Quantifying Coastal Marsh Erosion Using a LIDAR Terrestrial Laser Scanner: The Role of Waves, Soil, and Vegetation
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Coastal marshes on the Gulf Coast of Texas are an important transition zone between the ocean and land, acting as an ecological buffer and providing invaluable ecosystem services to people and the surrounding environment. Accelerated erosion threatens the stability of these regions and a greater understanding of the interacting processes is vital to the preservation of coastal marshes. The central objective of this study is to evaluate the impacts of wave energy, vegetation, and soil properties on coastal marsh edge erosion. To accomplish this, the first objective was to quantify tidal marsh edge erosion across temporal and spatial scales using TLS. The second objective was to evaluate the relationships between marsh edge erosion and incident wave energy. The final objective was to assess the correlation between vegetation roots and marsh edge erosion as well as the correlation between soil properties and marsh edge erosion. The study area is on an eroding edge of a salt marsh wetland known as Anchor Bay, located at the terrestrial-aquatic interface of Galveston Island and West Bay specifically, between Melager Cove and Oxen Bayou. Galveston Island is a barrier island on the Texas Gulf Coast, located about 50 miles southeast of Houston, Texas, U.S.A. Many methods were used to accomplish the objectives including LIDAR and photographic surveying, point cloud change analysis, wave modeling, image classification and soil analysis for bulk density, percent organic matter, and sediment grain size. Overall, lateral marsh edge erosion at the study site for the duration of the study was relatively large with greater than 1 meter of erosion observed at the study site in a 318 day period. Wave heights, as driven by wind direction and speed, affected the erosion at the study site. The site was prone to greater erosion when winds blew from the east-northeast to the north directions, and from the north-northwest to the west directions. While root concentration did not play an apparent role in preventing erosion, soil properties did have some influence on erosion.
Delgado Jr., Arturo (2016). Quantifying Coastal Marsh Erosion Using a LIDAR Terrestrial Laser Scanner: The Role of Waves, Soil, and Vegetation. Master's thesis, Texas A & M University. Available electronically from