Question

dird foot delta is formed at the mouth of

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 layersforming a delta.
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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 way. it builds up in layers forming a delta.