This something that concerns me greatly. I have 2 major rivers to cross between the house and work. My best route will take me just below large dams on each river. They are close enough I could go by the lake if they are spilling or generating. I have 34 miles to go and the rivers are 10-12 miles apart. I have found a portable boat which I don't know how well it would work, but only weights 26 lbs. Another thought was to get 2 of the manually inflatable life jackets with multiple inflater cartridges. That would suck in the winter though. Still searching for a good solution.