What occurs to sediment as a river forms a delta?

As a river approaches a delta, its velocity decreases significantly as it enters a standing body of water, such as an ocean or a larger lake. This slowdown in current allows sediment that the river has been transporting to settle out of suspension and be deposited on the riverbed and the surrounding areas, forming a delta. The process is primarily driven by gravitational forces, which cause heavier sediment particles to settle first as the energy of the flowing water diminishes.

In this context, sediment does not get completely removed from the area nor does it remain suspended in the water. While sediment may initially be transported with strong currents upstream, the characteristic of sediment deposition in a delta relates directly to the slowing of the stream's motion, allowing particles to settle and accumulate over time, creating the complex and rich ecosystems commonly found in delta regions.