基于流域尺度角半沟泥石流危险性评价

德昌县角半沟流域面积大、地形复杂多样、降雨充沛、物源丰富，具备暴发泥石流的潜在条件。本文通过分析角半沟泥石流的孕灾环境和形成条件，以地形地貌和地质条件为基础，对泥石流流域进行多尺度评价单元划分，采用地形因子、地质因子、水文因子等多因子耦合计算方法，对角半沟泥石流的危险性进行定量评价。利用水文分析方法将角半沟流域45.71km2范围细分为28个评价单元，其中8个处于沟谷发育壮年初期、13个处于沟谷发育壮年中期、5个处于沟谷发育壮年末期、两个处于沟谷发育老年期，运用沟谷型泥石流判定模型计算出角半沟泥石流定量化的危险性评价结果，准确地划分出角半沟泥石流的8处高危险区、6处中危险区、10处低危险区和4处安全区。评价结果能较好反映角半沟泥石流灾害的危险情况，对该地区减灾防灾有重要的指导意义。

HARZARD ASSESSMENT OF DEBRIS FLOW IN JIAOBANGOU BASED ON WATERSHED SCALE

The Jiaobangou Basin in Dechang county have some features such as large watershed area, complex and diverse topography, rich rainfall and abundant sources which provide the potential conditions for causing debris flow. This paper analyzes the pregnant environment characteristics and the formation conditions of debris flow, and divides the multi-scale assessment units of debris flow watershed based on topography and geological conditions. On the basis of analysis, the debris flow hazards are quantitative assessed by the multi-factor coupling method of topography, geology and hydrology. Using the method of hydrological analysis, Jiaobangou watershed, the watershed area of 45.71km2,which divided into 28 assessment units(8 units in the early mature stage, 13 units in the full mature stage, 5 units in the late mature stage and 2 units in the old stage), is accurately calculated 8 high hazard areas, 6 medium hazard areas, 10 low hazard areas and 4 safe areas. The hazard assessment is close to actual experiences in Jiaobangou watershed, which can provide great significance to the disaster prevention and mitigation in the area.