【作者】 赵庆良；

【导师】 许世远； 陈振楼；

【作者基本信息】 华东师范大学 ， 自然地理学， 2010， 博士

【摘要】 沿海城市不仅是自然灾害频发区域,也是世界各地人口集聚、经济发达的重要区域和战略中心。全球气候变暖、海平面上升和海陆交互作用使沿海城市的脆弱性和自然灾害风险水平显著增加,社会经济损失巨大。沿海城市地位的重要性和面临自然灾害的高风险性,促使沿海城市自然灾害风险研究备受关注。温州龙湾区受台风暴雨和风暴潮带来的洪涝灾害影响严重。龙湾区沿海滩涂水产养殖和渔业发达,每年台风汛期,常会造成人员伤亡和大量财产损失。在该区域开展洪灾风险评估和区划研究不仅能够弥补沿海山地丘陵型城市洪灾风险研究的不足,而且可以充实和发展城市洪灾风险管理的理论基础和方法体系。本文以国家自然科学基金重点项目“沿海城市自然灾害风险应急预案情景分析(40730526)”和国家自然科学基金项目“中国沿海城市自然灾害风险评估体系研究(40571006)”为依托,通过大量野外实地考察和调研得到第一手数据资料为基础,建立了沿海山地丘陵型城市洪灾风险评估的理论框架和方法程序;开展了温州龙湾区洪灾风险评估和区划研究。这对构建以“风险防范”为核心的洪灾风险管理体系,保障沿海城市公共安全、促进沿海城市可持续发展战略实施具有科学价值和现实意义。本文得到以下6方面成果:1.综合考虑洪灾系统中致灾因素、孕灾环境和承灾体的特征,对温州龙湾区进行洪灾系统风险识别分析。从气象水文因素、地理位置因素和防洪排涝工程措施三个方面进行洪灾系统致灾因素的辨识;从气象因素和下垫面因素两个方面进行洪灾孕灾环境分析;用不同土地利用类型作为洪灾承灾体,考虑快速城镇化对洪水灾害影响,进行洪灾承灾体类型和特征分析;根据温州台风暴雨洪灾历史数据资料,得到温州台风—暴雨强度相关关系及台风暴雨时空分布规律。2.根据温州龙湾区中小流域下游山地丘陵地形和不同重现期洪水淹没情景,重点进行了基于情景模拟的暴雨洪水风险危险性评价方法研究。考虑到地面径流、地形起伏和下渗作用等自然因素,基于“雨量体积法”洪水淹没情景模拟方法,利用自编GIS程序模拟不同重现期洪水水面高程和计算不同洪水淹没深度区间对应的淹没面积,并根据洪水淹没深度对温州龙湾区进行暴雨洪水风险危险性评价。本文还根据龙湾区2005年台风“海棠”暴雨实测资料进行典型历史台风暴雨事件洪水淹没情景模拟和危险性评价实证研究。3.根据不同土地利用类型上不同财产对洪水的耐淹性能和洪灾损失程度不同,构建了城镇土地利用类型洪灾脆弱性分类体系,开展了洪灾风险脆弱性评估。运用ARCGIS软件对温州龙湾区航拍影像进行目视解译,并确定温州龙湾区不同土地利用类型的洪灾脆弱度。温州龙湾区洪灾风险脆弱性评估结论揭示了不同洪水淹没模拟情景下洪灾脆弱区域的受灾面积变化规律以及不同脆弱度区域面积的变化规律。4.根据国内外不同土地利用类型成本价值估算方法和龙湾区社会经济水平,进行了龙湾区不同土地利用类型成本价值的估算,并开展了洪灾损失评估。研究表明:龙湾区不同重现期洪灾损失大小排序为瑶溪镇＞沙城镇＞海滨街道＞永中街道;龙湾区不同重现期洪水淹没模拟情景下不同土地利用类型洪灾损失大小排序为工业用地＞居住用地＞农业用地＞公共事业用地。5.基于GIS技术,以洪水风险值作为区划指标,据此构建了龙湾区洪水风险区划图编制方法。研究表明:龙湾区从5年一遇洪水到100年一遇洪水,洪水风险区的总面积逐渐增大,高风险区逐渐转化为中风险区,中风险区逐渐转化为低风险区,高风险区的面积逐渐减小,低风险区的面积逐渐增大。综上所述,本研究在多学科交叉基础上,从多角度对沿海山地丘陵型城市洪灾系统风险进行了综合分析,对沿海城市洪灾风险评估进行了系统研究,并以温州龙湾区为研究区域开展实证研究。建立了基于情景模拟的洪水风险危险性评价、基于洪灾脆弱度的洪灾风险脆弱性评估、基于GIS空间网格的洪灾损失评估以及根据洪灾损失值与发生概率关系进行洪灾风险评估四部分内容构成系统的中国东部沿海山地丘陵型城市洪灾风险评估的理论框架和方法程序。洪灾风险评估研究是一个涉及灾害学、风险学、地理学、环境学、气象学、水文水动力学等多学科交叉的研究课题。本文虽然在沿海城市洪灾风险评估和风险区划的研究上作了部分有益的探索,但是相对于本研究领域科学理论的拓展和现实问题的解决还仅仅是一个开端。洪灾风险评估研究是一个极其复杂的系统工程,还需要在理论和实践上做进一步深入细致的研究。更多还原

