Collaborative Research: Large-scale laboratory investigation and numerical modeling of sheet flow sediment transport dynamics across a surf zone sand bar

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Currently model predictions of beach erosion events are not very reliable because they do not account for all the complex physical processes that occur in the nearshore environment. Further study of nearshore physics will lead to improvements in coastal models. This study will investigate mechanisms that drive sediment transport across sand bars using a combination of laboratory experiments and numerical models. Previous studies have shown that movement of sediment in the surf zone is caused by breaking waves that stir up sediment on the seafloor and near-breaking waves that drive water near the bed offshore. As this water moves offshore, it takes sediment with it. Further study is required to determine the relative importance of these mechanisms under various wave conditions. Intellectual merit: This three-year project will investigate the detailed sediment transport processes associated with a surf-zone sand bar. Experiments will be conducted in a large-scale wave flume with a fixed beach form and two sand pits. Several novel sensors will be employed to measure velocity, pressure, and sediment concentration in the water. The combined laboratory and numerical experiments will lead to improvements in understanding and model prediction. Broader Impacts: The project team will conduct two educational outreach efforts. The first effort will use a portable wave flume to demonstrate storm and sea level rise response of the beach profile to middle school students, impacting approximate 350 students per year. The second effort will involve developing a permanent educational display on coastal erosion for the general public at the Hatfield Marine Science Center. Three PhD students will be trained in state-of-the-art laboratory and numerical approaches to near-shore dynamics in this project, and two to three undergraduate students per year will gain hands-on research experience in conducting laboratory experiments. This project will foster international exchange by including two researchers from The Netherlands and Japan. Graduate students will be given the opportunity to visit laboratories in both countries.