Centre for Geographical Studies of the Institute of Geography and Spatial Planning, University of Lisbon (CEG-IGOT-ULisboa), Edifício IGOT, Rua Branca Edmée Marques, Cidade Universitária, 1600-276 Lisboa, Portugal.
Centre for Geographical Studies of the Institute of Geography and Spatial Planning, University of Lisbon (CEG-IGOT-ULisboa), Edifício IGOT, Rua Branca Edmée Marques, Cidade Universitária, 1600-276 Lisboa, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences of the University of Trás-os-Montes and Alto Douro (CITAB-UTAD), Quinta de Prados, Ed. dos Blocos Laboratoriais Sala C1.10, 1° Piso, 5001-801 Vila Real, Portugal.
Sci Total Environ. 2019 Jun 1;667:325-337. doi: 10.1016/j.scitotenv.2019.02.328. Epub 2019 Feb 23.
River flooding is a specific worldwide type of flooding responsible for considerable human and material losses. An extensive knowledge about flood conditioning factors and a diverse set of methodologies for flood susceptibility evaluations are available, although there is still field for improvement regarding methodologies for small-scale flood susceptibility assessment, particularly relevant in data-scarce contexts. This research applied to mainland Portugal, introduces a multicriteria methodology to assess flood susceptibility at national scale considering three flood-conditioning factors: flow accumulation, average slope angle and average relative permeability. These three factors resume other factors usually considered in literature, related to morphology and potential runoff. This work includes data from the flood conditioning factors considering the cumulative role of the entire contributive area and not only the on-site characteristics. The weight of each factor was assigned based on expert opinion and validated using available flood damages databases with >150 years of records. From the several tested flood susceptibility models, the one that best fits the historical records was chosen, which corresponds also to a more valued role of flow accumulation factor. Results provide an accurate differentiation of transboundary, regional and local rivers. The scores of stream flood susceptibility were later transformed to a single value per each of the 278 municipalities of mainland Portugal. Representing the natural susceptibility to river flooding, these results can be cross-analyzed with structural mitigation measures, spatial planning instruments, exposure and vulnerability data along the respective floodplains, in order to identify water streams that require a more detailed and concerned future intervention and an exhaustive susceptibility study at the local scale.
河流洪水是一种全球性的洪水类型，造成了巨大的人员和物质损失。尽管在小规模洪水易感性评估方法方面仍有改进的空间，特别是在数据稀缺的情况下，但已经有广泛的洪水条件因素知识和多种洪水易感性评估方法。本研究应用于葡萄牙本土，引入了一种多准则方法，考虑到三个洪水条件因素：水流累积、平均坡度角和平均相对渗透率，来评估国家尺度的洪水易感性。这三个因素概括了文献中通常考虑的与形态和潜在径流量相关的其他因素。这项工作考虑了整个贡献区域的累积作用，而不仅仅是现场特征，包括洪水条件因素的数据。根据专家意见分配每个因素的权重，并使用有超过 150 年记录的可用洪水灾害数据库进行验证。从几个测试的洪水易感性模型中，选择了最适合历史记录的模型，这也对应于水流累积因素更有价值的作用。结果准确地区分了跨境、区域和地方河流。随后，将溪流水灾易感性的分数转换为葡萄牙本土 278 个城市中的每一个的单一值。这些结果代表了对河流洪水的自然易感性，可以与结构减灾措施、空间规划工具、洪水风险数据以及各自的洪泛区进行交叉分析，以识别需要更详细和关注的未来干预措施以及在当地范围内进行详尽的易感性研究的溪流。
