This may seem like a stupid question, but I never had to worry about this issue until moving to Puget Sound a couple years ago. What is the definition of navigable? I've seen local water that could barely float a canoe and was considered "navigable". I know of water in Eastern Washington that is stocked by the State and could be worked with a small drift boat, but seems to be off-limits even to float tubes. In fact, the land owners have strung barbed wire and razor wire all around public bridges, road right-of-ways, even across the river, to keep fishermen out. Some landowners string barbed wire 4 to 6 inches above the surface to snag lures. The worst owners put it just below the water... to snag unsuspecting waders or bare legs.