Hydro Geochemical Investigation of Groundwater in Miandoab Plain

Knowing the spatial and temporal changes in groundwater quality is one of the important issues for optimal management of groundwater resources. In this study, the hydro geochemical properties of groundwater resources in Miandoab plain (West Azerbaijan province of Iran) were investigated.

For this purpose, the data of 51 study wells during the time period (from 2014 to 2018) were used. The qualitative parameters such as the amount of Mg2+, Ca2+, Na+, K+, HCO3-, SO42-, Cl-, CO32- and the indexes such as TH (Total Hardness), TDS (Total Dissolved Solids), EC (Electrical Conductivity), SAR (Sodium Absorption Ratio) and pH were evaluated based on drinking, agriculture and industry water quality standards. Aquifer qualitative zoning maps were extracted by entering the descriptive layers obtained from the qualitative analysis in ArcGIS software and selecting the best interpolation method based on the validation technique.

The groundwater hydro chemical analysis based on the drinking water standards of the Energy Ministry indicated that the groundwater of the plain is in a relatively acceptable condition. This was also obtained from groundwater analysis by the Schoeller method. It was found that the largest areas of this plain had saline groundwater, in terms of agriculture. Industrially, sedimentation in the plain was more pronounced than corrosion.

Results showed that the aquifer quality declined from 2014 to 2017 and improved in 2018. Zoning maps showed that Miandoab aquifer has better quality and condition in the feeding areas in terms of drinking, agriculture and industry. In other words, according to the geography of the plain, the aquifer feeding areas were less vulnerable than the areas located in the evacuation areas.