LIVING IN EASTERN IDAHO allows me to fish some of the finest trout water in the country, from the South Fork of the Snake to the Madison in Montana. But lately, nostalgia has drawn me south, to northern Utah’s Logan and Blacksmith Fork rivers, both of which flow through the fifty-mile-long Cache Valley where I grew up. Each of these rivers had healthy salmonfly hatches when my grandpa was a kid, but now only the Blacksmith Fork does, and few people seem to know why.
The Logan’s annual salmonfly hatch used to
