ODFW plants summer steel at boat ramps, and the fish will return to them based on the smell of the water.
I posted it before, but they put them in at several areas around town: Beltline, Alton baker, D street, the next one and so on up the line to the middle fork dam (which is the mother of all plants on the Willy).
Look for decent holding water around any of those boat launches and you'll find the steel.
Good luck to you,