Cline, M.D.; Feagin, R.A., and Yeager, K.M., 2014. Modeling salt marsh cover response to relative water level: Local fault motion versus global eustatic rise.
The movement of growth faults on subsiding coastlines contributes to wetland losses, yet it has been unclear whether they can provide a point of reference for understanding the impacts of climate-induced relative sea level rise (RSLR) on wetland habitat. The objective of this study was to simulate land cover conversion as a function of RSLR within a wetland and to compare and contrast fault-induced elevation change with Intergovernmental Panel on Climate Change (IPCC) 2007 sea level rise projections. For an area surrounding a growth fault in Matagorda, Texas, aerial images were draped over a digital elevation model (DEM) to identify the dependent elevations of land cover classes and, subsequently, to model potential future outcomes based on variable RSLR rates. Modeling results show that rapid water-level rise can force wetland land-cover class conversion regardless of whether the rise is caused by vertical fault displacement or eustatic sea level rise. The model findings point to an RSLR rate of approximately 0.36 cm/y for complete loss of the Matagorda wetlands by 2100, although the sustainability of the wetlands in their current configuration and coverage will likely require rates well below the IPCC 2007 low rise rate. Current and historical record conditions of sea level rise, along the Texas Gulf Coast, greatly exceed the rates discussed, leaving a grim outlook for the coast in this region.