment for the first time with shots involving water and would like to try and acheive the same effect. It's a beautiful photo.
Ange my exposure on this photo was f7.1 at 20 seconds. Depending on what kind of light you have it determines what shutter speed you can use, with lower light the longer shutter speed you can shoot with. It is a little harder in pure sunlight to get these shots, unless you use a neutral density filter. I find anything over 10 seconds gives pretty cool results. Hope this helps!!! Please e-mail me if you have any questions. Thanks again nice photos by the way!!!