Altitude effect on deuterium isotopic composition of lakes and hydrogeochemical parameters of groundwater in humid and semi arid regions

Abstract

Lakes are bodies of water, where flow from one or several rivers is impounded by a natural obstacle.
Groundwater is an important component of lake budgets. In this study, isotope footprint compositions and analysis of
hydrogeochemical parameters of Ooty lake (2,220m above MSL), Pookode lake (770m above MSL), Mananchira lake
(20m above MSL) and Kollam Chira lake (1m below MSL) are carried out. The impacts of altitude effect on the isotopic
composition in lakes are assessed. The water type and water mixing patterns of lakes and wells were identified from the
hydrogeochemical data. The stable hydrogen isotope composition of the lakes and ground waters was determined. The
isotopic results show a vivid relationship with altitude which closely approaches a linear correlation. The precipitation
and surface waters become increasingly depleted in deuterium with increasing altitude and decreasing temperature. The
lake waters at high elevations on the leeward side of mountain ranges are strongly depleted in deuterium as compared to
waters on the windward side. Continental effect is also clearly visible in this study. There is observed a higher depletion
of isotopes in water samples from Ooty lake, which is farthest from the Calicut coast.