EVALUATION AND COMPARISON OF GROUNDWATER VULNERABILITY TO POLLUTION BY THE DRASTIC AND GOD METHODS: A CASE OF WADI NIL ALLUVIAL PLAIN (JIJEL, NE ALGERIA)

Abstract

The current research aims to compare the results of two vulnerability estimation methods (DRASTIC and GOD) in superficial and deep aquifer of Wadi Nil alluvial plain (NE Algerian). Analysis of the obtained results showed that the vulnerability of the superficial aquifer is divided into three classes of vulnerability according to the DRASTIC method, and only into two classes according to the GOD method. In deep aquifer, the study of vulnerability using DRASTIC method has shown us a dominance of the middle and high classes. On the other hand, GOD method shows an equitable distribution of high, low and middle classes. The statistical study of the agreement between the two methods shows a weak agreement in superficial aquifer and a strong agreement in deep aquifer. The surface analysis per class of the two methods shows an identical index of superficial and deep aquifers. In this study, we find that the DRASTIC method provides better results in both aquifers (superficial and deep). It provides better information and gives the necessary amount of information required in the vulnerability assessment compared to the GOD method.