水库运行对下游河道水环境影响的一维-二维耦合水环境模型

One-dimensional and two-dimensional coupled water environment model for studying the impact of upstream reservoir operation

以广西漓江为实例,建立了全河流一维和局部河段二维水环境模型,并通过实际观测数据对模型的参数进行了率定。该模型耦合了水动力学过程及生态学过程,可对水库运行造成的河道水流条件的改变给下游的水生态系统造成的影响进行定量评价。其中的一维模型分析全河段水环境变化趋势,二维模型分析关键区间水环境的特点,并为后续的生物栖息地模型的应用奠定基础。分析了典型水文年中自然径流和青狮潭水库调水两种运行模式下下游河道关键水环境因子的变化。模拟结果表明水库运行在平水年的影响大于丰水年和枯水年,局部浅水区的变化大于深水区,年内枯水期(10—12月)的影响大于年均值,而且这些变化沿程逐渐减弱。

A one-dimensional and two-dimensional coupled water environment model for the Lijiang River is established and the relevant parameters are calibrated by observation data. The model integrates the hydrodynamics with ecology process and is applied to quantitatively evaluate the impact of reservoir operation on downstream aquatic ecosystem. The 1-D module is used to simulate the eco-environment of the entire river and the 2-D module is used to analyze the eco-environment of the important river sections and the result provides the basis of the application of the model for simulating the habitat of biology. The changes of important water environmental factors in the downstream of Qingshitan reservoir in typical hydrological years under two reservoir operation modes are analyzed. The result indicates that the effect of reservoir operation in normal flood year is greater than those in wet year and dry year. The changes in local shallow regions are greater than those in deep water regions. The impact in the period from October to December is greater that of annual average magnitude. These changes decrease with the increase of distance from the dam.