Multifactor-based environmental risk assessment for sustainable land-use planning in Shenzhen, China.

The health and resilience of urban ecosystems are highly dependent on interactions between the natural and built environments. Rapid urbanization, however, brings potential risks to urban ecosystems. Therefore, it is important to justify land-use planning and to identify opportunities for regulating sustainable land use. We developed a framework of land-use planning based on an Environmental Risk Assessment (ERA) and applied it to an environmentally sensitive urban area in Shenzhen, China. The ERA used the analytic hierarchy process method to determine weights for various indicators, and further performed a multifactor-based spatial superposition analysis in the ModelBuilder of a geographic information system to produce a risk map. The selected indicators were topography, hydrology, ecosystem, land use, and traffic. The risk map was first compared with an existing map of ecological control lines to ensure the reliability of the ERA, and then applied to establish the necessity and priority of land-use measures for four different land-use types: nature reserves, green space, urban areas, and spare land. The map indicated that nature reserves and green space make up 84.7% of the area at high risk of degradation, whereas urban areas make up 13.7%. It also showed that a majority of the high-risk urban areas are distributed around water-source reserves and the Pingshan River, and 87.6% of them are residential, industrial, and commercial lands in which the potential risks of non-point source pollution are high. Corrective actions should be considered on an urgent basis in high-risk urban areas, where low-impact development practices are considered effective in reducing non-point source pollution at the source. Validation results affirmed that the proposed ERA approach can reliably provide insights into the distribution of environmental risks in the study area. The proposed framework of ERA-based land-use planning is applicable to sustainable urban development and revitalization of other urban regions.