Spring snowmelt runoff in the Colorado Rocky Mountains has triggered the spawning and emergence of endangered razorback sucker fish populations in the Green River downstream from Flaming Gorge Dam, Utah. Larval emergence in the river was observed on May 28, 2016.

To assist the survival of this endangered fish population, Bureau of Reclamation officials will gradually increase water released from Flaming Gorge Dam from the current flow of 800 cubic feet per second (cfs) to 8,600 cfs beginning Tuesday, May 31, 2016. The rate of release will reach 8,600 cfs on Friday, June 3, 2016, and will remain at that flow rate until further notice. However, Reclamation officials anticipate the release to remain at this rate for only 7 to 14 days beyond June 3.

At the highest rate, Flaming Gorge reservoir will release approximately 4,600 cfs through the Flaming Gorge Dam powerplant, allowing power generation to reach its full capacity of approximately 150 megawatts. Another 4,000 cfs will be released through the dam’s bypass tubes to reach the total of 8,600 cfs.

Projected peak flow on the Green River at Jensen, Utah, resulting from the combined flows of Flaming Gorge Dam releases and the Yampa River, will be approximately 22,000 to 24,000 cubic feet per second. These projections are close to flood stage and Reclamation officials urge caution while recreating or farming along the Green River during the next few weeks.

Scientists monitor critical habitat to detect the first emergence of razorback sucker larvae as a “trigger” for this type of release by Reclamation in cooperation with the State of Utah Division of Wildlife Resources, U.S. Fish and Wildlife Service and the Upper Colorado River Endangered Fish Recovery Program. A major purpose of the higher release is to transport as many larval fish as possible into critical nursery habitats located in the floodplains along the Green River, downstream of the confluence of the Green and Yampa rivers. The increased releases from the dam, combined with the Yampa River flows, will provide the maximum possible flow of water to transport the larval fish.

Reclamation consulted with the Utah Division of Wildlife Resources concerning possible impacts of the releases to the rainbow trout fishery below the dam. While releases during this period will make fishing the river more difficult, no adverse impacts to the fishery are expected.