The impact of inserting new bridge openings in the State Road 331 Causeway on the salinity and circulation of Eastern Choctawhatchee Bay is investigated numerically using a three-dimensional hydrodynamic and salinity transport model. Choctawhatchee Bay is a complex and dynamic estuarine system. Tides, freshwater inflows, wind, and bathymetry constitute parameters that affect circulation patterns and salinity distributions of this bay. An understanding of the physical, hydrodynamic, and environmental impacts on the bay due to these influences is important to understand how incorporation of bridge openings might impact the health of this estuarine ecosystem. A three-dimensional hydrodynamic and salinity transport model is applied to simulate the entire bay system. This model solves the Navier-Stokes and salinity transport equations in a Cartesian coordinate system. By inputting freshwater inflows, tides 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 the dynamic system. A bimonthly simulation was conducted to study the tide and freshwater induced circulation. The predicted salinity and velocity are in good agreement with the limited field measurements and the model adequately represents the physical system within the limits imposed by the small data set available. Simulations examined six scenarios during a particularly wet period. Surface flows appeared to be most affected by the presence of the causeway while the flows in the deepest areas appear to be more influenced by topography. Because of the location of the larger opening of the SR 331 Causeway, little change in bottom conditions was apparent when compared against the no-causeway scenario. Of the six scenarios, the 725m opening most closely resembled the no-causeway case and was significantly different than the other, smaller opening cases. Based on the simulation conducted here, it appears that it would take an opening or combination of openings of significant size to return the flow fields back to natural conditions.

  • Supplemental Notes:
    • Water Resources Special Report 94-5.
  • Corporate Authors:

    Northwest Florida Water Management District

    Route 1, Box 3100
    Havana, FL  United States  32333-9700

    Florida Department of Transportation

    Haydon Burns Building, 605 Suwanee Street
    Tallahassee, FL  United States  32301

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Jones, W K
    • Huang, Wei
  • Publication Date: 1994-12


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 59 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00676455
  • Record Type: Publication
  • Report/Paper Numbers: FL/DOT/RMC/637-4517, WPI 0510637, State Job 99700-7589-119
  • Contract Numbers: FDOT HPR Study No. 0637, C-4517
  • Created Date: Mar 31 1995 12:00AM