Who said they cant use boats in costa rica??

Ok i'm just curious as to why they cant use boats in costa rica according to our last discussion?? When Wieke mentioned that most of the rivers are white water and too shallow, does that apply to most of the rivers close to towns? or all of them in general??

this is a pretty random video of some people who went to costa rica, and the vidio in the post below also shows them on boats...
http://www.youtube.com/watch?v=PaLabgZZY00&mode=related&search=