Impacts of Yongding River Ecological Restoration on the Groundwater Environment: Scenario Prediction

Abstract

Core Ideas Our method can estimate groundwater recharge through multiple contrasting lithological layers. Both human activities and natural aquifer character impact groundwater flow and transport. Geomembrane liners can effectively control the leakage from Yongding River. The ecological restoration of Yongding River can alleviate the local water deficit. Reclaimed water was discharged into the Yongding River channels as ecological water. Pollutants from such water may leak into the underlying aquifer and put the groundwater environment at risk. River leakage estimation under different possible river lining conditions and the established groundwater flow and reactive solute transport model were jointly applied to investigate the impact of the ecological restoration of the Yongding River on the local groundwater environment. Scenario‐based investigations were conducted since the channel reconstruction in 2009. The results show that the seepage from the Yongding River without liners can greatly raise the groundwater level. Leakage through liners constructed with geomembranes can effectively control the seepage of water and the spread of solutes in the aquifer. From June 2009 to December 2010, the leakage amount has been only 1.65 × 104 m3, and the unconfined aquifer shows a negative budget of 4.55 × 107 m3. The spreading extent of flow and potential pollutants increases with the amount of leakage from the river. Water management strategies, such as the South‐to‐North Water Diversion Project and Yongding River restoration could help alleviate the water deficit of the Yongding River alluvium fan (YRAF) by reducing groundwater exploitation and increasing groundwater recharge. The necessity of the maintenance of riverbed liners and control of the water quality of Yongding River were highlighted by the scenario analysis. The methods applied in this study could be used for reference in the other polluted rivers, especially with liner installation.