Bottom sediment class polygons based on acoustic seabed classification data developed from side scan sonar data. These polygons were created as part of a study, funded by the National Park Service, to create a baseline inventory of submerged marine resources within and immediately adjacent to the Assateague Island National Seashore boundary. The study area included the Atlantic nearshore area extending out to approximately 1.5 km offshore, along the 58-km Assateague Island shoreline. In addition to the side scan sonar data, other geophysical data including bathymetry, sub-bottom seismic profiles, sediment, and underwater video imagery, were used to further delineate the bottom class polygons.

The influence of tropical and extratropical cyclones on coastal wetlands and marshes is highly variable in both space and time and depends on a number of climatic, geologic, and physical variables. The impacts storms can be either positive or negative with respect to the wetland and marsh ecosystems. Small to moderate amounts of inorganic sediment added during storms or other events helps to abate pressure from sea-level rise. However, if the volume of sediment is large and the resulting deposits thick, the organic substrate may compact causing submergence and a loss in elevation. Similarly, thick deposits of coarse inorganic sediment may also alter the hydrology of the site and impede vegetative processes. Alternative impacts associated with storms include shoreline erosion at the marsh edge as well as potential emergence. Predicting the outcome of these various responses and potential long-term implications can be obtained from a systematic assessment of both historical and recent event deposits. The objectives of this study are to 1) characterize the surficial sediment of the relict to recent washover fans and back-barrier marshes, and 2) characterize the sediment of 6 marsh cores from the back-barrier marshes and a single marsh island core near the mainland. These geologic data will be integrated with other remote sensing data collected along Assateague Island, Maryland / Virginia and assimilated into an assessment of coastal wetland response to storms.

The influence of tropical and extratropical cyclones on coastal wetlands and marshes is highly variable in both space and time and depends on a number of climatic, geologic, and physical variables. The impacts storms can be either positive or negative with respect to the wetland and marsh ecosystems. Small to moderate amounts of inorganic sediment added during storms or other events helps to abate pressure from sea-level rise. However, if the volume of sediment is large and the resulting deposits thick, the organic substrate may compact causing submergence and a loss in elevation. Similarly, thick deposits of coarse inorganic sediment may also alter the hydrology of the site and impede vegetative processes. Alternative impacts associated with storms include shoreline erosion at the marsh edge as well as potential emergence. Predicting the outcome of these various responses and potential long-term implications can be obtained from a systematic assessment of both historical and recent event deposits. The objectives of this study are to 1) characterize the surficial sediment of the relict to recent washover fans and back-barrier marshes, and 2) characterize the sediment of 6 marsh cores from the back-barrier marshes and a single marsh island core near the mainland. These geologic data will be integrated with other remote sensing data collected along Assateague Island, Maryland / Virginia and assimilated into an assessment of coastal wetland response to storms.

The reconnaissance maps upon which this data set is based show the areal distribution of the major bottom sediment types covering the sea floor off eastern New England between Cape Ann and Casco Bay. The maps were intended as a guide to the future mapping of gravel, sand, silt, and clay, and because these sediments reflect the hydraulic conditions, they are also helpful for deducing the important sediment transport mechanisms.

The reconnaissance maps upon which this data set is based show the areal distribution of the major bottom sediment types covering the sea floor off eastern New England between Cape Ann and Casco Bay. The maps were intended as a guide to the future mapping of gravel, sand, silt, and clay, and because these sediments reflect the hydraulic conditions, they are also helpful for deducing the important sediment transport mechanisms.

Side scan mosaic image of nearshore seafloor off Assateague Island. This raster image is one of eight side scan sonar (SSS) mosaic tiles (A through H, north to south), covering the marine nearshore adjacent to Assateague Island National Seashore. The SSS data was collected in May and June, 2011, as part of a study, funded by the National Park Service, to create a baseline inventory of submerged marine resources within and immediately adjacent to the Assateague Island National Seashore boundary. The study area included the Atlantic nearshore area extending out to approximately 1.5 km offshore, along the 58-km Assateague Island shoreline. In addition to the side scan sonar data, other geophysical data collected for the study included bathymetry, sub-bottom seismic profiles, magnetic field data, seafloor sediments, and underwater video imagery.

Side scan mosaic image of nearshore seafloor off Assateague Island. This raster image is one of eight side scan sonar (SSS) mosaic tiles (A through H, north to south), covering the marine nearshore adjacent to Assateague Island National Seashore. The SSS data was collected in May and June, 2011, as part of a study, funded by the National Park Service, to create a baseline inventory of submerged marine resources within and immediately adjacent to the Assateague Island National Seashore boundary. The study area included the Atlantic nearshore area extending out to approximately 1.5 km offshore, along the 58-km Assateague Island shoreline. In addition to the side scan sonar data, other geophysical data collected for the study included bathymetry, sub-bottom seismic profiles, magnetic field data, seafloor sediments, and underwater video imagery.

Understanding how sea-level rise will affect coastal landforms and the species and habitats they support is critical for crafting approaches that balance the needs of humans and native species. Given this increasing need to forecast sea-level rise effects on barrier islands in the near and long terms, we are developing Bayesian networks to evaluate and to forecast the cascading effects of sea-level rise on shoreline change, barrier island state, and piping plover habitat availability. We use publicly available data products, such as lidar, orthophotography, and geomorphic feature sets derived from those, to extract metrics of barrier island characteristics at consistent sampling distances. The metrics are then incorporated into predictive models and the training data used to parameterize those models. This data release contains the extracted metrics of barrier island geomorphology and spatial data layers of habitat characteristics that are input to Bayesian networks for piping plover habitat availability and barrier island geomorphology. These datasets and models are being developed for sites along the northeastern coast of the United States. This work is one component of a larger research and management program that seeks to understand and sustain the ecological value, ecosystem services, and habitat suitability of beaches in the face of storm impacts, climate change, and sea-level rise.