ABSTRACT: Man in Louisiana's Coastal Zone--From Reclamation to Subsidence
Donald W. Davis
For more than 300 years the United States' marsh lands were thought to be of no economic value. They were considered useless wastelands. Today, they are recognized as valuable and highly productive environments. As a renewable resource that operates with minimum capital expenditures, the wetlands are epitomized in Louisiana.
Even so, south Louisiana's first settlers were unaware of the wetlands' value. These coastal lowlands were considered a nuisance. They bred yellow fever-carrying mosquitos and contributed directly and indirectly to flooding. Consequently, to overcome the hardships of being sea-level citizens, for more than 250 years the inhabitants have systematically reclaimed the marshes and swamps. As a result of the intense utilization of levees and pumps, normally wet property began to dry out, losing some of its natural buoyancy, increasing regional subsidence.
Man-induced negative land surfaces are producing an urbanized population that must face the realities of subsidence caused by unregulated reclamation. New Orleans has, in fact, become North America's premier sinking city. The population has been forced to learn how to live with the problem. Nevertheless, these people are at risk, particularly if the current predicted sea-level rise of 1.2 mm/yr is correct. In the main, Louisiana's coastal issues will become those of the nation and represent the precursor of things to come. Louisiana's reaction and solutions to these issues will establish a precedent for the remainder of the country to follow.
AAPG Search and Discovery Article #90999©1990 GCAGS and Gulf Coast Section SEPM Meeting, Lafayette, Louisiana, October 17-19, 1990