Recharge processes in karstic systems at different time scales

Abstract : In karstic systems, the heterogeneity of the transfer processes within the different compartments of the critical zone (soil, epikarst, and saturated zones) controls the recharge -discharge relationship. The MEDYCYSS observatory (Multi scalE observatory of flooD dYnamiCs and hYdrodynamicS in karSt, belonging to OSU OREME and SNO Karst network) has been set up to better understand these transfers under a Mediterranean climatic context. On the Lez karst catchment (South of France), being part of MEDYCYSS, a 333 m deep borehole has been equipped with the PMPS Multi-level monitoring system (SolExperts) in the framework of the CRITEX project. The borehole is located 100 m from an intermittent river and 500 m from the main outlet (Lez Spring) of the aquifer where an intense pumping is performed. Continuous pressure and temperature monitoring is realized at 5 depth levels, isolated by packers, where discrete water sampling are also regularly achieved. The main objective of this monitoring is to assess the different mechanisms of the recharge process at various time scales. The collected data implement the existing spatio-temporal monitoring of the hydrodynamic and geochemical variations followed in bore-holes, karst features (caves and sink-holes), perennial and temporal springs of the karstic aquifer. In this study, we aim at specifying the contribution of the different karst compartments, from the recharge zone towards the main outlets. The results obtained during a one year monitoring show a contrasted hydrodynamic response and underline a pressure transfer between compartments, surface water and karst flow. Assessed by temperature monitoring, the hydrochemistry shows a stable water composition for each compartment of the bore-hole, in contrast with the high variability and water mixing identified at the Lez spring. These new data are essential to better assess the recharge processes and specify the role of the vadose zone in the flow organization at short and long timescale.
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Poster
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https://hal.umontpellier.fr/hal-02122773
Contributeur : Pascale Roussel <>
Soumis le : mardi 7 mai 2019 - 15:11:42
Dernière modification le : mardi 28 mai 2019 - 13:48:10

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  • HAL Id : hal-02122773, version 1

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Xavier Durepaire, Christelle Batiot-Guilhe, Jean Luc Seidel. Recharge processes in karstic systems at different time scales. 43rd IAH International Congress “Groundwater and society : 60 years of IAH”, Sep 2016, Montpellier, France. ⟨hal-02122773⟩

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