基于不规则离散格网的城市洪涝灾害损失评估与风险管理决策研究

Considering the complex environment and variety influence factors of the urban flood, the existed hydrologic dynamic modeling and risk assessment method based on catchment area or regular grid are difficult to assessment the risk precisely. And it also cannot meet the needs of precise risk decision in changing environment. With the increasing of big data related to flood disaster and developing technologies on remote sensing and GIS, it is possible to assess the flood risk precisely combining natural attributes and social attributes. By taking a full consideration of natural and social factors of the minimum homogeneous space unit of disaster system, the mechanism of urban flood disaster will be studies firstly based on the space unit of hazard-affected bodies. And then the irregular gird spatial discrete model based on many factors will be established. Based on that, the two-dimensional hydrodynamic model and the spatial discrete method of socioeconomic data are set up in order to realize the match of natural characteristics of urban flood and its social characteristics. And then the loss assessment model of urban flood based on irregular grids will be proposed. Based on the risk assessment, the decision mechanism of flood risk management for urban planning is studied. Finally, all the above methods are applied in Jingdezhen City. In conclusion, the theory and method of urban flood loss assessment and risk decision established by this study will provide the theoretic and practical foundation for the urban disaster prevention and mitigation.

面对城市洪涝灾害的复杂环境和诸多影响因素，现有的基于汇水区或规则格网的水文动态建模与风险评估方法难以实现自然和社会系统耦合下的灾害风险精确评估，不能满足变化环境下精准风险决策的需要。与孕灾-成灾-减灾高度关联的大数据日益丰富，为洪涝灾害全面、精细化评估提供了解决思路。本研究将充分考虑致灾系统最小均质空间单元的自然与社会要素，研究基于承灾体空间单元的城市洪涝灾害形成机制，建立城市地表多要素空间不规则离散格网模型，在此基础上利用二维水动力模型与社会经济要素空间化方法，实现洪涝灾害自然属性与社会经济属性的匹配，构建基于不规则格网的城市洪涝灾害损失评估模型，并研究面向城市规划的城市洪涝灾害风险管理决策机制，最后结合景德镇市实际进行洪涝灾害评估与风险管理决策的应用研究。建立的基于不规则离散格网的城市洪涝灾害风险管理理论与方法，为城市防灾减灾提供科学理论基础和实践指导。

受全球气候变化和人类活动双重的影响，特别是我国城市化快速发展，显著改变了降雨径流、汇流路径和方式等水文过程，使洪涝灾害演变更加复杂，洪涝灾害风险进一步加剧，城市洪涝灾害防控面临严峻挑战。从承灾体角度揭示城市洪涝复杂灾变过程，构建城市洪涝灾害的全社会风险评估技术，建立城市洪涝灾害风险管理体系是城市洪涝灾害风险管理的研究重点。项目组针对变化环境下城市洪涝灾害特点，研究城市洪涝灾害风险评估及风险管理策略，取得成果如下：. 1. 揭示了不规则格网下城市洪涝灾害复杂灾变过程. 建立全卷积神经网络的城市地表空间不规则格网承载体识别模型，实现任意不规则形状的城市洪灾风险分析单元提取；分析自然与社会系统耦合下的城市洪涝灾害复杂系统演变的压力、状态、响应过程，分析影响洪涝灾害风险的关键因素；构建一维河道、一维管网和二维地面模型耦合的城市二维淹水模型，模拟不同频率降雨强度、不同土地利用、防洪排涝工况下的洪水演进过程，揭示了不规则格网下城市暴雨洪涝-孕灾-成灾演变规律。. 2. 建立了城市洪涝风险及全社会损失评估技术体系.构建了孕灾-成灾全过程灾害风险多要素多维综合评估指标体系，提出了不规则格网的风险动态实时评估技术；建立了暴雨洪水等致灾要素与历史灾害损失的关系模型，提出了基于投入产出的灾害影响扩散损失计算方法，提高了全社会直接和间接灾损核算准确度。. 3. 提出了城市洪涝灾害风险及应急管理策略.提出洪涝灾害风险评估下工程与非工程结合的洪水风险管理综合规划方案；从灾前准备、灾中应对和灾后恢复过程，设计公众洪灾风险认知调研问卷，构建了不同因素对风险认知水平的影响机制；建立了多agent的城市社区洪灾疏散模拟模型，提出了基于社区的洪涝灾害互助应急疏散机制。. 该项目成果丰富了现代灾害风险评估与风险管理理论体系。成果在景德镇市推广应用，取得了显著的防灾减灾效益，为我国城市洪涝灾害的风险评估与防控提供理论和实践指导。