Anthropogenic impacts on the decreasing sediment loads of nine major rivers in China, 1954-2015

Ziyin Wu; Dineng Zhao; James P M Syvitski; Yoshiki Saito; Jieqiong Zhou; Mingwei Wang

doi:10.1016/j.scitotenv.2020.139653

Anthropogenic impacts on the decreasing sediment loads of nine major rivers in China, 1954-2015

Sci Total Environ. 2020 Oct 15:739:139653. doi: 10.1016/j.scitotenv.2020.139653. Epub 2020 May 29.

Authors

Ziyin Wu¹, Dineng Zhao², James P M Syvitski³, Yoshiki Saito⁴, Jieqiong Zhou⁵, Mingwei Wang⁵

Affiliations

¹ Key Laboratory of Submarine Geosciences & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China; School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address: zywu@vip.163.com.
² Key Laboratory of Submarine Geosciences & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China. Electronic address: zhaodineng@sio.org.cn.
³ Community Surface Dynamics Modeling System, INSTAAR, University of Colorado, Boulder CO 80309-0545, USA.
⁴ Estuary Research Center, Shimane University, Matsue 690-8504, Japan; Geological Survey of Japan, AIST, Tsukuba 305-8567, Japan.
⁵ Key Laboratory of Submarine Geosciences & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China.

PMID: 32758931
DOI: 10.1016/j.scitotenv.2020.139653

Abstract

Over the past 60 years, because of the combined impacts of human activities and climate change, the sediment load of the nine major rivers (the Yellow, Yangtze, Pearl, Songhuajiang, Liaohe, Haihe, Huaihe, Qiantangjiang, and Minjiang rivers) in China has dropped by 85%, which had caused serious environmental problems such as reservoir siltation and estuary erosion. However, quantitatively evaluating the impact of different human activities on this decline is still an unsolved and complex problem. Based on a big new data set from 27 gauge stations and 469 meteorological stations, we established five methods to assess sediment loss of China's nine major rivers. During 1954-2015, the sediment load into the marginal seas via these nine rivers was characterized by a marked decline, from 1.95 Gt/yr (1954-1968) to 1.40 Gt/yr (1969-1985), 890 Mt/yr (1986-1998), 450 Mt/yr (1999-2003), and 310 Mt/yr (2004-2015), reflecting an 85% decrease between 1954-1968 and 2004-2015. The cumulative sediment load into the marginal seas was ~71.0 Gt, constituting ~7% of the global sediment load. The Yellow River, Yangtze River, Pearl River, and other six major rivers contributed 40.9 (58%), 22.9 (32%), 4.1 (6%), and 2.96 Gt (4%), respectively. We estimate that ~53.0 Gt of terrestrial sediment has been retained on the mainland China because of human activities, with reservoir trapping, water resource utilization, and water-soil conservation measures accounting for 45.5%, 29%, and 25.5% of the total, respectively. The contribution of climatic factors was assessed to be secondary. This drastic reduction in river sediment load could lead to a series of negative effects on deltas: decreased sediment delivery, coastal erosion, aggravated reaction to storm disasters, and most importantly, loss of new land for human use. In addition, the large amounts of sediment trapping by reservoirs over long periods will cause siltation that could reduce reservoir water storage capacity.

Keywords: Chinese rivers; Climate change; Human activities; Quantitative assessment; Sediment load.