title: Water quality changes in response to urban expansion: spatially varying relations and determinants.
abstract: Urban expansion is an important stressor to water bodies, and the spatial variations of their relations are increasingly highlighted by recent studies. What remain unclear, however, are the underlying drivers to the spatial variability. The paper was not limited to modeling spatially varying linkages but also drew attention to the local anthropogenic influential factors that shape land-water relations. We employed geographically weighted regression to examine the relationships between urban expansion (measured by land use change intensity) and water quality changes (focusing on six water quality indicators) in a recently fast-growing Chinese city, Lianyungang. Specifically, we analyzed how the local characteristics including urbanization level, environmental management, industrial zone expansion, and land use composition, attributed to the varying responses of water quality changes. Results showed that urbanization level significantly affects land-water linkages. Remarkable water quality improvement was accompanied by urbanization in highly developed watersheds, primarily due to strong influence from extensive water management practices (particularly for COD, BOD, NH3-N, and TP). By contrast, water qualities of less-urbanized watersheds were more sensitive and negatively responsive to land use changes. Clustering industrial activities acted as distinct contributor to Hg contamination, while boosted organic pollution control in highly urbanized areas. The approach proposed in the study can locate and further zoom into the hot-spots of human-water interactions, thereby contributing to better solutions for mitigating undesirable impacts of urbanization on water environment.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China. njuzhaowj@gmail.com.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China. njuxdzhu@gmail.com.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China. sunxiang@nju.edu.cn.|School of Environment, Guangxi University, Nanning, 530004, People's Republic of China. sunxiang@nju.edu.cn.
authors.forename: Xiang
authors.initials: X
authors.lastname: Sun
authors.affiliation: International Water Management Institute (IWMI) Southern Africa, Pretoria, South Africa. yunqiaoshu1981@gmail.com.
authors.forename: Yunqiao
authors.initials: Y
authors.lastname: Shu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China. lyfcornell@gmail.com.|The Key Laboratory of the Coastal Zone Exploitation and Protection, Ministry of Land and Resource, Nanjing, 210008, People's Republic of China. lyfcornell@gmail.com.
authors.forename: Yangfan
authors.initials: Y
authors.lastname: Li
mesh_terms: D002681:China; D004784:Environmental Monitoring; D006801:Humans; D062206:Spatial Analysis; D014507:Urbanization; D060753:Water Quality
keywords: Anthropogenic factors; China; Geographically weighted regression; Land-water linkages; River pollution; Urbanization level