A delta is a landform that can form where a river meets a slower body of water, such as a sea, lake, or ocean. The river slows down and drops sediment it was carrying.
Why deltas spread out
As sediment builds up, the river may split into smaller channels called distributaries. Over time, this can create a broad, fan-like or triangular land area.
Why deltas matter
Deltas can create fertile land, wetlands, ports, and important settlements, but they can also be vulnerable to flooding, erosion, and sea-level change.
A delta is one of the many land and water features connected to continental geography.