Coastal erosion in Louisiana
Coastal erosion in Louisiana is the process of steady depletion of wetlands along the state's coastline in marshes, swamps, and barrier islands, particularly affecting the alluvial basin surrounding the mouth of the Mississippi River.
[1] One consequence of coastal erosion is an increased vulnerability to hurricane storm surges, which affects the New Orleans metropolitan area and other communities in the region.
The process of coastal erosion in Louisiana is the result of various factors, including sea level rise; ordinary subsidence of organic materials; deprivation of periodic sediment due to flooding prevention measures; tropical cyclones; oil and gas extraction and infrastructure; navigation infrastructure; and saltwater intrusion.
[4] Sea level rise attributed to global warming, though not a root cause, is also considered a contributing factor and future concern.
Canals dug for the oil and gas industry also allow storms to move sea water inland, where it damages swamps and marshes.
[8][9] Prior to the building of levees on the Mississippi River, the wetlands were kept in balance by occasional floods, which filled the area with sediment, and subsidence, the sinking of land.
[10] The Lake Pontchartrain Basin Foundation has developed a comprehensive management plan for the eastern regions of the Louisiana coast, placing emphasis upon restoration of riverine habitats, cypress swamps and fringing marsh.
[8] As if these problems were not enough, the introduction of nutria, an invasive wetland rodent from South America, in the 1930s provided an entirely new species of grazing mammal.
[19] Terrebonne and Lafourche Parishes in Southeast Louisiana, with a combined population of 209,136, are at great risk of going underwater due to coastal erosion.
[23] Although most oil and gas extraction has shifted offshore to the outer continental shelf, the construction of channels and pipelines continues in the wetlands.
[1] For example, the construction of the now-closed Mississippi River Gulf Outlet (MRGO) introduced salt water into freshwater and intermediate marshes in St. Bernard Parish, which is adjacent to New Orleans, and facilitated significant erosion.
[23] What was then the Orleans Levee Board, now the Southeast Louisiana Flood Protection Authority operating as the East and West divisions, filed a lawsuit in July 2013 against 97 oil and gas companies for damages, claiming the 50 miles of marsh swamps, with stands of cypress that buffered Gulf storms, were "shredded by oil industry canals".
It was considered to be an "entire ecosystem tanking", the "largest ecological catastrophe in North America since the dust bowl", and "a wetland dying".
[citation needed] This was not a new hypothesis as Percy Viosca, a Tulane graduate ultimately fired by then-Governor Long and brought back under another administration, stated in 1925, “Man-made modifications in Louisiana wetlands, which are changing the conditions of existence from its very foundations, are the result of flood protection, deforestation, deepening channels[,] and the cutting of navigation and drainage canals.”, and concluded by stating that the “time is ripe for an enormous development of the Louisiana wetlands along new and [more] intelligent lines.”[25] The many benefits of the wetlands found in this region were not recognized by a majority of policy makers early in the 20th century.
More than 70% of that amount stems from species such as shrimp, oysters and blue crabs that count on the coastal wetlands as a nursery for their young.
Additional recreational activities such as boating, swimming, camping, hiking, birding, photography and painting are abundant in wetland areas.
Wetland plants act as natural filters, helping to remove heavy metals, sewage, and pesticides from polluted water before reaching the Gulf of Mexico.
Animal species native to these areas include osprey, anhinga, ibis, herons, egrets, manatees, alligators, and beavers.
Although there are several naturally occurring forces that adversely affect the wetland regions of Louisiana, many believe it is human intervention that has caused the majority of the decline.
There are several projects and proposals to save coastal areas by reducing human damage, some of which have been attempted, including restoring natural floods from the Mississippi.
[29][31] Freshwater diversions have not been without controversy and have encountered some opposition, primarily from oyster harvesters who believe that the current high level salinity is needed in their state-licensed zones in order to maintain healthy production.
[34] Some have proposed the removal of river levees in certain low-populated areas to allow fresh water and silt dispersion into marshes, though this method is controversial and has yet to be attempted.
[35][30] Current Louisiana law stipulates that all oil and gas revenue royalties collected by the state go towards coastal restoration.
[36] Proceeds from part of the BP Deepwater Horizon oil spill lawsuits and federal fines have also gone towards coastal restoration.
