accumulated sediments on the bottom of the river
I believe that is from BC Science 7 and the answer is a delta.
This deposit is called a "delta".
a place where a river meets the shore
A deposit at the opening of a river is called 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.
the nile delta is a fan-shaped mud deposit at the mouth of the nile river
Sediment.
A rive cliff and a river deposit
dirt ,mud ,rocks ,and pebbles.
there is poo in them
Clay.
silt This trianguar deposit of sediment where a river empties into an ocean is called a delta.