Monitoring and Prediction of Supersaturation of Total Dissolved Gas in High Dam Cascade of Jinsha River
High dam discharge causes Total dissolved gas(TDG)supersaturation,and fish in the downstream reaches suffer from bubble disease and even die,causing deterioration of local water quality,which has become the aquatic envrionmental and ecological risk associated with high dam discharge operation.Wudongde and Baihetan have successively operated to form a high-dam cascade reservoir pattern of the Jinsha River.This paper,through prototype observation of the process from storage period to operation period of Wudongde,including the susaturation generation and release process of discharge gas before and after storage of Baihetan,establishes a prediction model according to the measured results,and carries out a simulation study on the influence of TDG on the section from Wudongde to Baihetan under different discharge operation scenarios.The results of prototype observation show that under different discharge scenarios in Wudongde dam,the TDG supersaturation phenomenon is caused,and the TDG supersaturation level increases with the increase of dischage flowrate.The process of TDG dissipate in Wudongde reservoir area and Baihetan reservoir area is similar,and the process of TDG dissipate is significantly slower than that in the natural river before Baihetan reservoir.The two-dimensional TDG simulation results of the facade of Baihetan Reservoir show that when the unit and the surface hole are used to flow through Baihetan,the high TDG flow generated by Wudongde discharge mainly runs on the surface,and the release rate is lower than that before impounding,and the bottom water body is less affected by the inflow flow,and the vertical distribution is significantly uneven.The lower the water level in front of the dam,the lower the TDG level under the dam,which can reduce the adverse effects of TDG in the downstream reaches.The research results provide important basic data and technical support for the understanding of supersaturated TDG generation and dissipation and the research and formulation of optimal scheduling measures.
Total dissolved gas supersaturationdischargefield observationmodelJinsha River
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