摘要:非点源污染因分布广泛、产生过程复杂、防治困难，近年成为影响饮用水源地水环境的重要污染源。以海南三亚赤田水库为例，开展了基于"源-汇"景观的非点源污染风险遥感识别与评价分析。首先，采用高分辨率遥感影像分类提取水源地不同类型景观分布信息；结合"源-汇"对污染的促进\阻碍作用，在考虑影响污染物迁移的"河道距离"因子、坡度因子情况下，利用非点源污染风险指数的计算实现对区域非点源污染风险的快速识别；并基于洛伦兹曲线分析水源地景观空间分布对非点源污染的影响。结果表明：一方面，流域非点源污染风险总体较低，"汇"景观占主导作用的子流域占整个区域的76.50%；污染风险呈现东高西低的特点，极高风险区主要分布于以居住用地、建设用地等"源"景观类型为主的流域东南部区域，占整体区域面积的1.28%，而西部以林地为主污染风险小；另一方面，基于坡度因子的"源""汇"景观污染负荷之比值大于1，"源"景观在低坡度区域分布范围广，景观布局较合理；基于"河道距离"因子的"源""汇"景观污染负荷之比值为2.30，"源"景观在距河道近的区域分布范围大，对污染影响大，近河道区域需进一步调整景观格局以降低对非点源污染的影响。基于遥感与"源-汇"景观指数计算是一种快速、客观、有效的饮用水源地的非点源污染风险识别与评价方法。



Abstract:Non-point source pollution has become an important source of pollution affecting the water environment of drinking water sources in recent years due to its wide distribution, complex production process and difficult prevention and control. This paper carried out remote sensing identification and evaluation analysis of non-point source pollution risk based on "source-sink" landscape in Chitian Reservoir. Firstly, high-resolution remote sensing image was used to extract different types of landscape distribution information of water source. Then, combined with the promotion/blocking effect of "source-sink" on pollution, considering the distance from the river and slope factor affecting the migration of pollutants, the non-point source pollution risk index was used to calculate the risk of non-point source pollution. And we analyzed the influence of spatial distribution of water source landscape on non-point source pollution based on Lorenz curve. The results showed that the risk of non-point source pollution was low, and the sub-watershed dominated by "sink" landscape accounted for 76.50% of the whole area. The risk of non-point source pollution in the basin was high in the east and low in the west. The extremely high risk areas mainly distributed in the southeast of the basin, which were dominated by "source" landscape types such as residential land and construction land, accounting for 1.28% of the overall regional area. And the western region was dominated by forest landscape with little pollution risk. The ratio of pollution load of "source" and "sink" landscape based on slope factor was greater than 1, indicating that the "source" landscape had a wide distribution range in the low-slope region. The landscape layout was more reasonable among slope elements. The pollution load ratio of "source" and "sink" landscape based on the factor of "distance from the river" was 2.30, indicating that the "source" landscape had a large distribution range near the river course and had a great impact on pollution. Therefore, the landscape pattern near the river should be further adjusted to reduce the impact of non-point source pollution. The method of "source-sink" landscape index calculation based on remote sensing is a rapid, objective and effective method for the identification and evaluation of non-point source pollution.





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