Hydrogeochemical Evaluation of Groundwater in a Micro-Watershed of Ranganadi River Basin in Arunachal Himalaya

Water is critical for maintaining ecological and environmental equilibrium, as well as meeting drinking, agricultural, and industrial needs. This study focuses on to map the springs and assess their water quality for drinking as well as agricultural use in a micro watershed in the Ranganadi river basin in Arunachal Pradesh, Northeast India. A total of 64 springs were analyzed for their Water Quality Index (WQI), revealing that 30 springs fall under the “good”category while 28 are categorized as “poor.” Spatial distribution maps of WQI indicated significant variability in groundwater quality, identifying regions with poor WQI that require immediate attention and further investigation. The pH levels in the study area are moderately acidic to basic, with 79.69% of the samples within the permissible range. The dominant geochemical composition of water includes Ca–Cl, Na–Cl, mixed Ca–Mg–Cl, and Mg–HCO₃ types, constituting 39.06, 31.25, 26.56, and 3.12% of the samples, respectively. Hydrochemical facies highlighted the dominance of alkaline elements over alkali (Ca + Mg > Na + K) and strong acidic anions over weak acidic anions (Cl + SO₄ > HCO₃). Irrigation feasibility was evaluated using parameters such as SAR, RSC, MH, %Na, PI, and KR. The SAR analysis showed that all samples are excellent for irrigation. The Wilcox, USSL diagrams, RSC, KR, and PI indicated all samples are suitable for irrigation and appropriate for irrigation purposes. The above findings suggest that a significant portion of the groundwater is suitable for sustainable agricultural practices. This study enhances understanding of groundwater sources and quality for the well-being of the local communities and safeguarding the environment.