Deltas

A delta is a landform made of sand, mud, and soil that builds up where a river meets the sea or a lake. As the river slows down, it drops the tiny bits of earth it has been carrying. Over time, these bits pile up and form new land shaped like a fan or triangle.

How Deltas Form

Rivers carry tiny pieces of rock and soil called sediment. When a river reaches the ocean, it slows down. The sediment sinks to the bottom. Over many years, layers of sediment build up. The river splits into smaller streams that spread out across the new land.

Famous Deltas

The Nile Delta in Egypt is one of the oldest and most famous deltas in the world. The Mississippi Delta in Louisiana is home to many wetlands and wildlife. The Ganges Delta in Asia is the largest delta on Earth and is home to millions of people.

Fun Facts

• The word delta comes from the Greek letter Delta, which is shaped like a triangle.
• The Ganges Delta is about the size of West Virginia.
• Deltas are some of the best places in the world for farming because the soil is very rich.

Did You Know?

The Mississippi River drops about 500 million tons of sediment into the Gulf of Mexico every year!