The dynamics of relative elevation change across three degrading wetland habitats: Implications for subsidence and relative sea level rise in the Manchac/Maurepas study area.

摘要

Global Mean Sea Levels are rising with mean global temperatures. Rates of relative sea level rise due to subsidence are variably influenced by anthropogenic changes to the hydrologic cycle. The complexities of subsidence mechanisms must be fully understood to accurately estimate land submergence potentials, and to effectively plan for wetland sustainability and infrastructural integrity. Cumulative elevation gains were recorded using a Surface Elevation Table in the Pontchartrain Basin, located in southeast Louisiana. These gains occurred in three degrading wetland habitats in absence of quantifiable accretion. Significant nonrandom patterns of elevation change detected by statistical and multi-spatial analyses suggested that wind-induced forces determine surface expression in hydromorphic saturated alluvial soils adjacent to Lake Maurepas. Further studies are necessary to illuminate the dynamic relationships between wind gradients (particularly northerly winds) and fluid/soil mechanics in estuarine environments, and the effects of these relationships on consolidation, geopressure, faulting and other factors that influence hydrogeological equilibrium.Key words: relative sea level rise, subsidence, Louisiana, Surface Elevation Table, SET, Pontchartrain Basin, Lake Maurepas, Manchac, alluvial soil, faults, geopressure, relative elevation, accretion