Groundwater recharge in typical geomorphic landscapes and different land use types on the loess plateau, China

Abstract

AbstractLand use significantly affects the rate and amount of groundwater recharge. To understand these patterns, stable isotope analyses (δ2H and δ18O) and hydrochemical methods were employed to study the recharge and evolution of groundwater. MixSIAR Bayesian mixture modelling and statistical regression techniques were utilized to investigate the influence of land‐use type on groundwater recharge and to calculate the contribution of various water sources to different groundwater types. These findings are important for effective management and conservation of groundwater resources. The groundwater in all studied areas displayed a magnesium bicarbonate type with notable cation exchange, and also demonstrated the dissolution of carbonate and weathering of silicate. Results from the Bayesian mixture model indicate that 69.3% of the groundwater in the Loess Plateau region was recharged by precipitation, while 86.9% of the groundwater in the loess hilly‐gully region was recharged from the surface water. Groundwater recharge was more rapid in the loess hilly‐gully region than in the Loess Plateau and was less sensitive to the land use type in the former. Dryland‐moderate coverage grassland was found to be most conducive to groundwater infiltration, whereas monotypic dryland and high‐coverage grassland inhibited infiltration to some degree. To maintain balanced soil erosion control, an increase the area of moderate‐coverage grasslands in the Loess Plateau region is recommended.