From State Bridge down past Dotsero toward Glenwood the Colorado is bigger, lower and warmer, a float angler's freestone with good browns and rainbows and a whitefish in every third drift. It fishes beautifully in the cool windows — post-runoff summer mornings, and especially the autumn when the BWOs come and the browns get aggressive. But this is the reach where temperature is the headline risk: it draws down and warms through July and August to the point where the right call is often no trout fishing at all. In late summer, the honest advice is simple: go early, head up the Eagle or the Fryingpan instead, or leave the trout alone.

• Mixed

• Aquatic life: Supporting