沟口公路小流域山洪危险性评价——以四川省凉山州美姑河省道公路为例

Flash flood hazard evaluation for highway at the outlet of small watershed——taking highway along Meigu river in Liangshan district of Sichuan province as an example

对美姑河沿线10个小流域山洪灾害对省道公路的危险性进行了评价,得出了山洪高危险性、中危险性和低危险性小流域的分布图件,山洪高危险性和中危险性小流域沟口处的公路路段为汛期高危险路段。利用最新获取的SRTM-DEM数据,基于GIS空间分析技术,提取了美姑河流域及10个子流域的典型地貌参数,综合考虑提取的地貌量化参数与小流域山洪危险性的关系,分级量化了小流域山洪对沟口公路的危险性大小。通过对流域地貌参数的分析,得出流域南北向伸展的狭长外形受区域构造和断层控制,美姑河流域新构造运动活跃,处于侵蚀循环的活跃阶段,与美姑河流域水土流失、泥石流等山地灾害发育的实际情况吻合。

The flash flood hazard of highway at outlet of ten small watershed channels along Meigu River was evaluated. The high, medium and low hazard distribution map of flash flood for small watersheds was put forward. The sections of highway at the outlet of small watersheds with high and medium flash flood hazard are of high danger for flood season. Using the latest SRTM-DEM data, based on the GIS spatial analysis technology, the quantitative parameters of watershed geomorphology for Meigu River basin and its ten subbasins was extracted. Comprehensively considering the relationship between the quantitative parameters of geomorphology and flash flood hazard for subbasin, the hazard degree of outlet sections of highway for the subbasins was quantified and classified. Through analysis of river basin geomorphology parameters, the results show that the long and narrow, north to south stretched shape of Meigu River basin is controlled by regional tectonic and faults. And the Meigu River basin is in the state of active new tectonic movement and in juvenility stage of erosion cycle, which is consistent with the actual mass wasting and debris flow development situation of Meigu River basin.