Observations and Models of Coastal Tidal Variations and Sedimentation in Response to Coastal Geomorphic Reorganizations: Northeastern North Carolina Coastal System
Abstract
There is much concern about coastal erosion in response to scenarios of future sea-level rise and increased tropical cyclone intensities. We are using observations of coastal stratigraphy in northeastern North Carolina to understand past changes of the coastal system in response to storms and sea-level change, in order to create an actualistic model of coastal evolution. The modeling approach is based upon geologic observations derived from seismic data, cores, and microfossil assemblages, temporally constrained by radiocarbon and optically-stimulated luminescence ages. Observations indicate that during the late Pleistocene, the estuarine system was dominated by astronomical tides, and contained extensive tidal flats. During the Holocene, the estuarine system became wind-tide dominated as the barrier system became more robust and continuous, separating the estuary from the adjacent shelf. Late Holocene sediments, however, suggest that segments of the barrier system periodically became less continuous or collapsed. This led to an increase in astronomical tidal range within the estuary. To further understand this transitional behavior, we are modeling the tidal effects using various representations of barrier island morphology, which are constrained by our geologic observations. The ADCIRC model is being used to investigate the degree of tidal change that corresponds to the geologic observations. These data will enable an understanding of the potential for a threshold response of the barriers and estuaries to future sea-level rise and storms, and evaluate the potential for future reorganization to a tidally-dominated system.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMOS53F..08M
- Keywords:
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- 4217 Coastal processes;
- 4235 Estuarine processes (0442);
- 4255 Numerical modeling (0545;
- 0560);
- 4546 Nearshore processes;
- 4560 Surface waves and tides (1222)