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. In the last century, coastal Louisiana has lost an estimated 4,833 square kilometers (1,866 sq mi) of land, approximately the size of Delaware's land area. Coast wide rates of wetland change have varied from −83.5 square kilometers (−32.2 sq mi) to −28.01 square kilometers (−10.81 sq mi) annually, with peak loss rates occurring during the 1970's. 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 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.

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. While land subsidence is dominated by Glacial Isostatic Adjustment (GIA), sediment compression is next factor further compounding the problem. Sea level rise attributed to global warming, though not a root cause, is also considered a contributing factor and future concern.