Physical Processes and Drivers on Landscapes in Coastal Louisiana and Cape Cod, Massachusetts

• Main Author: Green, Mandy Michelle
• Other Authors: De Hoop, Cornelis F
• Format: Others
• Language: en
• Published: LSU 2012
• Subjects: Geography & Anthropology
• Online Access: http://etd.lsu.edu/docs/available/etd-11132012-121722/

This dissertation comprises an analysis of wind frequency and magnitude data and resulting sand transport for Cape Cod, Massachusetts; wind speed and wave height data for coastal Louisiana; and habitat classification and elevation data for a retrogradational barrier island in coastal Louisiana. Chapter 2 presents an analysis of wind data for Cape Cod, Massachusetts in which annual, seasonal, niño, and storm-related wind patterns were investigated to analyze the potential for aeolian sand transport in a blowout dune located on Cape Cod. Results indicate that wind patterns, drift potential, and drift direction are seasonal. Sand drift potential varies at specific locations within the blowout dune based on the mean grain size for each morphological feature (i.e., deflation basin, depositional lobe, etc.). Winds above the threshold for sediment velocity occur during every season and topographic alteration and acceleration of winds can drive sand movement in a direction that is distinctly different from blowout orientation. Chapter 3 discusses several techniques (Gumbel and Beta-P probability distributions; Southern Regional Climate Center and Huff-Angel regression methods) used to derive quantile estimates (return period and event magnitude) for extreme wind speed and wave height events resulting from tropical, frontal, and airmass thunderstorm weather events in coastal Louisiana. Results indicate that the Huff Angel regression method provides the best fit distribution for the majority of wind speed and wave height data sets analyzed. The methods described here to derive wind speed and wave height quantile estimates should be considered when determining the impact of wind and wave processes on restoration projects in coastal Louisiana. Chapter 4 provides a classification of the habitats on Whiskey Island, a retrogradational barrier island along the Louisiana coast, as well as a comparison of habitat change over time and the elevation at which vegetated habitats occur. Specific attention is paid to the emergent and woody vegetation present on the back barrier marsh of the island. The analyses indicate that without continued restoration and maintenance of the island, the effects of sea level rise, subsidence, storms, and other physical processes may render the island incapable of supporting the vegetation that currently colonizes the island.