洪灾作为相当复杂的灾害系统,既有整个水系的泛滥,也有小范围暴雨的局部灾情;既有过量降雨引起的水灾,又有风暴、地震、火山、滑坡、海啸、雪崩、崩塌等引发的次生水灾;既有纯自然性质的水灾,也有人为造成并加剧的水患。一、1887年中国黄河大水灾黄河常被人们称为“中国的悲伤 As a rather complicated disaster system, floods are not only flooded in the whole water system, but also have some local torrential rainstorms. Floods caused by excessive rainfall, floods, earthquakes, volcanoes, landslides, tsunamis, avalanches, Health floods; both purely natural floods, but also caused and aggravate the floods. First, the great Yellow River flood in 1887 in China was often referred to as the “sadness of China.”