Sensitivity of tidal hydrodynamics to varying bathymetric configurations in a multi-inlet rapidly eroding salt marsh system: A numerical study
Kirby, James T.
Earth Surface Processes and Landforms
We describe the development of a high-resolution, two-dimensional hydrodynamic model for a multi-inlet rapidly eroding tidal wetland on the western shore of Delaware Bay, using the finite-volume, primitive equation community ocean model (FVCOM). Topo-bathymetric surveys, together with water surface and current velocity measurements during calm and stormy conditions, have been conducted to support model validation. The tested model is then used to quantify the tide-induced residual transport and asymmetry at major inlet entrances to determine the governing hydrodynamics. We chose a skewness method to calculate the tidal asymmetry and serve as a proxy for sediment transport estimates. The effects of the dredging of an artificial entrance channel and progressive channel deepening in shifting wetland hydrodynamics are shown by developing a scenario analysis. Model results show that the artificially dredged channel has altered the volume exchange at other inlet entrances and increased the net seaward export. The changes in the characteristic frequency of the frictional dissipation in the channel and the system's natural frequency are investigated using a simple ocean–inlet–bay analytical model. Subsequently, we have compared the channel friction scale to the inertia scale and observed that the new connection and gradual channel deepening reduce the overall frictional dominance. Ultimately, the study has shown how the short- and long-term channel bathymetry changes, mainly the artificially dredged channel and progressive channel deepening, can affect the connected system's net circulation and trigger internal marsh erosion.
This is the peer reviewed version of the following article: Deb, M., Abdolali, A., Kirby, J.T., Shi, F., Guiteras, S. & McDowell, C. (2022) Sensitivity of tidal hydrodynamics to varying bathymetric configurations in a multi-inlet rapidly eroding salt marsh system: A numerical study. Earth Surface Processes and Landforms, 1– 26. Available from: https://doi.org/10.1002/esp.5308, which has been published in final form at https://doi.org/10.1002/esp.5308. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
coastal wetlands , salt marsh erosion , tidal hydrodynamics , numerical modeling , channel morphology , Wetland inlet asymmetry
Deb, M., Abdolali, A., Kirby, J.T., Shi, F., Guiteras, S. & McDowell, C. (2022) Sensitivity of tidal hydrodynamics to varying bathymetric configurations in a multi-inlet rapidly eroding salt marsh system: A numerical study. Earth Surface Processes and Landforms, 1– 26. Available from: https://doi.org/10.1002/esp.5308