Understanding Spatio-Temporal Variability in Spring Water Hydrogeochemistry of the Chakrata Region, Lesser Himalaya, India

The Chakrata region in the Lesser Himalayas of Uttarakhand, India, is characterized by complex lithology, steep topography, and a strong dependence of local communities on natural springs for domestic and agricultural water supply. This study investigates the hydrogeochemical characteristics, controlling processes, and drinking-water suitability of representative springs across the region. The results suggest that the spring water is fresh, transparent, and odorless in nature. The results suggest that surface water is slightly acidic to highly alkaline in nature (pH: 6.7 to 9.02) and moderately mineralized (TDS: 8 to 252 mg L-1and EC:16 to 503 µS/cm). The temperature of springs water varied from 6.5˚C to 26˚C, which depends on the ambient temperature of the infiltrating water, thermal conductivity of reservoir rocks and groundwater movement along with its residence period.The major ionic composition followed the order Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃⁻ > SO₄²⁻ > Cl⁻ > F⁻, with Ca–HCO₃ and Ca–Mg–HCO₃ as dominant water facies. Various trace elements such as Al, As, Ba, B, Cr, Cu, Li, and Sr found in the spring water samples that contribute to its mineral profile and potential health benefits. Gibbs plot reveals that rock–water interaction, particularly the dissolution of carbonate and silicate minerals, primarily controls the chemistry of spring water. The LULC raster was clipped using WQI zone boundaries, and class-wise area statistics were computed. Zone III (WQI 18–47), is dominated by forest cover (~68.1%) and rangeland (~30.7%), while built-up areas (~0.2%), water bodies (~0.7%), bare land (~0.09%), and agriculture (~0.002%). Similar LULC patterns were observed in Zones I and II. Most samples fall within the permissible limits of BIS (2012) and WHO (2011) standards, indicating good to excellent water quality, although localized chloride enrichment suggest minor anthropogenic influence. The study provides critical baseline data for sustainable spring management and highlights the importance of lithology and recharge dynamics in governing spring water chemistry in the Lesser Himalayan region.