PREDICTION OF URBAN FLOOD AND ITS APPLICATION TO HAZARD MAP

结合城市区域的路网、建筑物、地下空间等特点，对城市防洪能力进行了研究，并用危险度图对结果进行了检验。本年度研究的主要成果如下：(1)建立了新的陆上洪水模拟模型。在回顾了常用的水平二维模型的基础上，提出了一种广义曲线坐标模型和街道网络模型来处理淹没水流传播的主要途径街道的影响。特别是街网模型能较好地表达建筑物对水流的阻挡作用和沿街道扩散的水流方面，具有广泛的实用价值。(2)考虑了地下空间顶板作用下明渠水流和管流共存和过渡的水力条件，对多层地下空间淹没水流进行了模拟和分析。模拟结果表明，在淹没流量较大的情况下，淹没水流行为复杂，局部出现管流条件，增加了上层淹没深度。(3)提出了两种新的淹没水流损失估算方法。其中一种是通过《防洪经济纲要》对常用方法中的停业损失估计进行改进而得到的。另一种是考虑到地理信息系统利用的情况下，根据区块的区域属性来估算损失的方法。尽管与通常的方法相比，新的两种方法略微低估了洪水损失，但得到的结果是合理的。尤其是基于区域属性的方法对于简化利用地理信息系统进行估算具有很好的潜力。

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.