Abstract
Human activities are increasingly recognized as having a critical influence on hydrological processes under the warming of the climate, particularly for dam-regulated rivers. To ensure the sustainable management of water resources, it is important to evaluate how dam construction may affect surface runoff. In this study, using Mann–Kendall tests, the double mass curve method, and the Budyko-based elasticity method, the effects of climate change and human activities on annual and seasonal runoff were quantified for the Yellow River basin from 1961–2018; additionally, effects on runoff were assessed after the construction of the Xiaolangdi Dam (XLD, started operation in 2001) on the Yellow River. Both annual and seasonal runoff decreased over time (p < 0.01), due to the combined effects of climate change and human activities. Abrupt changes in annual, flood season, and non-flood season runoff occurred in 1986, 1989, and 1986, respectively. However, no abrupt changes were seen after the construction of the XLD. Human activities accounted for much of the reduction in runoff, approximately 75–72% annually, 81–86% for the flood season, and 86–90% for the non-flood season. Climate change approximately accounted for the remainder: 18–25% (annually), 14–19% (flood season), and 10–14% (non-flood season). The XLD construction mitigated runoff increases induced by heightened precipitation and reduced potential evapotranspiration during the post-dam period; the XLD accounted for approximately 52% of the runoff reduction both annually and in the non-flood season, and accounted for approximately −32% of the runoff increase in the flood season. In conclusion, this study provides a basic understanding of how dam construction contributes to runoff changes in the context of climate change; this information will be beneficial for the sustainable management of water resources in regulated rivers.
Highlights
Water resources are of great significance to all organisms on Earth
The Mann-Kendall trend test revealed that annual precipitation decreased with insignificant trend (p > 0.05) from 1961 to 2018 (Table 1). Both the five-year moving average and decadal average analysis showed annual runoff to be highest in the 1960s and 2010s
Previous studies have reported a decrease in runoff in the Yellow River basin over the past six decades; this decrease has been attributed to both human activities and climate change
Summary
Water resources are of great significance to all organisms on Earth. Sustainable socioeconomic development across regional, national, and global scales depends on adequate water resources [1], but in recent decades the world has faced new challenges in this regard. Existing water resources are proving insufficient to meet booming demands due to population expansion and ecosystem degeneration [2,3]. An important component of the water cycle, influences river ecosystem functioning and the health of human beings. Runoff is critical to understanding alterations in the global water system, water-energy balances in the hydrological cycle, where water moves between the atmosphere and underlying surfaces [4]. Numerous studies to date have assessed how surface runoff changes in response to disturbance in different regions worldwide [5,6,7], in particular examining the interaction between climate change and human activities [8]
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