Rushing out of Kortes Dam, fluctuating currents run through the rugged Seminoe Mountains and out into the arid Wyoming plains until the North Platte River’s waters reach Pathfinder Reservoir. With a beautiful landscape surrounding the river, and swift, cold water filled with brown, cutthroat, and rainbow trout, this five and half mile stretch of the North Platte River has earned itself the name, “The Miracle Mile.”

The cold-water released out of Kortes Dam, fed by snowmelt from mountain streams, is highly desirable for trout, leading to the dense populations that thrive along the Miracle Mile. Though stocked annually, much of the trout population is naturally maintained through yearly spawning upstream near Kortes Dam. With fish numbering in the thousands per mile, the stretch is a figurative “fish in a barrel” site for anglers. But fishermen don’t travel from across the U.S. to cast their line into the Miracle Mile for any trout; they come in hopes of catching one of the 24-inch or longer trout that have made the Miracle Mile famous.

The success of this fishery would not be possible without the careful attention of humans. In 1998, a count by the U.S. Fish and Wildlife Service showed an average number of about 4460 fish per mile. By 2002, the numbers had decreased to approximately 1650 fish per mile, then as low as 1400 fish per mile by 2004.  Biologists concluded the precipitous drop in fish populations were the result of low water years on the Platte during a period of drought. When the flows from Kortes Dam decrease during periods of drought, fish quickly feel the pressure of limited space and resources, and populations decline as a result. If too many low water years go by with no change in management of water distribution, it poses a serious risk to both the long-term health of the fishery as well as the health of fishing-based recreation here.

Recreation is a major use of this stretch of the North Platte River. A 2011 estimate by Wyoming Game and Fish calculated approximately $157 million in angler expenditures that year alone. Without healthy fisheries like the Miracle Mile, which draw in fisherman from across the country, the recreation industry and local economies in Wyoming would suffer. Fortunately, stream flows have rebounded due to careful management and good levels of snowpack in recent years. Trout populations have increased, reaching up to 5000 fish per mile with high water years in 2010 and 2011.

A group of fishermen take a break for lunch and enjoy the scenery of the Seminoe Mountains sloping down towards the North Platte River. Photo by Aaron Lee

 Now every spring, in early March, the Bureau of Reclamation flushes the dam, increasing in-stream flows from 500 cfs to 4000 cfs over a five-day period to simulate spring flooding from snowmelt in the mountains. The flushing washes out unwanted gravel and mud from spawning beds, which helps improve the habitat needed to maintain a healthy population of trout without it having to be heavily stocked.Because the Miracle Mile is an important, highly populated fishery, the U.S. Bureau of Reclamation took legislative action to help maintain the Miracle Mile as a healthy ecosystem and fishery far into the future. In accordance with a bill Congress passed in the late 1960s, Kortes Dam’s flows are regulated to never drop below 500 cfs (cubic feet per second) to insure a healthy stream flow for the fishery and watershed downstream. Before the bill was passed, the river downstream of Kortes would often run dry with no restriction on water diversion behind the dam. This was a major issue not only for the wildlife that relies on the currents that flow from Kortes, but also for the people of Casper and other near by towns, who rely on power generated from the flows at the dam.

Regulations like this by the Bureau of Reclamation, along with careful management, are what have made the Miracle Mile a Blue Ribbon Fishery and will keep it that way for years to come. The North Platte River is a heavily managed river, with the Miracle Mile tucked between two of the river’s largest dams, Pathfinder and Seminoe, yet this comparatively small stretch of river thrives as an abundant fishery that maintains a high standard for wildlife and recreation.