长江三角洲地区城市化对洪灾风险的影响评价

EFFECTS EVALUATION OF URBANIZATION ON FLOOD RISK IN THE YANGTZE RIVER DELTA

在长江三角洲地区选择了里下河、秦淮河、武澄锡虞、浦东浦西、杭嘉湖和甬曹浦6个城市化典型区域,以1991、2001和2006年3个城市化发展阶段为代表,采用指标体系评价法研究了城市化对洪灾风险的影响。通过基于洪灾形成机制构建洪灾风险评价指标体系,采用层次分析法确定指标权重,计算得到洪灾危险性、暴露性、脆弱性和综合风险的评价结果。表明在城市化过程中,6个典型区域的洪水危险性和承灾体暴露性均有增加趋势,其中承灾体暴露性增加显著;尽管各区域的承灾体脆弱性随着防洪减灾能力的提升而有所降低,但综合洪灾风险总体上仍呈现加剧的态势,对城市可持续发展构成威胁。最后,结合评价结论提出了长江三角洲城市化地区洪灾风险管理的若干建议。

Six urbanization typical areas namely Lixiahe,Qinhuaihe,Wuchengxiyu,Pudongpuxi,Hangjiahu and Yongcaopu were selected in the Yangtze River Delta and 1991,2001 and 2006 were selected as the representative years of different urbanization stages in the study.The index system-based assessment method was used to reveal the effect of urbanization on flood risks.Risk evaluation index system was established based on the flood disaster formation mechanism,and the analytic hierarchy process was utilized to determine the index weights.Then,the hazard,exposure,vulnerability and composite risk of flood disaster were evaluated.The results showed that the flood hazards of 6 areas presented an increasing trend in the process of urbanization,and the increasing trends of hazard-affected bodies exposed in flood stricken area were especially obvious.Though the vulnerabilities of 6 areas presented an decreasing trend owing the enhancement of flood prevention ability,the composite flood risks of 6 areas tended to be exacerbated in whole,which would pose a serious threat to urban sustainable development.Finally,some flood risk management countermeasures for urbanization areas in the Yangtze River Delta were put forward based on the evaluation results.