Influence of Reservoir Operation in the Upper Reaches of the Yangtze River (China) on the Inflow and Outflow Regime of the TGR-based on the Improved SWAT Model

The impact of hydraulic engineering works and human activities on hydrology has become a hot issue along with the economy and social development. The water cycle model of the upper reaches of the Yangtze River (URYR) is established based on the improved Soil and Water Assessment Tool (SWAT) model. The inflow and outflow of the Three Gorges Reservoir (TGR) is simulated in 4 scenarios of the reservoir combination of the URYR:(1) reservoir is not considered; (2) all constructed, under construction and planed to be constructed reservoirs are considered; (3) reservoirs that have been constructed are considered only; (4) reservoirs have been constructed and being constructed are considered. The result shows that reservoir operation in the URYR decreases inflow to TGR at the end of flood season and increases that in dry season, and makes the TGR water storage start time earlier. The result of this study will be proved some references to the regional water resources management and reservoir ecological operation with the influence to eco-environmental flow of the lower reaches, when the schema reservoir constructed in the URYR.