Risk Assessment of Storm Surge and River Flooding in Cities in the Bay Areas

在湾区广泛发展的城市群中，洪水灾害区划、风暴潮和河流洪水造成的损失评估以及各种结构和非结构措施的有效性评估是危险源规划策略的关键。本文主要研究风暴潮和河流洪涝灾害危险区域的预测方法。用该方法估算风暴潮的发生和受保护的低洼地区的洪涝灾害结果，对于评估采取的风暴潮防御措施是非常有用的。通过这个模拟模型，可以预测21世纪海平面上升后由温室效应引起的风暴潮洪涝危险区域。海平面上升65厘米将在大阪湾地区造成严重洪水，大约是海平面上升之前设计的台风洪水的2.5倍。如果预测的海平面上升是正确的，大阪湾地区将不得不采取新的应对措施来应对风暴潮。我们的仿真模型及其计算结果可以作为此类对抗设计的基础。

In urban conglomerate cities extensively developed in bay area, flood-related hazard zoning, evaluation of losses due to storm surge and river flood, and evaluation of the effficacy of various structural and nonstructural measures are essential in planning strategy for hazares. This study mainly aims to present the method to predict the hazardous area due to storm surges and river floodings. Presented method, by which the occurrence of storm surges and the results of the flooding of protected low-lying areas are estimated, has been shown to be very useful for the assessment of countermeasures taken against storm surges. Zones at risk of storm surge flooding after the 21st century rise in sea level caused by the greenhouse effects could be predicted by this simulation model. A rise in sea level of 65cm would cause severe inundation in Osaka Bay Area about two and half times that flooded in a designed typhoon before the rise in sea level. If the predicted rise in sea level is valid, new countermeasures will have to be taken against storm surges in Osaka Bay area. Our simulation model and the results calculated from it can be used as the basis for the design of such countermeasures.