Which statement best describes bed load movement in rivers?

• A. Suspended load moves along the bed by traction.
• B. Bed load is dissolved minerals carried in solution.
• C. Suspended load is carried entirely in the water column.
• D. Bed load moves along the bed by traction or saltation.

Answer: (D)

Bed load movement describes sediment grains that travel along the river bed rather than being carried high in the water. These grains move by rolling or sliding along the bed (traction) and by short hops where they are briefly lifted and then settle back down (saltation). This combination keeps the grains in contact with the bed as they move downstream.

The other descriptions mix up transport modes. Minerals that dissolve in water form the dissolved load, not the bed load. So saying bed load consists of dissolved minerals is incorrect. The statement about suspended load highlights grains carried within the water column, not along the bed; suspended load stays in suspension rather than rolling or hopping on the bed. Therefore, the description that bed load moves along the bed by traction or saltation best matches how these solid particles actually travel in a river.