Singh, Abhay Kumar and Giri, Soma and Chaturvedi, Aaditya (2018) Fluvial Geochemistry of Subarnarekha River basin, India. Journal of Earth System Science, 127 (8). ISSN 0253-4126

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Abstract

The fluvial geochemistry of the Subarnarekha River and its major tributaries has been studied on a seasonal basis in order to assess the geochemical processes that explain the water composition and estimate solute fluxes. The analytical results show the mildly acidic to alkaline nature of the Subarnarekha River water and the dominance of Ca2+Ca2+ and Na+Na+ in cationic and HCO−3HCO3− and Cl−Cl− in anionic composition. Minimum ionic concentration during the monsoon and maximum concentration in the pre-monsoon seasons reflect concentrating effects due to decrease in the river discharge and increase in the base flow contribution during the pre-monsoon and dilution effects of atmospheric precipitation in the monsoon season. The solute acquisition processes are mainly controlled by weathering of rocks, with minor contribution from marine and anthropogenic sources. Higher contribution of alkaline earth (Ca2++Mg2+)(Ca2++Mg2+)to the total cations (TZ+)(TZ+) and high (Na++K+)/Cl−(Na++K+)/Cl−, (Na++K+)/TZ+(Na++K+)/TZ+, HCO−3/(SO2−4+Cl−)HCO3−/(SO42−+Cl−) and low (Ca2++Mg2+)/(Na++K+)(Ca2++Mg2+)/(Na++K+) equivalent ratios suggest that the Subarnarekha River water is under the combined influence of carbonate and silicate weathering. The river water is undersaturated with respect to dolomite and calcite during the post-monsoon and monsoon seasons and oversaturated in the pre-monsoon season. The pH–log H4SiO4H4SiO4 stability diagram demonstrates that the water chemistry is in equilibrium with the kaolinite. The Subarnarekha River annually delivered 1.477×1061.477×106 ton of dissolved loads to the Bay of Bengal, with an estimated chemical denudation rate of 77 ton km−2 yr−177 ton km−2 yr−1. Sodium adsorption ratio, residual sodium carbonate and per cent sodium values placed the studied river water in the ‘excellent to good quality’ category and it can be safely used for irrigation.

Item Type:	Article
Uncontrolled Keywords:	Subarnarekha River basin weathering solute acquisition dissolved flux saturation index water quality
Subjects:	Envieronmental Management Group
Divisions:	UNSPECIFIED
Depositing User:	Mr. B. R. Panduranga
Date Deposited:	20 Nov 2018 10:15
Last Modified:	20 Nov 2018 10:15
URI:	http://cimfr.csircentral.net/id/eprint/1943

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