Abstract:
The floods in Poyang Lake are prone to cause serious flood disasters, and analyzing the historical characteristics of floods entering the lake is of great significance for flood control in the lake area. Using hydrological statistical methods, this study focuses on analyzing the flood composition and encounter patterns of seven control hydrological stations (hereinafter referred to as the Five Rivers and Seven Mouth) in five rivers, namely Gan River, Fu River, Xin River, Rao River, and Xiu River, from the aspects of flood composition, peak return period, and flood encounter. Research shows that the peak of floods in the Poyang Lake Basin occurs from May to July; Within 71 years, the maximum 5-day flood volume of Rao River's main and tributary rivers, Fu River, and Xin River experienced 37 encounters, with an average encounter probability of 51.4%; The maximum 7-day flood volume of the two tributaries of Xiu River has encountered 12 times in the past 41 years, with a probability of only 28.6%. In 1954, Meigang Station and Wanjiabu Station experienced a maximum 7-day flood, while other stations did not experience it; In 1998, some stations in Raohe and Xiuhe experienced a 7-day flood encounter; In early July 2020, multiple stations in Wuhe and Qikou experienced the maximum 7-day flood volume simultaneously. The proportion of the maximum 1-day, 3-day, 5-day, 7- day, and 15 day flood volumes at Waizhou Station and Qiujin Station increases with the duration of the flood. Among them, the average maximum 15 day flood volume of the Ganjiang River over the years is 9.75 billion m
3, accounting for 50.2% of the inflow into the lake; The proportion of maximum 1-day, 3-day, 5-day, 7-day, and 15 day flood volumes at Lijiadu Station, Meigang Station, Hushan Station, Dufengkeng Station, and Wanjiabu Station decreases with the increase of flood duration, and the average proportion of maximum 7-day flood volumes over the years is less than 20%. The research results are conducive to strengthening the understanding of the typical flood patterns in the history of Poyang Lake, and can provide scientific basis for flood prevention and disaster reduction work in Poyang Lake.