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

在海湾地区广泛发展的城市群中，洪水灾害区划、风暴潮和河流洪水损失评估以及各种工程和非工程措施的有效性评估是灾害规划策略的重要组成部分。本研究主要目的在探讨风暴潮及河川淹没危险区的预测方法。所提出的方法，通过它的发生风暴潮和受保护的低洼地区的洪水的结果进行估计，已被证明是非常有用的评估，对风暴潮采取的对策。该模型可以预测世纪温室效应引起的海平面上升后风暴潮洪水的危险区。海平面上升65厘米将导致大坂湾地区严重的洪水泛滥，大约是海平面上升前设计台风洪水泛滥的两倍半。如果预测的海平面上升是有效的，大坂湾地区将不得不采取新的对策来应对风暴潮。我们的仿真模型和计算结果可以作为设计这种对策的基础。

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.