A delta.
The low water land that is formed at the mouth of a river is called a delta.
The answer is delta
swamp
lake
The Delta
delta
A delta
The land formed by deposited soil at the mouth of a river is called a delta (named for the Greek letter, which is similarly triangular in shape).
nile
it is called a delta
Land formed at the mouth of a river by deposited silt is known as a delta. It typically forms when the river's velocity decreases as it meets the ocean, causing sediment carried by the river to be deposited, building up land over time.
Delta