Abstract:
Since the 1980s, the intensity of groundwater extraction on the North China Plain has increased continuously, threatening water resource security. Groundwater has long been severely overexploited, which has led to the formation of large-scale groundwater depression cones. After years of comprehensive overexploitation management, groundwater levels have rebounded significantly. Against the backdrop of drastic changes in groundwater levels in recent decades, the temporal variation characteristics of lateral groundwater recharge on the Taihang Mountains piedmont plain remain unclear. This study used groundwater level observational data from three periods (1976–1980, 1991–2004, and 2018–2023), which represented the pre-intensive groundwater exploitation, intensive groundwater exploitation, and comprehensive groundwater management periods, respectively. By screening observation wells during the three periods, determining cross-sections, and using Darcy’s law to calculate lateral groundwater recharge, this study analyzed the lateral recharge of shallow groundwater and its temporal variation characteristics in the Hebei section of the Taihang Mountains piedmont plain. A systematic study and analysis were conducted on the decadal variation trends, as well as interannual and monthly variation characteristics of lateral groundwater recharge during the pre-intensive groundwater exploitation, intensive groundwater exploitation, and comprehensive groundwater management periods. The study found that: 1) The lateral recharge of shallow groundwater generally showed an increasing trend, with a multi-year average of 9.8×10
8 m
3·a
−1 during the pre-intensive groundwater exploitation period, increasing to 10.6×10
8 and 13.8×10
8 m
3·a
−1 during the intensive groundwater exploitation and comprehensive groundwater management periods, respectively. 2) Distinct fluctuations in lateral groundwater recharge were observed. During the pre-intensive groundwater exploitation period, the variation range of lateral groundwater recharge was nearly 0.70×10
8 m
3, whereas during the intensive groundwater exploitation period, the variation range reached 4.18×10
8 m
3, and during the comprehensive groundwater management period, the variation range slightly decreased to approximately 3.52×10
8 m
3. 3) The changes within the year of lateral groundwater recharge was distinct, with the minimum lateral recharge occurring during February. 4) With the development of groundwater management, the primary controlling factor of lateral recharge changes shifted from the hydraulic gradient to the combined action of hydraulic gradient and aquifer thickness. This study can enhance in-depth understanding of regional groundwater circulation laws and is of important scientific value for promoting sustainable groundwater resource utilization.