I don't know what courses it offers, but the CC in Hood River would be my first choice for paddling while pretending to go to college. Lane in Eugene and Mt. Hood in Gresham would also be super solid. You'll find very large boater communities in Portland and Hood River, and solid crews in Corvallis, Salem and Eugene. I don't know about the Ashland area kayakers (I just haven't paddled there), but I know the rafting scene is huge down there.
What are you studying? Both OSU and UO offer good Outdoor Program opportunities depending on whether you are more of an engineer or more of a writer. Both have business schools; OSU to catch the engineer fallout and UO for the liberal arts kids that wised up.
U of O's OP was my entry to whitewater. Now I can't park in my garage between the raft, skis and kayaks. Fortunately, their Business School set me up for a string of good jobs and I can afford to be a gear whore.