HYDROGEOCHEMICAL CHARACTERIZATION OF GLACIAL-FED SURFACE WATER RESOURCES IN THE CATCHMENT AREAS OF UPPER INDUS BASIN

Abstract

The current study focuses to examine the Physio-chemical parameters of the glacially-fed water resources in the elevated areas of Gilgi t-Baltistan, Pakistan. The glaciall y fed streams are the primary source for drinking and ilTigation in the entire region. The evaluation of quality of such streams is particularly important because it helps to understand the geochemical processes that take part in changing the geochemistry of water on a regional basis. In this research work, total 40 water samples fro m different glacier-fed streams were obtained following the standard practices. The in-situ testing of all the field samples were carried for temperature, pH, TDS, and Conductivity by using different apparatuses. Later, the water samples were brought to th e laboratory to perform the other major geochemical tests for characterization following standard procedures. The tests data of the geochemical parameters for all the water samples collected from the study region was tabulated and the variation in the physic-chemical parameters including Conductivity, Turbidity, pH, TDS, Hardness, Ca2+, K+, Mg2+, Na+, Cl-, S04-, NO}-, Pb, Cd, Cu, Zn, Fe, Mn, As, Cr and Hg was measured and analyzed their fitness for drinking and irrigation. To meet the study objectives different hydro-chemical and hydro-geostatistical analyses including WQI, HPI, Gibbs Plot, Piper Plot, Ionic ratios and irrigation suitability water quality data were compared to WHO's worldwide water quality standards. The water quality of the shldy area is classified as excellent (50%), good (32.5%), and medium (17.5%) based on WQI values. Heavy metal pollution index (HPT) values are found far below the critical values, indicating safe for human consumption in terms of heavy metal pollution. Furthermore, the study found water quality was found suitable for irrigation purposes in tenTlS of all irrigation quality parameters. According to Gibbs plot and ionic ratios, rock weathering is dominant especially carbonate weathering with li ttle contribution of v sili cate rocks in controlling the water chemistry. Piper plot for study area also revealed carbonate rocks as dominant geochemical facies and classified the water types as Ca HC03, Mixed Ca-Mg-Cl, Ca-CI, and Ca-Na-HC03 type.