Abstract: In order to study the adjustment of discharge and sediment concentration of inlet section from Dongting Lake to Yangtze River, we take Chenglingji hydrological section as an example. According to measured data from 1962 to 2010, we carry out multi-time scale analysis of flow discharge and sediment concentration of Chenglingji station in association with wavelet analysis method to obtain the periodic changes of water-sediment load at the section. Then, we select the section area of low water level as characteristic variables, and use wavelet coefficient of discharge to divide discharge and sediment concentration sequences into different periods. On the basis of delayed response principle, we establish an adjustment model with different time intervals, which is suitable for the response of the water and sediment concentration in the area of the Chenglingji station of Qilishan. Results show that the model could well simulate the regularities of inlet section’s adjustment of Dongting Lake, and the fitted coefficient R² between calculated and measured data is 0.77, which demonstrates that the model has adequate accuracy.

Key words: riverbed evolution, wavelet analysis, multi-time scale, delayed response, section area