Estimation of hydrogeological parameters of porous media in a radially convergent flow field in Kairėnai polygon, SE Lithuania

In this study, a salt-tracer method applicability in Quaternary aquifer system groundwater was tested. The tracer experiment was performed in Vilnius University Kairėnai polygon for hydrogeological investigations in 2021. In Lithuania, experiments with tracers are not prevalent. Therefore, this work describes the practical use of the tracer for the analysis of the hydrogeological environment, a methodology that enables experiments with salt tracers. After the tracer test, the water flow rate was calculated at the time of the peak concentration of Cl-, which reached 9.41 m/d. The effective porosity value was calculated manually (0.16) and using TRAC code (0.1389 and 0.1341; normalized for background values). The main results of tracer experiments show that sodium chloride solution is effective as a tracer in the Quaternary aquifer system of Lithuania for actual nef calculation, where aquifer hydraulic conductivity values are similar to the studied area. Tracer peak analysis performed in this study confirms a possibility of estimating the heterogeneity of aquifer nef on site.