三峡水库运行后长江汉阳段污染物扩散规律研究

Study on pollutant diffusion law in Hanyang reach of Yangtze River after operation of Three Gorges Reservoir

三峡水库及上游梯级水库的运行改变了长江中下游水文情势和水生态环境条件,使河流的纳污能力发生变化。以长江中游武汉河段的汉阳饮用水源、工业用水区为研究对象,采用河流二维水质模型和平面二维水动力水质模型对水功能区COD和NH_3-N等污染物的纳污能力、扩散规律进行了模拟研究。研究结果表明:枯季水文条件和水功能区横向分布宽度对水域纳污能力影响较大,三峡水库运行后研究河段岸边横向50m宽度内的COD和NH_3-N的纳污能力为17 850,1 233 t/a,纳污能力有所增加;三峡水库运行后枯季污染物扩散范围有所减小。研究结果可为河段排污总量控制、排污口设置管理和水环境保护提供科学依据。

The hydrological regime and water eco-environmental conditions in the middle reach of the Yangtze River have changed since the operation of Three Gorges Reservoir and the upstream cascade reservoirs.Taking Hanyang drinking water source and industrial water areas in Wuhan reach as the research objects,the river two-dimensional water quality model and the plane two-dimensional hydrodynamic water quality model are used to study the pollution bearing capacity of water function zones and diffusion law of COD and NH 3-N.The results show that in the dry season,hydrological condition and the lateral width of water function zones have a great influence on water pollution bearing capacity.Since the operation of Three Gorges Reservoir,the pollution bearing capacity of COD and NH 3-N in 50 m lateral width of the river reach are 17850,1233 t/a,which increased in some extent,and the diffusion scope of pollutants in the dry season has been reduced.The study results can provide scientific basis for the total amount control of river pollution,the management of sewage outfall and water environment protection.