Groundwater storage recovery in the North China Plain: Impacts of river replenishment, land use change, and climate variability

The North China Plain (NCP) has faced substantial groundwater depletion driven by rapid population growth, socioeconomic development, and high irrigation water demand in recent decades. Responding to this challenge, the Chinese government has implemented significant measures, including the construction of the South-to-North Water Diversion Project's middle route (SNWD-M) and the curtailment of groundwater use, aiming to alleviate water scarcity and overexploitation. The river replenishment initiative, utilizing surplus SNWD-M water, has injected over 9.5 km³ into NCP rivers. Simultaneously, policy-induced shifts in agricultural land use, such as transforming winter wheat and summer maize rotation to single crops through seasonal fallow, have reshaped the landscape. Additionally, extreme events like the record flood in the summer of 2023 have become influential contributors to groundwater recharge in the NCP under changing climate conditions.

To evaluate the joint impact of these anthropogenic and natural factors on groundwater levels and surface water-groundwater interactions, we established a coupled surface water-groundwater model across the NCP. Our findings reveal that river replenishment, coupled with the 2023 record flood, played a pivotal role in the rebound of groundwater levels. However, changes in agricultural land use introduce uncertainties. This study provides a holistic understanding of the drivers behind the recovery of groundwater storage in the NCP over the past decade, offering valuable insights for the enhanced management of the SNWD-M initiative.