Deltas, like the Mississippi River Birdsfoot Delta, are river-dominated ecosystems. A river-dominated delta is only partially influenced by tides and waves. In this instance, wave energy dissipates before connecting with the coastline.
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The Delta forms the most important bird and waterfowl migration corridor on the continent and supports North America's largest wetland area and bottomland hardwood forest. The Delta's cultural traditions are as rich and diverse as its natural resources.
The shifting river delta at the mouth of the Mississippi on the Gulf Coast lies some 300 miles south of this area, and is referred to as the Mississippi River Delta. Rather, the Mississippi Delta is part of an alluvial plain, created by regular flooding of the Mississippi and Yazoo rivers over thousands of years.
Land loss crisisEvery 100 minutes, a football field of land disappears into open water. Leveeing of the Mississippi River in the early 20th century severed the tie between the river and its surrounding wetlands, cutting off the Mississippi River Delta from its life-giving river and the sediment it carries.
For 7,000 years, the Mississippi River has snaked across southern Louisiana, depositing sediment from 31 states and 2 Canadian provinces across its delta. As sediment accumulated under water, plant communities began to develop, trapping more sediment and building land.
One big difference between the two is that while the Nile delta is shrinking (the Mediterranean Sea is eating away more sediment than the river can supply), the Mississippi delta is growing. The image below shows the growth of the Mississippi delta over the past 10,000 years.
The Ganges-Brahmaputra delta is the world's largest delta, covering most of Bangladesh and the state of West Bengal (India). The size of the delta is a reflection of the enormous input of sediment being washed off the still-growing Himalayan mountains into the Ganges river basin.
On average, the Mississippi River Delta loses one football field of land per hour and has shrunk by 5,000 square miles in the last 80 years. To understand more about why some parts of the delta are disappearing due to sea-level rise, a team of NASA scientists will begin collecting data this spring.