基于ERHIs法的雅鲁藏布江流域水文情势变化研究

Research on the change of hydrological regime in the Yarlung Zanbo River Basin based on ERHIs method

为探究变化环境下雅鲁藏布江流域环境流量组分与水文情势变化情况,采用改进后生态最相关水文指标ERHIs(The most Ecologically Relevant Hydrologic Indicators)、RVA(Range of Variability Approach)法定量分析了1965—2018年间不同阶段不同环境组分下的雅鲁藏布江流域内水文情势的变化情况,并结合5种突变检验方法对指标进行验证。结果表明,通过EasyDHM插补数据是可行的,参数优化后的Nash系数最大为0.97,最小为0.67,均在合理范围内,在缺资料地区运用较好。针对雅鲁藏布江2个断面强变异指标改变度计算结果均表明雅江中下游地区的水文改变度为高度改变。在指标选取方面,生态水文改变过程的指标体系(Indicators of Hydrologic Alteration,IHA)参数之间的相关性较高,指标间的冗余问题十分突出。ERHIs指标具有一定的合理性,不仅有效缓解了IHA的冗余性问题,还有利于抓住最关键的生态水文变量,对生态水文研究、流域水资源管理和生态保护都具有重要的参考价值和借鉴意义,为短缺水文资料地区的生态评估提供参考。

In order to explore the changes of environmental flow components and hydrological regime in the Yarlung Zanbo River Basin under changing environment,ERHIs(The most Ecologically Relevant Hydrologic Indicators)and RVA(Range of Variability Approach)methods were adopted to quantitatively analyze the change of hydrological regime under different environmental components at different stages during 1965—2018,and five mutation test methods were combined to verify the indicators.The results show that it is feasible to interpolate the data with EasyDHM model,and the Nash coefficient after parameter optimization is 0.97 at the maximum and 0.67 at the minimum,both of which are within the reasonable range.According to the calculation results of the change degree of strong variation index in the two sections,the hydrologic change degrees of the middle and lower reaches of the Yarlung Zangbo River Basin are both highly changed.In terms of index selection,the IHA(Indicators of Hydrologic Alteration)indices are highly correlated,and the redundancy problem among indicators is very prominent.ERHIs index has a certain degree of reasonableness,which not only effectively reduces the redundancy problem of IHA,but also helps to choose the key ecological and hydrological variables.It has important reference value and significance for the research on ecological hydrology,basin water resources management and ecological protection,and provides references for ecological evaluation in areas lacking hydrological data.