ABSTRACT: The contribution deals with interaction of surface and ground water in the Šášovské Podhradie locality solving ground water level regime in the given region by means of numerical modelIing using the finite element method. Design of a small hydro-power plant (SHP) on the Hron River at rkm 134,88 has been prepared. Under the designed profile of the SHP on the left side of the Hron River the construction should not affect the ground water regime. The problem is on the right side where the inundation area in front of and behind the designed profile is lower, and therefore a comprehensive analysis of the ground water surplus is necessary. Consequently, possible technical measures for elimination of ground water increases have been recommended on the right side inundation area of the Hron River.