If you use a polariser on a bright day, you will lose about 1 1/2 to 2 stops of light. So using Velvia at F16-F22 and a polariser should give you exposures of over 1 sec good enough for the smoothness of water your looking for. Plus practise at diffent times of day at the same place and then conpair results. Great photo BTW

Eggiwegs! I would like... to smash them!