• Nadeem A Bhat

      Articles written in Journal of Earth System Science

    • Geochemical characterization of surface water and spring water in SE Kashmir Valley, western Himalaya: Implications to water–rock interaction

      Gh Jeelani Nadeem A Bhat K Shivanna M Y Bhat

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      Water samples from precipitation, glacier melt, snow melt, glacial lake, streams and karst springs were collected across SE of Kashmir Valley, to understand the hydrogeochemical processes governing the evolution of the water in a natural and non-industrial area of western Himalayas. The time series data on solute chemistry suggest that the hydrochemical processes controlling the chemistry of spring waters is more complex than the surface water. This is attributed to more time available for infiltrating water to interact with the diverse host lithology. Total dissolved solids (TDS), in general, increases with decrease in altitude. However, high TDS of some streams at higher altitudes and low TDS of some springs at lower altitudes indicated contribution of high TDS waters from glacial lakes and low TDS waters from streams, respectively. The results show that some karst springs are recharged by surface water; Achabalnag by the Bringi stream and Andernag and Martandnag by the Liddar stream. Calcite dissolution, dedolomitization and silicate weathering were found to be the main processes controlling the chemistry of the spring waters and calcite dissolution as the dominant process in controlling the chemistry of the surface waters. The spring waters were undersaturated with respect to calcite and dolomite in most of the seasons except in November, which is attributed to the replenishment of the CO2 by recharging waters during most of the seasons.

    • Delineation of the recharge areas and distinguishing the sources of karst springs in Bringi watershed, Kashmir Himalayas using hydrochemistry and environmental isotopes

      Nadeem A Bhat Gh Jeelani

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      Water samples were collected from precipitation, streams and karst springs of the mountainous Bringi catchment of Kashmir Himalayas for major ions, stable isotopes (𝛿18O and 𝛿D) and 3H analysis. The main objective is to identify the potential recharge area for karst springs. The water in the Triassic limestone aquifer of the Bringi watershed is characterized by low levels of mineralization with TDS of the spring water samples ranging between 99 and 222 mg/l except the Kongamnag spring, which contained TDS up to 425 mg/l. As expected in an area with dominant carbonate lithology, Ca–HCO3 and Ca–Mg–HCO3 hydrochemical facies were found. Based on the amount weighed monthly averages (𝑛 = 6), the local meteoric water line (LMWL) for Bringi watershed is 𝛿D = 7.7 ×𝛿18O + 11.1 (𝑟2 = 0.99). The isotopic signature of winter precipitation is reflected in stream and spring water in late spring and is therefore, a representative of snow melting. The spring waters in September bear the 𝛿2H and 𝛿18O enriched isotopic signatures of summer rainfall. With the help of the local vertical isotopic gradient of precipitation (𝛿18O = −0.27‰ per 100 m increase in elevation), the mean elevation of precipitation that recharged the aquifer is estimated and ranges about 2500–2900 m amsl. There is a very strong correlation (𝑟2 = 0.97) between the seasonal isotope composition of streams and springs, indicating that streams and springs either share similar catchments or the springs are recharged by the streams.

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