Bear Trap can be good, especially below the dam but dress warm because there won't be much sun in the canyon and the wind can be awful some days. Skip 
a lot of water and only focus on the slower deep runs where fish are stacked. Dead drifting a crayfish or stonefly with a smaller egg pattern behind is a good rig. 
Other patterns to try include worms, midge larva and small mayfly style nymphs in sizes 14-18. The caddis are now showing up in bear trap along with the 
standard baetis. Look for fish in the slicks behind rocks or near weed beds on the lower end of the 'Trap