Discrepancy and estimates of groundwater recharge under different land use types on the Loess Plateau

Study region: The Dongzhi tableland on the loess plateau, China. Study focus: This study investigates how various land use types on the Loess Plateau affect groundwater recharge using the chloride mass balance method (CMB). By integrating data from Cl-, NO3/Cl-, and stable isotopes (delta 18O and delta 2H), the research develops a new approach to estimate the average ion concentration rates in soil profiles. This methodology provides a nuanced understanding of how precipitation infiltration recharges groundwater under different land use scenarios and the impact of land use changes on these processes. New hydrological insights for the region: The research findings highlight significant variations in groundwater recharge rates among different land uses. Grasslands show the highest recharge rate at 26 mm/yr, followed by forests at 23 mm/yr, while shrublands have the lowest at 5 mm/yr. Agricultural lands have moderate recharge rates ranging from 14 to 16 mm/yr. Transitioning from agricultural land to other land uses like shrublands and forests results in dramatic changes in recharge rates, with decreases and increases in recharge of 72% and 61%, respectively. These insights are crucial for developing strategic land-use planning to optimize groundwater recharge and enhance water security on the Loess Plateau. The study emphasizes the need for policies that balance hydrological science and land management to sustain both human livelihoods and ecological continuity.