Hydrogeological and hydrochemical investigation of limestone aquifer of southern Polatli (Ankara)

In this study, the hydrogeological and hydrochemical properties of the limestone aquifer located in the south of Polatlı District of Ankara Province were investigated. The Alagöz formation Limestone Member has a wide distribution and has a high permeability feature with its abundant fractures, cracks and karstic structure. The hydrochemical analyzes show that this part of the aquifer generally complies with drinking water standards. According to the water samples taken, the water types in the Halkabaşı region generally show the Ca-Mg-HCO3 feature, while in the Uzunbeyli location it shows the Ca-Mg-Na-HCO3 feature. This situation is due to the different lithological features of the Alagöz formation, recharge relationships or parameters such as water-rock interaction. When the groundwater in the region is evaluated for agricultural irrigation, it is classified as water with low sodium and low salinity risk. Groundwater level measurements made in the Halkabaşı Groundwater Operation Area reveal a continuous level decrease over the years. In the measurements made between 2014-2024, a decrease of approximately 40 meters in groundwater levels was detected. The findings show that groundwater exploitation in the region is not sustainable in the long term.