3534 20180516091154.0 10.1002/hyp.13138 DOI SCART-2018-0050 Poulain, Amaël Assessment of groundwater recharge processes through karst vadose zone by cave percolation monitoring 2018 KARAG project Recharge processes of karst aquifers are difficult to assess given their strong heterogeneity and the poorly known effect of vadose zone on infiltration. However, recharge assessment is crucial for the evaluation of groundwater resources. Moreover, the vulnerability of karst aquifers depends on vadose zone behavior since it is the place where most contamination take place. In this work, an in situ experimental approach was performed to identify and quantify flow and storage processes occurring in karst vadose zone. Cave percolation monitoring and dye tracing were used to investigate unsaturated zone hydrological processes. Two flow components (diffuse and quick) were identified and respectively account for 66 and 34% of the recharge. Quickflow was found to be the result of bypass phenomenon in vadose zone related to water saturation. We identify the role of epikarst as a shunting area, most of the storage in the vadose zone occurring via the diffuse flow component in low permeability zones. Relationship between rainfall intensity and transit velocity was demonstrated, with 5 time higher velocities for the quick recharge mode than the diffuse mode. Modelling approach with KarstMod software allowed to simulate the hybrid recharge through vadose zone and shows promising chances to properly assess the recharge processes in karst aquifer based on simple physical models. FRS-FNRS/ FRS-FNRS/ FRS-FNRS NO Karst aquifer Vadose zone Cave monitoring Dye tracing Stalactite drip Groundwater recharge Epikarst Watlet, Arnaud Kaufmann, Olivier Van Camp, Michel Jourde, Hervé Mazzilli, Naomi Rochez, Gaëtan Deleu, Romain Quinif, Yves Hallet, Vincent Hydrological Processes 2018 michel.vancamp@observatoire.be https://onlinelibrary.wiley.com/doi/pdf/10.1002/hyp.13138 published in REFERD