The simulation research of dissolved nitrogen and phosphorus non-point source pollution in Xiao-Jiang watershed of Three Gorges Reservoir area.
The simulation research of dissolved nitrogen and phosphorus non-point source pollution in Xiao-Jiang watershed of Three Gorges Reservoir area.
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DOI：
10.2166/wst.2010.852
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发表时间：
2010-03
期刊：
影响因子：
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通讯作者：
Lei Wu;Tian-yu Long;Chong Li
中科院分区：
文献类型：
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作者：
Lei Wu;Tian-yu Long;Chong Li
小江流域位于三峡库区中部，是三峡库区中部最大的支流，流域面积约5, 276 km（2），长182.4km，流域内耕地占流域面积的很大比例，紫色土丘陵耕地占流域耕地的绝大部分。三峡水库二期蓄水后，库区大部分支流频繁出现富营养化现象，面源污染已成为小江流域的重要污染源。针对溶解态氮磷非点源污染与地表径流和壤中流相关的特点，利用互联网和研究机构提供的气候、地形和土地覆被数据，采用半分布式土地利用径流过程水文模型（SLURP）对小江流域进行了完整的水文循环模拟。基于SLURP分布式水文模型，分别建立了土地利用和农村居民非点源污染年输出负荷模型。为此，利用GIS技术，考虑溶解态氮、磷在迁移过程中的流失，将SLURP水文模型与土地利用产出模型有机耦合，建立了溶解态非点源污染负荷动态模型。通过上述动力学模型，对2001 - 2008年三峡库区溶解性非点源氮、磷污染输出量及不同类型污染负荷进行了模拟和定量估算，并计算了三峡库区小江流域氮、磷污染负荷的时空分布。模拟结果表明：流域内溶解态氮、磷负荷的时间变化与降雨径流的年际变化较为接近，不同土地利用类型分布对流域内溶解态氮、磷负荷的空间变化影响较大;不同土地利用类型的氮磷负荷大小依次为：格莱贝及混交地、水田、草地、城镇用地、林地;在磷负荷方面，格莱贝和混合地的单位面积输出负荷与水田基本相同，土地利用对氮磷污染负荷的输出贡献占78%~ 85%，畜禽养殖对氮磷污染负荷的输出贡献占13%~ 20%.利用实测数据对所建立的负荷模型进行了验证，仿真结果表明所建立的模型合理，仿真精度较高。
Xiao-jiang, with a basin area of almost 5,276 km(2) and a length of 182.4 km, is located in the center of the Three Gorges Reservoir Area, and is the largest tributary of the central section in Three Gorges Reservoir Area, farmland accounts for a large proportion of Xiao-jiang watershed, and the hilly cropland of purple soil is much of the farmland of the watershed. After the second phase of water storage in the Three Gorges Reservoir, the majority of sub-rivers in the reservoir area experienced eutrophication phenomenon frequently, and non-point source (NPS) pollution has become an important source of pollution in Xiao-jiang Watershed. Because dissolved nitrogen and phosphorus non-point source pollution are related to surface runoff and interflow, using climatic, topographic and land cover data from the internet and research institutes, the Semi-Distributed Land-use Runoff Process (SLURP) hydrological model was introduced to simulate the complete hydrological cycle of the Xiao-jiang Watershed. Based on the SLURP distributed hydrological model, non-point source pollution annual output load models of land use and rural residents were respectively established. Therefore, using GIS technology, considering the losses of dissolved nitrogen and phosphorus in the course of transport, a dissolved non-point source pollution load dynamic model was established by the organic coupling of the SLURP hydrological model and land-use output model. Through the above dynamic model, the annual dissolved non-point source nitrogen and phosphorus pollution output as well as the load in different types were simulated and quantitatively estimated from 2001 to 2008, furthermore, the loads of Xiao-jiang Watershed were calculated and expressed by temporal and spatial distribution in the Three Gorges Reservoir Area. The simulation results show that: the temporal changes of dissolved nitrogen and phosphorus load in the watershed are close to the inter-annual changes of rainfall runoff, and the different land-use type distribution has great impacts on the spatial changes of dissolved nitrogen and phosphorus load in the watershed; The nitrogen and phosphorus load of different land-use types in size with descending order is, glebe and mixed land, paddy, grassland, urban land, forestland; however, for the phosphorus load, the unit area output load of glebe and mixed land is almost the same as for paddy fields; The output contribution of nitrogen and phosphorus pollution load from land-use accounts for 78%-85%, while the output contribution from livestock and poultry occupies 13%-20%. The established load model was verified by observation data, simulation results show that the established model is reasonable, simulation accuracy is higher.