عنوان مقاله [English]
Located in an arid/semi-arid region, Iran calls for special attention to its water resources. More importance should, however, be attached to the groundwater resources due to their hidden nature and the excessive costs associated with their extraction as well as qualitative and quantitative monitoring. Due to the significance of the water resources for activities in the neighborhood of the Urumia Lake, the present study was designed to conduct a qualitative investigation of an aquifer in the area adjacent to the lake. Teh importance of water is especially foregrounded by the increasing daily human demands for drinking, irrigation, industrial activities, and home use. Shiramin area has an aquifer of approximately 34 square kilometers in area and is one of the plains bordering the Urmia Lake. The groundwater resources in Shiramin plain were evaluated by collecting samples from 18 points well distributed across the plain and subjected to analysis to determine 12 water quality parameters. A multivariate statistical analysis (namely, principal components analysis and factor score) was used and GIS and saturation index were also integrated. Four components were extracted as a result of applying Principal Components Analysis, one resulting from the impact of carbonate formations, one caused by water recharge, one due to the effects of sulfate and fluoride, and the fourth one due to the high factor loading of nitrate caused by human activities. Interpolation of the factor scores with GIS showed that the greatest area with positive factor scores was related to the first component and that the area covered by positive factor scores reduced moving from the first to the fourth component. Generally speaking, such factors as reduced rainfall, increased water extraction, and intensive agricultural activity accounted for the degradation observed in the water quality in Shiramin area so that samples collected upstream the plain and those from the plain end exhibited more positive values of saturation index with respect to their carbonate and halite rocks.