This month, anglers who flock to Montana in search of their own authentic A River Runs Through It experience are out of luck. On September 4, the Blackfoot River, centerpiece of Norman Maclean's beloved story (and its film adaptation that gave the entire fly-fishing industry a boost in the early 1990s), was closed to fishing by officials from Montana Fish, Wildlife, and Parks. They cited "an effort to protect fish from the stress of low stream flows." (The river has since been reopened to fishing, but drought conditions remain.)

Such river closures have become more common in recent years, in Montana and beyond. They've become necessary as coldwater fish populations struggle to deal with low flows and warmer