The Upper Green Flaming Gorge Reservoir Watershed (HUC 14040106) covers approximately 1,130 square miles in Wyoming and Utah. The watershed is largely mountainous and is characterized by steep terrain, sparse vegetation, and significant snowpack accumulation. Snowmelt runoff supplies the majority of water to the Green River, which flows through the watershed and into the reservoir. The reservoir is used for water storage, irrigation, and recreation. Constituents of the reservoir include rainbow and brown trout, kokanee salmon, and smallmouth bass. Interesting climatic facts include the area's high snowfall, with an average of 400 inches annually at mountain peaks, and its semi-arid climate with hot summers and cold winters. Trends in the area include declining snowpack due to climate change, leading to reduced streamflows and increased water demand for irrigation and other uses.