关键词: 黄河下游, 溃决, 二维非恒定流模型, 洪水特性

Abstract: Flood disaster is still a threat in the lower Yellow River due to unusual precipitation caused by the deposit of channel, the hidden danger in the embankment and unfavorable riverbed in the lower Yellow River. Study on the embankment-break flood characteristics of the lower Yellow River can afford the scientific basis for flood disaster mitigation. According to the characteristics of the embankment-break flood in the Yellow River,flood routing characteristics of embankment-break is simulated at four different locations of the lower Yellow River by inputting terrain data, typical historical flood data and land use data of the study area to two-dimensional unsteady-state flow model. Simulated results show that: Firstly, routing flood encroach the rivers on the way and enter into the rivers after reaching the lower reaches;secondly, in the same river reach, flood submerged area of north band is bigger than the corresponding location of south bank towards the same historical flood;thirdly, it is different in flood submerged degree of different regions due to the different spatial locations of floodplain; and fourthly, the area of mainstream where flood depth is high and flood velocity is quick is relatively small, but the area of non-mainstream where flood depth is low and flood velocity is slow is relatively big. Flood disaster risk in the protected zone of the embankment will be analyzed by using the results of the simulated flood in this paper, on the basis of the simulated results, the spatial pattern of the flood disaster risk in the protected zone will be analyzed in the lower Yellow River in the future. The attempt on the simulated methods and technique of the flood routing can serve as a reference to the researches in other similar regions. In this study, some factors such as the sediment, infiltration and evaporation weren't considered, which is a limitation to research the hydraulic characteristic of the levee-breaking flood in the Yellow River. In the succeeding simulation, the sediment should be considered to research the long-term influence on the local environment of preventing flood due to the deposit of the sediment in the riverway. At the same time the surface features should the whole way be close to the reality.

Key words: the lower Yellow River, embankment-break, 2-dimensional unsteady-state flow model, the characteristics of flood \@ 表1 Tab.1 图1 Fig.1