: This paper presents a research conducted as part of development of the graduation thesis entitled: "Hydraulic numerical analysis of groundwater in the left hinterland of the Mostar hydroelectric power plant dam", which was developed and successfully defended at the Faculty of Civil Engineering, University of Mostar in 2020. The Mostar hydroelectric power plant, in tandem with the Salakovac HPP, levels the flows in the downstream course of the Neretva River. In the area around the embankment and the diaphragm wall, there are indications of filtration deformations of soil, and development of dominant directions of groundwater flows. The paper examines the area of the left hinterland of the Mostar hydroelectric power plant dam in the MAGNET 4 WATER program, and compares the obtained results with the existing verified results from the DHI WASY FEFLOW program as well as the field results. It was concluded that the spatial model is suitable for further research and analyses, e.g. for monitoring groundwater flows in the area, and for the analysis of risks of contaminant transport underground the left hinterland of HPP Mostar.