三峡水库蓄水运行初期(2003—2012年)水环境演变特征的“四大效应”

自2003年三峡水库首次蓄水至2012年工程竣工验收启动，针对三峡水库蓄水运行初期的水环境演变研究较多，但整体性、综合性科学认识仍然缺乏.基于水环境多要素跟踪观测研究，综合采用现场观测、室内试验、数理统计、模型模拟、同位素及保守离子示踪等技术手段，系统剖析了特大型、高变幅水位水库运行背景下水动力变异及其所伴生的水环境演变特征，从水动力、水质、水生态、污染物输移角度，提出了三峡水库水环境演变过程中的“四大效应”，主要包括干支流水动力特性的“分化”效应、上游-干流-支流水质演变“同步”效应、水动力变化对藻类水华暴发的“胁迫”效应、水动力变化对同等负荷条件下污染源危害的“迭加”效应等.考虑到大型水库生态系统的演替和稳定是一个长期过程，建议继续强化长江上游梯级水电开发影响下的三峡水库水环境演变跟踪调查研究，适时开展三峡工程对库区水环境影响的后评估. 

Four Effects of Water Environment Evolution in Early Period (2003-2012) after Impoundment of the Three Gorges Reservoir

From the first impoundment of the Three Gorge Reservoir (TGR) in 2003 to the completion of the construction project in 2012, the water environment evolution in the initial operation period of the TGR still lacks overall and comprehensive scientific understanding although there are many related studies. Based on multi-parameter tracking observation of the water environment, and through field observations, laboratory experiments, mathematical statistics, model simulation, isotope analysis and conservative ion tracing, the hydrodynamic variation and the accompanying water environment evolution characteristics (characterized by high water level variation) were systematically analyzed. From the perspective of hydrodynamics, water quality, water ecology and pollutant transport, the four major effects of the water environment evolution are proposed, namely the differentiation effect of hydrodynamic characteristics of mainstream and tributaries, the synchronization effect of the upstream-mainstream-tributary water environment evolution, the stress effect of hydrodynamic changes on algae blooms, and the additive effect of hydrodynamic changes on pollution source hazards under the same load conditions. Considering that the succession and stability of the large-scale reservoir ecosystem is a long-term process, taking the unpredictable impact of upstream cascade hydropower development in the upper reaches of the Yangtze River into account, it is recommended to continue the follow-up investigation and research of the TGR water environment evolution process. In addition, it is also necessary to carry out the post assessment of the impact of the Three Gorges Project on the water environment.