Steep mountain streams have rough beds and shallow water, affecting how sediment moves. Researchers studied a steep stream in Switzerland to see if existing equations could predict sediment transport on different slopes. Despite a tenfold increase in slope, sediment transport rates did not change much. The researchers found that by considering the roughness of the stream bed, they could accurately predict sediment transport rates on steep slopes. This suggests that the equations used for lower-gradient streams also work well for very steep slopes.