Doctoral Dissertation Research: Investigation of Factors Controlling the Dynamics of Beach-Surface Moisture Content

Louisiana State University, Baton Rouge LA

Investigators

Abstract

The spatial and temporal variability of beach surface moisture content is widely recognized as a critical parameter affecting the operation of aeolian sediment transport systems, and therefore represents a critical control on coastal dune development over time. A number of recent studies have investigated the variability of beach surface moisture content; however, a practical method to model or simulate the considerable spatial and temporal variability in surface moisture revealed by these studies remains elusive. This variability is controlled by complex interactions between a suite of hydrological, meteorological and sedimentary parameters that include precipitation, groundwater flow, capillary transport, evaporation, condensation, soil texture, and tidal oscillations. Accurate modeling of surface moisture content requires more precise relationships describing the interactions between these controlling parameters and their influence on beach surface moisture dynamics than are currently available. The fundamental goal of this doctoral dissertation project is to develop these relationships. In order to accomplish this objective, a series of field and laboratory experiments will be conducted to monitor the dynamics of surface moisture content in conjunction with fluctuations in these controlling parameters. Field investigations for this study will be conducted at Padre Island National Seashore, Texas to monitor the influence of the controlling hydrological and meteorological parameters on the dynamics of surface moisture content. Sediment texture has a profound influence on beach hydrology and it is to be expected that the relative magnitudes and influences of the key processes under investigation will vary at beaches with differing sediment characteristics. Therefore, in order to enhance the applicability of this study, a series of laboratory experiments will be conducted to document the influence of sediment texture on surface moisture dynamics. Results of this project will both broaden and deepen our understanding of beach hydrology, specifically in relation to the spatial and temporal dynamics of beach surface moisture content. This knowledge is vital to improving our ability to forecast both short and long term dune recovery from storm erosion. In addition, the basic understanding of surface moisture dynamics resulting from this study will contribute to an extensive range of important issues where surface moisture content has a significant impact, such as ecosystem structure and development, environmental management applications, global climate modeling and earth-atmosphere energy fluxes, and the terrestrial hydrologic cycle. For example, this research has the potential to contribute to enhancement of precipitation prediction associated with global climate change models, as surface moisture dynamics has a profound effect on the development local climatic circulation patterns. It may also contribute to the literature on coastal water resource management issues. With increasing anthropogenic pressure on coastal hydrological systems, proper knowledge and understanding of beach hydrology is paramount to consideration of the dispersal of contaminants through the soil matrix which is highly sensitive to the spatial and temporal dynamics of moisture content.