In 2000, the stretch of the South Platte that ran through the Eleven Mile Canyon was named a catch-and-release-only section. Authorities figured they had a winner when it was realized in 2003 that numbers of fish had tripled. However, by 2008 fish numbers were dwindling even though the catch-and-release regulation was still in place.
Enter aquatic wildlife biologist Jeff Spohn. Analyzing a decade’s worth of flow data from the near Eleven Mile Reservoir and Spinney Mountain Reservoir, both upstream of the Eleven Mile Canyon stretch, Spohn realized that the river was not getting the flow it needed. “If you can give us the required flow regimes during spawning, egg incubation and fry emergence, I can guarantee we will see the fishery come back,” Spohn says.