At dusk watch for the olive caddis, especially in the high gradient sections of the streams. I use a Mr. Rapidan Delta Wing Caddis, Olive size 16 to fish to the rising trout and to cover the water when there are few rising trout. I am using a 6X or 7X leader.
The water levels are getting low so use a cautious approach as the trout are wary in these conditions. If you need help on deciding which streams to fish, call me at 540-984-4212 or check out my book Trout Fishing in the Shenandoah National Park.