Sources of major ions and processes affecting the geochemical and isotopic signatures of subsurface waters along a tropical river, Southwestern India

Gurumurthy, GP and Balakrishna, K and Tripti, M and Riotte, Jean and Audry, Stephane and Braun, Jean-Jacques and Lambs, Luc and Shankar, Udaya HN (2015) Sources of major ions and processes affecting the geochemical and isotopic signatures of subsurface waters along a tropical river, Southwestern India. In: ENVIRONMENTAL EARTH SCIENCES, 73 (1). pp. 333-346.

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Abstract

Systematic monitoring of subsurface hydrogeochemistry has been carried out for a period of one year in a humid tropical region along the Nethravati-Gurupur River. The major ion and stable isotope (delta O-18 and delta H-2) compositions are used to understand the hydrogeochemistry of groundwater and its interaction with surface water. In the study, it is observed that intense weathering of source rocks is the major source of chemical elements to the surface and subsurface waters. In addition, agricultural activities and atmospheric contributions also control the major ion chemistry of water in the study area. There is a clear seasonality in the groundwater chemistry, which is related to the recharge and discharge of the hydrological system. On a temporal scale, there is a decrease in major cation concentrations during the monsoon which is a result of dilution of sources from the weathering of rock minerals, and an increase in anion concentrations which is contributed by the atmosphere, accompanied by an increase in water level during the monsoon. The stable isotope composition indicates that groundwater in the basin is of meteoric origin and recharged directly from the local precipitation during the monsoonal season. Soon after the monsoon, groundwater and surface water mix in the subsurface region. The groundwater feeds the surface water during the lean river flow season.

Item Type:	Journal Article
Publication:	ENVIRONMENTAL EARTH SCIENCES
Publisher:	SPRINGER
Additional Information:	Copy right for this article belongs to the SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
Keywords:	Major ions; Stable isotopes; Groundwater chemistry; Nethravati-Gurupur catchment; Southwestern India
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	20 Feb 2015 12:01
Last Modified:	20 Feb 2015 12:01
URI:	http://eprints.iisc.ac.in/id/eprint/50835

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