城市洪涝的水文水动学机理与耦合模拟

Rapid urbanization and human activities have greatly changed the land surface and underground structure of cities, which has led to profound changes in the process of urban hydrology and the characteristics of flood and waterlogging. Now the flood and waterlogging has become the most important problems to be solved in urbanized regions in China. Rain-runoff mechanism and its simulation model of cites with complex underlying surface is the most urgent need for urban hydrology as well as sustainable urbanization. The research work will be held in typical city area, including hydrological observation, physical experiment and modelling. Based on the observation datasets and physical experiments, the mechanism and mathematical model of interception, evapotranspiration, infiltration，runoff yield will be established for six different kinds of basic units: the impervious unit, the semi-permeable unit, the permeable unit, the strongly permeable unit and the pseudo-permeable unit. Then the distributed urban hydrological model and a hydrodynamic model of surface / subsurface drainage systems will be established. The hydrological model and hydro-dynamic model are supposed to be integrated to a multi-functional modeling system, which could simulate urban flood on land surface and in underground drainage pipe networks, for one-dimensional and two-dimensional flows, including hydrological process and hydro-dynamic process. The modeling system will be used to simulate the runoff peak, total water discharge and the time that runoff-peak appears in typical cites under a specific rainfall conditions. The evolution of flood characteristics in cites will be analyzed based on the simulation results, such as the value of runoff-peak for combined scenarios of different urbanized pattern and rainfall-intensity. The research would provide scientific basis for urban-flood control and the construction of sponge cites.

快速城市化和强人类活动的作用巨大地改变了城市地表和地下结构，导致城市水文过程和洪涝特性发生了深刻的变化，城市洪涝灾害已成为新型城市化必须解决的关键问题。复杂城市下垫面的产汇流机理与模型研究是水文学理论发展和城市建设实践的迫切要求。本项目拟在城市水文原型观测与实验的基础上，研究揭示城市不透水面、半透水面、透水面、强透水面、伪透水面等不同水文响应单元的截留-蒸发-入渗-产流机理和水文响应函数；构建城市单元水文模型；将单元水文模型与一维管网/河道水动力学模型、易涝区的地表二维水动力学模型进行系统集成，形成地表/地下互动、一/二维嵌套的城市水文水动力学耦合模拟模型；应用建立的模型模拟不同重现期降雨对应的城市径流峰值、径流总量、峰现时间等特征值，研究不同城市化模式和降雨强度组合情景下的城市洪涝特性，定量揭示变化条件下城市洪涝演变规律，为城市防洪排涝和海绵城市建设提供科学基础。

城市洪涝是当前快速城镇化过程中面临的突出问题之一，项目针对传统地面硬化、海绵设施建设等人类活动导致的城市水文水动力过程变化，开展了系统的理论和实验研究，定量揭示了城市复杂下垫面的产汇流机理，构建了城市水文水动力关键过程的数学模型，集成研发了紧密耦合的分布式城市水循环模拟工具。项目已发表论文89篇，其中SCI收录论文50篇，EI收录论文20篇；申请专利16项，已授权发明专利12项；获省部级奖励8人次；项目组成员获国家级人才称号3人次，受邀做主旨/特邀报告10余人次，培养博士研究生14人，硕士研究生14人。.项目开展了“比尺模型-原型单元-典型片区”多尺度的城市水文水动力机理实验，测定了强渗透、渗透、半渗透、伪渗透等不同类型下垫面的导水特性，提出了四类透水下垫面的入渗速率变化曲线；揭示了城市复杂下垫面产流及汇流机理，以及特大暴雨情景下城市积水片区汇流激增现象的成因；为科学解析变化条件下的城市洪涝特性，应对城市水文非一致性挑战提供了基础认知。.项目系统解析了高空间变异性城市下垫面的产汇流过程，以及管网、河湖水系、二维网格单元之间的复杂水文水动力连接关系，构建了新一代城市水文水动力学耦合模型。提出了考虑“自然-社会”二元信息的城市水文响应单元划分方法，改进了城市水文-水动力、一二维“垂向连接”的模式和连接方程，提出了基于方程联立求解的城市一二维水动力学动态紧密耦合算法，有效提高了城市洪涝模拟的稳定性和可靠性。.项目构建了基于云计算和GPU加速的城市洪涝模拟平台，研发了基于LIM-SWM混合模式的城市洪涝模拟技术，识别了上海、深圳、海口典型城市的洪涝特性及其演变规律，提出了城市洪涝立体缓释与智慧调控方法。主要成果在北京、厦门、东营等城市验证应用，为城市洪涝防治体系建设和防汛应急调度提供了基础支撑。研发的城市水文水动力学耦合模型应用于郑州“7•20”特大暴雨灾害复盘推演，受到应急部、住建部、水利部致谢表扬。