广州东濠涌流域城市洪涝灾害情景模拟与风险评估

Scenario simulation and risk assessment of urban flood in Donghaochong basin Guangzhou

  • 摘要: 绘制直观与可靠的城市洪涝灾害风险区划图,为城市防洪排涝相关部门决策提供参考依据。以广州市东濠涌流域为研究区域,综合考虑城市降雨、径流、地形和排水系统特性,构建基于InfoWorks ICM的一维-二维耦合城市洪涝仿真模型,模拟暴雨重现期为1年、5年、50年情景下的洪涝过程并获取致灾因子数据。调研分析区域的孕灾环境、承灾体和防灾减灾能力概况,结合层次分析法、评价等级和阈值划分等进行洪涝灾害风险评估。结果表明:城市洪涝仿真模型在一维排水系统和二维地面淹没模拟上均有较好的精度和可靠性,保证了致灾因子数据的可靠性;风险区划图能较好地反映流域的风险分布;随着重现期增大,较高、高风险区的面积显著增加,为防洪排涝重点关注区域。

     

    Abstract: This study developed an intuitive and reliable urban flood-risk zoning map for scientific decision-making by departments related to urban flood control and drainage. The Donghaochong (DHC) basin of Guangzhou city was the study area. A 1 D-2 D coupled urban flood simulation model was constructed based on InfoWorks ICM to obtain disaster-causing factor data by simulating the flood process under the rainstorm return periods of 1 a,5 a,and 50 a. This study also investigated the surveyed areas of hazard-inducing environment,hazard-bearing body,and hazard prevention and mitigation capacity. Risk assessment of flood disasters was carried out in combination with the analytic hierarchy process (AHP),assessment grade,and threshold value division. The results revealed that the urban flood simulation model had good accuracy and reliability in the 1 D drainage system and the 2 D ground submergence simulation,thus ensuring the reliability of the disaster-causing factor data. Also,the risk-zoning map adequately reflected the risk distribution within the basin;moreover,as the return period increased,medium-high risk zones and high risk zones increased significantly,requiring flood prevention and drainage.

     

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