Linking sediment transport in gravel bed rivers to channel migration and bed stability

最近在山区取得的进展，我们的大多数主要交通路线、通信基础设施、城镇至少部分位于活跃的砾石基流形成的沉积物上。因此，横向河流的迁移往往会将道路、房屋和铁路置于危险之中，而垂直切割可能会暴露并可能破坏埋在地下的基础设施，如管道和光纤通信电缆。管理这类危险的技术是不够的。我的团队最近的工作表明：随机模拟方法可能比传统的确定性方法更适合描述河道变化；而且，描述床料泥沙输送的工作主体不足以理解河道稳定性(如先前假设的那样)。目的本研究项目的长期目标是完善河道对环境变化响应预测的理论基础，包括河道稳定性本身的发展、独立的研究课题。短期目标有三个：(1)量化水流和泥沙供应变化对河道动力学的影响；(2)探索河床表面结构和组织(它们共同代表河床状态)和产生河道稳定性的过程之间的关系；(3)将推移质输运的时空变化与河道的横向活动联系起来。方法第一组实验将测试恒定流量和泥沙供应速率的河流是否表现出与可变流量和泥沙供应速率的河流相似的动力学；特别是，我们希望确定在可变流量实验中发生的河道迁移和撕裂过程是否也在恒定流量实验中以类似的速率发生。为了更好地了解床层状态如何影响通道稳定性，我们将测试一种使用小波方法测量床层状态的新方法。通过将这些测量与使用UBC首创的光台法进行泥沙输送的最新数据相结合，我们将弥合泥沙输送和河道稳定性之间的差距。最后，我们将利用我们的实验结果来开发一种量化河流稳定性的方法，并将其用作现场估计河流稳定性的诊断工具。HQP这笔探索基金将资助不列颠哥伦比亚大学生物地貌实验实验室的实验研究。这项工作将由研究生和本科生研究人员组成的团队进行，而一名博士后研究员将帮助开发各种实验之间的概念联系。我将用这笔资金培训1名博士后、4名博士、4名硕士和5名本科生。最终，我的目标是大幅提高理解河流在与人类发展和河流毗邻的基础设施相关的空间尺度上的行为的科学基础。

Recent progress In mountainous regions, most of our major transportation routes, communication infrastructure, cities and towns are located at least in part on a deposit created by an active gravel bed stream. As a result, lateral stream migration often puts roads, houses and railways at risk, while vertical incision can expose and potentially rupture buried infrastructure such as pipelines and fiber optic communications cables. The techniques for managing these kinds of hazards are inadequate. Recent work by my group suggests that: a stochastic modelling approach may be more appropriate than the conventional deterministic ones for describing stream channel change; and, the body of work describing bed material sediment transport is not sufficient for understanding stream channel stability (as has been previously assumed). Objectives The long-term objective of my research program is to improve the theoretical basis for predicting stream channel response to environmental change, including the development of channel stability as it own, independent topic of study. There are three short-term objectives, to: (1) quantify the effect of flow and sediment supply variability on stream channel dynamics; (2) explore the relation between bed surface texture and organization (which together represent the bed state) and the processes producing channel stability; and (3) relate the spatial and temporal variations in bedload transport to the lateral activity of the stream. Methodology The first set of experiments will test whether streams subject to constant flow and sediment supply rates exhibit similar dynamics to those with variable flows and sediment supply rates; in particular, we wish to ascertain whether the processes of channel migration and avulsion that occur during variable flow experiments also occur at similar rates in the constant flow experiments. To develop a better understanding of how bed state influences channel stability, we will test a new approach for measuring the bed state using a wavelet approach. By combining these measurements with state of the art data on sediment transport using the light table approach pioneered at UBC, we will bridge the gap between sediment transport and channel stability. Finally, we will use our experimental results to develop a method to quantify river stability, and use it as a diagnostic tool for estimating river stability in the field. HQP This Discovery Grant will fund experimental research in the Biogeomorphic Experimental Laboratory at UBC. The work will be conducted by teams of graduate and undergraduate researchers, while a post-doc fellow will help develop the conceptual links between the various experiments. I will use this grant to train 1 post-doc, 4 PhDs, 4 MSc and 5 Undergraduates. Impact Ultimately, I aim to substantially improve the scientific basis for understanding how rivers behave at the spatial scales relevant to human development and infrastructure adjacent to rivers.