A tailwater is the river section flowing out of a dam. The dam releases water from deep in the reservoir — cold, oxygenated, and clear regardless of weather above. That single fact makes tailwaters distinct: they fish through summer, hold trophy trout, and produce dense midge and BWO hatches year-round.
Famous tailwaters: the San Juan, the Madison below Hebgen, the Henry's Fork below Island Park, the Provo Middle below Jordanelle. Each one has a release schedule that matters more than the daily weather report.