The Fall River is always the safe bet when the heavy rains come as it has no outside influences to run off. It is just the springs, and they are pretty static.
There have been good BWO and Midge hatches on the Fall and it offers some of the best dry fly options for the area for sure.
Small streamers like a Soccer Mom, Slum Lord and Mini Gulp fished as a euro nymph, stripped or animated with a jigging motion pay off here, and a Balanced Leech using a strike indicator is a good bet in the slower pools too.
Eggs, Mops, Zebra Midges and small mayfly nymphs like a 2 Bit Hooker and Tungsten Micro May in a BWO tone and size match are good for sure. Tungsten Micro May’s are tied in an Olive and also a Black and usually #18 or 20 are the best.