If you’ve watched Mayflies and a few other migrational insects like Stoneflies and Midges hatch, they always fly upstream.
Four times a day (peak occurrences at first and last light) these little critters let go of where they are and drift downstream.
Immature bugs drift downstream, mature insects fly upstream, nature’s way of distributing the biomass.
When Fran Gough did his insect study on the Little Lehigh, behavioral drift was apparent.
Fran Gough’s study also displayed the phenomenon of Terrestrial Drift. At first light substantial numbers of ants appeared in the drift.
It’s worth being on the stream at sun up with a box full of ant patterns.
Between hatches Constant Drift is sparse but continual consisting of main hatch stragglers or maturing nymphs which lose their foot hold.
Anchor ice, drought and chemicals have an obvious affect on the stream eliminating fishing but flooding can make for interesting fishing.
Rising water sweeps Crane flies and terrestrials from rocks, branches and debris providing a plethora of fine dining to our finned friends. Have crane fly and terrestrial patterns in your fly box.
High water allows predatory big trout to access the shallows where bait fish usually find shelter.
Big fish feed use their lateral line to detect prey. High discolored water provides concealment. A rattle in your high water pattern won’t hurt.
Heavily fished special regulation areas result in leader shy trout limiting anglers to fine tippets which won’t handle the large flies necessary to catch the denisons of the deep. High discolored water allows The opportunity to whip out the 3x tippet ad size 6 flies.