Collaborative Research: Defining controls on incisional avulsions in alluvial basins

合作研究：确定冲积盆地切割崩裂的控制措施河流崩裂发生在河水改道并在周围的洪泛区形成新的河道时。相关的洪水对居住在河流沿岸的人们来说可能是灾难性的，但减灾是困难的，因为模型无法预测河流崩裂的时间、地点或类型。当新的河道通过侵蚀而不是沉积形成时，就会发生切口崩裂。尽管在某些河流系统中很常见，但人们对这种崩裂类型的了解特别少。本研究的目的是确定与切口撕脱有关的沉积学和水动力条件。通过结合建模和现场方法，pi将评估洪泛区地形、坡度、地表覆盖和岸上沉积等特征如何控制撕裂类型，并测试在地形粗糙、无植被、排水良好的洪泛区缺乏丰富的岸上悬浮沉积物供应的陡峭河流系统中发生切口撕裂的假设。建模工作将使用Delft3D进行，这是一种基于物理的数值模型，可以解决水流和沉积物运输的方程，现场数据收集将侧重于古代地层，在那里可以测量大量古崩裂沉积物的河道和洪泛平原特征。该项目的研究结果将有助于提高对崩裂洪水灾害的预测，并将加深对河道崩裂与漫滩侵蚀和沉积之间关系的认识。撕脱作用也是河流油气、地下水和二氧化碳储层分布的主要控制因素。通过这项研究获得的对撕脱过程的更好理解将有助于地下储层质量和位置的预测。这项工作的更广泛影响还包括开发一个关于河流和侵蚀的自定进度、基于网络的教育模块。在与地球科学推广基金会的合作下，pi将设计一个河流从上面的课程，包括使用谷歌地球和谷歌地图的河流和剥落的导游。河流从上面将侧重于河流的形式和模式，河流崩解和崩解对社会的影响。pi将与宾夕法尼亚州立大学和波士顿学院的外联办公室合作，在匹兹堡和波士顿地区的学校开发、试点测试和评估模块活动，针对每个地区服务不足的社区。最后，该提案还将支持几名研究生和本科生的教育和培训，以及两名初级教员的早期职业生涯。

Collaborative Research: Defining controls on incisional avulsions in alluvial basinsRiver avulsion occurs when water is diverted out of a river and creates a new channel on the surrounding floodplain. The associated flooding can be catastrophic for people living along rivers, but hazard mitigation is difficult because models cannot predict the timing, location, or style of river avulsion. Incisional avulsion occurs when a new river channel is established through erosion rather than deposition, and, although it is common in some river systems, this avulsion style is particularly poorly understood. The goal of this study is to define the sedimentologic and hydrodynamic conditions associated with incisional avulsions. Using combined modeling and field approaches the PIs will evaluate how characteristics such as floodplain topography, slope, ground cover, and overbank deposition control avulsion styles and test the hypothesis that incisional avulsions occur in steep fluvial systems with topographically rough, unvegetated, well-drained floodplains that lack abundant overbank suspended-sediment supply. Modeling work will be conducted with Delft3D, a physics-based numerical model that solves the equations for water flow and sediment transport, and field-data collection will focus on ancient strata where channel and floodplain characteristics can be measured for large numbers of paleoavulsion deposits.The results from this project will help improve prediction of avulsion flood hazards and will enhance understanding of the relationships between channel avulsion and floodplain erosion and deposition. Avulsion is also a primary control on the distribution of fluvial hydrocarbon, groundwater, and CO2-storage reservoirs. Better understanding of avulsion processes gained through this research will aid subsurface predictions of reservoir quality and location. Broader impacts of this work also include development of a self-paced, web-based education module about rivers and avulsions. In collaboration with the Geoscience Outreach Foundation the PIs will design a Rivers from Above curriculum comprising guided tours of rivers and avulsions using Google Earth and Google Maps. Rivers from Above will focus on river forms and patterns, river avulsion, and avulsion impacts on society. The PIs will work with the outreach offices at Penn State and Boston College to develop, pilot test, and evaluate module activities in Pittsburgh- and Boston-area schools, targeting underserved communities in each region. Finally, this proposal will also support the education and training of several graduate and undergraduate students and the early careers of two junior faculty members.