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长江中游螺山站1998年洪水实测洪峰水位比1954年洪水实测洪峰水位偏高1.78 m,经综合分析认为主要有洪水特性差异、54洪水分洪影响、洞庭湖分汇流变化影响、长江干流河道变化影响4个方面的原因。为研究各影响因素对螺山站’98洪峰水位偏高的影响程度,建立了一套适用于长江中游河道的洪水演进水动力学数学模型,在“81.7”洪水和’98洪水复演计算的基础上,进行了54洪水还原、’98洪水演进和54洪水演进计算。计算成果分析表明:由于54洪水分洪使得螺山站54洪峰水位降低了0.83 m(即相当于使得98洪峰水位抬高了0.83 m),洞庭湖分汇流和长江干流河道变化联合影响引起的螺山站’98洪峰水位抬高值为0.74~0.84 m,而仅长江干流河道变化引起的螺山站98洪峰水位抬高值为0.33~0.36 m。
The flood peak water level of Luoshan Station in the middle reaches of the Yangtze River in 1998 was 1.78 m higher than the actually measured flood peak in 1954. According to a comprehensive analysis, there are mainly differences in flood characteristics, influence of flood diversion, influence of Dongting Lake diversion, influence of river changes in the main stream 4 reasons. In order to study the impact of various influencing factors on the high level of flood peak at ’98, which is located at Luoshan Station, a set of mathematical model of flood evolution hydrodynamics suitable for the middle reaches of the Yangtze River was established. After the “81.7” flood and “98” Based on the 54 floods, the evolution of the ’98 floods and the evolution of the 54 floods were calculated. The calculation results show that the Loess Hill caused by the combination of the Dongting Lake diversion and the change of the Yangtze River main channel due to the flood diversion of 54 floods reduced the flood level of Luoshan Station 54 by 0.83 m (equivalent to raising the flood peak of 98 flood waters by 0.83 m) The elevation of flood peak of station ’98 was 0.74 ~ 0.84 m, while the elevation of 98 flood peak of Luoshan station was only 0.33 ~ 0.36 m caused by the change of the main channel of the Yangtze River.