One option is to take the dam out. I realize that there are both social and economic costs with doing this but it does solve the problem as I understand it.
More and more, as our wild anadromous stocks continue their decline into extinction, dam removal becomes the only viable option to save fish. It is happening on the Elwha and at some point in the future, could well become reality on the lower Snake. The question is, can it happen in time to save the wild runs? In the case of the Snake, probably not.