Research on the Influence of Reservoir Construction on the Deposition and Hydrodynamic Conditions in the Spawning Area at the End of the Reservoir.

After the construction of reservoir, the uplift of the water level leads to changes in flow rate, water depth and sediment movement, which may also affect the habitat of fish and other organisms. In order to demonstrate the influences of reservoir construction on the siltation and hydrodynamic conditions of the spawning site area and by taking a power station in LC Basin as an example, this paper establishes 1D and planar 2D nested water and sand mathematical model to study the form and position of siltation in the spawning ground, the changes of the reservoir backwater, and the hydrodynamic conditions based on the recommended normal storage level and the operating water levels during the flood season. The results show that the distribution of sediment in the spawning area under the recommended scheme is basically the same as in nature, there is no mutation area in the sediment content, and the construction of reservoir has little effect on siltation in the area. After construction, the area of spawning ground with "flow rate meeting 1.0-2.0 m/s, water depth meeting 0.5-1.0 m" increases in each month from April to July, and the change rate ranges from 8.74% to 317.36%. Under the recommended scheme, the construction of the reservoir has little impact on the habitat and hydrodynamic conditions of the spawning site area at the end of the reservoir, and can still meet the demand of fish. The research results can provide a technical reference for similar engineering planning and design. [ABSTRACT FROM AUTHOR]