Recent stepwise sediment flux increase with climate change in the Tuotuo River in the central Tibetan Plateau

Fan Zhang; Xiaonan Shi; Chen Zeng; Li Wang; Xiong Xiao; Guanxing Wang; Yao Chen; Hongbo Zhang; Xixi Lu; Walter Immerzeel

doi:10.1016/j.scib.2019.12.017

Recent stepwise sediment flux increase with climate change in the Tuotuo River in the central Tibetan Plateau

Sci Bull (Beijing). 2020 Mar 15;65(5):410-418. doi: 10.1016/j.scib.2019.12.017. Epub 2019 Dec 19.

Authors

Fan Zhang¹, Xiaonan Shi², Chen Zeng³, Li Wang⁴, Xiong Xiao⁴, Guanxing Wang⁴, Yao Chen⁴, Hongbo Zhang⁵, Xixi Lu⁶, Walter Immerzeel⁷

Affiliations

¹ Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zhangfan@itpcas.ac.cn.
² Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: shixiaonan@itpcas.ac.cn.
³ Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
⁴ Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China.
⁵ College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China.
⁶ Department of Geography, National University of Singapore, Arts Link 1, 117570, Singapore.
⁷ Department of Physical Geography, Utrecht University, Utrecht 80115, the Netherlands.

PMID: 36659232
DOI: 10.1016/j.scib.2019.12.017

Abstract

The riverine sediment flux (SF) is an essential pathway for nutrients and pollutants delivery and considered as an important indicator of land degradation and environment changes. With growing interest in environmental changes over the Tibetan Plateau (TP), this work investigated the variation of the SF in response to climate change in the headwater of the Yangtze River over the past 30 years. Annual time series of hydro-meteorological variables during 1986-2014 indicate significantly increasing trends of air temperature, precipitation, ground temperature, river discharge, suspended sediment concentration and SF. Stepwise changes were identified with significantly higher values of the above variables in 1998-2014 compared with 1986-1997, which could potentially be attributed to the strong 1997 El Niño event. Double-mass plots indicated that both meltwater and rainfall contributed to the increased river discharge while the increased SF mostly resulted from enhanced erosive power and transport capacities of the increased discharge. However, it was buffered by a decrease in sediment source due to the shift of maximum monthly rainfall from June/July to July/August during which period a denser vegetation cover prevents soil erosion. Partial least squares structural equation modeling analysis confirmed the dominance of warming on the increase of discharge amplified by increased precipitation. It also confirmed that the increased precipitation drives the increase in suspended sediment concentration. Both processes conspire and equally contribute to the stepwise increase of SF. This study provides important insights into the controlling processes for recent SF changes and gives guidance for water and soil conservation on the TP.

Keywords: Alpine catchment; Changing trend; Climate change; Sediment flux.