SPATIAL DISTRIBUTION OF SALINITY IN SHALLOW GROUND WATER USED FOR CROP IRRIGATION

Abstract

The main objective of this study was to evaluate the salinity of ground water of the shallow wells and delineation of maps using spatial statistics approach. The water samples were collected from 833 wells located in the rural areas at shallow depth (<100 ft) of Lahore district and recorded their geographic coordinates. In order to achieve this objective, all samples were analyzed for electrical conductivity (EC). Regarding electrical conductivity (EC) in the shallow ground water, 432 samples (51.9% of the samples) were found fit for irrigation, 160 samples (19.2%) were found marginally fit and 241 samples (28.9%) unfit when compared with the standard values for irrigation purpose. Ordinary Kriging and Bayesian Kriging are used to interpolate and observe the behavior of EC in the entire domain of the study. The performance of ordinary Kriging and Bayesian Kriging were compared by means of cross validation. It is concluded that Bayesian Kriging produced less mean square prediction error as compared with that by Ordinary Kriging. It was observed that the value of electric conductivity was very high between longitude 74o 27′ to 74o 33′ and latitude 31o 3′ to 31o 34′ whereas in North-East of Lahore district the electric conductivity was very low. Overall, electric conductivities of the ground waters examined in the present study were higher with reference to the standard values used for crop irrigation.