Deltas are formed by rivers carrying sediment that is deposited at their mouths, typically where they enter a larger body of water like an ocean, lake, or even another river.
Here's a breakdown of the process:
Sediment Transport: Rivers flow downhill, carrying along eroded soil, sand, and other materials from their watersheds. This sediment is suspended in the water and travels with the current.
Slowing Down: As the river reaches its mouth, the flow slows down due to factors like the wider expanse of the receiving body of water or encountering shallower water depth. This slowing down reduces the river's ability to carry the sediment.
Deposition: When the water slows down enough, the suspended sediment starts to settle and accumulate, forming the delta. This process is most active at the river mouth but can also occur along the riverbanks and in areas where the flow is naturally slower.