Atmospheric cold fronts are frequently occurring perturbations to the northern Gulf of Mexico coastal region. Given the low-lying elevations in this region and the connectivity between distributary channels and deltaic wetlands, the nonlinear interplay between the cold frontinduced storm surge and tidal oscillations are likely important hydrodynamic processes regulating circulation and sediment dynamics. This study uses the Delft3D Flexible Mesh numerical modeling suite to assess the water level fluctuations resulting from the non-linear interaction between cold front induced storm surge and tidal oscillations in Wax Lake Delta (WLD) between December 2022 and January 2023. The WLD is a small, dynamic sub-delta located in Louisiana, USA, known for its ongoing progradation. The primary focus of this study lies on analyzing two cold fronts that approach from the northwest direction. The results illustrate that within the shallow, vegetated wetland interiors with spatially-variable inundation, the water level fluctuations resulting from non-linear interaction can exceed four times the water depth, while the variations relative to the water depth in the relatively deep primary channels are insignificant. Analysis for two cold fronts from the northwest and further numerical experiments revealed that the water level variation response to the non-linear interaction between the cold front storm surge and tides is predominantly influenced by the intensity of the cold front and the magnitude of the tidal range. This study emphasizes the notable impact of the non-linear interaction between cold front and tide on water level variation, which, in turn, influences inundation extent, sediment transport, and ecological factors in the WLD.  

AGU 2023, H51N-1280, San Francisco

Link: https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1293693