【Abstract】 Coastal cities are not only regions with frequent natural disasters, but also important regions and strategic centers with high population density and highly-developed economy. Owing to the global warming, sea-level rising, and the interaction of land and ocean, the vulnerability and the natural disasters risk level of the coastal cities have remarkably increased, and the losses caused by natural disasters are enormous. Therefore, the research on the natural disaster risk of the coastal cities has become a focus owing to the importance and the high risk of the coastal cities exposure to natural disasters.Longwan District of Wenzhou City has seriously affected by flood disaster resulted from rainstorm of typhoon and storm surge. Beach aquaculture and fishery in Longwan District are well developed, but the annual typhoon flood season often results in casualties and great economic losses. Flood risk assessment and regionalization research in this region is not only able to make up inadequate study on flood risk in mountainous and hilly cities, but also able to enrich and develop the theories and methodologies of urban flood risk management.In this dissertation, the author establishes a theoretical framework and methodological procedure for assessment of flood risk in coastal mountainous and hilly cities. The research was supported by two foundations (key Foundation of National Natural Science of China"Scenario Analysis of Emergency Responses to Natural Disasters Risk in Coastal Cities" No: 40730526; National Natural Science Foundation of China "Study on Natural Disasters Risk Assessment System in Chinese Coastal Cities" No: 40571006). and the first-hand data obtained from the field studies and makes an overall risk assessment and regional study on flood risk in Longwan District, Wenzhou City, which shall be of scientific value and practical significance in construction of the flood risk management system with"risk prevention" as the core, safeguard of public safety and promotion of sustainable development strategy in coastal cities. The six main conclusions can be summed up as follows.Based on the overall consideration about the characteristics of the flood-causing factors, formative environment and hazard-affected bodies in the flood system, the author analyses the flood system risk in Longwan District discriminatorily. Flood disastrous factors are identified from three aspects: hydrometeorology, geographical position, and flood prevention and drainage facilities. Formative environment is analyzed from meteorology and underlying surface. Taking into consideration of rapid urbanization impact on flood disaster, types and characteristics of flood hazard-affected bodies are analyzed with different land use types. The correlation and spatial and temporal distribution of typhoons and rainstorms in Wenzhou are obtained by using the data on historical flood disasters caused by typhoons.Scenario-based studies on rainstorm flood risk assessment are especially carried out on the basis of mountainous and hilly region in medium-small watershed down streams and flooding scenarios at different return periods in Longwan District, Wenzhou. With the aid of self-compiled GIS program and flood scenario simulation on the basis of "precipitation volumetric method" , and taking consideration of natural factors such as surface runoff, topographic relief and infiltration, the author simulates flood surface level at different return periods, calculates respective flooding areas corresponded to different submerge depths range, and evaluates rainstorm flood hazard in Longwan District in terms of flood submerge depths. The author simulates typical flooding scenario caused by history-recorded typhoon rainstorms and evaluates the risk with the data observed when typhoon "Haitang" took place in Longwan District in 2005.The author establishes the classification scheme of different land use types flood vulnerability and assesses flood risk vulnerability on the basis of flood-resistance capability of various properties on different land use types and degree of flood losses. The author visually interprets aerial-images over Longwan District by ARCGIS software and determines flood vulnerability of different land use types in the study area. The results of the assessment on flood risk vulnerability in Longwan District reveal changes of flooding area in flood-vulnerable regions and area changes at various vulnerable degrees regions under different flooding simulation scenarios.Cost of different land use types and flood losses are evaluated in terms of foreign and domestic cost evaluation method for different land use types and social economic level of Longwan District. The following counties in Longwan District are sorted in descending order by flood losses at different return periods shown in the study: Yaoxi community > Shacheng community > Haibin community > Yongzhong community. Different land use types are sorted in descending order by flood losses at different return periods under simulated scenarios: industrial land > residential land > agricultural land > public land.The author constructs a method to compile flood risk zoning map in Longwan District by means of flood risk value as a regionalization indicator by means of GIS technology. The study shows that total flood risk areas are increasing while the frequency flood occurrence is decreasing from once in 5 years to once in 100 years. High risk regions are becoming medium risk regions and medium risk regions are becoming low risk regions. Additionally, the area of high risk regions is decreasing while that of low risk regions is increasing.In summary, this dissertation, on the basis of interdisciplinary studies, comprehensively analyzes flood risk system in coastal mountainous and hilly cities from various perspectives, makes a systematic research on flood risk assessment on coastal cities and takes a case study in Longwan District, Wenzhou. The author establishes a systematic flood risk assessment theory framework and methodological procedure for Chinese eastern coastal mountainous and hilly cities, which includes four parts: scenario-based flood hazard assessment, flood vulnerability-based flood vulnerability assessment, mesh-based flood losses assessment and flood risk assessment by correlation between flood losses value and occurrence frequency.Flood risk assessment study is an interdisciplinary research subject involving Disaster Science, Risk Science, Geography, Environmental Science, Meteorology, Hydrology and Hydro-dynamics, etc. Although the dissertation makes a partial useful exploration on flood risk assessment and risk zoning study in coastal cities, it is just at the threshold of the development of scientific theory in this study circle and solves actual problems. Flood risk assessment is a very complex work, and it shoud be further studied theoretically and practically.更多还原