Effects of Flaming Gorge Dam Hydropower Operations on Downstream Flow, Stage, and Sediment Transport

S.C.L. Yin, Argonne National Laboratory
D. Tomasko, Argonne National Laboratory
H. E. Cho, Argonne National Laboratory
G. Williams, Argonne National Laboratory
J. McCoy, Western Area Power Administration
C. Palmer, Western Area Power Administration



Hydropower operations at Flaming Gorge Dam, located on the Green River in Utah, can produce rapid downstream changes in flow and stage. These changes can in turn affect sediment transport and ecologic resources below the dam. To evaluate these effects, four hydropower operational scenarios with varying degrees of hydropower-release fluctuations were examined. This study demonstrates that the combined use of river-flow routing, water-surface profile, and sedimenttransport models can provide useful information for evaluating the potential impacts of hydropower operations on ecological and other resources downstream of the dam. Study results show that flow fluctuations mayor may not persist for a long distance,' depending on the initial magnitude of fluctuation and the duration of hydropower peaking. Stage fluctuations depend not only on flow fluctuations but also on river channel characteristics, such as channel width and longitudinal slope.