河道型水库过饱和总溶解气体释放模型及应用研究

随着一系列梯级水电站的建成运行,因上游电站泄水引起下游河道型水库水体中总溶解气体(TDG)过饱和,导致库区鱼类患气泡病甚至死亡的风险增加。针对河道型水库过饱和TDG释放预测问题,建立河道型水库的纵向一维过饱和TDG释放预测模型,研究不同洪水条件下河道型水库在变水位运行条件下的水动力学和过饱和TDG释放特性,分析了过饱和TDG沿程释放和代表性断面的TDG过程,探讨了横断面滩地区域的水深变化和鱼类补偿水深的满足性。结果表明降低来流的TDG水平是减小其不利影响的重要手段,在来流TDG饱和度一定时,河道型水库适当以高水位运行能够为滩地区域鱼类提供足够的躲避水深。本文结果对梯级电站优化调度以减缓TDG影响的研究和方案实施提供了技术支撑,在梯级水电开发河流的水生态保护方面具有重要意义。

Prediction Model and Application Study of Supersaturated Total Dissolved Gas Release in Channel Reservoirs

With the construction and operation of a series of cascade hydropower stations,the total dissolved gas(TDG)in the water body of downstream channel reservoirs is oversaturated due to the discharge of upstream power station,which leads to an increased risk of gas bubble disease and even death of fish.Aiming at the problem of prediction of supersaturated TDG release in channel reservoirs,a longitudinal one-dimensional supersaturated TDG release prediction model for channel reservoirs was establishedto study the hydrodynamics and supersaturated TDG release characteristics under variable flooding conditions in channel reservoirs under different flood conditions,and the TDG process of the release of supersaturated TDG along the representative section was analyzed,and the water depth variation of the cross-section beach area and the satisfaction of fish compensate water depth were discussed.The result showed that reducing freestream TDG level is an important means to reduce adverse effects.When freestream TDG saturation is constant,the channel reservoir operating at a high water level can provide sufficient refuge for the fish in beach area.The results of this paper provide a technical support for the research and implementation of mitigating the impact of TDG through optimizing dispatch of cascade hydropower stations,which is of great significance in the water ecological protection of cascade hydropower development for river.