平原河流水沙运动对污染物输运作用机理及环境调控

Plain river region has the characteristics of highly developed economy,large population and serious pollution. Therefore, the water environment problem is more crucial there. In these area, the spatial and temporal distribution of water resources is very uneven, river network is dense and the hydrodynamic condition is weak and self-purification capacity of water is poor. Meanwhile, the sediment particles in plain river are fine and may change the transport of pollutants due to their strong adsorption capacity. These bring great difficulties to the management and protection of the river water environment. Therefore, the mechanism of action of plain river flow and sediment transport on the pollutant is a key scientific issues of governance and protection of plain river water environment to be solved. However, there are many gates, dam and pumping station in the plain rivers, providing convenient conditions for the adjustment of water and sediment processes, and thus bring a way to solve the water environment in the plains. The project intends to use the field investigation, field observations, laboratory experiments and theoretical analysis, to find out the mechanism of action of flow and sediment movement on pollutant transport and environmental effects induced by this complicate process.. Control strategies and measures will be also found out. The research results will help enrich and improve the river sediment-pollutant theory and research methods, provide the scientific basis for environmental management of river water.

平原河流地区经济发达，人口众多，水环境问题突出；水资源时空分布不均，河网密布，以过境水为主，水沙运动复杂；地势低洼，水动力条件不足，水体自净能力弱；泥沙颗粒细，对污染物的亲和力强，污染物的输运复杂。这些特点给河流水环境的治理和保护带来了极大的困难。因此，平原河流水沙运动对污染物的输运作用机理是治理和保护水环境亟待解决的关键科学问题。此外，平原河流闸坝泵站众多，为水环境调控提供了条件。本项目拟选用淮河为研究对象，采用野外调查、现场观测、室内实验和理论分析相结合的方法，开展泥沙颗粒与污染物微界面动力学问题，水沙运动对污染物的输运作用机理，植被、沙波等不同边界条件对污染物迁移影响，及平原河流水沙过程对污染物作用规律与环境效应研究，建立水沙与污染物动态耦合模型，提出联合利用闸、坝、泵的水沙-污染物环境调控对策和措施。成果将丰富和完善河流泥沙对污染物输运作用的理论，为平原河流水环境管理提供科学依据。

平原河流的特点是以过境水为主，河网密布，水动力条件不足，水体自净能力较弱，同时平原河流泥沙颗粒较细，对污染物的亲和能力强，污染物的输运规律复杂。平原河流的这些特点给河流水环境的治理和保护带来了极大的困难。因此，平原河流水沙运动对污染物的作用机理是治理和保护平原河流水环境亟待解决的关键科学问题。同时，平原河流闸坝泵站众多，为水环境调控提供了条件。.本项目选用淮河为研究对象，采用野外调查、现场观测、室内实验和理论分析相结合的方法，取得了以下重要成果：①揭示了泥沙的环境效应。采用现场原样采集技术，对淮河干流典型断面以及交汇口水体和底泥的环境指标开展了采集和检测，研究了淮河典型河段中重点污染物的泥沙环境效应。②发展了水沙运动与污染物的作用机理。研发了微观尺度的水沙-污染物耦合数值模型，建立了基于微观过程的污染物吸附/解吸附模型；考虑泥沙运动形式及过程的变化和污染物在水沙界面的输运过程，分析了泥沙运动对污染物吸附/解吸附的主要影响规律。③研究不同河床边界对泥沙和污染物在河流中运移特征的影响。研究了沙波存在的条件下，泥沙和污染物在河流中迁移过程，泥沙输运对污染物在水沙界面交换量影响；植物存在的条件下，泥沙运动规律的变化，引起污染物的变化，以及植物对床沙和河床污染物迁移转换的影响；河道交汇口区域，水沙和污染物输运特征及规律；复式河道条件下，水动力过程及水沙污染物输运特征，以及侧岸潜流交换过程。④开展了淮河流域工程体系多目标协同调控。针对典型天然平原河流（淮河蚌埠段）建立了大尺度水沙-污染物耦合模型，展开了污染物输运特性研究，揭示并分析了闸坝调控方式对污染物输运的规律及机理，提出了处理水污染事故的闸坝调度策略。.本项目的成果丰富和完善了河流泥沙对污染物作用的理论，为平原河流水污染治理的核心问题——平原河流水沙运动对污染物输运的作用机理提供了理论和方法基础，为平原河流水环境管理提供科学依据。