Fly Fishing Grey Reef on the North Platte River. Erik Aune

      Grey Reef (North Platte River, Central Wyoming)

      Location: The Grey Reef section of the North Platte River originates in central Wyoming near Alcova, about 25 miles southwest of Casper. Grey Reef is a 4-hour drive from Denver and 5½ hours from Salt Lake City. Casper is served by flights from major airlines in Denver and Salt Lake City.

      Although the most popular sections of Grey Reef are in the upper 13 miles, there are actually 83 miles of highly productive trout water in the Grey Reef system. The upper 13 miles maintain good water quality through the brief spring runoff; the entire stretch fishes well during the rest of the year.

      Grey Reef produces year-round, as it’s ultra-insulated from runoff by five reservoirs tightly spaced upstream. Grey Reef Dam was completed in 1961 and has performed its duty as an afterbay to Alcova Reservoir ever since. Prior to the Grey Reef Dam, the North Platte River below Alcova Dam was subject to wild changes in daily flow due to electricity demands. Now, the flows are consistent and increase or decrease only with seasonal demand. The river intersects classic Western sagebrush prairie and is flanked by a variety of landscapes, including rolling hills, mountains, and cottonwood bottoms.

      The North Platte originates in northern Colorado just across the Continental Divide from major tributaries of the Colorado River system. It relies on snowpack from the mountains of the Routt National Forest in northern Colorado and the Snowy and Sierra Madre Ranges in the Medicine Bow National

      Forest of southern Wyoming. The river flows north out of Colorado to Casper, where it turns east and joins the Missouri River in Nebraska. Grey Reef was historically a warmwater environment, but the construction of several dams—most importantly Grey Reef Dam—gave rise to a spectacular coldwater fishery. The lower North Platte was stocked with trout in the 1980s, and Grey Reef was first stocked the spring following the dam’s completion. The lower sections are still stocked today. The upper 8 miles from Grey Reef Dam to the Lusby Access are a “trophy fishery,” where natural reproduction is the only source of trout recruitment. The Wyoming Game & Fish Department and the U.S. Bureau of Reclamation have instituted a flushing flow program for Grey Reef. For 5 days each spring (and sometimes in the fall) the flows from the dam are dramatically increased