Groundwater Quality Assessment for Sustainable Water Management In Semi-Arid Chitradurga District, Karnataka

Groundwater pollution reduces water quality and negatively impacts human wellbeing, social and economic development, and agricultural land value. Therefore, to evaluate the pre-monsoon groundwater quality in Chitradurga district, Karnataka, 55 randomly collected pre-monsoon (February- March, 2023 & 2024) bore well water samples from farmlands across different villages in Hiriyur, Hosadurga, Challakere, Chitradurga, Molakalmuru, and Holalkere taluks were analyzed for pH, EC, Ca, Mg, Na, K, SO , CO , HCO , Cl, and B. The samples were also tested 4 3 3 for Total Hardness (TH), Total Dissolved Salts (TDS), Soluble Sodium Percentage (SSP), Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Kelley' s Index (KI), Permeability Index (PI), Magnesium Hazard (MH), Potential Salinity (PS), and Water Quality Index (WQI). Results showed that WQI ranged from 30 to 81, with 87% of samples recording less than 50, indicating excellent water quality; 13% recorded between 51 and 81, indicating good quality for drinking. Similarly, irrigation suitability revealed that SAR indicates excellent to good. SSP indicates good to poor, RSC indicates good to bad, and PI indicates good. KI indicates permissible to non-permissible. The MH ranged from 60-98.65, indicates 100 % of water samples are non-acceptable. PS indicates excellent to good and to injurious. It was concluded that for drinking water samples are excellent to good. For irrigation, 66 % of water samples need to be treated before irrigation to cropland to control soil sodicity and salinity, sodium and sodium carbonates hazards, as it recorded RSC >2.5. Also, 100% of groundwater samples are found to have magnesium hazard, thus it leads to alkalinity/sodicity upon irrigation, which needs suitable irrigation water management practices, thereby elevating crop production and productivity and maintaining soil health and quality, besides controlling chemical land degradation.