Publications des scientifiques de l'IRD

Buvaneshwari S., Riotte Jean, Sekhar M., Kumar M. S. M., Sharma A. K., Duprey J. L., Audry S., Giriraja P. R., Praveenkumarreddy Y., Moger H., Durand P., Braun Jean-Jacques, Ruiz Laurent. (2017). Groundwater resource vulnerability and spatial variability of nitrate contamination : insights from high density tubewell monitoring in a hard rock aquifer. Science of the Total Environment, 579, p. 838-847. ISSN 0048-9697.

Titre du document
Groundwater resource vulnerability and spatial variability of nitrate contamination : insights from high density tubewell monitoring in a hard rock aquifer
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000391897800086
Auteurs
Buvaneshwari S., Riotte Jean, Sekhar M., Kumar M. S. M., Sharma A. K., Duprey J. L., Audry S., Giriraja P. R., Praveenkumarreddy Y., Moger H., Durand P., Braun Jean-Jacques, Ruiz Laurent
Source
Science of the Total Environment, 2017, 579, p. 838-847 ISSN 0048-9697
Agriculture has been increasingly relying on groundwater irrigation for the last decades, leading to severe groundwater depletion and/or nitrate contamination. Understanding the links between nitrate concentration and groundwater resource is a prerequisite for assessing the sustainability of irrigated systems. The Berambadi catchment (ORE-BVET/Kabini Critical Zone Observatory) in Southern India is a typical example of intensive irrigated agriculture and then an ideal site to study the relative influences of land use, management practices and aquifer properties on NO3 spatial distribution in groundwater. The monitoring of >200 tube wells revealed nitrate concentrations from I to 360 mg/L. Three configurations of groundwater level and elevation gradient were identified: i) NO3 hot spots associated to deep groundwater levels (30-60.m) and low groundwater elevation gradient suggest small groundwater reserve with absence of lateral flow, then degradation of groundwater quality due to recycling through pumping and return flow; ii) high groundwater elevation gradient, moderate NO3 concentrations suggest that significant lateral flow prevented NO3 enrichment; iii) low NO3 concentrations, low groundwater elevation gradient and shallow groundwater indicate a large reserve. We propose that mapping groundwater level and gradient could be used to delineate zones vulnerable to agriculture intensification in catchments where groundwater from low-yielding aquifers is the only source of irrigation. Then, wells located in low groundwater elevation gradient zones are likely to be suitable for assessing the impacts of local agricultural systems, while wells located in zones with high elevation gradient would reflect the average groundwater quality of the catchment, and hence should be used for regional mapping of groundwater quality. Irrigatiori with NO3 concentrated groundwater induces a "hidden" input of nitrogen to the crop which can reach 200 kgN/ha/yr in hotspot areas, enhancing groundwater contamination. Such fluxes, once taken into account in fertilizer management, would allow optimizing fertilizer consumption and mitigate high nitrate concentrations in groundwater.
Plan de classement
Pollution [038] ; Hydrologie [062] ; Sciences du monde végétal [076]
Description Géographique
INDE
Localisation
Fonds IRD [F B010068920]
Identifiant IRD
fdi:010068920
Contact