ABSTRACT: Research aimed at increasing the temperature of groundwater is currently focused mainly on the study of factors, impacts, as well as the possibilities of potential use of geothermal energy. Numerical modeling is one of the useful tools that can be used to evaluate heat transport in an aquifer. Through numerical modeling of transport processes, it is possible to perform transport calculations based on a computer algorithm, as well as quantify and visualize the process. This makes it possible to identify locally or regionally the factors leading to an increase in groundwater temperature and also to assess the time evolution and the depth impact of the changes. Two localities were chosen as the investigated areas, namely the Sihoť water source and the Aupark department store in Bratislava. The Sihoť water source represents a site that is anthropogenically unaffected and the Aupark in Bratislava, on the other hand, is a site with a strong anthropogenic influence. Groundwater level and groundwater temperature were monitored at the sites. These data were an essential part of the model, especially in the calibration process. Both sites were modeled using the MODFLOW-USG tool, which is part of the Groundwater Vistas 8 program. The anthropogenic impact, represented mainly by the Aupark basement, was visible to a depth of 17 m, which represented the entire aquifer. In the case of the Sihoť water source, the groundwater temperature was influenced mainly by the air temperature and the temperature of the Danube, which manifested itself to a depth of 13 meters.