2023 CSDMS meeting-096
Representing fluxes within upper Galveston Bay using ROMS (Regional Ocean Modeling System): Initial efforts toward a coupled hydrological / oceanic / sediment transport model
Zhiyun Du, Virginia Institute of Marine Science Gloucester point Virginia, United States. email@example.com
Courtney Harris, Virginia Institute of Marine Science Gloucester Point Virginia, United States. firstname.lastname@example.org
Dongxiao Yin, Virginia Institute of Marine Science Gloucester Point Virginia, United States. email@example.com
Daoyang Bao, Louisiana State University Baton Rouge Louisiana, United States. firstname.lastname@example.org
A critical part of predicting and representing coastal responses during large storms is to represent the areas of compound flooding where both oceanic factors (tides and surge), and hydrologic factors (i.e., rainfall-runoff processes), as well as their interactions impact water levels and flow velocities. During extreme events, these compound flood waters can remobilize thick layers of sediment, exposing material that had been buried for many years. One such event was Hurricane Harvey which made a landfall along the Texas Gulf Coast (US) on August 26, 2017. Within Galveston Bay, compound flooding occurred and persisted for weeks as the result of the interaction between the storm surges created as storm approached the coast, and a subsequent long-lasting flood pulse induced by the torrential rainfall associated with the hurricane. The flooding mobilized thick layers of sediment, including contaminated sediment from the Buffalo Bayou shipping channel. Sediment core data taken after the storm showed that these contaminants were transported several 10s of km. To predict the response of this type of event requires numerical models that can account for the rainfall-runoff processes, sediment erosion and transport, and oceanographic processes including storm surges, tides and wind-driven currents. These types of coupled models are currently being developed and tested as part of the NOAA funded Coastal Ocean Modeling Testbed (COMT). The eventual goal of our project is to develop the capability to represent compound flooding and the associated particulate and contaminant fluxes across the river – to ocean continuum. Specifically, we plan to link a hydrological model (WRF-Hydro) to a Galveston Bay hydrodynamic model (ROMS) and apply it to large compound flooding events such as Hurricane Harvey. A higher resolution model capable of representing the Buffalo Bayou shipping channel will then be nested within the Galveston Bay model and used to reproduce sediment erosion and contaminant exposure patterns that were observed in the wake of Hurricane Harvey. In this poster we present preliminary model development that links the high – resolution (~20m) hydrodynamic model of Buffalo Bayou with the lower – resolution (~100 m) hydrodynamic model of Galveston Bay. The 20-m model grid resolves the relatively deep shipping channels and is being used in initial model runs to represent typical conditions in the upper Galveston Bay and Buffalo Bayou shipping channel.