Determination of Dominant Chemical Processes in an Alluvial Aquifer System of Wadi Ghiran Using Multivariate Statistical Analysis

Abstract

Factor analysis (FA) was applied to groundwater chemistry data of Al-Barzah town located in the upper part of Wadi Ghiran western Saudi Arabia to assess the usefulness of such method for interpreting commonly collected groundwater quality data and relating the data to specific hydrochemical processes. Six factors were retained; The first three factors were adequate for describing the groundwater chemistry processes that have taken place in the area: Factor 1 represents the degree of the overall mineralization of the groundwater due to intensive evaporation rates. Factor 2 reflects the dissolution and precipitation of carbonate minerals, Factor 3 may reflect groundwater pollution by on-site sewage disposal systems used in these regions and Factor 4 displays the buffering of the HCO3 content by CO2 exchange between groundwater and the atmosphere. Factors 5 and 6 represent single variables, dissolved oxygen (DO) and groundwater temperature and both show high association in these two factors. This confirm that the two variables are largely independently controlled and describe the unique factors assumed to be uncorrelated with each other and with common factors.