SPATIAL MODELING OF GROUNDWATER QUALITY ASSESSMENT: A CASE STUDY OF PESHAWAR DISTRICT

Abstract

High population growth and increased exploitation of groundwater resources causes the degradation of groundwater quality. To evaluate the venerability of groundwater pollution a GIS based study on groundwater quality was conducted in Peshawar district. The objectives of the study were (a) physiochemical properties analysis of groundwater quality (b) geodatabase development, geospatial analysis & mapping of groundwater pollutant distribution and (c) vulnerability assessment of groundwater pollution with DRASTIC model. A field survey was conducted to collect 105 water quality samples from the study area. The lab analysis of ground water samples revealed that the maximum value for pH, Ec, TDS, Alkalinity (HCO3), total hardness, Ca hardness, Mg hardness, NO3 (Nitrate) concentration, Cl-1 concentration and turbidity was found to be 8.05, 1695 μS/cm, 795 mg/L with, 540 mg/L, 770 mg/L, 368 mg/L, 430 mg/L, 41.7 mg/L, 95 mg/L and 7.36 NTU, respectively. Spatial statistical techniques were applied to map the spatial and directional distribution of each parameter. Groundwater vulnerable zones to pollutions were assessed using DRASTIC model. The DRASTIC scores obtained from the model vary from 47 to 147. These values were reclassified into three classes using the quantile classification scheme i.e., low vulnerable zones (399.7 km2), moderate vulnerable zones (505.7 km2) and high vulnerable zones (374.6 km2). It recommended that remedies should be taken to reduce the groundwater pollution in the Peshawar Valley.