This deposit is called a "delta".
A deposit at the mouth of a river is called a delta. This land form is created because of the deposition of sediments carried by a river as the flow leaves its mouth.
This land deposit you speak of is called a delta.
DELTA
the nile delta is a fan-shaped mud deposit at the mouth of the nile river
A fan-shaped deposit at the mouth of a river is known as a delta. Deltas form when a river flows into a larger body of water, like a sea or ocean, and deposits sediment and other material it has carried downstream. Deltas are typically characterized by their flat, triangular shape.
An alluvial plain, sometimes also referred to as a fluvial plain.
Delta.
delta
dirt ,mud ,rocks ,and pebbles.
Alluvial fan
It is called a delta.