EVALUATION OF GROUNDWATER QUALITY USING WATER QUALITY INDEX (WQI) AND GIS TECHNIQUES

Abstract

Eighty-four water samples were collected to evaluate the groundwater quality in western part of Iraq using water quality index (WQI) with the help of Geographical Information System (GIS) technique. These samples were analyzed to define the chemical parameters including cations and aniona in addition to physical parameters including dissolved solids (TDS), pH and electrical conductivity (EC). The analytical data has been manipulating by Piper diagram to determine the type of groundwater in the studied area. Na⁺- SO₄^-2and Na⁺- Cl^- facies are a bulk groundwater type representing 51% and 31% respectively. All physiochemical data were transferred to the geographic information systems (GIS) platform to generate the database of water quality including spatial distributions map for each parameter. These parameters have been used to calculate the value of water quality Index (WQI) which is transfer also to the platform of GIS to produce the WQI map. This map represents the spatial distribution index of the potable water in the studied area. It shows only13% of the studied water samples located in the middle and western part of the study area can be used for drinking purpose and remaining samples unsuitable water for drinking purpose and need to be treated in the case of use.In terms of the irrigation, generally groundwater in the studied area becomes more suitable for irrigation purposes in the central part and towards the south-west.