水文变异下东江流域枯水径流风险率分析

Analysis on low flow risk of runoff in the East River Basin under the hydrological aberrance

探求人类活动与气候变化对径流枯水风险的影响,对实现区域经济与环境的可持续发展有着重要的意义。以东江流域为例,通过对相对关联距离熵Hd辨识水文系统状态的跳跃,识别水文变异点,采用信息扩散风险分析模型评估径流的枯水风险率,分析径流枯水风险率在水文变异前后的变化趋势及演变情势。研究结果表明:东江流域在1972-1973年发生水文变异,与东江上游枫树坝建设运行时间基本一致。枯水风险率大于0.8的年份皆发生强厄尔尼诺事件,表明了厄尔尼诺现象出现时,当年东江流域月径流量普遍发生减少。在水文变异后,径流的枯水风险率降低,但变化幅度更加剧烈,同时枯水径流的风险率与降雨的相关性减弱,但与降雨的相关性还是超过0.9,这些都揭示了径流在水文变异后在主要受到气候变化影响的同时,越来越受到水利工程的调节作用的影响。研究成果可为流域综合管理部门决策提供参考。

The impact of the human activities and climate change on the risk of low runoff has an important significance for the regional economy and the environment to achieve sustainable development.By analyzing the variation of relative correlation distance entropy Hdwhich in chaos theory was presented for identifying hydrological system status,the hydrological aberrance point of runoff in East River Basin be recognized.The information diffusion model was used to assess the low risk of runoff before or after hydrological variation in the East River Basin.The results showed that： hydrologic variation of the East River Basin occurred in 1972-1973,and its variation time and the time of the construction and operation of the FengShu dam was basically the same.The low flow risk over 0.8 has related to the occurrence of Elni-no event,and the magnitude of monthly runoff decreased at this year.After hydrological variation,the low flow risk of runoff in the East River Basin was decreased,the magnitude of change was more intense and Correlation with rainfall decrease but still have a greater correlation,which also beyond 0.9.And the low flow risk of runoff in the East River Basin mainly affected by the rainfall,in addition,affected by the regulating role of water projects.The result should be helpful for integrated watershed management decision-making.