How do erosion, transportation, and deposition shape landforms in fluvial (river) systems?

• A. Rivers erode valleys, transport sediment downstream, and deposit it as floodplains, bars, and deltas, building and reshaping landscapes.
• B. Rivers only erode without depositing material.
• C. Rivers deposit material only at their source.
• D. Rivers move water but do not affect landforms.

Answer: (A)

Erosion, transport, and deposition work together to sculpt the landscape in river systems. Erosion carves channels and valleys by wearing away bedrock and banks as water grinds and scours. As rivers flow, they carry sediment downstream in different forms: heavier material moves along the bed (bed load), finer material is carried in suspension, and dissolved minerals are carried in solution. When the river’s energy drops—on gentle slopes, inside bends where water slows, during floods, or at the river’s mouth where it enters a lake or sea—sediment settles out and is deposited. This creates features like broad floodplains along the valley floor, sand and gravel bars within the channel, and deltas at the mouth. Over time, these processes continually build and reshape landscapes as flow conditions change.

Rivers do more than move water; they actively modify landforms through erosion and deposition, and sediment is deposited in many places, not just at the source.