长江流域“2017·07”暴雨洪水分析

Analysis of Storm Flood Occurred in the Yangtze River Basin in July, 2017

2017年6月下旬至7月初,受持续强降雨影响,长江发生中游区域性大洪水。以实时报汛数据为基础,分析长江"2017·07"暴雨洪水特性,依据洪峰水位判断,强降雨导致洞庭湖水系湘江发生超历史最高水位特大洪水,资水、沅江发生超保证水位大洪水,洞庭湖超过保证水位;鄱阳湖水系乐安河上游发生超历史最高水位特大洪水,昌江、乐安河中下游、修水发生10a一遇较大洪水,鄱阳湖超过警戒水位;长江干流莲花塘以下江段全线超过警戒水位。在应对此次洪水过程中,长江上中游重点水库防洪效益十分明显,有效避免中游干流莲花塘至螺山江段超保,缩短洞庭湖城陵矶站超保时间6d左右。

From late June to early July in 2017, the regional flood was led by the continuously intensive precipitation that occurred in the middle stream of the Yangtze River basin. Based on the real time flood data, this paper analyzed the characteristics of the "2017·07" flood in the Yangtze River. According to the judgment of flood peak water level, heavy rainfall had caused catastrophic flood that exceeded measured maximum record in the Xiangjiang River of the Dongting Lake watershed;Zishui River and Yuanjiang River reached the water level at which the security of the rivers could not be guaranteed, so was the Dongting Lake. For rivers that belong to the Poyang Lake watershed, water level in the upper stream of the Anle River exceeded measured maximum record while the Changjiang River, Xiushui River and the middle and lower streams of the Anle River occurred a flood with a 10-year return period. The water level of the Poyang Lake exceeded the warning stage. For the mainstream of the Yangtze River, water level in the stream below Lianhuatang water section exceeded the warning stage. However, some vital reservoirs distributed along the upper and middle streams of the Yangtze River played effective roles in lowering the water level of river reach between Lianhuatang and Luoshan, and duration of water level exceeding the warning stage was shortened by 6 days at the Chenglingji station in the Dongting Lake.