Which term describes the movement of material along the river bed by rolling?

Which term describes the movement of material along the river bed by rolling?

• A. Traction
• B. Suspension
• C. Weathering
• D. Waterfalls

Answer: (A)

Traction describes bedload transport where particles are moved along the river bed by rolling, dragging, or pushing under the action of flowing water. The key idea is that these grains stay in contact with the bed as they move, which matches the notion of rolling along the bottom. This differs from suspension, where fine particles are carried within the water column, and from saltation (not asked but related), where grains hop along the bed. Weathering is the breakdown of rock in place, not transport, and waterfalls are geomorphic features, not a transport process. So, rolling along the bed is traction.

Traction describes bedload transport where particles are moved along the river bed by rolling, dragging, or pushing under the action of flowing water. The key idea is that these grains stay in contact with the bed as they move, which matches the notion of rolling along the bottom. This differs from suspension, where fine particles are carried within the water column, and from saltation (not asked but related), where grains hop along the bed. Weathering is the breakdown of rock in place, not transport, and waterfalls are geomorphic features, not a transport process. So, rolling along the bed is traction.