基于NLM的三峡重庆库区面源污染负荷研究

BASED ON THE NUTRIENT LOADING MODEL STUDY ON LOADINGS OF NON-POINT SOURCE POLLUTION IN CHONGQING REGION OF THREE GORGES RESERVOIR

随机性、模糊性、不确定性很强的面污染源是水环境污染中最主要的污染源。面源污染负荷的准确估算是研究和治理面源污染的基础。现在的面源污染数字模型大多数建立于DEM之上，高成本的DEM限制着这类模型的发展。新兴模型——NLM以面源污染发生机理完善而著称。借助于NLM，以三峡重庆库区为例研究分析面源污染的机理，面源污染负荷随时间的变化以及面源负荷受各因素的影响程度等。从硝化、反硝化、矿化、吸附等作用过程中更深层地剖析了面源污染行为；掌握了面源污染物TP、NH3-N、NO3-N的随时间的变化规律及降雨量、土壤有机成分、土壤气温、总辐照等因子对各污染物负荷的影响及相互关系。总之，NLM为开展面源污染负荷及影响因素的研究提供了科学依据。

Non-point source pollution that generally occurs over an intermittent period from sporadical sources and closely correlates with climatic events is the main pollution sources. Accurately estimating loadings of non-point source pollution is the foundation of researching and administering the non-point source pollution. Existing non-point source pollution loadings model is mostly established on the Digital Elevation Model （DEM） whose utilization value is restricted for its high cost. The Nutrient Loading Model （NLM） that is famous of perfect theory on development mechanism of non-point pollution is a novel model. Through research on the Non-point source pollution in Three Gorges Reservoir Region, by means of NLM this paper analyzed the mechanism of non-point source pollution, the effect on pollution loadings of each factor and variations of loading with the time, and so on. It had analyzed non-point source pollution behavior from courses of nitrification, denitrification, mineralization, and adsorption. Such as, nitrification transferred from the ammonium to the nitrate pool, denitrification occurred only when the soil water exceeded the field capacity, mineralization of organic nitrogen and phosphorus to ammonium and phosphate. Day＇s loadings of run off, total phosphorus, ammonia nitrogen and nitrate nitrogen in Three Gorges Reservoir Region were simulated and calculated, which can be reflected dynamic variance of pollution loadings. Every loadings-time curve was analyzed and it could be concluded that the fluctuation in winter and spring was small, whereas fluctuation from May to September was great, fluctuation always lagged behind of influential factors, in which some factors were steady and great, some factors were variable and sensitive. In all, NLM consummated mechanism of non-point source pollution and provided more scientific basis to research non-point source pollution for control of non-point pollution source in the future.