Which landform is formed at a river mouth by sediment deposition, often expanding into a fan-shaped area?

• A. Coastal Cell
• B. Berm Crest
• C. Delta
• D. Beach

Answer: (C)

Sediment deposition at the mouth of a river builds a landform that extends into the water in a fan-shaped area, called a delta. When a river carrying a heavy load meets standing water, its flow slows abruptly, causing sediment to settle out. The river then deposits this sediment in multiple distributaries that spread across the mouth, forming a broad, fan-like delta plain. This process is unique to regions where a river enters a larger body of water and supplies enough sediment to build new land outward rather than just along the shore. A beach, by contrast, forms mainly from wave action shaping sediment along the shoreline; a berm crest is a beach-dune feature created by wind and storm overwash; a coastal cell describes the larger system of sediment transport along a coastline rather than a specific landform at a river’s mouth.