Origin and Dynamics of Nearshore Wetlands: Central Georgia Bight, USA

Abstract

A historical understanding of the origin and dynamics of wetlands is fundamental to efficient wetland management, conservation and restoration measures. The subject wetlands are located within 100 m of an actively retreating marine shoreline. A new collection of undisturbed vibracores, geospatial analyses of historical maps and imagery, an evaluation of Late Holocene sea level, and a synthesis of historical hurricane data provide insights regarding the origin and dynamics of the nearshore wetlands. The framework for the wetlands was established by the progradation of beach ridges, forming swales that were subsequently flooded during the Late Holocene. Beach Pond was transformed into a palustrine environment due to the emplacement of a washover fan attributed to the Great Sea Islands Hurricane of 1893, and shoreline retreat resulted in Beach Pond becoming an intertidal sand flat in May 2012. Flag Pond is an intertidal marsh that was formerly a palustrine wetland that underwent a transition to an intertidal wetland as the result of shoreline retreat and the “Storm of the Century” in the Spring of 1993. The long term stability of similar nearshore non-tidal freshwater environments along the Georgia Bight appears to be temporally limited by modern sea level rise and shoreline retreat.