Piece 3 - Recharge
How does water enter the aquifer?
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Recharge is one of the most difficult components of the groundwater budget to quantify in semi-arid crystalline aquifers.
The double water table fluctuation method
A two-step method combining groundwater budgets and water-table fluctuations: the dry season is used to estimate specific yield, while the wet-season water-table rise is then converted into natural groundwater recharge.
Key findings
- Groundwater recharge can be quantified from long-term water-table fluctuations, using complementary approaches such as the Double Water Table Fluctuation and groundwater budget methods.
- Recharge is highly seasonal, closely linked to the monsoon rainfall regime in the semi-arid crystalline-rock aquifers of southern India.
- Recharge is spatially heterogeneous, reflecting the strong heterogeneity of the weathered and fractured profile.
- Fracture distribution strongly controls recharge pathways, with preferential infiltration occurring where fractures provide hydraulic connections between the surface and the transmissive fractured layer.
- The weathered zone plays a dual role, acting both as a temporary groundwater storage reservoir and as a buffer controlling the transfer of recharge towards the underlying fractured aquifer.
- Borehole observations revealed distinct recharge dynamics and flow paths, providing a basis for understanding how artificial recharge structures interact with the heterogeneous crystalline aquifer.
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Managed aquifer recharge
From natural recharge to managed rechargeThe understanding of infiltration and groundwater storage was also applied to artificial/managed recharge in fractured basement aquifers.
Managed aquifer recharge (MAR) can enhance groundwater replenishment, but its efficiency depends strongly on the local hydrogeological structure and connectivity of the fractured zone. Your work included both the assessment of recharge structures and their long-term sustainability.
Recharge cannot be represented as a uniform flux: it depends on climate, land use, soil properties, topography and preferential infiltration pathways.
Key publications
Jean-Christophe Maréchal, Pierre Perrochet, Yvan Caballero
Hydrogeology Journal, vol. 31, 2023 Nov, pp. 1991--1995
Mapping Economic Feasibility of Managed Aquifer Recharge
Jean-Christophe Maréchal, Madjid Bouzit, Jean-Daniel Rinaudo, Fanny Moiroux, Jean-François Desprats, Yvan Caballero
Water, vol. 12, 2020
Laurent Ruiz, Murari R.R. Varma, M. S.Mohan Kumar, M. Sekhar, Jean-Christophe Maréchal, Marc Descloitres, Jean Riotte, Sat Kumar, C. Kumar, Jean Jacques Braun
Journal of Hydrology, vol. 380, 2010 Jan, pp. 460--472
Indirect and direct recharges in a tropical forested watershed: Mule Hole, India
Jean-Christophe Maréchal, Murari R R Varma, Jean Riotte, Jean-Michel Vouillamoz, M S Mohan Kumar, Laurent Ruiz, Muddu Sekhar, Jean-Jacques Braun
Journal of Hydrology, vol. 364, 2009 Jan, pp. 272--284
Jean-Christophe Maréchal, Benoit Dewandel, Shakeel Ahmed, Laurent Galeazzi, Faizal K Zaidi
Journal of Hydrology, vol. 329, 2006 Sep, pp. 281--293