Using a numerical model based on scalar diffraction of singular beams, we qualitatively show the peculiarities of the evolution of phase singularities upon reflection from a surface possessing a microrelief of a given height and shape. The cases of degeneration of the vortex "core", formation of topological dipoles, and doubling of singularities under the influence of phase inhomogeneities on the initial beam are demonstrated. The obtained results demonstrate the applicability of singular beams in the problems of analyzing the topography of reflecting surfaces whose longitudinal scale of inhomogeneities is of the order of quarter wave length. Keywords: optical vortex, Laguerre-Gauss beam, diffraction.