The division of flood season of lixianjiang river basin based on fisher optimal division method

It may provide a good basis for regulating the reservoir's stage flood control levels to divide flood season into stages properly, for making best use of flood water resources with the fully guaranteed safety of the reservoir. This paper focuses on the application of Fisher optimal division method to division of flood season for Lixianjiang river basin which is located in southwest China. The basic principles and steps of this method are introduced at first. Then, 5 indexes are selected as the characteristic indicators of torrential rain and flood of the basin, and by use of this method, the flood season is divided into four stages, i.e. June 1 to June 30 for pre-flood stage, July 1 to September 10 for main flood stage, September 11 to October 31 for the interim stage, and November 1 to November 30 for post-flood stage. Also, this result is compared with those by the common statistics method and by the fuzzy set theory method in the end, and it is indicated that Fisher optimal division method is of advantages in comprehensively reflecting the characteristics of climate and underlying surface of the basin, so the flood season division result by this method is more objective and more reasonable.