Geochemical Characterization and Evolution of Groundwater in Parts of Kashmir Valley, Western Himalaya

The present study describes the hydrogeochemistry and chemical evolution of groundwater in parts of Srinagar and Ganderbal districts of Kashmir valley, Western Himalaya. A systematic and seasonal groundwater sampling from bore wells, dug wells and springs was carried out during December 2004 (premelting season) and June-July 2005 (post melting season). A total of 140 samples were collected to assess the physico-chemical characteristics, sources of major ions (Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42− and NO3−), chemical evolution and quality of the groundwater. On the basis of chemical characterization, three groups of groundwater were identified and designated as G-I, G-II and G-III respectively. The G-I indicated the abundance of Ca2+, Mg2+ and HCO3− ions, thereby, indicating the dissolution of mainly carbonates whereas the G-II revealed also the abundance of Na+ ions that indicated the influence of weathering and dissolution of primary/or secondary silicates in the area. The G-III, although similar to G-II indicated a feeble enrichment of Cl− content in addition to Na+ that is attributed to anthropogenic sources. Thus, the G-I and G-II indicated dominantly a lithological control on the source of major ions whereas, the enrichment of Cl− ions in G-III documented the control of anthropogenic factors (a non-lithological control) as well. Further, the chemical imprint taken by groundwater through a complex interplay of hydrogeological processes, flow patterns and higher time of residence of ions in aquifer matrix characterized the groundwater dominantly as of primary facies type (i.e., Ca-HCO3 and Ca-Mg-HCO3 water types). The secondary facies/hybrid types (i.e., Ca-Mg-Na-HCO3 and Ca-Mg-Na-HCO3-Cl water types) were also present at places in the area. Overall, the chemical characteristics of groundwater indicated that the groundwater has largely retained its meteoric character that is suitable for domestic uses and the system is in its primary stage of evolution with a limited migratory history. Further, the predominance of bicarbonate waters documented the existence of open nature of groundwater system in the area.