pasco,
As long as a person is standing in water it makes no difference that their feet are on private property, they have a legal right to be there.

Years ago the fellow who owned the property at the confluence of the Queets and Clearwater rivers allowed the public to launch. It was a nightmare for him with trash and rude insulting behavior by some of the people using his land. Of course it is now posted NO TRESPASSING and he will SHOOT. Most access restrictions are created by a few slobs. Sadly, I don't foresee that changing.