The correlation between land use and water quality in the typical urbanized region of China: A case study in the river net area of Pearl River delta

Abstract

The Pearl River delta is one of the most densely populated areas in China, with high urbanization and rapid economic development. The drama change of land use in recent years has been matched by rising pollution of water. With monitoring data of water quality and Landsat OLI8 images 2013, this paper analyzed the relationship between land use and water quality in the river net area of Pearl River delta. Using redundancy analysis method, correlations were conducted at four spatial scales from 100 m to 1000 m in the riparian buffers. The results showed that the land use structure had a great impact on water quality parameters. The urban land had negative effect and the increase of urban impervious surface exacerbated the deterioration of water quality. The arable land showed positive effect on water quality. This was partly because the arable land had a certain absorption and retention, preventing pollutants to the river. On the other hand, the negative impact of arable land was covered up by urban land for the relatively low area proportion. The forest and water had a positive effect on water quality. The forest was more relevant to water quality in small riparian zone scale. With the increase of riparian zone scale, the correlations of the arable land and urban land to COD Mn were first increased and then decreased. The correlation between the water in the riparian buffers and the water quality in the net river was strong, which increased constantly with the scale of riparian zone. The research could provide critical information in landscape planning and environmental protection.