Journal of Marine Sciences ›› 2022, Vol. 40 ›› Issue (4): 52-64.DOI: 10.3969j.issn.1001-909X.2022.04.005

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Characteristics of runoff and sediment discharge in the Pearl River Basin in recent 70 years and analysis on the affecting factors of human activities

DU Yichao1,2, LUO Xiaowen*1,2,3,4, WANG Jun1, CUI Jiaxin1,2   

  1. 1. Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China;
    2. Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, MNR, Hangzhou 310012, China;
    3. Key Laboratory of Ocean Space Resource Management Technology, MNR, Hangzhou 310012, China;
    4. Marine Academy of Zhejiang Province, Hangzhou 310012, China
  • Received:2021-12-14 Online:2022-12-15 Published:2023-02-09

Abstract: The variation characteristics of water and sediment in the Pearl River Basin over the past about 70 years were analyzed by using the runoff and sediment discharge data at three major hydrological stations in the Pearl River Basin, Gaoyao Station (Xijiang River), Shijiao Station (Beijiang River) and Boluo Station (Dongjiang River) from 1954 to 2019, and applying the Mann-Kendall nonparametric test and accumulative anomaly curves. The results showed that the change of the runoff in the Pearl River from 1954 to 2019 was not obvious while the sediment discharge was decrease, among which the sediment discharge at Gaoyao and Boluo Stations changed abruptly in 2003 and 1991, decreasing by 71.3% and 48.88%, respectively, compared with before the abrupt change, while the sediment discharge at Shijiao Station did not change abruptly. On this basis, the change of vegetation cover in the basin and its relationship with the change of water and sediment were studied by using the precipitation data and Normalized Difference Vegetation Index (NDVI) in the basin from 2000 to 2019. The NDVI in the Pearl River Basin showed an overall increasing trend from 2000 to 2019, and the improvement area of vegetations cover accounted for 89.27% of the total basin area. Among which NDVI in the Pearl River Basin was poorly correlated with sediment discharge from 2000 to 2008, NDVI in the Xijiang River Basin and Dongjiang River Basin were positively correlated with precipitation in the basin but not with sediment discharge form 2009 to 2019, and only in the Beijiang River Basin, NDVI was insignificantly negatively correlated with sediment discharge. The influence of human activities on sediment discharge in the Pearl River at different periods was discussed using the double cumulative curve method. Since the 1980s, human activities such as deforestation, reservoir construction, and soil and water conservation had a significant impact on sediment discharge. After 2000, the construction of Longtan Reservoir was the main reason for the decline of sediment discharge in the Xijiang River, but the improvement of vegetation coverage had no significant impact on the sediment discharge in the Pearl River Basin.

Key words: sediment discharge, runoff, NDVI, human activities, the Pearl River

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