Shutter speeds

I finished up taking a large number of photos of a nearby river and spotted this mini waterfall. This photo was taken on a setting of 1/10 sec with an aperture of f11. I learnt that any longer exposure completely over exposed the subject. From doing this exercise and a bit of research I learnt that a slow shutter speed of any less than this was impossible as I was taking photographs in the bright midday sun. I now realise that it is easier to take long exposure photographs when there is less light i.e in the early morning or at dusk. I have also learnt that a Neutral Density filter would have helped as it can reduce the strength of light hitting the camera sensor which can force the shutter speed to lengthen.

From viewing all the photos I have taken I would say that the slowest shutter speed in which the water was sharply frozen is probably between 1/250 and 1/500 of a sec.