Picture made with a Canon G11, a point-and-shoot camera, using a small tripod and the incorporated ND filter. You need an ND filter to get this motion blur effect on water during day light. It just reduces the amount of light coming to the film/sensor. Don’t confuse it with the f-stop. In fact as a parameter to measure the “darkness” of the filter, an equivalent f-stop value is used but the purpose is to indicate the reduction in the amount of light and it doesn’t produce any other effects related to the depth of field.

Picture made at Asakusa Temple. There is a small waterfall, just go and look for it by yourself :)