effects and any surface or bottom influences. West and Reid (1972), using a 

 two-layer quasi-geostrophic model, were able to qualitatively simulate the 

 annual cycle of Loop Current intrusion. Hurlbert and Thompson (1980) used a 

 similar model, a barotropic and a reduced gravity model to simulate the 

 dynamics of the Loop Currents and its eddy shedding. 



Past studies on sediment dynamics in the Mississippi Sound and offshore 

 areas are even more scarce. The primary source of sediment in the study area 

 is sediments derived in the large river basins. The Mississippi River has 

 contributed and still contributes large amounts of sediments to the western 

 reach of the study area. To a smaller degree, the Pearl, Pascagoula, and 

 Mobile Rivers also introduce considerable quantities of sediments into the 

 Mississippi Sound and the Mobile Bay (Boone, 1973). Based on limited studies, 

 Upshaw, et al. (1966) indicated the overall surface sediment distribution 

 pattern of the study area as shown in Figure 1.3. In general, the surface 

 sediments in the offshore area become increasingly coarse eastward, from the 

 silty sediments off the Mississippi Delta to the sandy sediments off the 

 Florida Coast. 



1.5 Purpose and Scope of the Present Study 



The major purpose of this study is to construct the framework of a 

 predictive mathematical model for coastal currents and sediment transport. 

 The basic framework that we intend to follow is shown in Figure 1.4. A 

 comprehensive model constructed from this framework, we believe, should 

 ultimately meet the need for impact analyses of a wide variety of coastal 

 projects within the Corps of Engineers. 



Our approach combines the efforts of mathematical modeling, laboratory 

 experiments, and field studies. Of primary importance in this study is the 

 development of a comprehensive and efficient three-dimensional hydrodynamic 

 model of coastal currents. At the early stage of the present study, extensive 

 hydrodynamic data were being collected within the Mississippi Sound. These 

 data are used to compare with predicted results of the three-dimensional 

 hydrodynamic model. In addition, laboratory experiments are carried out to 

 quantify the settling, deposition, and entrainment of cohesive sediments from 

 the Mississippi Sound. Other aspects studied include the effect of turbulence 



