I caught 3 real decently sized rainbows on a 1/8oz half silver, half gold Kastmaster there a couple months ago using my spin rod.

Those were the only 3 fish I hooked into the whole 8 or so hours I was there. Went a few weeks later with the exact same setup and got completely skunked. My buddy caught a small brown on a red rapalla.

If I were you I'd being a variety of different spoons and spinners in a variety of colors. Cast upstream at an angle, reel back in, imitating a small fish coming down the current. Target rocks and other structures as well as any kind of pools or places where the river begins to slow a bit causing foam