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| Titel |
Managed aquifer recharge in weathered crystalline basement aquifers in India: Monitoring of the effect of tank infiltration on water quality over several monsoon events |
| VerfasserIn |
Marina Alazard, Alexandre Boisson, Jean-Christophe Maréchal, Benoît Dewandel, Jerome Perrin, Marie Pettenati, Géraldine Picot-Colbeaux, Shakeel Ahmed, Dominique Thiéry, Wolfram Kloppmann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107115
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| Publikation (Nr.) |
 EGU/EGU2015-6807.pdf |
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| Zusammenfassung |
| Managed aquifer recharge (MAR) structures like percolation tanks are considered by the
Indian national and regional governments as major option for tackling declining groundwater
levels due to overexploitation for irrigation purposes (Boisson et al., 2014). Their main
purpose is to restore groundwater availability under strong climatic and anthropogenic
pressure. Furthermore, MAR-induced dilution with fresh surface water is generally expected
to improve groundwater quality with respect to both anthropogenic and geogenic
contaminants (total mineralisation, nitrates, chlorides, sulphates and fluoride contents). The
impact of a percolation tank on groundwater quality was investigated in a context that is
typical for hydro-climatic and geological settings in southern and eastern India:
fractured crystalline basement aquifers overlain by a weathering zone under semi-arid
climate. Water level data and geochemical indicators (stable isotopes and major ions)
were monitored for both groundwater and surface water, over several successive
monsoon events. In case of high to very high water levels, the groundwater quality is
globally improved. However, in a few cases, the quality of the groundwater can be
negatively impacted due to leaching of salts under the tank, particularly during
the first rain events of the monsoon. Geogenic fluoride contents in groundwater,
induced by water-rock interaction and enhanced by recycling of agricultural return
flow under paddy fields, is found to be relatively stable over the year. This finding
points out that the underlying processes, mainly dissolution of F-bearing phases
like fluorapatites combined with Ca/Na cation exchange and calcite precipitation,
both limiting the possibility of F-removal via fluorite precipitation (Pettenati et al.,
2013, 2014), are not impacted by the hydrological conditions. This work highlights
the complexity of the recharge processes in crystalline aquifers, enhanced by the
variability of hydrological conditions. It also provides insights into the possible
risk for groundwater quality deterioration in cases of light and short monsoons
periods.
This research was conducted within the framework of the Saph Pani project and
co-financed by the European Commission within the Seventh Framework Programme, grant
agreement No. 282911 and the Research Division of BRGM.
Boisson A., Villesseche D., Baisset M., Perrin J., Viossanges M., Kloppmann W.,
Chandra S., Dewandel B., Picot-Colbeaux G., Rangarajan R., Maréchal J. C., and
Ahmed S. (2014) Questioning the impact and sustainability of percolation tanks as
aquifer recharge structures in semi-arid crystalline context. Environ Earth Sci., DOI
10.1007/s12665-014-3229-2.
Pettenati M., Perrin J., Pauwels H., and Ahmed S. (2013) Simulating fluoride evolution in
groundwater using a reactive multicomponent transient transport model: Application to a
crystalline aquifer of Southern India. Appl. Geochem. 29, 102-116.
Pettenati M., Picot-Colbeaux G., Thiéry D., Boisson A., Alazard M., Perrin J., Dewandel
B., Maréchal J.-C., Ahmed S., and Kloppmann W. (2014) Water Quality Evolution During
Managed Aquifer Recharge (MAR) in Indian Crystalline Basement Aquifers: Reactive
Transport Modeling in the Critical Zone. Procedia Earth and Planetary Science 10, 82-87. |
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