Deltas. Mangoky River Delta. All images courtesy of NASA (http://earth.jsc.nasa.gov). The Nile Delta: a Prototype. Early geographers, reminded of the Greek letter delta when noting its roughly triangular shape, named it accordingly. Introduction. Deltas are transitional environments
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Mangoky River Delta
All images courtesy of NASA (http://earth.jsc.nasa.gov)
Early geographers, reminded of the Greek letter delta when noting its roughly triangular shape, named it accordingly.
Jetties have been built and dredging occurs to allow large vessels to navigate the delta channel
Note the large amounts of sediment that surrounds the delta
A bird’s foot delta located in Louisiana adjacent to the Gulf of Mexico
This is one of the few areas where the Louisiana coastline is growing
This delta is considered to be the Mississippi’s largest distributary
The Atchafalaya diverts large quantities of water from the Mississippi
large mangrove forest (largest remaining habitat of the Bengal tiger)
Prone to devastating floods
Wave action has smoothed the coastline
Rhone River Delta
Well developed distributaries
Smooth delta front
A mixed or intermediate delta influenced by both river and wave forces
Aswan Dam (1971)
The dam provides flood control, increased irrigable land area, and much needed hydroelectric power (about 40 percent of the country’s electricity).
The Aswan Dam has disrupted the Nile Delta’s normal development. The dam traps sediments formerly used to build the delta and agricultural area, allows saltwater intrusion, and reduces the amount of nutrients present in the Nile’s water.
Sediment once transported by the Nile River to the coast, average of 100x10 6 t yr-1, is now almost cut off.
Sediment deposited by distributaries
The channel requires frequent dredging so that large vessels can navigate the channel
Note the large sediment plumes
Although the Mississippi River still carries 200 million tons of sediment into the Gulf of Mexico every year, much more sediment would be carried if not for the dams and levees constructed by people in its drainage basin for flood control & other purposes.
This delta attracts many tourists who enjoy watching the delta’s birds and other inhabitants
The Danube is the second longest river in Europe
The Danube Delta is the second largest in Europe (4300 square kilometers) and is home to one of the biggest reed beds in the world, vast stretches of other wetland types, and much wildlife.
Fertile mud and sand have been deposited here during the last 2 million years
This river delta in Burma is one of the world’s great rice producing regions
The delta is a site of some of the earliest European settlements in India
Both Rivers are sacred to the Hindu Religion
Godavari and Krishna River Delta