泥石流输沙与长江洪水

Sediment Transport by Debris Flow and Fresh Flood of Yangtze River

1998年夏季发生的长江全流域性的特大洪水,又一次敲响了中华民族的水患警钟。形成水灾的主要因素有:季风活动和副热带高压位移等天气条件,决定了雨量大、历时长的降水过程,增大了流域汇流水量;上游地区采伐森林、毁林开荒、陡坡耕种等,导致了环境退化、侵蚀加剧和泥沙来量增多,抬高了河床。

Debris flow is the sediment high-way.It sends huge sediment into river in extremely short time.Those sediment plugs not only add sediment of river and rise the river bed,but also reduce flow section and even block up river and also cause river bank erosion,which further leads to flood directly and indirectly.