Water Quality of the Green River: Serial Discontinuity Concept and the Flaming Gorge Dam

ABSTRACT
Although water quality in the Green River is said to be very good since the construction of the Flaming Gorge Dam in 1962, this has historically been considered within the context of fishery and recreational purposes because of colder water temperatures and increased water clarity since dam closure. On the contrary, construction of the impoundment marked the inception of a sharp decline in water quality in the Green River downstream of the dam. The water quality parameters indicative of this decline include temperature, turbidity, dissolved oxygen, pH, and specific conductance. The decrease in water quality was marked by a sharp descent in native warm-water fish populations and an increase in cold-water trout populations. The dam was then modified in 1978 to further improve trout habitat. This modification slightly improved conditions for some native fishes, but the temperature and flow conditions still favored cold-water species. Although recent agency attention has been shifted toward restoring native endangered fish species in the river, Flaming Gorge Dam operations are still dominated by hydropower and river storage demands. There is controversy as to whether re-prioritization of management goals in the river to further promote the restoration of pre-dam water quality conditions in the Green River is really the best option.