Local scour may occur when a hydraulic structure is positioned in a channel with an erodible bed. Herewith investigated experimentally are the erosion and flow pattern due to a water jet passing over a channel bed at the asymptotic (final) state. The development of the scour hole, its maximum scour depth and length, are recorded and compared with available scour-depth relations. Two sets of experiments (see Table 1) were carried out. Set 1 (3 runs) was concerned with measuring the vertical instantaneous velocity distribution in the scour hole. The scour hole at the asymptotic (final) state, t = 100 [h] was investigated. Set 2 (5 runs) was concerned with studying the physics of scouring. The scour hole at about mid-state, t = 0.5 [h], was investigated; subsequently the scour-hole depth was linearly extended on the semi-log scale to 72 [h]; no velocity measurements were performed. The present data are put in context with some (popular) existing relations; recommended is a modification of some of these rel With the development of the scour may occur when a hydraulic structure is positioned in a channel with an erodible bed. Two sets of experiments (see Table 1) were concerned with measuring the vertical instantaneous velocity distribution in the The scour hole at the asymptotic (final) state, t = 100 [h] was investigated. Set 2 (5 runs) was concerned with studying the physics of scouring. The scour hole at about mid-state, t = 0.5 [h], was investigated; followed the scour-hole depth was linearly extended on the semi-log scale to 72 [h]; no velocity measurements were performed. The present data are put in context with some (popular) existing relations; recommended is a modification of some of these rel