Présentations Colloques

Poster
6.03
Session 6.03: Innovative tools to improve understanding of groundwater recharge processes
Nicolas Madeleine Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. India Chandra Subash Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. India Choudhury Joy Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. India Bour Olivier Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. France Selles Adrien Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser. India Maréchal Jean-Christophe jc.mar
Constraining the impact of weathering intensity, its associated heterogeneities and climate on recharge processes using non-invasive geophysical methods on a crystalline fractured aquifer in a semi-arid environment
In arid and semi-arid environments, hard-rock aquifers often constitute the only perennial source of freshwater. The short-term and long-term viability of these groundwater resources as well as the ecosystems and livelihoods they sustain depend on the replenishment of groundwater by recharge. The aim of this study is to improve the understanding on recharge processes by analysing cross-scale recharge processes (both natural and artificial) in a hard-rock aquifer in Southern India. Here, we take advantage of a well-studied site where a dense observation network and boreholes are available to test the contribution of non-intrusive methods such as electrical resistivity tomograph. First, the mapping of the critical zone was performed by implementing electrical resistivity tomography profiling at different key locations on the selected study zone, which were chosen to represent the range of weathering observable at the catchment scale. Then, in order to link the shape and thickness of the critical zone to recharge, subsequent ERT profiling has been performed at the same locations after recharge events. The ratio between the resistivity before and after these events will be an indicator of the entering or exiting of water into the system. Finally, it will be necessary to link qualitative information of recharge distribution to actual recharge values. It is important to note that all quantitative relationships established between structure and recharge will be thoroughly tested at our densely equipped experimental hydrological park. This should allow us to constrain and quantify the modalities involved in the recharge process, and obtain relationships which can be extrapolated onto further research zones using non-invasive methods. The obtained results will be compared with classical methods to estimate the accuracy of our methodology. This final aim of our study is to improve the understanding of the links between structure, climate and recharge in hard-rock aquifers under semi-arid climates, and allow easier estimation of recharge distribution and quantification in order to ameliorate groundwater management and decision-making processes.