CAREER: Morphodynamics of Mixed-Energy Tidal Inlets: Sediment Bypassing Processes

人口主要集中在沿海地区，因此，沿海生态系统是世界上受影响和改变最严重的环境之一。由于海平面、风暴强度和人类活动的增加，我们迫切需要更好地了解沿海的水流动力学、泥沙运输以及海岸线和海底形状的变化（形态动力学）。过去，人们曾试图更好地了解和预测沙滩地区的海岸线演变。然而，河口和邻近海滩对外力（如波浪、潮汐、河流流出）的形态动力学响应却很少受到关注。尽管如此，入口在与河口、邻近海滩和后屏障泻湖相关的各种生态、经济和社会服务中发挥着关键作用。该项目的主要研究目标是提高对导致泥沙从进水口上漂向下漂（旁路）的过程的理解。研究人员将分析潮-潮三角洲上沙洲向岸边移动的主要过程，潮-滨流相互作用如何影响沿岸和跨岸沉积物的输运，以及次重力波的形态动力学效应。该项目还将整合实践经验，以加强海岸形态动力学的教学。将针对中学科学教师编写课程和教材，并对研究生进行培训，使其在高中阶段运用建构主义方法进行学习。由于高度时空变化的形态、波浪、潮汐、河流流量和混合条件之间的复杂反馈，混合能入口的形态动力学尚未完全了解。入口形态动力学的关键过程之一是泥沙旁路。它影响了进水口的泥沙收支和内湾、滩涂三角洲及邻近滩涂的供沙。最被接受的进口旁路概念模型可以从两个改进中获益。首先，潮退三角洲上的冲积沙洲可能不会被运送到岸上，主要原因是海浪冲刷。相反，它们应该主要由表层洋流输送。此外，沿海流不仅在波浪主导的进气道中，而且在混合能量的进气道中，都有助于进气道的旁路。潮汐和沿岸流如何相互作用并影响沿入口和穿过入口的沉积物运输值得进一步研究。亚重力波也可能在入口沉积物输运过程中起主要作用。该项目将结合马坦萨斯入口（FL）的现场和远程现场观测和数值模拟，分析、测试和整合这些过程，以提高我们对混合能量入口沉积物运输过程的认识。这项研究的结果将有助于我们更好地了解这些沿海系统的动态，并有助于改进沿海管理工具和程序。通过PI研究小组的研究生参与教育活动，将促进研究和教育。该团队将与佛罗里达大学大学预科教育和培训中心合作，开发并实施面向高中生和中学科学教师的四门5E课程。此次合作将为研究生提供在高中阶段应用5E教学方法的培训机会。作为这个项目的一部分，还将为面向中学科学教师的暑期学院课程开发一个课程模块。通过这一合作计划与教师的直接互动将促进海岸形态动力学（海滩、河口和入海口）的关键概念纳入K-12科学课程。

Human populations are strongly concentrated along the coasts, and, consequently, coastal ecosystems are some of the most impacted and altered environments worldwide. Due to increasing sea levels, storm intensities, and human activities, there is an imperative need to better understand coastal dynamics of flow, sediment transport, and changes in the shape of the coastline and the bottom (morphodynamics). In the past, there have been some attempts to better understand and predict coastline evolution of sandy beach areas. However, the morphodynamic response of estuary mouths and adjacent beaches to external forces (e.g. waves, tides, river outflows) has received less attention. Nonetheless, inlets play a key role in the wide variety of ecological, economic, and social services associated with estuaries, adjacent beaches, and back-barrier lagoons. The main research goal in this project is to improve the understanding of the processes that lead to sediment movement from the up-drift to down-drift sides of inlets (bypassing). The investigator will analyze the main processes driving the shoreward movement of sand bars over the ebb-tidal delta, how the interactions between tidal and littoral currents affect the alongshore and cross-shore sediment transport, and the morphodynamic effects of infragravity waves. The project will also integrate hands-on experiences to enhance the teaching of coastal morphodynamics. Lessons and educational material will be produced targeting secondary science teachers, and graduate students will be trained and engaged in applying a constructivist approach to learning at the high school level.Morphodynamics of mixed-energy inlets are still not fully understood due to the complex feedbacks between the highly temporally and spatially varying morphology, waves, tides, river flow, and mixing conditions. One of the key processes in inlet morphodynamics is sediment bypassing. It affects the sediment budget of the inlet and the sand supply to the inner bay, ebb-tidal delta, and adjacent beaches. The most accepted conceptual models of inlet bypassing could benefit from two improvements. First, swash bars over the ebb-tidal delta may not be transported onshore due, primarily, to wave swash. Rather, they should be primarily transported by surfzone currents. Additionally, littoral currents contribute to inlet bypassing not only in wave-dominated inlets, but also in mixed-energy inlets. How tidal and littoral currents interact and affect sediment transport along and across the inlet deserves additional studies. Infragravity waves might also play a primary role in inlet sediment transport processes. This project will combine in situ and remote field observations and numerical modeling at Matanzas Inlet (FL) to analyze, test and integrate these processes to improve our knowledge of sediment transport processes in mixed-energy inlets. Findings generated from this study will help us better understand the dynamics of these coastal systems and will contribute to the improvement of coastal management tools and procedures. Research and education will be fostered through the involvement of the graduate students in the PI's research group in the educational activities. In collaboration with the Center for Precollegiate Education and Training at the University of Florida, the team will develop and implement four 5E lessons geared towards high-school students and secondary science teachers. This collaboration will provide the graduate students with the opportunity to be trained in the application of the 5E instructional method at the high-school level. A curricular module for a Summer Institute course directed towards secondary science teachers will also be developed as part of this project. The direct interaction with teachers through this collaborative initiative will promote the inclusion of key concepts of coastal morphodynamics (beach, estuaries, and inlets) into the K-12 science curriculum.