Most tailwaters (below hydroelectric dams) yield big trout, though the bulk of fish are caught on tiny little mayfly and midge patterns. The Green is an anomaly in this regard. Trout below Flaming Gorge Reservoir key on the abundance of naturally occurring terrestrials, specifically cicadas and in some years Mormon crickets. When a 23-inch brown trout eats a terrestrial dry fly, it happens in one of two ways: Either it’s a sudden and violent surge, or it’s a deliberate, painstaking stalk. In both cases, it’s a take that the flyfisherman won’t soon forget. Be sure to try the “B” and “C” sections to avoid the crowds. They’re best accessed via a boat or a guide, but there is plenty of public access for the wading angler. More info: Trout Creek Flies, 435-885-3355;

Next Best: San Juan River, New Mexico The mix of high desert heat with icy cool water under the spillway of Navajo Dam creates not only year-round dry-fly action with some signature hatches (Baetis, PMDs, midges) but also healthy populations of football-shaped rainbows. Guides on the Juan measure trophy trout back-to-belly, not nose-to-tail. More info: Abe’s Motel and Fly Shop, 505-632-2194;