Currents and Circulation in the Coastal Waters of Louisiana




Murray, S. P.

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Center for Wetland Resources, Louisiana State University


A review of our knowledge of circulation and currents in the coastal water of Louisiana indicates that, despite notable progress in a few specific areas, we lack a rudimentary knowledge of the mechanics of water motion along most of the coastline. The Mississippi River salt wedge and the mixing of its effluent plume into the open water of the Gulf of Mexico are generally understood, but detailed salt balance and turbulent mixing studies should now be undertaken. The portion of the Louisiana shelf within the area 80 km west of the Mississippi has been studied in detail with regard to tidal currents, long-term drift, hydrography, and local wind drift. Outside of this area, apparent ignorance prevails except for seasonal salinity patterns and the occasional isolated study. Summer current reversals toward the east and high tidal ranges in the vicinity of Calcasieu Lake, for example, remain unexplained. Detailed knowledge of the dynamics of our prolific coastal bays and estuaries is embarrassingly poor. Numerical modeling perhaps offers a shortcut to overcoming this disadvantage, but realistically this technique will only be effective after the controlling forces are better defined and understood by dynamically oriented field studies. Existing numerical models of Barataria Bay and Chandeleur-Breton Sound are cases in point. Tidal passes, minor river mouths, and the circulation within the wetlands proper have been subject to sporadic short-term measurement programs, but definitive studies of the flux of mass, heat, salt, and other important scalars have yet to be performed. A list of research priorities to eventually allow better utilization of our coastal waters is presented at the end of this report.


33 pages; available for download at the link below.


wetlands, coastal currents, ocean currents, ocean circulation