Hydrochemical Characteristics and Spatial Variability in Coastal Aquifers Southern IraqUtilizing a GIS Technique

The present study investigates water quality regarding drinking and irrigation supplies by gathering and analyzing twelve groundwater samples south of Basrah, south Iraq. Many wells in the area concerned are exploited mainly for various industrial and agricultural activities, impacting the ground water quality. The standard guidelines recommended by the Iraqi Quality Standard limits and the World Health Organization have been used to determine the suitability of drinking. The physicochemica analyses showed that all sampled waters are unsuitable for the drinking supply due to high total dissolved solids (TDS) levels reaching 12925 mg/L. Four valuable indices have been applied for estimating the irrigated water quality, namely, the sodium adsorption ratio (SAR), the soluble sodium percentage (SSP%), the magnesium hazard (MH%), and Kelly’s ratio (KR%). The results of water class as regards the percent of samples showed: SAR results, 25% excellent water, 41.7% good water, and 33.3% doubtful water; SSP% results, 16.7 % good water, 75% permissible water, and 8.3 % doubtful water; MH% results, 100% suitable irrigated water; and KR% results show 41.7% suitable water and 58.3 % unsuitable water. The USSL salinity diagram (Wilcox) result revealed 83.3 % of samples fall in very high salinity-very high sodium hazard class C4S4, and 16.7 % of samples fall in very high salinity-high sodium hazard class C4S3 and very high salinity-medium sodium hazard class C4S2, respectively. Increasing salinity of coastal aquifers has impacted sources such as seawater intrusion and intensive irrigation, and usages of excessive fertilizers and herbicides can largely pollute the groundwater quality.