Spatial distribution of groundwater quality indices using decision support system in Cheyyeru Watershed, YSR District, India

Abstract

Due to industrialization and overblown population, the quality of groundwater has become an issue of major concern at global level. Groundwater Quality Index (GWQI), a technique of rating water quality, is an effective tool to assess spatial and temporal changes. Water samples collected from fourteen well locations and analyzed for physico-chemical parameters viz., pH, Alkalinity, Calcium (Ca2+), Magnesium (Mg2+), Total Hardness (TH), Chlorides (Cl−), Nitrates (No3−), Sulphates (So42− ), Total Dissolved Solids (TDS). In this study, methodology based on Multi Criterion Decision Making analysis is developed to create a GWQI, with the aim of identifying places with best quality for drinking within the Cheyyeru Watershed, YSR District. Weights proposed through Analytical Hierarchical Process are applied using National Sanitation Foundation method for determining GWQI. Indices revealed that GWQI varied from 117.02 to 408.74. The impact of land use changes has favored the deterioration of groundwater quality in the basin. Overall assessment of the basin reveals that almost all the parameters analyzed are above the desirable limits. The higher concentration of Mg2+ during post-monsoon samples exhibits poor quality of water as compared to summer season. Sample test results were cross-correlated and significant influence on GWQI is observed from Mg2+, TH, and TDS. An interpolation technique Inverse Distance Weighted was used to obtain the spatial distribution of GWQI. The analysis revealed that the groundwater in the basin needs some degree of treatment before consumption, and it also needs to be protected from the perils of contamination.