柳江“88.8”、“94.6”、“96.7”暴雨洪水特点及比较分析

Rainstorm and Flood Comparison Analysis of Liujiang River

"88 8"、"94 6"、"96 7"这3场洪水各具特色:"88 8"洪水的暴雨区主要覆盖在流域的中上游地区,暴雨历时长,降水较分散,强度一般,由于洪水传播距离远,水面比降较大,最大流量达27000m3/s,最高水位89 04m,所受灾害最小;"94 6"洪水的暴雨区主要覆盖在流域的中下游地区,暴雨历时短,降水集中,强度一般,由于洪水传播距离近,水面比降较小,最大流量为26500m3/s,最高水位89 25m,所受灾害较大;"96 7"洪水的暴雨区覆盖整个流域,暴雨历时长,降水强度大,最大流量34000m3/s,最高水位达92 43m,所受灾害最大.

There are different characteristics for the floods in August 1988,June 1994 and July 1996 in Liujiang river.The region of the rainstorm in August 1988 is distributed over the middle and upper reaches and the rainfall period is long and the precipitation is scattered and its intensity is average.The maximum water level is only 89.04 m with some damage,but the maximum discharge of the river reaches 27 000 m^(3)/s because of the long-distant flood propagation and the steep water surface gradient.The region of the rainstorm in June 1994 is distributed over the middle and lower reaches and the rainfall period is short and the precipitation was concentrated and its intensity is average.The maximum water level is 89.25 m,but the maximum discharge of the river reaches only 26 500 m^(3)/s with much damage because of the short-distance flood propagation and the gentle water surface gradient.The region of the rainstorm in July 1996 is distributed over the whole basin .Not only the rainfall period is long ,but also the intensity of precipitation is strong.The maximum water level reaches 92.43 m and the maximum discharge of the river reaches 34 000 m^(3)/s Aug 1988 June 1994 July 1996 and leads to most serious damage.