Might I suggest adding the Rogue River in particular? Just seems like a really important one to include, much more significant that something like the Clackamas River. Also the Hood River would be nice, although much smaller.
Edit: on consideration, here's the full list of what I would add, in (what i would consider) order of significance, though the Rogue is definitely the one really big one
Edit: on consideration, here's the full list of what I would add, in (what i would consider) order of significance, though the Rogue is definitely the one really big one
Rogue River
Hood River
Santiam River
McKenzie River
Siletz River