Numerical simulation of dissolved oxygen supersaturation flow over the three Gorges Dam spillway

The dissolved oxygen concentration in a flow changes with distance downstream of the spillway crest and depends on the geometric configuration of the spillway and the hydraulic and operating conditions. A mathematical model was developed to simulate the turbulent structure of the flow over the spillway of the Three Gorges Dam at the 145 m reservoir water level to study the aeration characteristics and the gas transport. The model was calibrated and verified with measured data. The analysis of distribution of the aeration and the dissolved oxygen showed that the downstream water level, upstream dissolved oxygen content, and the flow discharge all affect the dissolved oxygen saturation downstream of the sluicing dam. The simulation provides guidance for controlling the dissolved oxygen supersaturation and environmentally friendly operation of the Three Gorges Dam.