PREDICTION OF URBAN FLOOD AND ITS APPLICATION TO HAZARD MAP

考虑城市街道网、建筑物、地下空间等特征，对城市河流洪水、暴雨洪水和风暴潮洪水的防洪能力进行了研究，并检验了用灾害图表达的结果。通过这一年研究的主要结果如下：(1)建立了新的陆上洪水流量模拟模型。在回顾了常用的水平二维模型的基础上，提出了广义曲线坐标模型和街道网络模型来处理街道作为洪水传播的主要途径的影响。特别是，街道网络模型可以表达建筑物对人流的阻塞效应和沿街蔓延的人流方面，这表明该模型具有广泛的实用性。(2)对进入多层地下空间的淹没流进行了建模和分析，考虑了明渠流和管道流在地下空间顶板作用下共存和过渡的水力条件。模拟结果表明，在淹没流量较大的情况下，一些地方出现管流状态，增加了上层淹没深度，流动行为复杂。(3)提出了两种新的洪水灾害估算方法。其中一种是通过《防洪经济纲要》对常用的停业损失估算方法进行改进而得到的。另一种方法是在考虑GIS利用的情况下，根据每个地块的区域属性估算损失。与传统方法相比，这两种方法对洪涝灾害的估算值略有低估，但结果是合理的。特别是基于区域属性的估算方法，在简化利用GIS进行估算方面具有很好的潜力。

Flood control and prevention capacites in urban cities against river flood, urban flood due to heavy rain and storm surge flood have been investigated considering the characteristics of urban area such as street network, buildings and underground spaces, and the expressions of the obtained results by a hazard map have been examined. The main results studied through this year are as follows.(1) New overland flood flow simulation models were developed. After the review of the usual horizontally two-dimensional model, a generalized curvilinear coordinate model and a street network model were proposed to treat the effects of streets which are the main route of inundation flow spread. Especially, the street network model can express the flow blocking effects by buildings and the flow aspects of spreading along streets, which suggests that this model can be very applicable to wide and practical use.(2) The inundation flow into a multi-layred underground space was also modeled and analyzed, in which the hydraulic conditions of co-existence and transition of open channel flow and pipe flow by the effect of ceiling of underground space are considered. The simulation results show the complicated flow behavior that in the case inundation flow is large, pipe flow condition appears in some places, which increases the inundation depth in the upper layr.(3) Two new estimation methods of inundation flow damages were proposed. One of them is obtained by improving the estimaion of business suspension damages of the usual method by "flood control economic outline". The other is the method which estimates the damages based on the zone attribute for each block taking into account of GIS utilization. Even though the new two methods underestimate the flood damages slightly compared with the usual one, the results obtained are appropriate. Especially, the method based on the zone attribute has a good potential to simplification of estimation by use of GIS.