远期洪水的了解,人们主要依赖于文献资料的考证及水文考古,但毕竟年代久远,洪水情况难以核清,更难于进行洪水定量。一般河流上的实测水文系列均很短,多数为二、三十年,极少超过百年。这样如何确定稀遇洪水事件的量级及在洪水总体中的位置,就成了水文工作者所面临的最棘手也是最关心的问题之一。 Long-term understanding of floods, people rely mainly on textual research and hydrological archeology, but after all ages, the flood situation is difficult to clear, more difficult for flood quantification. The measured hydrological series on the general rivers are very short, mostly for two or three decades, rarely exceeding one hundred years. One of the toughest and most concerned issues facing hydrologists is how to determine the magnitude of the rare flood event and its location in the flood overall.