I wasn't asking about salmon, only steel runs. And, AGAIN, NOT streams that simply "have fish in them all year". Rather, streams that have active runs all 12 months. You're all reading too much into the original quiz question.
So to correctly answer you original quiz question the answer would be;
Columbia, Clackamas, Willamette, N Santiam, S Santiam, Trask, Wilson, Siletz, Nestucca, Umpqua, and Rogue.... Clearly your question was too vague to specify only three rivers. I have seen the question posed before, What three coastal rivers have native populations of steelhead year round.. The answer is simply Rogue, Umpqua, Siletz.
Just thought I would try to help out on the Natural History of Oregon's steelhead runs.