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 to 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.