Are you targeting only rainbows and brook trout or are you also going after bigger brownies?
High water or low, the artificials that have harvested for me have been Rapala rainbow colored small jointed and Rapala in orange and gold. Both floating. These simply KILL 'bows and brookies.
For browns . . . Rapala white countdown.
15 miles below the damn . . . pretty good setup. At least you're mostly away from the canoe/kayak maelstrom.