Wetland loss dynamics in southwestern Barataria basin, Louisiana (USA), 1945?1985

We determined spatial associations of wetland loss rates in a 950-km super(2) study area in the southwestern Barataria Basin of Louisiana's Mississippi River delta plain for four intervals spanning 40 years, 1945-1985. A geographic information system was used to analyze spatial and temporal changes. Annual wetland loss rates increased over the 40 years; the rate of increase in annual rates accelerated through 1980 and then began to decelerate. The average annual rate of wetland loss for the entire study area increased from 0.2%/yr during 1945-1956, to 1.2%/yr for 1956-1969, 1.9%/yr for 1969-1980, and 2.0%/yr for 1980-1985. Wetland loss was not uniform throughout the study area. Eight sub-areas were identified as having different densities and/or causes of loss. Processes implicated in the differing loss rates include sea level rise, shoreline erosion, accelerated subsidence along natural levees, canal modification of hydrologic flows, interference of dredged material with sheet flow, and saltwater intrusion. In some areas, several processes are believed to operate together to induce wetland degradation and wetland loss. (DBO)