The paper summarizes the continual studies (begun in 1963) of longitudinal profile evolution in the erosion forms cut by ephemeral streams into calcareous Caucasian slopes facing the Black Sea. The profile deformations depend on water discharge and alluvium thickness at the valley bottom. During years with average water supply the bed profile fluctuates around some average position as sand waves move downstreams. Years with severe channel-forming floods bring about considerable changes of the profile. Most of the studied channels have gorges and waterfalls which interrupt the sediment transport and sorting. Stream profile deformations are also controlled by the alluvium thickness which depend on weathering rate and scree and rockfall intensity, the latter being controlled by water supply and seismicity.