Journal of Geographical Sciences ›› 2015, Vol. 25 ›› Issue (8): 917-929.doi: 10.1007/s11442-015-1210-y

• Orginal Article • Previous Articles     Next Articles

Enhanced lakebed sediment erosion in Dongting Lake induced by the operation of the Three Gorges Reservoir

Yongqiang ZHOU1,2,3(), Jingbao LI1,*(), Yunlin ZHANG2, Xinping ZHANG1, Xichun LI4   

  1. 1. College of Resources and Environmental Sciences, Hunan Normal University, Changsha 410081, China
    2. Nanjing Institute of Geography and Limnology, CAS, Nanjing 210008, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
    4. Hunan Hydro & Power Design Institute, Changsha 410007, China
  • Received:2015-02-09 Accepted:2015-03-20 Online:2015-08-15 Published:2015-07-17
  • Contact: Jingbao LI E-mail:yohnchou917251@126.com;lijingbao1951@126.com
  • About author:

    Author: Zhou Yongqiang (1988-), PhD, specialized in unraveling the dynamics of lake ecosystem. E-mail:yohnchou917251@126.com

  • Supported by:
    National Natural Science Foundation of China, No.41071067;Program of the Key Discipline Construction of the Physical Geography in Hunan Province

Abstract:

Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion (S/E) regimes of the Dongting Lake after the operation of the Three Gorges Reservoir (TGR) were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets (r2=0.859, p<0.0001), and between the flow rate and sediment delivery rate at the Three Outlets (r2=0.895, p<0.0001). This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from +4796.4×104 t during the period before the operation of TGR (1999-2002) to +684.1×104 t, +449.8×104 t and -559.6×104 t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m3/s, 466.82 kg/s and 0.481 kg/m3 for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake.

Key words: The Three Outlets, The Three Gorges Reservoir (TGR), flow rate, sediment delivery rate, Dongting Lake