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Evidence and Causes of Spatiotemporal Changes in Runoff and Sediment Yield on the Chinese Loess Plateau

Zhao, Guangju, Mu, Xingmin, Jiao, Juying, An, Zhengfeng, Klik, Andreas, Wang, Fei, Jiao, Feng, Yue, Xiaoli, Gao, Peng, Sun, Wenyi
Land degradation & development 2017 v.28 no.2 pp. 579-590
climate change, humans, runoff, sediment yield, sediments, soil, subwatersheds, water conservation, China, Yellow River
Climate change and human activities are strongly influencing the eco‐hydrological processes of the Chinese Loess Plateau. It is challenging to investigate the spatiotemporal changes of water and sediment yields and identify their potential causes. In this study, we used the annual runoff index (WI) and specific sediment yield (SSY) derived from 58 hydrological stations to quantify the changes and attempted to explain their potential causes. The WI exhibited significant (P < 0.05) decrease ranging from −0.1 to −2.6 mm yr⁻¹ during 1957–2012 in 44 sub‐catchments. Similarly, the SSY in 52 sub‐catchments reduced in a range between −2.86 and −636 Mg km⁻² yr⁻¹. The region of Toudaoguai–Longmen has extremely high SSY ranging from 8000 to 41 000 Mg km⁻² yr⁻¹ during 1957–1969. Budget analysis suggested that the area of Lanzhou–Toudaoguai contributed limited sediment but extracted large amount of water. The areas with negative SSY were increasing and mainly distributed along the mainstream of the Yellow River. The Loess plateau was becoming drier and warmer since the 1950s, whereas the intensive human activities including water withdrawal, soil and water conservation projects and the operation of dams and reservoirs are the dominant factors for the decline in WI and SSY on the Loess Plateau. Copyright © 2016 John Wiley & Sons, Ltd.