Shoot the sea lions that congregate at Ballard Lock to feed on salmon and steelhead. Get rid of the flocks of birds on Rice Island that prey on salmon smolts. Offer bounties for fishermen to catch more of the squawfish that prey on smolts in the lakes behind the dams. It may not be possible to have all the dams and viable salmon runs in the upstream river stretches. There are economic considerations on both sides.
Barge transportation does provide a marginal saving over rail transportation.
Even small amounts of hydropower do have value as do the disappearing salmon fisheries. But there are also values beyond calculations with pencil and green eyeshade. In 1856, Isaac Stephens, the Governor of Washington territory, set out to make treaties with northwest Indian tribes. The Columbia River tribes ceded land and agreed to reservation boundaries on one condition - that they would be entitled for all time to use customary fishing sites and to share equally in the salmon harvest. Yet without fish there can be no harvest, and the tribes are demanding that the United States, in execercise of its trust responsibilities, take steps to protect and restore the salmon runs.