Question

What do you mean by
deltas

Answer 1

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 layers forming a delta.

Hope it helps..^___^

Answer 2

The triangular deposition of sediments at the mouth of a river is known as delta...

hope this will help you