关键词: 山洪灾害, 小尺度, 下垫面, 潜在受灾, 防范预警, 官山河流域

Abstract: The purpose of this study is to offer basic data support for the construction of small-scale mountain flood disaster prevention and early warning in response to national requirements. The Guanshan River drainage basin is taken as a case study. By using multiple approaches including geoscience statistics, vegetation index calculation, object-oriented and human-computer interaction interpretation, spatial superposition analysis, field survey, and etc., the underlying surface characteristics, such as the topography, slope, vegetation coverage, and land use pattern are obtained, and the potentially affected villages and populations are comprehensively analyzed. The Guanshan River Basin is characterized by low middle part and high edges with the lowest point as the basin's outlet. The average historical disaster elevation and slope are 415 m and 21°,respectively. The average vegetation coverage of the Guanshan River Basin is 71%. Most of the basin is covered by forest and grass, and historical disasters mainly happened in less-vegetated area along rivers, ditches and roads. Residential houses as the major disaster-bearing body for mountain flood disasters, account for 1% of the total area; bare land and sloping land account for 2% of the total area. Potential disaster-stricken houses mainly concentrate in the lower positions of Guanshan River, Yuanjia River, Lyujia River and Xihe River, with a total of 8,106 people and 2,023 households affected. The bend, narrow river segment, and upstream and downstream bayonet area at the exit of Guanshan River Basin are not conducive to rapid flood discharge and easily lead to mountain flood disasters. Under heavy rainfall, bare land and steep slope in low-vegetation area are prone to breed mountain flood disaster, while less-vegetated along rivers and roads are subjected to mountain flood disasters. Early warning and prevention work should be strengthened as twelve villages in the Guanshan River Basin are threatened by potential hazards, among which Wulongzhuang, Dahewan, Zhaojiaping, Lyujiahe, Horseshoe Mountain, Xihe and Guanting Village are key points of mountain flood disaster prevention and construction.

Key words: mountain flood disaster, small scale, underlying surface, potential disaster, early warning and prevention, Guanshan River Basin