东江流域近50年来径流极值变化特征

Analysis of Characteristic of Runoff Extremum Change in Dongjiang River Basin in Recent 50 Years

流域径流极值事件由于突发性且破坏性强而得到广泛关注。依据东江流域主要水文站1959～2008年历年逐月径流资料及水文控制站博罗站历年逐日径流资料,采用Mann-Kendall、R/S分析等方法,对流域近50年来径流及其极值变化特征和原因进行了分析。结果表明,近50年来,东江流域径流增长不显著;博罗站流量极大值指标对应汛期流量减少不显著,而极小值指标对应非汛期流量显著增长;主要水文站月均流量与博罗站极值流量Hurst指数均大于0.5,表明各流量指标未来与过去具有相同变化趋势,变化环境下东江流域径流极值朝着有利于流域水资源开发利用的方向变化。

Runoff extreme events have received extensive attentions due to their unexpectedness and high destructiveness.Based on the monthly runoff data during 1959 to 2008 from main hydrometrical stations of Dongjiang River Basin and the daily runoff data from Boluo hydrometrical station,this paper analyzes the variation characteristics and cause of runoff and its extremum in the last 50 years by using Mann-Kendall method and R/S method.Three conclusions have been summarized by the analysis： firstly,the runoff of the basin has an indistinctively increasing trend in the last 50 years;secondly,the maximum value of runoff as well as the runoff during flood season of Boluo hydrometrical station has an indistinctively decreasing trend,while the minimum value as well as the runoff during non-flood season has a significantly increasing trend;thirdly,the Hurst values of the monthly average runoff from the main hydrometrical stations of Dongjiang Basin and that of the runoff extremum of Boluo hydrometrical station are all greater than 0.5,which indicates that the runoff index mentioned above has the same variation tendency between the future and the past.