Journal of Marine Sciences ›› 2023, Vol. 41 ›› Issue (2): 61-70.DOI: 10.3969/j.issn.1001-909X.2023.02.005

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Variations in water and sediment fluxes in Oujiang River during flooding and non-flooding seasons

ZHANG Wanying1(), LU Shasha1,2,*(), XIA Xiaoming1, LIU Jingui3   

  1. 1. Second Institute of Oceanography, MNR, Hangzhou 310012, China
    2. Key Laboratory of Ocean Space Resource Management Technology, MNR, Hangzhou 310012, China
    3. College of Ocean and Meteorology Guangdong Ocean University, Guangdong 524088, China
  • Received:2022-04-18 Revised:2022-06-11 Online:2023-06-15 Published:2023-07-27


Oujiang River is a typical mountain river whose water and sediment fluxes are characterized by a great disparity between flood and dry seasons. Based on the measured data of water discharge and sediment load at the mainstream control hydrological station of Oujiang River in the past 71 years (1950—2020) and 43 years (1956—1998), respectively, the coefficient of nonuniformity, Mann-Kendall non-parametric statistical test and double mass curve were used to analyze the variations of runoff and sediment load during the flood seasons (including plum rain season from April to June and typhoon season from July to September) and dry seasons (non-flooding season from October to March in next year) in the Oujiang River. The results showed that: (1) The peak and valley month of runoff were the same as sediment load. The peak month of both runoff and sediment load appeared in June, while their valley month appeared in December. The plum rain season was the most important period of water and sediment transporting to sea from Oujiang River. (2) The runoff showed significant decreasing trend in the plum rain season, significant increasing trend in non-flooding season, and non-significant trend in typhoon season during 1950—2020 in Oujiang River. The nonuniformity of intra-annual distribution for runoff had become more uniform obviously, resulting from the regulation of reservoirs. (3) The sediment load showed significant decreasing trend in the plum rain season due to the interception of reservoirs, and no significant trend in typhoon season and non-flooding season during 1956—1998 in Oujiang River. The nonuniformity of intra-annual distribution for sediment load showed little change, which might relate to the nonuniformity of intra-annual distribution for precipitation. (4) The relationship between sediment load and runoff during typhoon and non-flooding season changed in 1975 and 1959, respectively, both of which were related to the heavy rainfall within the river basins.

Key words: Oujiang River, flooding season, non-flooding season, water and sediment fluxes, the nonuniformity coefficient

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