Suspended load is the grains that are light enough to be carried in the water and do not contact the bed of the river unless there is an obstruction or topographic change in the bed. The way these particles erode a bedrock river is by contact with these obstructions. Being as they are carried as part of the river flow they have a significantly higher kinetic energy and coming into contact with an abnormality in the river bed can cause more damage than a larger grain with lower energy. The grain size that is normally held in the suspended load ranges from very fine to fine; clays and silts.
