Assessment of Temporal Variation in Hydrogeochemical Facies of River Water in the Central Himalayan Region

The water quality of a region is greatly influenced by the environment and its quality is a function of rock-water interaction and anthropogenic processes. 90% of the rural population of Uttarakhand depends on rivers and springs sources for their daily uses. Therefore, water characterisation and monitoring over time is important for human health and aquatic life. The basic understanding of hydrochemistry can be extracted by a trilinear piper diagram. The study also intends to develop hydro-chemical analysis for water quality at various locations in Uttarakhand to represent four major river catchments. The study attempted over 50 locations from 2010 to 2019 during pre and post-monsoon seasons. Four anions and four cations were used to understand hydrogeochemical facies. Result reveals that the most dominant hydrogeochemical facies were Ca-Mg-HCO₃ in the entire region followed by Ca-Mg-Cl or Ca-Mg-SO₄ facies due to limestone-dominant geology. Na-Cl or Na-SO₄ facies enhanced due to agriculture activities while NaHCO₃ facies due to the rapid weathering processes along the river course over the period. The study recommended for the area where the water type is either Na-Cl or Na-SO₄ or Na-HCO₃, intensive water resource planning should be implemented. These areas are highly vulnerable to human health costs.