Throughout the Holocene, appreciable changes in bathymetry are hypothesized to have resulted in large changes to tidal datums in coastal and estuarine areas. An understanding of tidal change is an important contribution to the knowledge of relative historical sea-level change and future coastal planning. To test this hypothesis, the Advanced Circulation (ADCIRC) model was used, with representative bathymetric grids based on glacial isostatic adjustment models and semi-empirical sea level rise predictions, in order to model the time-varying tidal behavior of the Delaware Bay. Model runs were conducted at various time slices between 10,000 years before present and 300 years into the future on high resolution grids that allowed for inundation moving forward in time. Open boundary tidal forcing was held constant in time to highlight the effect of the changing regional bathymetry. With each change in sea level, the shape of the Delaware Bay was considerably altered, leading to changes in the tides. Resonance and shallow water dissipation appeared to be the primary mechanisms behind these changes. Results showed that tidal ranges have nearly doubled in the upper Delaware Bay over the past 3000 years, while decreasing in the lower bay by 8%. Tidal range change represents a possible correction to past sea level rise estimates from the geologic record. Scenarios incorporating future sea level predictions primarily showed a small decrease in tidal range, potentially impacting future water levels and tidal sediment transport. Trends modeled were consistent with field measurements of relative change over similar time periods. / Graduation date: 2012
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/30032 |
| Date | 21 May 2012 |
| Creators | Hall, George F. |
| Contributors | Hill, David F. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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