Water quality assessment of river Ujh in district Udhampur, J&K for drinking and agricultural purposes

The present study reveals the water quality of River Ujh, which is originating from South of the Kaplas in Seuj Dhar and flowing through the district Udhampur. The water of this river is used for drinking and agricultural purposes. The objective of this study is to assess the river water's potability using WQI and HPI, and its suitability for irrigation through the following parameters such as Na%, SAR, MAR, Kelly’s Ratio, and Wilcox diagram. The water samples were collected from 22 sites (labelled as UD1-UD7) and analysed using fourteen parameters i.e., pH, EC, TDS, TA (as CaCO3), TH (as CaCO3), Ca2+, Mg2+, Na+, K+, Cl−, NO3−, SO42−, PO43−, and F− to determine the Water Quality Index (WQI). The Heavy-metal Pollution Index (HPI) was determined by analyzing the following heavy-metals: As, Cr, Hg, Pb and Cd. Pre-monsoon WQI revealed that the water from location UD4–UD7 was unfit for drinking due to excessive fluoride levels (4.31 ± 2.45 mg/L), while post-monsoon dilution reduced fluoride levels to 0.86 ± 0.41 mg/L, improving water quality except UD5 reflecting poor water quality status. Piper plots and Durov diagrams highlighted the dominance of Ca2⁺ > Mg2⁺ > Na⁺ + K⁺ and Cl⁻ > HCO₃⁻ > SO₄2⁻ in both the seasons (pre-monsoon and post-monsoon). The Na⁺/(Na⁺ + Ca2⁺) and Cl⁻/(Cl⁻ + HCO₃⁻) ratio indicates that rock-water interaction influences water chemistry, while post-monsoon samples show precipitation dominance due to rainfall and snowfall. During pre-monsoon season, Pearson’s correlation showed negative relationships between pH and most parameters (pH, EC, TDS, TA (as CaCO3), TH (as CaCO3), Ca2+, Mg2+, Cl−, NO3−, SO42−, PO43−, and F−) while post-monsoon correlations were predominantly positive except for PO₄3⁻ and Na⁺. As per HPI, the water samples from from all the locations fall under unfit category for drinking purpose during pre-monsoon season whereas, during post-monsoon season 72% of water samples fall under poor to very poor categories. River water analyzed for agricultural purposes indicates that SAR falls below 10 in both the seasons, making the water to fall in the excellent category for irrigation purpose. The MAR values along with Kelly's Ratio and Wilcox diagram for all the water samples from all the locations analyzed and plotted supports the suitability of water use for agricultural purposes.