| This study aims to develop an enhanced version of a three-dimensional curvilinear-grid modeling system, CH3D-IMS, which include a 3-D hydrodynamics model, a 3-D sediment transport model, and a 3-D water quality model, to simulate circulation and water quality of the Charlotte Harbor Estuarine System and to provide quantitative assessment of various management practices.; In the past decade, the upper Charlotte Harbor system has been suffering summer hypoxia in bottom water. Field study indicated that hypoxia in the upper Charlotte Harbor is related to a strong stratification caused by high freshwater flows and dissolved oxygen fluxes at the air-sea and sediment-water interfaces. To simulate the hypoxia event, models of oxygen balance and oxygen fluxes at the air-sea and sediment-water interfaces in previous versions of CH3D-IMS are enhanced. The three dimensional temperature model and physics-based light model in CH3D-IMS are also enhanced to enable better understanding of the temporal and spatial variations of temperature and light and their effect on water quality processes.; The water quality model of the CH3D-IMS was calibrated with the systematic calibration procedure and validated using hydrodynamic, sediment, and water quality data provided by the USGS and the United States Environmental Protection Agency (USEPA) in 1996, and by the USGS, the South Florida Water Management District (SFWMD) and the Southwest Florida Water Management District (SWFWMD) in 2000. This validated model was used to examine the temporal and spatial dynamics of factors which can affect hypoxia in upper Charlotte Harbor, such as freshwater inflow, tidal variation, sediment oxygen demand (SOD), water column oxygen consumption, and dissolved oxygen (DO) re-aeration. The model results suggest that hypoxia in the upper Charlotte Harbor System is primarily caused by a combination of vertical salinity stratification and SOD, while water quality also affected by the oxygen re-aeration and water column oxygen consumption. This model was applied to assess the effects of hydrologic alterations and to provide a preliminary evaluation of pollutant load reduction goal (PLRG). (Abstract shortened by UMI.)... |
