城市山洪灾害多目标评估方法探讨

Approach to Mutil-objectives Assessment for Urban Torrent Hazard

本文针对目前城市山洪灾害的突出问题,分析了国内外研究状况和发展趋势;探讨了城市山洪灾害多目标评估系统方法,包括山洪灾害泛滥范围的危险区划、城市易损性分析、城市山洪灾害损失评估和风险评价四个主要内容。关于山洪孕灾环境、致灾因子和承灾体的社会经济状况,本研究提出一套基于GIS的从数据采集→空间属性数据库建立→评价指标体系选择→预测评价分析→山洪灾害危险性评价与风险区划的技术路线和方法体系。山洪灾害危险区划采用地貌学和数值模拟方法;以高分辨率遥感卫星影像为数据源,分析了城市土地覆盖类型,应用GIS进行了山洪灾害损失评估和风险评价。山洪灾害多目标评估可用于指导城市洪泛区不同危险、风险地带的土地利用规划与决策,从而达到规避风险和减灾的目的,并为山洪灾害影响区的居民提供灾害风险信息,以作为避难和防洪的依据。

This paper focuses on the problems of urban torrent hazard in the recent years and reviews the current study status and future research work about assessment of urban torrent hazard. According to torrent-breeding environment, triggering factors, social and economic situation of flooded area, this research formed a GIS based technical methodological system, which is shown as following： collect data→establish database of spatial attribute →choose the system of assessed indexes→analyze forecasting estimation→torrent hazard assessment and risk zonation. Based on this, an integrated methodology for urban torrent risk assessment is approached. Procedure of the methodology for torrent hazard zonation in the flooded area, urban vulnerability analysis, loss evaluation and risk assessment, torrent hazard zonation on the alluvial fan are created via geomorhologic method and the numerical simulation method. Detailed land cover information was derived by using the high resolution satellite imagery and then we evaluated the vulnerability values on different land-use features. Based on a GIS statistical and analytical tool,urban torrent loss and risk for urban area is evaluated. These assessments can be used for torrent mitigation by identifying hazard areas, allowing for avoidance through zoning or other land use policy decision. In addition, residents who live in torrent areas need risk information for evacuation and flood control.