变化环境对NamLik1-2水库下游生态水文情势的影响研究

Study on the Influence of Changing Environment on the Eco-hydrological Regime of Downstream NamLik1-2 Reservoir

为探究重要国际河流湄公河支流NamLik河在NamLik1-2水库建设后下游的生态水文情势变化,基于水库下游Hinheup水文站1980—2018年日平均流量数据、流域ERA5再分析气象数据以及NamLik流域地理信息数据,采用IHA_RVA法定量分析水库运行后河流水文情势改变;基于SWAT模型分析了气候变化和水库调度对水库下游径流年内分配变化的贡献率。结果表明:(1)NamLik1-2水库建库后下游水文情势发生较大改变,整体水文改变度达79%,属于高度改变;下游河道流量年内分配变化显著,月均流量指标的水文改变度达到70.4%。(2)基于SWAT模型对无水库情景的天然径流还原结果,计算得到水库对径流汛期减少和枯季增加的贡献率分别为142%和71%,而气候变化的相应贡献率分别为-42%和29%,水库运行是引起下游径流年内分配变化的主要原因。

In order to investigate the change of eco-hydrological regime in the lower reaches of Namlik River,a tributary of Mekong River,following the NamLik1-2 reservoir,this paper selected the daily runoff data of Hinheup hydrological station from 1980 to 2018,ERA5 reanalysis meteorological data and geographic information data,and applied IHA_RVA method to evaluate the hydrological regime change after the operation of NamLik1-2 reservoir.Additionally,the SWAT model was used to analyze the contributions to the annual runoff distribution in the lower reaches of the reservoir.The results show that,(1)After the operation of NamLik1-2 reservoir,the hydrological regime of the downstream has changed significantly with a high variation of 79%,and the monthly runoff with a significant change of 70.4%.(2)It is indicated that the operation of the reservoir contributes to 142%of the runoff reduction during the flood season and 71%of the increase during the dry season,however,the corresponding contributions of climate change are-42%and 29%respectively,which indicates that the reservoir operation could be the main factor to the runoff regime.