157-Predicting Groundwater Quality Using Geo-Statistical Approach.

Abstract

The sustainable management of groundwater resources needs information on its quantity and quality in space and time. Knowledge of spatial variability of groundwater quality is essential for making reliable groundwater quality interpretations and for making accurate prediction of groundwater quality at any particular location. In this study, ground water quality of open wells was monitored in Jammu, Kathua and Udhampur districts during pre-monsoon period of 1995 to 1999. Various physico-chemical parameters viz., pH, EC, total hardness, alkalinity, chloride, nitrate, sulphate, calcium, magnesium, sodium, potassium, phosphate, etc. were determined following standard methods. Semi-variograms were developed using geo-statistical analysis for the ground water quality parameters obtained during pre-monsoon period of 1995 to 1999 to study spatial variability in the study area. In this study, magnesium, pH and phosphate were fitted with spherical model showing distinct correlation with distance; conductance and alkalinity fitted with linear model showing moderate continuity of the variables. The semi-variograms various fitted spherical model indicated that magnesium of groundwater is spatially co-related upto a distance of 17.21 km, pH upto a distance of 55.03 km., and phosphate upto a distance of 57.1 km in the study area. A pure nugget effect was observed in the semi-variograms for calcium, chloride, potassium, sodium, nitrate, total hardness and sulphate indicating no any clear sign of spatial correlation of these variables. In this study, kriged contour maps of different water quality parameters were developed based on various semi-variograms, which are useful to guide about prevailing groundwater quality in the study area at un-sampled locations. The results of this study would also be useful for better planning of groundwater quality monitoring network in the study area.