Adjustment Processes of Runoff Among River, Lake and Reservoir Along Mid-lower Reaches of Changjiang River During 2006 Extreme Drought Year
Lakes are important water supplies to the discharge of the mid-lower reaches of the Changjiang ( Yangtze) River (MLRCR) , which take vital function of adjuster in maintaining constant runoff of the mainstream in the Changjiang River. Based on the measured hydrological data, during 1978 extreme drought year and 2000 -2006, of the gauge stations including Yichang, Datong, Hukou and Chenglingji, the change of runoff along the MLRCR and water adjustment processes among of river, lake and reservoir in response to abnormal historical record of the 2006 extreme drought year were analyzed. The results showed that it could be characterized as " no flood in the flood season, no drought in the dry year for the changes of runoff along the MLRCR. During the period of 2006 year, there was usual water flux in the dry season along the MLRCR in comparison with those of normal years, and the water flux in the flood season was only 60% -70% of normal years. "No flood in the flood season" results from rapid decreases in runoff of the upper reaches of the Changjiang River. In addition, it was benefit to the increased water flux to some degree in the MLRCR due to the adjustment of the Three Gorge Reservoir. However, supplies and adjusted function from Dongting and Poyang lakes resulted from constraint effects by obvious decrease in water level in the stream was an important part to the MLRCR in maintaining the runoff characteristics of "no drought in dry season".
lakesrunoff adjustmentthe Three Gorges Reservoirextreme drought year