The paper describes the scouring process of a river bed downstream of a block ramp hydraulic structure situated in Raba river at Rabka-Zdrój. We calculated the scour depth of river bed downstream of the block ramp using several different empirical formulae from the literature. The calculated results were verified with the measured results collected during the field campagine. Along the paper we present which are the best formulae, when comparing the scouring results with our field measurements. We found that calculated values of scouring are usually much higher than those observed in the field. For practice: formulae can be used to comparative evaluations of scours downstream of hydraulic structures this they give an opportunity to understand the relationships between scour depth, a drop of a structure, unit discharge and downstream water depth. In that context the main aim of this paper is verification of the gathered here empirical formulae for scouring, downstream of block ramps based the results of field measurements.