Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210023, China.
Yellow River Institute of Hydraulic Research, Zhengzhou 450003, China.
Sci Total Environ. 2018 May 15;624:1187-1194. doi: 10.1016/j.scitotenv.2017.12.212. Epub 2017 Dec 27.
The Yangtze River is one of the largest and most important rivers in the world. Over the past several decades, the flow regime of the Yangtze River has been altered by human activities, particularly dam construction. Hydrological regimes will be further influenced due to more dams that have been planned and are being built in the upper reach of the Yangtze River (URYR). In this context, to assess the impacts of cascade dam development on the natural flows, four different scenarios of the reservoirs' combination are simulated with a hydrological model (the Soil and Water Assessment Tool) in the URYR. Flow regime changes were investigated using the eco-flow metrics and minimum/optimal ecological flow with the simulated daily river flows. The results indicate that eco-surplus in low flows and eco-deficit in high flows greatly increases due to reservoir operations when more reservoirs are put into service. The minimum ecological flow and the optimal ecological flow cannot be guaranteed from September to November, which is a crucial time for fish spawning. To maintain the natural regime while meeting the requirements for the river ecosystem, we propose that the lower and satisfactory operation limits are 11,680m/s and 7235m/s and 16,300m/s and 9130m/s, respectively. Optimizing cascade reservoir operational rules is needed to achieve a better balance between ecological and socio-economic demands in the Yangtze River Basin.
长江是世界上最大和最重要的河流之一。在过去几十年中，人类活动，特别是水坝建设，改变了长江的水流状况。由于在长江上游规划和正在建设更多的水坝，水文状况将进一步受到影响。在这种情况下，为了评估梯级大坝开发对自然水流的影响，利用水文模型（土壤和水评估工具）模拟了 URYR 中水库组合的四种不同情景。利用模拟的日流量，采用生态流量指标和最小/最佳生态流量来研究水流状况变化。结果表明，随着更多水库投入运行，水库运行导致低流量时生态盈余增加，高流量时生态赤字增加。9 月至 11 月期间，无法保证最小生态流量和最佳生态流量，这是鱼类产卵的关键时期。为了在满足河流生态系统要求的同时维持自然状况，我们建议将下游和满意的运行下限分别设定为 11680m/s 和 7235m/s，以及 16300m/s 和 9130m/s。需要优化梯级水库运行规则，以实现长江流域生态和社会经济需求之间的更好平衡。
