* River Velocity: Rivers carry sediment downstream due to their relatively high velocity. This velocity allows the water to keep the sediment suspended.
* Ocean Encounter: As the river flows into the ocean, the water encounters a much larger body of water. This causes the river's velocity to dramatically decrease.
* Sediment Deposition: With the reduced velocity, the water can no longer keep the sediment suspended. The heavier sediments settle out first, forming deltas and other landforms at the river mouth.
This process is called sedimentation and is a crucial part of how coastlines and river systems evolve over time.
