- A delta is a fan-shaped area of land found at the mouth of a river.
- It is a feature of river deposition.
Formation of a Delta
When a river reaches a lake or sea, it slows down and loses the power to carry sediment. The sediment is then dropped at the mouth of the river. Some rivers drop so much sediment that waves and tides can not carry it all away. This is what forms the delta. The large deposits build up over time at the mouth of the river and block the river's entry to the sea. The river then has to break through the delta in many small channels called distributaries.