Doctor of Philosophy (PhD)
The first and most critical step in any coastal hydrodynamics and transport process modeling is identifying land-water boundaries. In a coastal wetland, this has always been a challenge due to the complexity of the wetland and lack of efficient methods, calling for efficient and effective methods to extract and digitize the shorelines. While coastline feature extraction has been increasingly researched, its application in hydrodynamic and environmental modeling, without morphological adjustment, remains limited and suboptimal. Further, there has been a paucity of cost-effective, contextually adaptive and high-quality methods to generate meshes, especially for coastal hydrodynamic modeling. This study has developed and demonstrated innovative, automatic, efficient, cost-effective and high-quality methods for addressing the above needs. Specifically, the study has developed a library of unique algorithms to digitize, morphologically adjust shorelines, and yield finished geometries for hydrodynamic and environmental modeling by employing a hybrid remote sensing and image processing method. The study has also developed a novel element sizing algorithm for generation of high-quality unstructured grids. The study derived mathematical formulations for computations of three components of hydroperiod in a coastal wetland. The major methods developed in this dissertation, including automatic shoreline extraction, the element sizing algorithm for mesh generation; and mathematical formulations of hydroperiod components, have direct advantages to hydrodynamic modeling efforts and its application to ecosystem modeling. The application of the methods was demonstrated using Advanced CIRCulation (ADCIRC) hydrodynamic model. The ADCIRC model was used to simulate hydroperiod in a coastal wetland and captured the spatial and temporal dynamics of hydroperiod, hydrologic signature of the wetland. The results have been evidenced with suitable examples, and model runs with verifiable findings and quality checks.
Kefelegn, Henok, "Automatic Shoreline Digitization and Mesh Element Sizing for Hydrodynamic Modeling" (2020). LSU Doctoral Dissertations. 5133.