梯级开发对河流径流过程和水温过程均化作用的研究

STUDY ON AVERAGING EFFECT OF CASCADE HYDROPOWER DEVELOPMENT ON FLOW AND WATER TEMPERATURE PROCESS

长江中上游干流及主要支流正在大规模地进行水电开发,随着这些梯级水库群的建设,自然河流中具有重要生态意义的流量过程和水热过程发生变化,导致流量和水温均化,引起了一些河流生态环境问题。根据现有资料统计,结合金沙江下游正在建设的溪洛渡和向家坝水电站,对比分析了梯级水电工程径流调节后与天然过程的差异程度,探讨了河流径流过程和水温过程均化现象对生境的影响。将均化系数λ引入,定量计算了水库调节对天然径流的均化作用;采用宽度平均的立面二维k-ε水温模型,初步分析了梯级水电工程对水温过程均化作用。最后提出减小梯级水库对长江生态环境影响的对策和建议。

In the upper and middle reaches of the Yangtze River main stream and major tributaries,large-scale hydropower development is now being conducted.As the construction of these cascade reservoir groups,the flow and hydrothermal process being of ecological significance to natural river have been changed.These changes caused flow and water temperature averaged,and a few of river ecological environmental problems.According to attainable statistical data,taking Xiluodu and Xiangjiaba hydropower stations being built in the lower reaches of Jinsha River as examples,this paper analyzed the differences between natural and changed runoff,discussed the effect of averaging phenomenon of natural runoff and water temperature on the ecological habitat.It calculated the averaging effect of cascade reservoirs development on the natural runoff by using averaging coefficient λ.It also primarily analyzed how the cascade hydropower projects had averaged the water temperature process by taking k-ε water temperature model.At last,some measures to reduce the negative effects of cascade reservoir on the Yangtze River ecological environment were put forward.