Collaborative Research: NSF/EAR-BSF: Coupled Sand and Clay Motion, Bed Morphodynamics, and Porewater Exchange

水和沉积物之间的相互作用塑造了水体，为鱼类、贝类和其他水生生物提供了栖息地，并控制着河流漫滩和沿海地区的土地稳定性。虽然桑迪系统的行为是相当好的理解，砂和更细的沉积物，如粘土和泥之间的相互作用的信息很少。粘土-砂混合沉积物在河流和沿海河口中非常常见，但目前还不可能预测粘土-砂混合物的重要行为，例如沙丘、海滩和海岸线侵蚀后的通道的变化。该项目将提高测量和预测淡水和海洋系统中水流、沙子和粘土之间相互作用的能力。这一能力将使美国关键水资源得到更好的管理，减少海岸侵蚀造成的损害，并促进沿海浅水沃茨的航运和军事行动。该项目旨在表明，粘土-砂-水耦合遵循一套规则和基本的过程：粘土迁移到砂层，粘土沉积物的积累，以及粘土填充孔隙空间和胶结砂粒的反馈。这项工作将由美国和以色列的研究小组联合进行。实验将使用一套新的光学，声学和X射线成像方法来测量水流，粘土砂动力学和沉积物床的形成。这些成果将被用于开发新的数学理论和计算机模型，从而能够预测粘土-砂系统中的水流和沉积物动力学。该奖项由地貌学和土地利用动力学计划、水文科学计划和国际科学与工程办公室共同资助。

Interactions between water and sediments shape water bodies, set habitat for fish, shellfish, and other aquatic organisms, and control land stability in river floodplains and coastal regions. While the behavior of sandy systems is fairly well understood, little information is available on interactions between sand and finer sediments such as clay and mud. Mixed clay-sand deposits are very common in rivers and coastal estuaries, yet it is not currently possible to predict important behavior of clay-sand mixtures, such as changes in sand dunes, beaches, and channels following shoreline erosion. This project will advance capability to measure and predict interactions between water flow, sand, and clay in freshwater and marine systems. This capability will enable better management of critical U.S. water resources, reduce damage from coastal erosion, and facilitate shipping and military operations in shallow coastal waters. This project aims to show that clay-sand-water coupling follows a regular and fundamental set of processes: migration of clay into sand beds, accumulation of clay deposits, and feedbacks from clay filling pore spaces and cementing sand grains. Work will be conducted jointly by U.S. and Israeli research teams. Experiments will use a suite of new optical, acoustic, and X-ray imaging methods to measure water flow, clay-sand dynamics, and sediment bed formation. These results will be used to develop new mathematical theory and computer models enabling prediction of water flow and sediment dynamics in clay-sand systems.This award is cofunded by the Geomorphology and Land-use Dynamics Program, the Hydrologic Sciences Program, and the Office of International Science and Engineering.