Really Simple Scenery - Mississippi River Delta

Making the Mississippi Over Again: The Development of River Control in Mississippi

“The military engineers of the Commission have taken upon their shoulders the job of making the Mississippi over again — a job transcended in size by only the original job of creating it.” Mark Twain

New Orleans

Because estuaries are the hydrologic connection between freshwater inputs and the open oceans, they often receive large pollutant loads, with accompanying water-quality impacts. Estuarine fishery nursery grounds are especially sensitive to upstream point and non- point pollutant sources. Because large rivers can carry huge volumes of soils and suspended sediments, estuaries are typically turbid. Further, when the inflowing sediment load becomes large, rivermouth deltas can form as the sediment drops out of the water column with the reduction in water velocity as the river enters the coastal waters. Prominent examples of this phenomenon are the major deltas located at the mouth of the Mississippi River (Photo 34), in the Gulf of Mexico and the mouth of the Nile River in the Mediterranean Sea.

Disappearing Delta Overview

Three years ago this month, NOW presented a two-part story on the disappearance of the Mississippi River delta. "Losing Ground," uncovered how one of the biggest civil engineering projects in U.S. history — the leveeing of the Mississippi River — had brought Louisiana and the nation to the brink of what could be the most costly environmental disaster in history. In "The City in a Bowl," NOW examined another ominous effect of this crisis — the risk that a massive hurricane could drown New Orleans. Hurricane Katrina has now made these predictions a reality.

The river annually empties four hundred and six million tons of mud into the Gulf of Mexico — which brings to mind Captain Marryat's rude name for the Mississippi — 'the Great Sewer...' The mud deposit gradually extends the land ... it is much the youthfulest batch of country that lies around there anywhere. --Mark Twain, LIFE ON THE MISSISSIPPI

Great picturtes of the Mississippi Delta (shrinking)

Animation of Mississippi Delta (shrinking)

Gulf of Mexico
The types of terrain created by a living delta

The Bay of Campeche in Mexico constitutes a major arm of the Gulf of Mexico. Additionally, the gulf's shoreline is fringed by numerous bays and smaller inlets. A number of rivers empty into the gulf, most notably the Mississippi River. The land that forms the gulf's coast, including many long, narrow barrier islands, is almost uniformly low-lying and is characterized by marshes and swamps as well as stretches of sandy beach.

Rich pickings on a delta...

The continental shelf is quite wide at most points along the coast. The shelf is exploited for its oil by means of offshore drilling rigs, most of which are situated in the western gulf. Another important commercial activity is fishing; major catches include red snapper, amberjack, tilefish, swordfish, and various grouper, as well as shrimp and crabs. Oysters are also harvested on a large scale from many of the bays and sounds. Other important industries along the coast include shipping, petrochemical processing and storage, paper manufacture, and tourism.


Because of the ever increasing amount of nitrogen and phosphates dissolved in the waters of the Gulf of Mexico, pollution has more than doubled since 1950. Current estimates suggest that three times as much nitrogen is being carried into the Gulf today compared with levels 30 years ago or at any time in history. Blooms of photosynthesizers die and sink, and the processes of their decay exhausts the available supplies of oxygen dissolved in the water. Every summer there is now an area south of the Louisiana coastline, larger than the U.S. state of Massachusetts at over 7,000 mi² (18,000 km²) that is hypoxic. These waters do not carry enough oxygen to sustain marine life. This annually enlarging dead zone is a major threat to the fishing industry and to public health.

Also, there are frequent "red tide" algae blooms that kill fish and marine mammals and cause respiratory problems in humans and some domestic animals when the blooms reach close to shore. This has especially been plaguing the southwest Florida coast, from the Florida Keys to north of Pasco County, Florida.

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