The researchers conducted a laboratory experiment to study how sediment moves in steep streams. They used a transparent flume filled with gravel and monitored the bed and sediment transport. They found that the channel slope and sediment feeding rate affect the migration of bedforms, like antidunes, which can lead to changes in the overall channel slope. Steeper channels and lower sediment transport conditions can cause more instability and lead to the formation of tall and fast-moving antidunes. These findings suggest that the evolution of steep channels is influenced by the movement of bedforms over time.