Groundwater recharge via precipitation in the Badain Jaran Desert, China

Precipitation infiltration serves as a significant source of groundwater in the Badain Jaran Desert. To investigate variations in precipitation infiltration within the desert, this study collected data on moisture content and temperature from the vadose zone through in-situ field monitoring. Utilizing these data, a numerical model is employed to explore the mechanism of groundwater recharge via precipitation. The results are as follows: (1) Moisture content and temperature in the shallow vadose zone exhibit significant seasonal variations, with moisture content diminishing with increasing depth; (2) Groundwater recharge via precipitation infiltration initially increases and then decreases with groundwater level depth (GWD). Peak groundwater recharge via precipitation occurs at a GWD of 0.75 m, decreasing to merely 0.012 cm at GWDs exceeding 2 m; (3) Groundwater is no longer susceptible to phreatic water evaporation when the GWD reaches approximately 3.7 m. Therefore, GWD plays a crucial role in governing groundwater recharge via precipitation in the Badain Jaran Desert.