Several such diagrams can be found by web search
7
mahanadi
It forms a delta by sedimentation of debris brought by the river stream.
delta looks like a hand inside the river
Africa
delta
The Orinoco River runs through Venezuela. It forms a large delta and empties in to the Atlantic Ocean. The river is also called Orinoquia River.
A floodplain is not in triangular shape but a Delta is in triangular shape.
delta
Delta
delta
It is the River Nile.