Acta Geographica Sinica ›› 2011, Vol. 66 ›› Issue (7): 953-960.doi: 10.11821/xb201107008

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A Comprehensive Assessment Method of Hydropower Development Impact on Runoff and Sediment Change

LIU Xinyou1,2, HE Daming1   

  1. 1. Asian International Rivers Center, Yunnan University, Kunming 650091, China;
    2. Yunnan Bureau of Hydrology and Water Resources Management, Kunming 650106, China
  • Received:2011-03-02 Revised:2011-04-20 Online:2011-07-20 Published:2011-07-20
  • Supported by:

    National Special Basic Research Fund, No.2008FY110300

Abstract: The rivers in Southwest China are the major base for large-scale hydropower development, and its change and responses of sediment and runoff are quite complicated. The assessment of the change and response has been the focus topics for the cascade hydropower dams building. In this paper, the Lancang River, which has 25 years' large-scale hydropower development, was chosen as a study case for establishing the affected evaluation indexes system of runoff and sediment and the reduction model of indexes, determining the indexes weight by AHP and factor analysis method, and setting up the indexes affected level evaluation models using the "marginal efficiency" principle. After the assessment of runoff and sediment change under the cascade development in Lancang River based on these methods and the model mentioned above, the results are obtained as follows. (1) During the 30 years of the hydropower development from 1986 to 2007, the impact of sediment transport affected by the cascade development is much greater than that of runoff change; 72.7% of the years with "very low" impact level of sediment transport change, 18.2% with "low" level, and 9.1% with "average" level. (2) The change process of runoff and sediment level affected presents a "U"-shaped pattern of "high-low-high" under the disturbing Manwan dam running and Dachaoshan dam building, which indicates a balance of sediment change due to the joint effect resulting from sediment reduction by Manwan reservoir and sediment increase by the Dachaoshan dam building.

Key words: hydropower development, the features of runoff and sediment, evaluation method, Lancang River