Geospatial approach for assessment of groundwater quality

The increasing population, erratic distribution of rainfall, and their rising demand for water in domestic and irrigation are fulfilled by groundwater resources. Due to overexploitation, there is the deterioration of groundwater quality, and hence to evaluate the groundwater quality, a study was undertaken to understand the water suitability for drinking as well as for irrigation purposes. For this study, five villages, namely Kumulur, Tachankurunchi, Pudurutamanur, Pandaravadai and Poovalur, were selected from Trichy District, Tamil Nadu, India, with an aerial extent of 45.1 -km2. For the water quality assessment, samples were drawn from 53 locations from the sources like open wells, bore wells and hand pumps, etc. Parameters of pH, EC, TDS, Anions- CO -2 3, CO3 (2-), -HCO3-, -Cl-, SO2 (4), Cations-Ca2+, -Mg2+, -B3+, -Na+ and potassium -(K+) were estimated using the standard analytical procedure in three different seasons, viz., S-I (September 2019), S-II (December 2019) and S-III (March 2020). The WQI was computed for drinking water quality and found that 25% of samples in S-I, 80% samples in S-II and 83% samples in S-III were above the permissible limit for drinking purposes. Indices like Sodium Percentage, Sodium Adsorption Ratio, Permeability Index, Kelly's Ratio, Magnesium Hazard Ratio, Potential Salinity, USSL Diagram, Wilcox Plot, Piper Diagram and Gibbs plot were evaluated for examining irrigation water quality. The results revealed that in 90% of the area, the water is suitable for irrigation purposes and a few locations (10%) wherein the salt content of water is relatively higher than the entire study area.