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International audienceDue to extensive irrigation, most crystalline aquifers of south India are overexploited. Aquifer structure consists of an upper weathered saprolite followed by a fractured zone whose fracture density decreases with depth. To achieve sustainable management, the evolution of hydrodynamic parameters (transmissivity and storage coefficient) by depth in the south Indian context should be quantified. Falling-head borehole permeameter tests, injection tests, flowmeter profiles, single-packer tests and pumping tests were carried out in the unsaturated saprolite and saturated fractured granite. Results show that the saprolite is poorly transmissive (T fs = 3 × 10–7 to 8.5 × 10–8 m2 s–1) and that the most conductive part of the aquifer corresponds to the bottom of the saprolite and the upper part of the fractured rock (T = 1.0 × 10–3 to 7.0 × 10–4 m2 s–1). The transmissivity along the profile is mostly controlled by two distinct conductive zones without apparent vertical hydraulic connection. The transmissivity and storage coefficient both decrease with depth depending on the saturation of the main fracture zones, and boreholes are not exploitable after a certain depth (27.5 m on the investigated section). The numerous investigations performed allow a complete quantification with depth of the hydrodynamic parameters along the weathering profile, and a conceptual model is presented. Hydrograph observations (4 years) are shown to be relevant as a first-order characterization of the media and diffusivity evolution with depth. The evolution of these hydrodynamic parameters along the profile has a great impact on groundwater prospecting, exploitation and transport properties in such crystalline rock aquifers

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The present study focuses on the hydrodynamic characterization of the Lez karst aquifer (Southern France) on the basis of hydraulic field tests performed at different scales of space and under distinct hydrological conditions. Depending on the water level conditions, the organization of the flow paths linked to the geological structure of the reservoir changes and a compartmentalization of the system due the hierarchization of hydraulic connections to the main flow paths was assessed. For the same parameter characterized at borehole scale and at regional scale, a difference of 10-10 5 has been quantified. This quantification of hydrodynamic parameters provides important constraints on multiscale modeling and the characterization of main flow paths in such a karst system.