Date of Award

1994

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Oceanography and Coastal Sciences

First Advisor

John W. Day, Jr

Abstract

Processes leading to land loss in Louisiana are defined, measured and analyzed with special emphasis on the deposited and suspended sediment budgets. The findings were used to assess coastal management in Louisiana. In a spatial model of long term habitat succession, the degradation of a Louisiana wetland was based upon simulated exchanges of sediments across irregularly shaped polygons. Habitat distribution within a cell was estimated by elevation. The model findings were confirmed when the impact of two Louisiana marsh management plans caused reduced short-term sedimentation due to impaired water and materials flux. The sedimentation-erosion table (SET) is described and applied to assess the effect of experimental sediment fences on the elevation developments in intertidal and shallow sub tidal areas. The SET is precise to within a 1.5 millimeter range. SET measurements made over a three year period showed a significant elevation increase of 1.38 cm/yr at sites close to sediment fences, and a non significant decrease of $-$0.73 cm/yr at sites away from the fences. The wave transmissivity coefficient for sediment fences is presented. The potential impact of Louisiana marsh management and sediment fences on elevation changes and subsequently vegetation establishment were evaluated with the use of the hydrodynamic sector of the General Ecosystem Model (GEM) which was calibrated for intertidal water bodies. The results of this research are important because they provide more insight on the sediment dynamics of coastal wetland systems and the potential impact of different management options. The simulation models are designed to predict spatial changes and potentially can be used to develop dynamic geographic information systems (GIS).

Pages

164

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