Minimum Ecological Flow of the Kaidu River in Xinjiang

YUE Jinlong; XING Xiaoyan; DING Zhihong

doi:10.3969/j.issn.1004-7328.2025.07.006

Abstract：Reasonably determining the minimum ecological flow of a river is crucial for maintaining its ecological health and stability.Based on the fundamental principles of the intra-annual distribution calculation method,two improvements were made:replacing the minimum monthly average flow with the 95%frequency flow for each month(Improved Method 1)and replacing the annual average of the minimum monthly flows with the driest year's average flow(Improved Method 2).These methods were applied to the Kaidu River in Xinjiang.The results showed that the Kaidu River's flow varied monthly,with an uneven coefficient of 0.589 for the intra-annual monthly average flow.The differences among the results of the original intra-annual distribution method and its two improved versions were minimal.According to the Tennant method evaluation,all the three methods yielded"optimal"ecological benefits for the river habitat and were applicable to the Kaidu River.Considering the entire basin,it was recommended to adopt the largest result from Improved Method 2 as the minimum ecological flow for the Kaidu River.Statistical analysis of the guarantee degree indicated that the Kaidu River's minimum ecological flow was relatively well assured.Mann-Kendall trend tests revealed that the average flows from January to April and July to December had shown increasing trends,while those from May to June had decreased.R/S analysis showed that the average flows from January to April and July to December would continue to increase in the future,while those from May to June would decrease.The assurance level of the minimum ecological flow at Dashankou station during May to June was concerning in the future.Relevant departments in the basin should pay attention and plan measures in advance to maintain the long-term health and stability of the river ecosystem.