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设定了栖息地，并控制了河流泛滥平原和沿海地区的土地稳定性。虽然人们对砂质系统的行为有了很好的了解，但关于沙子与粘土和泥土等更细的沉积物之间的相互作用的信息却很少。粘土-沙混合沉积物在河流和沿海河口非常常见，但目前还不可能预测粘土-沙混合物的重要行为，如沙丘、海滩和河道在海岸线侵蚀后的变化。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。这种能力将使美国能够更好地管理关键水资源，减少海岸侵蚀造成的破坏，并为沿海浅水水域的航运和军事行动提供便利。该项目旨在说明粘土-砂-水耦合遵循一套规则和基本的过程：粘土迁移到砂层中，粘土沉积积累，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团队联合进行。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-沙子动力学和沉积物床形成。这些结果将用于开发新的数学理论和计算机模型，从而能够预测粘土-砂土系统中的水流和泥沙动力学。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.