河流近域土地利用格局与水质相关性分析——以巢湖流域为例

CORRELATION BETWEEN THE WATER QUALITY AND LAND USE COMPOSITION IN THE RIVER SIDE AREA——A CASE OF CHAOHU LAKE BASIN IN CHINA

以河流近域土地利用构成与水环境质量间定量关系为研究对象,基于巢湖流域40个水质监测断面和320个河流近域作用区,运用GIS空间分析功能计算不同尺度作用区内土地利用构成,借助相关分析、冗余分析(RDA)等数理统计手段,分析土地利用构成与水质指数间的相关关系;并分析和比较了流域内山区和平原地区土地利用构成与水质之间关系。结果表明,巢湖流域近河道地区土地利用构成对各水质指数有重要影响,且受地形因素影响。其中,建设用地对河流水质恶化具有明显作用;河流沿岸林地布局能显著改善水质,尤其是对氨氮和高锰酸盐指数敏感;耕地面积变化与水质相关性不显著。RDA冗余分析证实了不同尺度下的土地利用类型对水环境影响具有尺度效应。研究成果对巢湖流域水环境管理具有重要的实际指导意义,并为同类研究提供借鉴。

The relationship between land use and water quality is one of the important components of land use environmental effects research.Based on monitoring water quality and land use data,this paper focused on quantitative relationships between land use pattern and water quality in Chaohu Lake basin.Firstly with the help of GIS spatial analysis tool,strip types of contributing zones with different buffer radii were developed around the monitoring sites for water quality assessment,and the proportions of four types of land use types were extracted from the buffer zones.Then correlation and redundancy analysis（RDA） methods were used to analyze the relationship between water quality and land use patterns within buffer zones,and a comparison between mountainous areas and flat areas was made.Results showed that the land use structure in the river side area in Chaohu Lake basin had great impacts on water quality parameters.Urban construction land showed negative effects on water quality,and was the dominant factor for river pollution in Chaohu Lake basin.The forestland exhibited a significant positive relation with water quality,especially with CODMn and NH3-N.It suggested that the closer forestland tend to improve water quality.The impacts of cultivated land on the river water quality were complicated.In addition,under different terrain conditions in Chaohu Lake basin,there were some differences in the way and to the degree of land use influencing the variables of water quality in the same contributing zone scale.RDA demonstrated that there existed obvious scale effect caused by different land use types.The study results should provide practical guidelines for the management of water environment in Chaohu Lake basin.