关键词: 水文情势, 蓄水期, 水动力模型, 三峡水库, 洞庭湖

Abstract: The variation of hydrological regime in Dongting Lake would directly affect regional flood prevention, water resources utilization, water environment protection and water ecology protection, which is of great significance. Based on the measured data, the variation of the hydrological situation in Dongting Lake area before and after the Three Gorges Reservoir operation was analyzed. The results showed that the inflowing and outflowing water volume of Dongting Lake from 2003 to 2016 had decreased by 26% and 23.7% respectively and the water level in lake area dropped 0.76~1.27m from August to November, compared with the period from 1981 to 2002, due to the combined factors, such as the diversion decrease of three distributaries from Jinjiang River and the decrease of incoming water, etc. A 1D and 2D coupled hydrodynamic model of the Yangtze River and Dongting Lake was established to simulate the hydrological processes of the study area during the water storage period of Three Gorges Reservoir under the initial-designed scheduling scheme, optimal scheduling scheme and protocol scheduling scheme. The corresponding average annual flow of Chenglingji station decreased 1 220,928 m3/s and 900 m3/s respectively, and the average annual water level of the Lujiao Station in the lake area decreased 1.47,1.23 m and 1.20 m respectively; however, the average flow decreased 812 m3/s and the water level decreased by 1.14 m under the actual scheduling practice, indicating that the actual scheduling is optimal. From the comparison of different scheduling schemes, the actual dispatching advanced the storage starting time and slowed down the adverse impact on the hydrological situation in Dongting Lake area.

Key words: hydrological regime, water storage period, hydrodynamic model, Three Gorges Reservoir；Dongting Lake