Hydrodynamic responses of estuarine bays along the Texas-Louisiana coast during Hurricane Harvey

Hurricane Harvey (2017) delivered an extraordinarily large amount of freshwater, sediment, and pollutants to the Texas-Louisiana (TX-LA) coastal ocean. While the impact of extreme precipitation and river discharge on the freshwater plumes has been investigated, the role of winds has rarely been addressed. Using a 3D creek-to-ocean mode, SCHISM, we conducted numerical experiments including/excluding wind effects and quantitatively assessed the wind impacts on the freshwater plumes from four estuarine bays along the TX-LA coast including Galveston Bay, Sabine Lake, Calcasieu Lake, and Vermilion Bay. Our results indicate the important role of wind in shaping the freshwater plumes and circulations around the four bays, and highlight the wind induced circulations in the four bays under varying wind conditions during Hurricane Harvey from August 26 to September 2, 2017. In addition, the volume and salt fluxes between these bays and the coastal ocean are compared between the experiments with or without wind. In addition, a Lagrangian particle tracking is used to track pollutants released from these bays. The wind is found to exert a great impact on the trajectories of the particles released from Galveston Bay, Sabine Lake, and Calcasieu Lake, extending the particles 10-50 km further southward (seaward) and 50-100 km westward compared to the case without wind. For Vermilion Bay, particles would not have been transported outside of the bay without wind but were transported 170 km westward away from the bay with wind. Lastly, the residence times in the four bays are calculated. Vermilion Bay has the longest residence time pre- (-34 days) and post-Hurricane (-5 days). Our results demonstrate that the wind associated with Hurricane Harvey had a significant impact on the exchange between the estuarine bays and the coastal ocean along the TX-LA coast.