GES Fall 2026 Colloquium Series: Sea-level Rise and Riverine Wetlands
October 30 @ 3:30 pm – 5:00 pm
Speaker: Jonathan Phillips, Chief Scientist at Croatan Earth Systems, NC and Professor Emeritus, Department of Geography at the University of Kentucky
Most studies of wetland response to sea-level rise are concerned with changes in elevation of salt marsh surfaces relative to the rate of coastal submergence. Marsh surface area increases if there is an accretionary surplus or declines due to fringe erosion or internal fragmentation. The most common case is a net loss of wetlands due to erosion and drowning. Maintaining marsh habitats and minimizing the rate of loss is seem primarily as a function of the ability of marshes to “climb” adjacent uplands by expanding laterally as the marsh surface accretes. Application of this framework to riverine wetlands at the head of estuaries or in the fluvial-estuarine transition zone (FETZ) often leads to the concern or conclusion that riverine wetlands lack “room to migrate,” due to space limitations for lateral spreading imposed by relatively steep valley-side slopes. However, riverine wetlands–freshwater and brackish are more diverse than salt marshes, ecologically, geomorphologically, and hydrologically. They are also less prone to sea-level driven fringe erosion and have more degrees of freedom to respond to coastal submergence. This study examines sea-level driven changes in wetlands in the FETZ of coastal plain rivers of the Carolinas, based on state-and transition models. Preliminary finds suggest net loss of wetlands only at the head of the estuary, but wetland transitions throughout the FETZ. Room to migrate is not the main issue for riverine wetlands, but rather the relative functions and values of different wetland landforms and ecosystems.
