Question

How is a delta formed

Answer 1

A delta is a landform that forms from deposition of sediment carried by a river as the flow leaves its mouth and enters slower moving or standing water

Answer 2

When a river reaches a lake or the sea the water slows down and loses the power to carry sediment . The sediment is dropped at the mouth of the river. Some rivers drop so much sediment that waves and tides can't carry it all away. It builds up in layersforming a delta.