Delta

Maiko SuzukiGeography (period

5)

Delta

The name comes from the Nile, because this delta has a characteristic triangular shape like the Greek letter, “delta”.

An area of low land where a river spreads into many smaller rivers near the ocean

Nile Delta

Mississippi River Delta

The Mississippi river delta covers an area of 26,000 km2 and the river carries 450 million tons of sediment to the sea every year. This amount of soil obviously builds up in some places as the water flow speed changes. Land areas are built up channels are formed as sediment is laid down. This activity changes constantly it left uncontrolled.

In North America

Ganges Delta

Ganges delta (Brahmaputra delta) is twice the area of the Mississippi, situated in the South Asia region of Bengal. It coves an area of 105,000 km2. It has many water ways, swamps, and lakes, and a population of up to 143 million people, despite the risks of flooding. The flood plains are very fertile and crops of jute tea and rice are grown. Fishing is also important and new methods of fish forming salmon and shrimps help support the local economy.

In India

How Is a Delta Formed??1. A delta is formed when a river

leaves behind debris such as sand gravel and mud at its mouth. When it reaches the sea, the rivers ferocity is checked.

2. The larger sediment is dropped making a bar, and the finer slit is carried into the sea to form and unseen extension of the delta.

3. At the sides of the river, sediment is also dropped and creates channels and embankments. Banks are built up and the river branches into several smaller streams.

Topographic Map

This is a topographical example of a typical delta region, showing the river, as it reaches the sea, causing areas of land where debris has been dumped.

Okavango Delta

Satellite Images

From this satellite image, it is easy to see how the rivers have broken up as it reaches the sea. The debris dropped by the river creates areas of embankments and low lying land area between the separated branches (streams) of the main river.

Mississippi River Delta

NarsarsuaqGreenland-ArcuateDelta

Mekong Delta

Bibliography

• http://www.georgiaencyclopedia.org/nge/Multimedia.jsp?id=m-7714

• http://www.wef.org/NR/rdonlyres/4301A1EB-B6FA-4B72-AA72-EBBED7B34C77/0/BiographyRiver912.pdf

• http://www.digistar.mb.ca/minsci/geology/delta.htm• http://www.earthkam.ucsd.edu/public/images/pdf/

Ganges_River_Delta.pdf• http://www.bushways.com/delta.html• http://www.sarepta.org/en/folder.cfm?

aid=82&bid=223• http://www.eyesonafrica.net/african-safari-botswana/okavango-info.htm

• http://en.wikipedia.org/wiki/Image:Mississippi_delta_from_space.jpg

• http://fermi.jhuapl.edu/avhrr/gallery/coast/la_97feb16.html