Characterization of Circulation and Salinity Change in Galveston Bay

Abstract

Circulatory change and alteration of salinity in Galveston Bay is investigated numerically by using a three‐dimensional hydrodynamic and transport model. Galveston Bay is an extremely complex and dynamic estuarine system. Tides, freshwater inflows, wind, and bathymetry all affect the circulation patterns and salinity distribution. A thorough understanding of the physical hydrodynamic and environmental impact on the estuary, due to the influences of stream inflows, wind, tides, bathymetry, and pollutant transport, is essential to develop a rich and healthy estuarine ecosystem. A three‐dimensional hydrodynamic and salinity transport model is applied to simulate the whole Galveston Bay. This model solves coupled full Navier‐Stokes equations and salinity transport equations in a curvilinear coordinate system. By inputting freshwater inflows, tide, and wind data into the model, the time variation of the three‐dimensional circulation patterns, free‐surface elevations and salinity profiles are obtained to describe this dynamic system. A curvilinear grid of the Galveston Bay is generated for computation. A monthly simulation has been conducted to study the tide and freshwater induced circulation. The free‐surface elevations and salinity distribution are also presented. The predicted free‐surface elevations in the bay are in good agreement with the field measurements. The results also indicate that the bottom salinity in the bay increases during a monthly tidal‐forcing. The impact of velocity and the salinity field caused by the freshwater inflows are discussed.