Prediction Study on the Impact of Engineering Waste Rocks on Water Quality During Reservoir Construction

Abstract

The impact of dammed reservoirs on the local ecological environment during the operational phases has garnered significant attention. However, there is limited research on the ecological risks posed by reservoirs during the construction period, particularly regarding the waste rock at the bottom of the reservoir. Based on the results of release experiment, the water quality risks of engineering waste rocks to reservoirs were analyzed by a three-dimensional model using the MIKE 3 FM HD and ECO Lab module. The calculation results showed that as the waste rock yards are inundated, SO42− and Fe3+ in the reservoir are released and gradually affecting the water quality in the area in front of the dam. During the process of water storage, the release of pollutants from the waste rocks at the bottom of the reservoir had a significant impact on the underlying water body after two months and then spread from the bottom to the upper layer of water. After three months of water storage, when the water level of the reservoir reached 867 meters, the pollutants released by the waste rock had an impact on the surface water quality. After four months, the release of pollutants from the waste rock yards essentially ceased, and the pollutants gradually accumulated in the bottom water body in front of the dam after dilution and diffusion. In the future, special attention should still be given to the risk assessment of pollutants in the bottom sediments during long-term operation and management of the reservoir.