Groundwater Recharge and Dynamics in Northern China: Implications for Sustainable Utilization of Groundwater

This paper reviews diffuse recharge studies in (semi)arid northern China, which are mainly based on environmental tracers of the unsaturated zone (chloride mass balance, natural tritium, artificial tritium, and bromine). Diffuse recharge in the northwestern part is commonly less than 3.6 mm/yr, where precipitation is less than 200 mm/yr and groundwater is mainly recharged by mountain runoff. The recharge rates increase in the rain-fed Loess Plateau, ranging from 30-100 mm/yr beneath the main crop (wheat). Due to enhanced irrigation in the North China Plain, it can reach thousands of millimeters per year. Due to the limited recharge and sometimes thick unsaturated zone, some shallow groundwaters (e.g., the western Ordos basin and desert area) in northwestern China are even palaeowaters (1.6-30 ka). Insufficient groundwater recharge cannot make a mass balance aquifer under present water exploitation patterns. Mining unrenewable water resources has caused severe water-table subsidence (0.5-2 m/yr). Several suggestions based on the limited groundwater recharge rate and water table subsidence in northern China were proposed for groundwater sustainable utilization.