太湖流域2016年、1991年大洪水对比分析

采用数理统计方法比较分析太湖流域2016 年、1991 年2 场大洪水对应的降水、水位、洪水蓄 泄及工程调控情况,结果表明:(a) 这2 个年份致洪降水发生日期和降水总量十分接近,但在时程 分布上差异明显,2016 年致洪性降水较1991 年对流域防洪更为不利;( b) 受降水影响,1991 年洪 水期太湖水位具有2 次明显上涨过程,而2016 年太湖水位系连续上涨;(c)在2016 年洪水期,作为 太湖水量主要来源的湖西、浙西入湖水量明显超过1991 年,且湖区降水量也明显大于1991 年,这 是导致太湖最高水位超过1991 年的重要原因;( d) 因治理太湖骨干工程的建成,2016 年流域洪灾 损失占GDP 的比重远低于1991 年。

Comparison of the two flood events occurred in 2016 and 1991 in the Taihu Lake Basin

In this study, we comprehensively compared the rainfall, water level, flood discharge & storage and water project regulation of two flood events occurred in 2016 and 1991 for the Taihu Lake Basin with the method of mathematical statistic. Results show that: (a) Rainfalls leading to floods of these two events were similar in amount and occurring date, but different in temporal distribution, and rainfall in 2016 was severer to flood control than 1991; (b) Influenced by rainfalls, two obvious rising periods of the Taihu water level were observed in 1991, while a continuous rise was observed in 2016; (c) During the flood period of 2016, the water quantity into the Taihu Lake from the Huxi area and the Zhexi area, which are main sources of water into the Taihu Lake, significantly exceeded that of 1991. Besides, the rainfall over the lake area in 2016 also took over that in 1991, which could mostly account for the highest water level of Taihu Lake in 2016 exceeding that in 1991; (d) Fundamental changes have occurred in the drainage pattern of 2016 due to the construction of water projects in the Taihu Lake Basin and methods for regulation also became mature in 2016, resulting in much lower damage accounting for the proportion of GDP caused by floods than 1991.