Why Does a River Form a Delta?

A delta forms when a river enters a standing body of water (ocean, lake, reservoir) and slows down, causing it to deposit its sediment load. Over time, this sediment accumulates into a fan-shaped landform—the delta.

Key Factors

• High discharge and sediment load increase deposition.
• Sheltered coastlines reduce wave/current erosion of deposited sediment.

Process

1. River carries sand, silt, clay.
2. At standing water, velocity drops; sediment settles.
3. Deposits build up, shaping the delta.
4. Delta provides habitat, filters water, and creates fertile agricultural land.