Recovery Times of Salinity in Galveston Bay: Comparison of Impact from Hurricanes versus Riverine Flooding

Wind driven-circulation and freshwater inflow can drive rapid salinity fluctuations within the shallow bays of the Texas Gulf Coast. Such salinity fluctuations can have far-reaching impacts on the physiological processes of estuarine organisms. Hurricanes and non-hurricane induced flood events are common disturbances to Texas estuary ecosystems, delivering significant amounts of freshwater inflow which can increase shallow water habitat, contribute to the dilution of harmful contaminants, maintain low salinity nursery habitats, and enhance the biogeochemical cycling of essential nutrients (Longley 1994). This study aims to examine salinity changes in the mid-Galveston Bay from inflow delivered by ten landfall hurricanes compared to two riverine flood events. Daily salinity data derived from the TxBLEND 2D hydrodynamic model from 1982 to 2015 was combined with long-term datasonde observations from 1986 to 2018 to determine the change in salinity due to storm and flood events. Major riverine flood events, of 1992 and 2015, of the Brazos and Blanco rivers, respectively, maintained salinity below 5 PSU for 2-3 months throughout mid-Galveston Bay. There were no inflow events resulting hurricanes, including Harvey, which maintained salinity below 5 PSU for the same duration. Determining the differences in impact between these extreme weather events is important for characterizing future salinity recovery times for estuarine habitats.