Over the past few decades, the shape of the delta has changed significantly, as ocean waves have carved away at the coastline, submerging and shrinking habitats. ... However, it's unclear how such protective measures will affect the shape of the river delta, and its communities, over time.

How does river deltas change over time?

The most significant effect is that the site of deposition shifts dramatically with time. This occurs because the channel gradient and transporting power of a delta river decreases as the deltaic lobe extends farther seaward and shorter routes to the ocean become available.

How do deltas change?

The sediment is dropped at the mouth of the river. Some rivers drop so much sediment that waves and tides can't carry it all away. It builds up in layers forming a delta.