land Article Relative Contribution of the Xiaolangdi Dam to Runoff Changes in the Lower Yellow River Qinghe Zhao 1,2 , Shengyan Ding 1,2,*, Xiaoyu Ji 1,2, Zhendong Hong 1,2, Mengwen Lu 1,2 and Peng Wang 3 1 College of Environment and Planning, Henan University, Kaifeng 475004, China;
[email protected] (Q.Z.);
[email protected] (X.J.);
[email protected] (Z.H.);
[email protected] (M.L.) 2 Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Henan University, Ministry of Education, Kaifeng 475004, China 3 Yellow River Engineering Consulting Co., Ltd., Zhengzhou 450016, China;
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[email protected] 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 Citation: Zhao, Q.; Ding, S.; Ji, X.; combined effects of climate change and human activities. Abrupt changes in annual, flood season, Hong, Z.; Lu, M.; Wang, P.