ASSESING THE GROUNDWATER SUITABILITY FOR IRRIGATION IN WESTERN IRAQ

Abstract

The main objective of this study is to map of the groundwater quality irrigation index (IWQI) in the western part of Iraq for the purpose of determining ideal locations for groundwater quality, to meet the demand for water in the future. To achieve this purpose, 84 wells distributed in the study area have been sampled. The collected samples analyzed chemically for varies parameters that affect to the irrigation water quality. These chemical parameters are Electrical Conductivity (EC), Na+, Cl-, HCO3- and calculated sodium adsorption ratio (SAR). These chemical analyses have been transferred to the platform of geographic information systems (GIS) to create water quality database including spatial distributions map for each parameter using the inverse distance interpolation technique (IDW). These parameters were used to calculate the values of Irrigation Water Quality Index that have been moved to the platform of GIS for the production of IWQI map. The results show that small part of the study area belong to Low Restriction (LR) categories for irrigation water and about 50% of the groundwater samples belong to Moderate Restriction (MR) category. The results also showed that 28% of the groundwater covering 39 Km2 falls within the High restriction (HR) category while 20% of studied water samples classified as Sever Restriction (SR). Accordingly, this groundwater is only suitable to use with high permeability soils, which have the ability to tolerate high content of salts.