what is a delta in geography
Sacramento Delta at flood stage, early 2009. A river delta is a landform that forms from deposition of sediment carried by a river as the flow leaves its mouth and enters slower-moving or standing water.This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot transport away the supplied sediment.Despite a popular legend, this use of the word delta was not coined by Herodotus.his occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot transport away the supplied sediment. Despite a popular legend, this use of the word delta was not coined by Herodotus.