Analysis and Prediction of Surface Water-Groundwater Interaction under Water Transfer Scenarios in the Liangji Canal Project Area

The implementation of inter-basin water transfer (IBWT) projects effectively alleviates water supply-demand imbalances. Most such projects rely on natural river channels or canals for water conveyance. Prolonged high-water-level delivery can influence the interaction between surface water and groundwater (SW-GW) at the regional scale. This study focuses on the Liangji Canal project area of the South-to-North Water Transfer Project (SNWTP) Eastern Route, using the SWAT-MODFLOW coupling model to analyze and predict the SW-GW interactions under different water transfer scenarios. Three distinct water transfer scenarios were established to further predict and analyze the SW-GW interactions in the study area. The results show that the coupled model effectively simulates the dynamic changes of SW-GW in the region. Spatially, mutual recharge between SW-GW occurs in the Liangji Canal Hu-kou to Changgou section and the Denglou to Baligang section, while the Changgou to Denglou section experiences sustained river leakage recharging groundwater. Temporally, there is a strong interaction between SW-GW, with groundwater recharge to surface water primarily occurring in November and December.