Abstract
The climate is becoming warmer and more humid in the inland area of northwestern China. In addition, human activities have changed the underlying surface of the river basin, and the instability of the runoff changes has intensified. As a component of river runoff, the base flow reflects the impacts of climate change and human activities. Therefore, it is necessary to carry out research on the change in the base flow and its influencing factors in the context of climate change and human activities. In this study, a base flow method suitable for the inland rivers in northwestern China was assessed, and the variation rules and influencing factors of the base flow were analyzed. The results reveal that since the 1980s, the base flow of the Hexi inland rivers has exhibited an increasing trend, and the growth rate has exhibited the following order: western > central > eastern. The Base Flow Index (the proportion of the base flow to the total runoff in a period) values are in the range of 0.45–0.65. Overall, the change in the base flow of the Hexi inland rivers is the result of the coupling of climate factors and land-use change. The influence of land-use change on the base flow of the Hexi inland rivers gradually weakens from east to west, except for the Xiying River, while the influence of climate change gradually increases. The contribution rates of land-use change to the base flow in the eastern, central, and western regions were 75%, 55%, and 27%. Temperature and precipitation are the main climate factors affecting the change in the base flow in the western and central regions, respectively.
Highlights
It is necessary to carry out research on the change in the base flow and its influencing factors in the context of climate change and human activities in the Hexi inland river basin
Using five types of base flow segmentation methods and the principal component analysis method, this study aims to analyze the variation of the base flow in the Hexi inland river basin by comparing the various methods and quantitatively discuss the driving factors of the base flow change from the aspects of climate and human activities
This is due to the fact that the Hexi inland rivers originate from the Qilian Mountains, and the river recharge is dominated by the precipitation and glacial melt water in the mountainous areas
Summary
Base flow is a vital part of river runoff and is one of the most important hydrological characteristics in arid and semi-arid areas. It plays a significant role in many aspects, such as maintaining ecosystem health, water safety, industrial and agricultural water supply and constructing rainfall-runoff relationship models [1,2]. As a slow response to the precipitation in the dry river basin, the base flow often permeates and replenishes the river in the form of groundwater, which plays an important role in maintaining the continuous flow and the stability of the water source [3]. It is imperative that the base flow in arid and semi-arid areas be studied
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