Rapid urbanization reshapes landscape patterns and intensifies stormwater runoff pressure,yet the shifting cost-effectiveness of green infrastructure across different urban development phases remains poorly quantified...Rapid urbanization reshapes landscape patterns and intensifies stormwater runoff pressure,yet the shifting cost-effectiveness of green infrastructure across different urban development phases remains poorly quantified.Focusing on Beijing’s 150 km2 urban subcenter,this study quantified 21 block-level landscape metrics,which were distilled via principal component analysis into five landform indicators:dominance,fragmentation,edge,aggregation,and shape.K-means clustering classified each block into constructed,constructing,or unconstructed phases.A life-cycle cost analysis then estimated the bioretention investment required to meet an 80%-85%annual runoff volume control target.The constructing phase,characterized by contiguous impervious surfaces at the urban edge,demands 45%more bioretention investment per unit area than the unconstructed phase and 4%more than the constructed phase.As land transitions from unconstructed to constructed,bioretention costs increase by approximately 109%for agricultural land and 86%for green space,whereas changes for residential and commercial areas remain minimal.These results indicate that uniform runoff control investment policies risk underfunding rapidly developing fringes and overfunding consolidated urban centers.A phase-specific and land use-sensitive investment strategy is therefore necessary to avoid capital inefficiency while achieving runoff control goals.By linking dynamic landscape evolution with infrastructure economics,this study provides a forward-looking tool to guide runoff control investment during urban expansion.展开更多
基金supported by the Science and technology development project of Transport Planning and Research Institute of Ministry of Transport of China(No.092517-905).
文摘Rapid urbanization reshapes landscape patterns and intensifies stormwater runoff pressure,yet the shifting cost-effectiveness of green infrastructure across different urban development phases remains poorly quantified.Focusing on Beijing’s 150 km2 urban subcenter,this study quantified 21 block-level landscape metrics,which were distilled via principal component analysis into five landform indicators:dominance,fragmentation,edge,aggregation,and shape.K-means clustering classified each block into constructed,constructing,or unconstructed phases.A life-cycle cost analysis then estimated the bioretention investment required to meet an 80%-85%annual runoff volume control target.The constructing phase,characterized by contiguous impervious surfaces at the urban edge,demands 45%more bioretention investment per unit area than the unconstructed phase and 4%more than the constructed phase.As land transitions from unconstructed to constructed,bioretention costs increase by approximately 109%for agricultural land and 86%for green space,whereas changes for residential and commercial areas remain minimal.These results indicate that uniform runoff control investment policies risk underfunding rapidly developing fringes and overfunding consolidated urban centers.A phase-specific and land use-sensitive investment strategy is therefore necessary to avoid capital inefficiency while achieving runoff control goals.By linking dynamic landscape evolution with infrastructure economics,this study provides a forward-looking tool to guide runoff control investment during urban expansion.
