Effects of Landscape Development Intensity on River Water Quality in Urbanized Areas

Yuncai Wang,Jiake Shen,Chundi Chen,Wentao Yan

doi:10.3390/su11247120

Abstract

Urban development and human activities have greatly changed the appearance of urban landscapes, and also affect urban river water environments. Rapidly urbanized regions in China face particularly severe pressures and challenges in alleviating degradation of river water quality. Information is needed on which indexes of landscape development intensity in rapidly-urbanized areas are the key factors affecting the quality of river water environments, and how these factors affect water quality. In order to answer these questions, this research selected six indexes belonging to three dimensions for landscape development intensity evaluation. Based on five water quality parameters of 20 rivers and the land use data of 20 small watersheds of Liangjiang New Area, Chongqing, China in 2014, this research explored the correlation between the landscape development intensity indexes and river water quality through redundancy analysis. We found that the impervious surface rate and the land average fixed asset investment are the key indexes to affect river water quality. Regulating the corresponding indexes at the urban planning and design level, as well as the decision making level, can effectively achieve the goal of improving urban river water quality. The conclusions inspire strategies in planning and design, and are helpful for government decision making to effectively protect river water environment in rapidly urbanized areas in the developing countries.

Highlights

Rivers in the city, serving as reliable surface water sources, are important natural geographical elements and ecological corridors in urban landscape, beneficial to public health and ecological environment [1,2,3]
Some scholars argued that even with similar or same land use types and proportions, different land use intensities may result in a wide range of water quality [35,36]; only using the quantitative proportion of land use in the watershed to explain the water quality performance will often lead to different findings [10,11,12,13,37,38]
It can be seen that the mean concentration of total nitrogen (TN), NH3+-N and total phosphorus (TP) was inferior to the minimum allowable value of Class V water in the “National Surface Water Environmental Quality Standard” (GB3838-2002) [68], and about 70% of the sampling sites exceed the limit value of the Class IV water quality parameters

Summary

Introduction

Rivers in the city, serving as reliable surface water sources, are important natural geographical elements and ecological corridors in urban landscape, beneficial to public health and ecological environment [1,2,3]. Under the influence of urbanization, non-point source pollution caused by rainwater runoff has become one of the important reasons for the deterioration of urban water environment [15,16]. Water quality parameters such as total soluble solid (TSS), chemical oxygen demand (CODMN), total nitrogen (TN), ammonia nitrogen (NH3+-N), and total phosphorus (TP) are representative pollutant parameters, which describe the physical and chemical characteristics of water bodies, have attracted more attention in water quality studies in urbanized areas [17,18,19,20,21,22]. Some scholars argued that even with similar or same land use types and proportions, different land use intensities may result in a wide range of water quality [35,36]; only using the quantitative proportion of land use in the watershed to explain the water quality performance will often lead to different findings [10,11,12,13,37,38]

Methods

Results

Discussion

Conclusion