| In the northern region of Qaidam Basin, there are three parks of "one district and four parks", which are currently facing a scarcity of water resources, but the runoff has changed significantly due to climate change in recent 20 years, which has a certain impact on water resources evaluation, river ecology and non-zonal vegetation. In order to comprehensively evaluate regional runoff characteristics, WEP model is used to simulate the long-series runoff of 6 rivers in the northern basin, and the data combined with the measured and simulated data are combined with 8 representative IHA indicators selected by PCA method are used to analyze the spatio-temporal law of runoff production typical environmental flow components. The result shows that:(1) The runoff depth in mountain area increases by 8%～28% after 2001, and the area of non-flow producing area in plain decreases by 58%. (2) From 1981 to 2020, the runoff series had a sudden change at the beginning of this century. After the sudden change, the increase rate of average runoff is 8%-25%. And the increase in the past 10 years is divided into two situations: the increase of glacier-fed rivers is 14%～41%, and the increase of rivers without glacier feed is 26%～28%. Considering the inconsistency of runoff series, the average annual runoff of 6 small rivers in the northern region is 1.052 billion m3 by using the short-period series. (3) Flood becomes the most typical environmental characteristic flow because it stimulates fish spawning. The study finds that the frequency and duration of flood increases, and the flood peak increases by 13%～37%. |
