TIDAL WETLAND ACCRETION AND ELEVATION CHANGE ALONG THE ATLANTIC COAST OF THE NORTHEASTERN UNITED STATES

Vertical accretion and elevation gain are a critical factor in the maintenance and survival of tidal wetlands in the face of rising sea level. Given the value of coastal wetlands as important habitat and their role in buffering coastlines from flooding and erosion, it is necessary to monitor current trajectories of coastal marshes. This study compiles and reviews previously published accretion and elevation change rates for tidal wetlands along the Atlantic coast of the northeastern United States. To facilitate further analyses and interpretations of regional variability in and controls on accretion and elevation change rates across the region, all data were entered into a database in a standardized format and tagged with additional geospatial and physical attributes. We provide an initial overview and interpretation of the regional dataset in addition to releasing the data in the form of an interactive web map application. The median value of all accretion and elevation change rates compiled for the database was 2.9 mm/yr. A majority (59%) of accretion and elevation change rates are not presently keeping pace with local rates of relative sea-level rise, which regionally, averaged 3.2 mm/yr from 1971-2020. We further compared accretion and elevation change rates to the unvegetated to vegetated ratio (UVVR) metric of horizontal marsh integrity and show that across the region, marshes exist in all combinations of apparent vertical and horizontal stability and instability as influenced by local conditions.