A correlative analysis of ground water depth and quality parameters of Bhubaneswar city using water quality index

Abstract

Groundwater depth and quality data of six different locations in the capital city of Bhubaneswar for the year 2017 were collected from the Directorate of Ground Water Development, Department of Water Resources, Bhubaneswar and were analysed for their physiochemical characteristics. Ordinary kriging interpolation method was applied in the ArcGIS platform to know the spatial variability of groundwater depth over the city. A total of ten water quality parameters like pH, total hardness, electrical conductivity(EC), Total dissolved solids (TDS), Chloride, Magnesium, Calcium, Alkalinity, Nitrate were analysed using the Water Quality index (WQI) to know quality of water available for the given year within the city. A graphical presentation of all the ten quality parameters were analysed with their respective desirable and permissible limit as mentioned in the BIS Water Quality Standards (IS:10500). A correlation matrix of ground water depth and water quality parameters was determined to identify highly correlated parameters and it was seen that ground water depth has only positive correlation with pH out of the rest nine parameters and EC was seen sharing strong positive correlation with seven parameters out of total ten parameters analysed. Each of the parameters were assigned some weights ranging between 1 to 5 as per their importance in water quality assessment and the WQI values were calculated and a grading was done i.e. value<50 = Excellent; 50-100 = Good; 100-200 = Poor; 200-300 =Very poor and >300 = Unsuitable. All the parameters considered for assessing the suitability of ground water for drinking purpose came under the excellent category except iron which seems to have wider range of effect on ground water and needs proper attention by geologists to minimise its effect in best possible way for the betterment of society in mere future.