River Delta

geography · rivers · landforms · sediment

Triangular shape. River deltas are named after the Greek letter delta (Δ) because they look like an upside-down triangle. The river splits into smaller branches as it spreads out, creating that distinctive pointy shape pointing toward the water.

Built by rivers. A river delta forms where a river slows down and can't carry all its sand and mud anymore, so it drops everything in a pile. Over thousands of years, these deposits build up and create brand new land.

Where rivers meet water. Deltas happen wherever a river flows into something slower like an ocean, sea, lake, or even another river. The slower water can't sweep away all the sediment, so it settles and stacks up.

Balance of forces. Whether a delta grows or shrinks depends on how much sediment the river brings versus how much the ocean or lake can wash away. It's like a constant tug-of-war between the river and the water it flows into.