In drylands, the scarcity of streams and their temporal variability have led to a particular interest forgroundwater. The alluvial fans describe complex sedimentary patterns. In order to understand thecurrent and future behavior of groundwater resources, especially under climate change, the rechargeprocesses need to be properly characterized. The study focus on Northern Chile, where high seasonalprecipitation events occur between December and March in the Precordillera (4500 m a.s.l)associated with ENSO variations. These events lead to local flooding above the alluvial fans in thedownstream hyperarid Central Depression (1000 m a.s.l)+ where the regional size Pampa delTamarugal Aquifer is located. This strategic resource is one of the main issues in Northern Chile.Groundwater recharge through the Tarapaca Alluvial Fan (TAF) - around 150 kmC - is assessed bycombining environmental tracers, piezometric records, geomorphic surveys and flow modelling at different scales of space and time. Vertical flows in the vadose zone were assessed by sensitivityanalysis, computed with Hydrus -1D software, at the flood events scale. The saturated flows, at theTAF scale, were assessed by 2D flow modeling (Feflow software). These results are in line with thepiezometric records analysis and highlight contrasted recharge areas, correlated with geomorphicpatterns, implying various recharge rates between few mm.d-1 and mm.yr-1. In some areas, atdistance from the TAF, the recharge can be considered as nil. Groundwater age inferred from 14C(between 14 and 107 pMC) and dating tools (3H He, SF6, CFCs) sampled at the water table depth,are compared with groundwater ages estimated from flows modeling. The assessment ofgroundwater recharge in dryland alluvial fans, need to be quantified by multidisciplinary approaches(environmental tracers, piezometric records, geomorphic surveys, flow modelling) at different scales ofspace and time.