For what it's worth Doug Kelly has it right for many of the rivers, the owner just does not feel like enforcing the law for his land,

We ran into the very same thing on the Yakima River, we used to hunt a spot for years and this guy finally was fed up and posted the land and ran us off one morning,

the short is, just like Doug says, float on by but dont touch bottom or the bank Period!! and no it is not on Tribal Land, Dad says he has run into other areas just like this all over the state over the years, old rights that have been grandfathered in.

Bud.