作者：Zhu, Q., Kang, Y., Wen, Z. et al.

The construction of the Three Gorges Dam (TGD) has profoundly altered the groundwater cycle downstream. The obscure spatiotemporal patterns of exchange fluxes between the Yangtze River and groundwater hinder the resolution of water resources and environmental issues in the watershed. This study investigated the spatial extent of the Yangtze River's influence on adjacent groundwater in the Four-Lake Basin, the first river-lake wetland plain downstream of the TGD, using multiple clusters of monitoring wells installed along the river. A coupled SWAT-MODFLOW model was applied to quantify period-specific surface water-groundwater exchanges. A counterfactual scenario without TGD operation, holding other conditions constant is also simulated for comparison. The results show: (1) Under the combined influence of hydrogeological conditions and distance from the TGD, the influence range of the Yangtze River on confined groundwater is significantly greater in the upper section than in the lower section of the Four-Lake Basin, with a difference of approximately one order of magnitude. (2) River and groundwater exchanges exhibit pronounced seasonal and spatial characteristics: river-to-aquifer recharge dominates during drawdown and flooding periods, while aquifer-to-river discharge dominates during impounding and dry periods. Additionally, the interaction rates between river and aquifer are consistently higher in the upper section than in the lower one. (3) Relative to natural conditions, TGD operation dramatically dampens Yangtze River-groundwater interactions overall. The effect is most pronounced during the dry period in the upper section, when the interaction rate decreases by 40.6 %. These research outcomes serve as a vital theoretical foundation for assessing the effects of the TGD's regulation on the hydrological interaction in the riparian zone of the Yangtze River.

三峡大坝（TGD）的建设深刻改变了坝下游地区的地下水循环。长江与地下水之间交换通量的时空格局尚不明晰，制约着流域水资源与环境问题的解决。研究以四湖流域——三峡大坝下游首个河湖湿地平原——为研究区，利用沿长江布设的多组监测井群，探明长江对其毗邻地下水影响的空间范围；构建了SWAT-MODFLOW耦合模型，量化了不同调度时期的地表水—地下水交换量；并模拟了在其余条件不变的情况下、无三峡调度的反事实情景以供对比。结果表明：（1）在水文地质条件与距坝距离的共同影响下，长江对承压含水层地下水的影响范围在四湖流域上段显著大于下段，二者相差约一个数量级；（2）河道与地下水交换呈现明显的季节性与空间性特征：水位消落期与汛期以河水补给地下水为主，蓄水期与枯水期以地下水排泄补给河道为主；且河道—含水层相互作用速率上段始终高于下段；（3）与天然条件相比，三峡调度总体上显著削弱了长江—地下水相互作用，其中以枯水期上段最为突出，相互作用速率降低40.6%。研究成果可为评估三峡调度对长江岸带水文相互作用的影响提供重要的理论基础。

（来源：Hydrology and Earth System Sciences 2026 Issue 7  DOI: 10.5194/hess-30-2037-2026）