从了解高含沙洪水“揭河底”现象入手，在前人对“揭河底”发生条件研究成果的基础上，认为“揭河底”的出现，主要是高含沙洪水期水力、泥沙因子引起水流挟沙力剧增所致，并由此给出新的判别指标及其条件。 From the understanding of the phenomenon of “exposing the river to the river” of the high sediment flood, based on the research results of the conditions of the “exposing the river to the river”, the author thinks that the appearance of " The sand factor causes the sharp increase of the sediment carrying capacity of the water flow, and gives a new discriminant index and its conditions.