Acta Geographica Sinica ›› 2013, Vol. 68 ›› Issue (9): 1240-1250.doi: 10.11821/dlxb201309007

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Trends and causes of suspended sediment concentration variation in the turbidity maximum zone at the Yangtze River Estuary

YANG Yunping, LI Yitian, SUN Zhaohua, FAN Yongyang   

  1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
  • Received:2013-04-18 Revised:2013-06-04 Online:2013-09-05 Published:2013-09-05
  • Contact: 李义天, 教授, 博导, E-mail: ytli@whu.edu.cn E-mail:ytli@whu.edu.cn
  • Supported by:
    Foundation Fund from the Ministry of Science and Technology of China, No.2010CB429002)

Abstract: Based on the analysis of suspended sediment elements at estuaries, influences of human activities and estuarine regulation projects on the turbidity maximum zone are studied. Data comes from the measurement between 1959 and 2011. It is found that human activities had little effect on the seawards water and that the sharp decrease of sediment volume and concentration in runoff led to the sharp decrease in the estuary. The concentrations off the coast and at Hangzhou Bay did not change. The concentrations along the coast of northern Jiangsu decreased a little and had no influence on the turbidity maximum zone. Affected by the hydrodynamics of runoff and tide, the area of maximum turbidity zone is related to the volume of seawards sediments. Comparisons between 1959 and 1999 show that the concentrations in 2000-2009 decreased by about 24.73% and the range reduced along the river to the sea. The peak of concentration moved upstream in the estuary. The suspended sediment concentrations in North Passage are low in upstream and downstream reaches because of the decrease of seawards sediments, spilt ratio and coarsening of bed material. In the middle of the North Passage, the concentrations increased because of the influence of the sediments across the north jetty.

Key words: suspended sediment concentration, Yangtze River Estuary, trends and causes, turbidity maximum zone (TMZ)