I was at Dry Falls two weeks ago, before Memorial day. if it hasn't changed
you'll need a full fly box so you can try everything. I would try
Chironimids, adult Damsels, tan mayfly. However, in the section most
directly under the visitor's Center, hang in the shallows at dusk. we had a
great two evenings with a major hatch with large rainbows and browns
recklessly slurping bugs. CDC emergers were great but they really didn't
care all that much when they really got going. Make sure you bring a
flashlight, we forgot and left when we couldn't see anymore. Its a long
paddle in pitch dark.
Phil