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
Vegetative filter strip (VFS) is a main kind of Best Management Practices for the control of non-point source pollution. The goal of this paper is to evaluate the effectiveness of VFS in Chinese northwest regions. Thr...Vegetative filter strip (VFS) is a main kind of Best Management Practices for the control of non-point source pollution. The goal of this paper is to evaluate the effectiveness of VFS in Chinese northwest regions. Three VFSs with natural grass and Hippophae rhamnoides/grass patterns have been constructed in the bank slope of Xiaohuashan reservoir, Huaxian County, Shannxi Province. The removal effects of VFS and influencing factors have been analyzed based on field experiment data. The result reveals a positive effect on reducing the transportation of suspended solids, phosphorus and nitrogen in surface runoff, and it is more efficient on suspended solids removal. The experiment also shows that most of the suspended particles and pollutants bound to them were entrapped in the first 10 m of VFS. The main factors influencing effectiveness of VFS include vegetation patterns and inflow rate. In addition, inflow pollutant concentration has a larger impact on reducing total nitrogen and total phosphorus by VFS, but the reduction effect on SS has no significant difference.展开更多
[Objeetive] We aimed to calculate the flow of controlling units in a small watershed based on GIS technology. [Method] Hydrologic analysis on Qingyi River was conducted by using ArcGIS9.0, and the controlling units wi...[Objeetive] We aimed to calculate the flow of controlling units in a small watershed based on GIS technology. [Method] Hydrologic analysis on Qingyi River was conducted by using ArcGIS9.0, and the controlling units with response of water-land were divided according to the riv- er monitoring sections of Xuchang City; considering the wastewater entering the river and the water from its upper reach, the runoff of controlling sections in the driest month （ with guarantee rate of 90% ） was calculated by means of isoline, runoff coefficient and hydrologic analogy method, and the calculated value of Gaocun Bridge section in Linying was contrasted with the measured value in 2010. [Result] The results showed that the cal- culated value and measured value of Gaecun Bridge section in Linying in the driest month of 2010 were 6.03 and 5.93 m^3/s respectively, with relative error of 1.69%, which revealed that the result of calculated runoff was reasonable. [ Conclusion] The way to divide controlling units was reason- able, and the calculation result of runoff was accurate and can meet the precision of water environment capacity calculation.展开更多
Flood control detention basins （DBs） can act as water quality control structures or best management practices （BMPs）. A key pollutant that DBs serve to settle out is particulate phosphorus, which adsorbs onto sedi...Flood control detention basins （DBs） can act as water quality control structures or best management practices （BMPs）. A key pollutant that DBs serve to settle out is particulate phosphorus, which adsorbs onto sediment. This study examines the sediment phosphorus concentration and its relationship with the particle size of sediment microcosms from pre- and post-rain event samples obtained from six DBs located in Clark County, Nevada. DBs were allotted a land use classification to determine if there was a correlation between the sediment phosphorus concentration and surrounding land use. The curve number method was used to calculate the runoff and subsequent phosphorus carried into the DB by the runoff. Our data show sediment phosphorus concentrations to he highest in soils from undeveloped areas. Runoff amount also plays a substantial role in determining the amount of phosphorus brought into the DB by sediment. This research has implications for improvement of water quality in arid regions.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.
文摘Vegetative filter strip (VFS) is a main kind of Best Management Practices for the control of non-point source pollution. The goal of this paper is to evaluate the effectiveness of VFS in Chinese northwest regions. Three VFSs with natural grass and Hippophae rhamnoides/grass patterns have been constructed in the bank slope of Xiaohuashan reservoir, Huaxian County, Shannxi Province. The removal effects of VFS and influencing factors have been analyzed based on field experiment data. The result reveals a positive effect on reducing the transportation of suspended solids, phosphorus and nitrogen in surface runoff, and it is more efficient on suspended solids removal. The experiment also shows that most of the suspended particles and pollutants bound to them were entrapped in the first 10 m of VFS. The main factors influencing effectiveness of VFS include vegetation patterns and inflow rate. In addition, inflow pollutant concentration has a larger impact on reducing total nitrogen and total phosphorus by VFS, but the reduction effect on SS has no significant difference.
文摘[Objeetive] We aimed to calculate the flow of controlling units in a small watershed based on GIS technology. [Method] Hydrologic analysis on Qingyi River was conducted by using ArcGIS9.0, and the controlling units with response of water-land were divided according to the riv- er monitoring sections of Xuchang City; considering the wastewater entering the river and the water from its upper reach, the runoff of controlling sections in the driest month （ with guarantee rate of 90% ） was calculated by means of isoline, runoff coefficient and hydrologic analogy method, and the calculated value of Gaocun Bridge section in Linying was contrasted with the measured value in 2010. [Result] The results showed that the cal- culated value and measured value of Gaecun Bridge section in Linying in the driest month of 2010 were 6.03 and 5.93 m^3/s respectively, with relative error of 1.69%, which revealed that the result of calculated runoff was reasonable. [ Conclusion] The way to divide controlling units was reason- able, and the calculation result of runoff was accurate and can meet the precision of water environment capacity calculation.
基金supported by the Urban Flood Demonstration Program of the United States Army Corps of Engineers(Grant No.W912HZ-08-2-0021)
文摘Flood control detention basins （DBs） can act as water quality control structures or best management practices （BMPs）. A key pollutant that DBs serve to settle out is particulate phosphorus, which adsorbs onto sediment. This study examines the sediment phosphorus concentration and its relationship with the particle size of sediment microcosms from pre- and post-rain event samples obtained from six DBs located in Clark County, Nevada. DBs were allotted a land use classification to determine if there was a correlation between the sediment phosphorus concentration and surrounding land use. The curve number method was used to calculate the runoff and subsequent phosphorus carried into the DB by the runoff. Our data show sediment phosphorus concentrations to he highest in soils from undeveloped areas. Runoff amount also plays a substantial role in determining the amount of phosphorus brought into the DB by sediment. This research has implications for improvement of water quality in arid regions.
