Atchafalaya Basin - Degradation of The Buffer Marshes

Degradation of The Buffer Marshes

The control of the river's floods, along with those of the Mississippi River, has become a controversial issue in recent decades. It is now widely suspected that the channeling of the river and subsequent lowering of siltation rates has resulted in severe degradation of the surrounding saltmarsh wetlands as well as widespread submerging of populated and agricultural lands of the bayou country. The US Geological Survey (USGS) reports that over 29 square miles (75 km²) of land is lost to the sea each year.

The decrease in water movement and siltation rates has been caused by damming the bayous and laying sluices, by the US Army Corps of Engineers. Also, the placing of a levee along the Atchafalaya Basin has contributed to cutting off the swamp from the river, preventing the swamp from functioning as a buffer. This decrease has caused reduced aeration of the water, causing it to change color. Where the water was formerly brown, it is now black.

The coastal salt marshes form a buffer zone protecting the entire coast of Louisiana from the effects of hurricanes in the Gulf of Mexico by dissipating their accompanying storm surges. The marshes depend on replenishment from deposited silt, which is now being deposited instead over the edge of the continental shelf, due to the artificially canalized flow of the Mississippi. Also, from the 1950s through 1970s, the oil industry dredged deep channels into the marsh so that they could move barges in as work platforms. The edges continued to degrade, until wide shallow channels in the saltmarsh have resulted.

The disappearance of the delta country is considered by many environmentalists, as well as by the State of Louisiana, to be one of the most significant ecological threats in the United States. The loss of the delta lands was discussed by author Mike Tidwell in his 2003 book Bayou Farewell: The Rich Life and Tragic Death of Louisiana's Cajun Coast.