Groundwater-recharge estimation in the Ordos Plateau, China: comparison of methodsEstimation de la recharge en eau souterraine dans le plateau d’Ordos, Chine: Comparaison de méthodesEstimación de la recarga de agua subterránea en el Ordos Plateau, China: comparación de métodos中国鄂尔多斯高原地下水补给估算:方法的比较Estimação da recarga de águas subterrâneas no Planalto de Ordos, China: comparação de métodos

Groundwater recharge is a key factor in water-balance studies, especially in (semi-)arid areas. In this study, multiple methods were used to estimate groundwater recharge in the Ordos Plateau (China), including reference to water-table fluctuation, Darcy’s law and the water budget. The mean annual recharge rates found were: water-table-fluctuation method (46–109 mm/yr); saturated-zone Darcian method (17–54 mm/yr); and water-budget method (21–109 mm/yr). Generally, groundwater-recharge rates are higher in the eastern part of the plateau where the land surface is covered by permeable sand that is favorable for infiltration. Along with results from previous studies using the empirical method, the chloride-mass-balance method, the unsaturated-zone Darcian method and the hydrograph-separation method, groundwater recharge rates were compared. There is no one method that would consistently produce the largest or smallest estimate of annual recharge for all groundwater systems. The largest recharge estimates were usually determined using the unsaturated-zone Darcian method and the smallest estimates were usually determined using the chloride-mass-balance method. Comparison of multiple methods is found to be valuable for determining the range of plausible recharge rates and for highlighting the uncertainty of the estimates.