Hydrogeochemical assessment and quality evaluation of spring water for drinking and irrigation purposes in lower Shivalik Himalayan region

The spring water sources in the Himalayan foothills are a key source of drinking and irrigation water but are being overrun by urbanization, land-use development, and weather variation. It is an assessment of hydrochemical properties and applicability of five significant springs of the Dehradun district, Uttarakhand, in the winter, when surface recharge is low and geochemical processes in the aquifer are controlled. Fifteen physicochemical parameters were determined according to the standard procedures, and the quality of water was determined using the Water Quality Index (WQI), Sodium Adsorption Ratio (SAR), and sodium percentage (%Na). The Piper diagrams and Principal Component Analysis (PCA) were used to interpret hydrochemical facies and controlling processes. The findings suggest that the spring waters are moderately alkaline to moderately acidic, highly oxygenated, and of low organic pollution. The predominant ion chemistry is Ca²⁺, Mg²⁺, and HCO₃ ions, indicating the dissolution of carbonates and weathering of silicates are the main geochemical processes. The values of the springs in the classification of WQI categorize them as excellent and good to drink, and SAR and the values of the percentage of Na verify that they can be used in irrigation. The multivariate analysis shows that lithological control is the main cause of water chemistry, and there are only found to be localized anthropogenic effects. The paper highlights the relevance of geogenic processes to influence the quality of spring water and continues to reiterate the fact that these freshwater resources in the Himalayan region, which are vital, require regular monitoring and sustainable care.