长江中下游设计最低通航水位变化分析

Variation of Design Lowest Navigable Water Level in Middle and Lower Reach of the Yangtze River

用综合历时曲线法,利用1981—2002年水文资料,计算了长江中下游部分水文站不同保证率时的设计水位,结合影响枯水位变化的因素,比较分析了保证率为98%的设计水位计算结果与上世纪70年代和80年代计算值的差别及其变化过程。结果表明,长江中下游河床形态、水流条件发生了较大变化,设计水位也随之有一定幅度的升降。

Adopting synthetic duration curve method and based on the hydrological data of Year 1981-2002, the design water level of part hydrographic stations at the middle and lower reach of the Yangtze River at different guaranteed rates were calculated. Combining factors influencing low-water level, the paper compared the design water level calculation result at the guaranteed rate of 98% with those of the 1970′s and the 1980′s, and analyzed the variation process. The result showed that the bed form and flow condition at the middle and lower reach have changed a lot, following which, the design water level has risen or reduced to some degree.