流域城镇化格局与河流氮磷的空间关系

Spatial relationship between basin urbanization pattern and river nitrogen and phosphorus

流域景观格局对河流氮磷污染物的发生、迁移和转化的有重要影响,人类活动干扰加剧了河流氮、磷污染的季节性变异,使河流污染的复杂性、随机性、空间分异明显。为探究流域城镇化格局对河流季节性变化中氮磷的空间分异的影响,研究基于天津于桥水库流域近4年33个点的定位监测,采用冗余分析、地理加权回归模型等方法,定量分析了景观格局组成及景观结构特征与河流氮磷污染的空间响应关系。结果表明,城镇用地比例(Red%)、不透水面指数(ISA)对水质指标TN、TP的解释度最为显著(p<0.01),Red%与TN、TP正相关子流域集中分布于高城镇化聚集区域,ISA与TN、TP正相关子流域集中于不透水面扩展较快的山区村镇,两个指数能较好地反映氮磷的空间分异。探究因子对流域水质空间分异的影响,对评价和控制河流非点源污染排放具有重要意义。

The landscape pattern of the river basin had an important impact on the occurrence, migration and transformation of nitrogen and phosphorus pollutants in the river. Human activities aggravated with the seasonal variation of nitrogen and phosphorus pollution in the river. In order to explore the influence of basin urbanization pattern on spatial differentiation of nitrogen and phosphorus in seasonal changes of rivers, in this paper, based on the location monitoring of 33 points in the Yuqiao reservoir watershed of Tianjin in recent 4 years, the spatial response relationship between the composition of landscape pattern and the characteristics of landscape structure and the nitrogen and phosphorus pollution in the river was quantitatively analyzed by means of redundancy analysis and geographic weighted regression model. Results showed that the urban land scale (Red %), opaque surface index (ISA) on the water quality indexes of TN and TP explained the most significant (p < 0.01), Red % and TN, TP was related to watershed concentration distribution in the high concentrated areas of urbanization, The positive correlation between ISA and TN and TP was concentrated in the mountainous villages and towns with fast expansion of impervious water surface, two index can well reflect the spatial differentiation of nitrogen and phosphorus. It is of great significance to explore the influence of factors on spatial differentiation of water quality in river basin for evaluation and control of nonpoint source pollution discharge.