Another economic issue we haven't touched is what it costs taxpayers to build and maintain the riversystems. Billions are spent annually. And on the Snake/Columbia system, traffic volume is pretty slim----if the barge lines had to pay even a fraction of the costs of river operation and maintainance they would never get out of Portland. (Further, locks on at least 3 dams [don't recall the names off the top of my head] are going to require major work in the very near future in order to remain operational and congress might not want to spend the money to keep them going.) Mississippi River system has decent traffic volume, but if the barge lines were expected to pay any significant amount for the upkeep the resulting rate increases would shift quite a bit back to rail.