Collaborative Research: Catchments and Coastlines--The Influence of Sediment Load and Type on Delta Morphodynamics and Deposits

合作研究：流域和海岸线--沉积物负荷和类型对三角洲形态动力学和沉积物的影响

• 批准号: 1329542
• 负责人: Doug Edmonds
• 金额: $ 5.68万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-11-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1329542&HistoricalAwards=false
• 关键词: Collaborative; Research; Catchments; Coastlines; Influence

The various shapes of river deltas were thought to be dependent mainly upon downstream processes, such as the wave- and tidal-power of the ocean basin and the energy flux of the river, but recent work has suggested that upstream controls, such as load and sediment type (i.e. cohesive vs. noncohesive sediment) may also be a major factor controlling delta morphology. The PIs propose a theoretical and field study of how sediment load and type,and thus source terrain, control a delta?s planform morphology and internal stratigraphy. A series of numerical experiments using Delft3D, a morphodynamic physics-based model simulating 3D fluid flow and sediment transport, will extend the parameter space of earlier work by varying sediment fluxes and grain size distributions of a parent river subject to one flood wave per year.A final set of experiments will include the effects of wave and tides. The numerical predictions will be compared to cores, serial aerial photography, bathymetry, and ground penetrating radar datasets from modern deltas representing end-members of the modeling results. Candidate deltas include Wax Lake and Mossy deltas of Louisiana and Saskatchewan, and El Coyote fan delta on the western coast of the Gulf of California, where already existing data will be supplemented by limited fieldwork, Pleistocene shelf-edge deltas such as off Apalachicola, FL, and ancient deltas such as the Cretaceous Ferron and Panther Tongue deltas of Utah. A better understanding and predictive capability of delta planform and stratigraphy could improve our ability to predict coastline evolution in the face of changes in sediment feed volume and type and changes in the rate of creation of accommodation space due to global and local sea level rise. Broader Impacts Resulting from This Study: The lead PI?s involvement with the National Center for Earth-surface Dynamics will ensure that this work will contribute to the science needed to restore the Mississippi delta and reverse the trend of land loss. This work will also be the dissertation topic and financial support for two graduate students and theses for two undergraduate students. All students will benefit from exposure to a problem requiring the integration of geomorphology, sediment transport, hydrodynamics, and morphodynamic modeling.

人们认为河流三角洲的各种形状主要取决于下游过程，例如海洋盆地的波浪和潮汐能以及河流的能量通量，但最近的研究表明上游控制，例如负荷和沉积物类型（即粘性沉积物与非粘性沉积物）也可能是控制三角洲形态的主要因素。 PI 提出了关于沉积物负荷和类型以及源地形如何控制三角洲平面形态和内部地层的理论和实地研究。使用 Delft3D（一种模拟 3D 流体流动和泥沙输送的基于形态动力学物理的模型）进行的一系列数值实验将通过改变每年遭受一次洪水波的母河的泥沙通量和粒度分布来扩展早期工作的参数空间。最后一组实验将包括波浪和潮汐的影响。数值预测将与代表建模结果最终成员的现代三角洲的岩心、连续航空摄影、测深和探地雷达数据集进行比较。候选三角洲包括路易斯安那州和萨斯喀彻温省的瓦克斯湖和莫西三角洲，以及加利福尼亚湾西海岸的埃尔狼扇三角洲，其中现有的数据将通过有限的实地工作、更新世陆架边缘三角洲（例如佛罗里达州阿巴拉契科拉附近）进行补充以及古老的三角洲，例如犹他州的白垩纪费龙三角洲和黑豹舌三角洲。更好地理解和预测三角洲平面和地层学的能力可以提高我们预测海岸线演化的能力，以应对由于全球和局部海平面上升而导致的沉积物供给量和类型的变化以及可容纳空间创造速率的变化。这项研究产生更广泛的影响：首席研究员与国家地球表面动力学中心的合作将确保这项工作将为恢复密西西比三角洲和扭转土地流失趋势所需的科学做出贡献。这项工作也将成为两名研究生和两名本科生论文的论文题目和经济支持。所有学生都将受益于需要整合地貌学、沉积物迁移、流体动力学和形态动力学建模的问题。