River–groundwater interactions in the arid and semiarid areas of northwestern China

River–groundwater interactions play a vital role in the hydrological cycle and have close hydraulic linkages, which dominate the watershed macro-ecological processes in arid and semiarid areas. Based on the achievements of the team focusing on interactions between rivers and groundwater over several years, as well as an assessment of the relevant literature, this report summarizes six modes of river and groundwater interactions in the arid and semiarid areas of northwestern China. The summary covers the dynamic processes of river–groundwater interactions controlled by geomorphic features and geological structures, including the recharge origin, flow path, flow velocity, water circulation amount, and discharge position of the different modes. The ecological effects driven by river–groundwater interactions were analyzed from the basin-scale perspective, as well as the human impacts of such interactions. The interaction between rivers and groundwater in the basin manifests as the unity of the upstream, midstream, and downstream areas, which can be clearly divided into four belts, namely, the mountainous belt, piedmont belt, channel belt, and plain belt. In addition, four belt regulation measures for the utilization of water resources, with ecological protection as the goal, are proposed from a systemic viewpoint of watershed water circulation. The results of this study could contribute to improved management plans for the joint development of rivers and groundwater systems, and the related ecological environment, in arid regions to help cope with the increasing pressures caused by water scarcity and intensive human activities.