To put some results onto Salmo's comment about Chinook in the Deschutes, WDFW did a study there where passed a lot of adults to see the returns. The unmarked returns were so few in number that they easily could have been "drops"; hatchery fish that were not marked in the mass-marking process.

For quite a while, the Deschuites was one of the wild coho index streams for PS. Smolts were trapped, adults enumerated, etc. I think that when the Deep SS survival issue for yearling smolts surfaced the run petered out. The system could produce coho returns but not Chinook.