Water storage changes in the North China Plain from 2004 to 2019

In the past few decades, the irrational use of water resources has resulted in many issues such as land subsidence in the North China Plain (NCP), hindering its socio-economic development. An accurate understanding of water resource changes is important for the allocation of water resources in the NCP. In this study, we employed Gravity Recovery and Climate Experiment (GRACE) satellite data to monitor the total water storage (TWS) change in the NCP during 2004-2019. Evapotranspiration, precipitation, and runoff during 2004-2019 were sequentially examined, using the water balance formula (WBF), to retrieve TWS change. Furthermore, the soil moisture, snow water equivalent, and canopy water storage from the Global Land Data Assimilation System were used to calculate the natural component of the TWS variations. A comparison of these results revealed the drivers of the changes in water resources. The results showed that: (1) overall TWS retrieved by GRACE decreased substantially as a consequence of human activity, while TWS obtained by WBF fluctuated periodically around zero under the impact of three natural drivers; (2) TWS in the NCP fell at a remarkable rate of -12.39 mm/y from 2004 to 2019, and the natural part of TWS experienced two significant declines, during 2004-2010 and 2013-2016; (3) variations in runoff, precipitation, and evapotranspiration from 2004 to 2019 were not significant, but human activities contributed more to the decreasing TWS than natural factors. This study provides a reference for water resource management and groundwater exploitation across the NCP under climate change.