Mississippi State University
Anna C. Linhoss
Prem B. Parajuli
Date of Degree
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Complete embargo for 1 year
Dissertation - Open Access
Doctor of Philosophy
James Worth Bagley College of Engineering
Department of Agricultural and Biological Engineering
Coastal Louisiana U.S. is facing wetland loss caused mainly by geologic subsidence and sea-level rise. These losses are accelerated by human activities such as the creation of canals and waterways for gas and oil extraction. Wetland loss in coastal Louisiana has encouraged to the implementation of various wetland restoration techniques. Marsh terraces are a one restoration technique consisting of segmented berms of soil that are built in inland coastal ponds. They are designed to increase marsh area, dissipate wind driven waves, encourage marsh expansion, and possibly reduce shoreline erosion. Marsh terraces have been implemented for almost 30 years; however, little research has been conducted to determine their effectiveness at reducing wave energy. Therefore, the overall goal of this research is to find the most optimal terrace design at reducing significant wave height, and therefore wave energy. The specific objectives of this study are to 1) assess terrace performance and longevity over time, 2) simulate wave climates in marsh terrace sites and determine the effectiveness of marsh terraces for the reduction of wave energy, and 3) assess the effectiveness of different terrace designs at reducing significant wave height during low winds and cold front passages in coastal Louisiana. These objectives were accomplished through remote sensing and numerical wave modeling. This study found that there was more predominant deposition than erosion in 20 marsh terrace fields. The study also used a numerical model to simulate small, high frequency waves in two terrace sites, finding an agreement between modeled and observed data. Moreover, wave height was reduced in terrace sites compared to unterraced sites. Finally, it was found that the chevron design is the most optimal terrace design at reducing significant wave height in a variety of wind conditions. This study adds to our knowledge of marsh terrace performance. In this way, marsh terraces may be used as an effective restoration technique at reducing wave energy, not just in Louisiana, but throughout the Gulf Coast, the U.S., and other coasts worldwide that are facing wetland loss.
National Academies of Sciences, Engineering and Medicine. Gulf Research Program. grant number 2000008944
Morillo, Raúl Jefferson Osorio, "Assessment and optimization of marsh terracing for wetland restoration in the northern Gulf of Mexico using remote sensing and a wave model approach" (2021). Theses and Dissertations. 5262.
Available for download on Monday, August 15, 2022