I'll second jfrazierjr there...
but i'd go over the river with a nice scatter brush, maybe a bit cloudy and make some highlights and ripples... On some places the highlights is a bit off and you can cover those areas with some ripples and foam
(chalk brush, 2-3px size, 100% size and angle jitter, scatter a bit, for/back color jitter with white and a light blue, apply with 30-50% opac and draw along the edges)