![]() ![]() Some researchers estimate that the state is losing a land mass equivalent to 30 football fields every day. As sea levels continue to rise, the land subsidence rates among Louisiana's coast will also increase. Rising sea levels attributed to global warming have exacerbated the problem. Canals dug for the oil and gas industry also allow storms to move sea water inland, where it damages swamps and marshes. Swamps have been extensively logged, leaving canals and ditches that allow saline water to move inland. Man-made levees, which were designed to protect residents and property adjacent to the river, block spring flood water that would otherwise bring fresh water and sediment to marshes. The solutions were not implemented and the issues the report sought to fix, are still issues. In 1973, Louisiana State University published “Environmental Atlas and Multi-Use Management Plan for South-Central Louisiana” analyzing the issue and possible solutions. Sea-level rise attributed to global warming, though not a root cause, is also considered a contributing factor and future concern.ĭiorama picturing wetland loss in coastal Louisiana as attributed to human activitiesĬoastal erosion is defined as "the loss of coastal lands due to the net removal of sediments or bedrock from the shoreline." South Louisiana is one of the main places being affected. While land subsidence is dominated by Glacial Isostatic Adjustment (GIA), sediment compression is next factor further compounding the problem. Other factors exacerbating coastal erosion in Southeast Louisiana include the presence of canals and navigational routes dug through marshes and swamps, often to accommodate logistical needs of the petrochemical industry, as well as the previous practice of logging, all of which have allowed the incursion of saltwater (saline) from the Gulf into previously fresh and brackish water plant habitats. As fresh and brackish water plant habitats recede, salt water from the Gulf of Mexico further encroaches, killing off more non-saltwater plants, thus further eroding pre-existing mud formations that these plants had once supported. The deterioration results in the death of fresh and brackish water plants historically part of the ecosystem, which are not only a vital feature of the wetlands' topography, but also serve to capture silt, and thus are needed to build up and sustain marsh structures. Contributing factors include the blockage of traditionally occurring deposits of fresh water and silt from the river caused by man-made levees which have been built up and down most of the river over the last century, which now impede the river's ability to replenish its southernmost alluvial plains which are constantly dependent on the infusion of the river's once plentiful deposits which usually occurred during annual high stage floods in the springtime, the kind of which the river-levees now serve to buffer against for the protection of residents, livestock, and property residing in regions adjacent to the river throughout the Mississippi River valley. The process of coastal erosion is the result of various factors, including sea level rise, the loss of deposition of sediments to the Mississippi River delta, and the consequent permanent flooding of marshes, wetlands, and neighboring areas along the Louisiana coast of the Gulf of Mexico. The state has outlined a comprehensive master plan for coastal restoration and has begun to implement various restoration projects such as fresh water diversions, but certain zones will have to be prioritized and targeted for restoration efforts, as it is unlikely that all depleted wetlands can be rehabilitated. 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. In the last century, Southeast Louisiana has lost a large portion of its wetlands and is expected to lose more in the coming years, with some estimates claiming wetland losses equivalent to up to 1 football field per hour. Land loss in coastal Louisiana since 1932 NOAA2013Ĭoastal 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 at the foot of the Gulf of Mexico on the Eastern half of the state's coast. ![]()
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