Observing USGS flow gauges reveals much information, even for streams not hosting such items. The big rain we had the last few days increased flows significantly according to readings on these gauges. So it is likely that a temporary flush happened on all these streams including those upstream of a reservoir (most of which are just beginning or soon to be impounding water). The increases are enough to bring about a temporary change in fly-fishing strategy by causing enough bank erosion that such as worms and immature burrowing insects are temporarily abundant food forms. So for the next few days, be sure to have such as San Juan worms, Suede Juan worms, and wooly buggers in that fly box.