基于冗余分析的城市河湖水污染成因及尺度效应

以武汉中心城区的东沙湖流域为研究对象，以7项下垫面及3项降雨因子为影响因子，以18项河湖水环境因子为响应变量，基于冗余分析研究多尺度下两者之间的关系.结果表明：在所研究的10项影响因子中，硬质铺装面积率和河网水面率是东沙湖流域城市河湖水环境的主要影响因子，贡献率达0.703和0.652，城市道路面积率则是3000m及以外缓冲区尺度下的主要影响因子，贡献率达0.796，降雨的空间分布不是主要影响因子，贡献率低于0.371；影响因子对水环境影响的尺度效应与排水管网的有无和水文汇水单元尺度的大小密切相关；东沙湖流域的河湖水污染可归因于以硬质铺装为代表的不透水面上的面源污染和经由排水管网运移排放的点源污染，河网水面率则是改善水环境的关键因素.

Analysis of the causes for pollution of urban river and lake waters based on the redundancy analysis method and the influence from selection of scales

The relation between the factors potentially causing pollution of urban water bodies and the quality of the water was analyzed based on redundancy analysis method. The basin of Dongsha lake at the central urban area of Wuhan was selected as the target area. Ten characteristics of rainfall and the underlying surface were selected as the factors and 18water quality indicators were selected as the response variables. The results showed that the ratios of the areas of impermeable pavement and river water are the main factors and the contribution rates were 0.703 and 0.652, respectively. The ratio of urban road area was the main factor when the size of buffer was more than 3000 m and the contribution rate was 0.796. Spatial distribution of rainfall had a contribution rate lower than 0.371 and was not the main factor. The scale of buffer had influence on determination of the factors and such an influence was closely related to the presence or absence of the drainage system and the area of the hydrological catchment unit. The river and lake pollution in the basin of Dongsha lake was due to the non-point source pollution at the surface of the impermeable pavement and the point source pollution at the discharge points of the drainage system. The ratio of the area of rivers was the key factor to improve water quality.