Comparison of fluvial and pluvial flood risk curves in urban cities derived from a large ensemble climate simulation dataset: A case study in Nagoya, Japan
Comparison of fluvial and pluvial flood risk curves in urban cities derived from a large ensemble climate simulation dataset: A case study in Nagoya, Japan
复制标题
DOI：
10.1016/j.jhydrol.2020.124706
复制
发表时间：
2020-05
影响因子：
6.4
通讯作者：
Tomohiro Tanaka;Keiko Kiyohara;Y. Tachikawa
中科院分区：
文献类型：
--
作者：
Tomohiro Tanaka;Keiko Kiyohara;Y. Tachikawa
洪水灾害由两种类型的洪水引起：洪水洪水和河流洪水。这两种类型的水动力特性的不同已在一篇文献中得到了深入的讨论。然而，由于缺乏极端降雨量数据和/或洪水模拟的计算成本，它们的影响和由此造成的损害尚未得到全面审查。最近，越来越多的集合气候模拟数据成为可能，提供基于数值气候模拟的长期降雨数据。这是日本名古屋市市区发生洪水的一个案例。我们将大型集合气候模拟数据库d4PDF应用于洪水和河流洪水模型，得到了每种洪水类型的洪水风险曲线。结果表明，洪涝灾害具有与河流洪水相当的经济风险(50年和100年重现期的损失分别减少16%和17%)，尽管洪水深度明显较浅(洪水深度超过45厘米的面积分别只有10.5%和5.4%)。洪灾的重大影响可归因于洪灾面积较大(尽管水深较浅)，影响了遍布全市的主要经济资产，包括远离河流的地区。此外，通过将名古屋城堡(现在的中心经济区)安置在更高的海拔上，控制了河流洪水风险。结果表明，在主要经济资产不集中在河流周围的城市地区，洪涝灾害可能具有与河流洪水相当的经济风险，而且历史上已制定了应对河流洪水的对策。
Flood disasters are caused by two types of flooding: pluvial and fluvial flooding. The different hydrodynamic characteristics of these two types have been intensively discussed in a literature. However, their impact and the resulting damage have not yet been examined in a comprehensive manner due to the lack of extreme rainfall data and/or computational costs of flood simulations. Recently, an increasing number of ensemble climate simulation data has become available, providing long-term rainfall data based on numerical climate simulations. This is a case study of a flooding in an urban area set in Nagoya City, Japan. We applied a large ensemble climate simulation database, d4PDF, to a pluvial and fluvial flood model and derived the flood risk curves for each type of flooding. The results indicated that pluvial flooding presents comparable economic risk to fluvial flooding (only 16% and 17% lesser damage at 50- and 100-year return periods, respectively) despite its significantly shallower flood depths (area with flood depth over 45 cm was only 10.5% and 5.4%, respectively). The significant impact of pluvial flooding is attributable to its wider flood area (despite shallower depths), impacting major economic assets sprawled over the city, including areas further away from the river. Furthermore, fluvial flood risk was managed by settling the Nagoya Castle (now the central economic district) on higher altitudes. The results suggest that pluvial flooding could have comparable economic risks to fluvial flooding in urban areas where major economic assets are not concentrated around streams as well as historical countermeasures are installed against fluvial flooding.