土地利用/景观格局对水环境质量的影响

Effects of land use/landscape patterns on the water quality

土地利用/景观格局已成为影响中国水环境质量的重要因素,但目前仍然欠缺土地利用/景观格局和水环境质量之间复杂关系的深入研究。以湟水流域小峡桥断面上游为例,兼顾水环境承载力与人为活动所产生的压力,建立土地利用/景观格局对水环境质量影响的结构方程模型,计算不同土地利用/景观格局指标对水环境质量的贡献率。研究表明:点源污染是湟水流域水环境质量恶化的主要因素,其贡献率最大(37.3%);而土地利用/景观格局的4个指标(不透水面面积占比、建设用地中绿地面积占比、湿地连通性和湿地聚集度)对水环境质量的贡献率相对较大,分别为9.14%、 7.91%、 7.44%和6.96%。加大点源污染控制力度、增强湿地连通性与聚集度、增大建设用地中绿地面积并减少不透水面面积是改善湟水流域小峡桥断面上游水环境质量的有效措施。

Land use/landscape pattern has become an important factor affecting water environment quality in China. Nonetheless,in-depth study of the complex relationship between land use/landscape pattern and water environment quality is still lacked. We applied a structural equation model (SEM) which accounted for the bidirectional regulation of water environmental carrying capacity and environmental pressures in the upstream of Huangshui River basin. Subsequently,we calculated the contribution rates of various variables of land use/landscape pattern on water environment quality in accordance to their relative weights. The results indicated that the contribution rate of point source pollution on the water quality is the greatest (37.3%). From landscape pattern perspective,the contribution rates of the spatial distributions of impervious surface and green space,the connectivity and aggregation of the wetland on the water quality are 9.14%,7.91%,7.44% and 6.96%,respectively. To significantly improve the water quality in the study area,more efforts are needed to control point source pollution,enhance the connectivity and aggregation of the wetland,increase green space and decrease impervious surface in the upstream of Huangshui River basin.