Sediments and sediment transport in mountain channels

在最近的地质历史中，无数的冰川雕刻和重组了不列颠哥伦比亚省的景观，在大片地区重新分配沉积物，并经常导致厚厚的可蚀物质沉积。这些副冰川山谷填充物已被确定为低地河流的主要沉积物来源。现代土地利用变化和气候变化给不列颠哥伦比亚省河流生态系统带来越来越大的压力，并导致其逐渐恶化。未来的气候预测预测，随着降水季节性的增加，气候变暖的趋势将会增加，导致冬季/春季极端洪水的增加和春季淡水的减少。更频繁的滑坡可能会增加供应给河道的泥沙量，并可能增加山体河流中滑坡筑坝的可能性，从而改变河道形态。这些可能的水文气候变化将如何影响淡水生态系统，尤其是河流和山涧？我的研究计划的长期目标是建立一个更完整的山区河流系统知识库。在接下来的五年里，我计划通过分析以下四个主题，涵盖广泛的渠道形态、泥沙供应制度和景观：(1)低强度泥沙输送制度下砾石床流的床载运动；(2)非定常条件下泥沙输运与河道演化；(3)滑坡筑坝溃坝对河道的响应；(4)景观连通性、泥沙来源、储存量。为了实现我的目标，我建议进行水槽实验、理论建模、数值模拟和实地考察。拟议的主题将整合跨时空尺度（从粮食尺度（主题1）到流域尺度（主题4））的信息。拟议的项目将为研究生提供即时和持续的培训和研究机会。通过研究本提案中概述的研究问题，学生将接触到广泛的研究课题，并将获得最先进的测量技术，数据分析程序以及数学和数值建模的宝贵经验。总的来说，我预计这个DG将培养22名研究生和本科生。该建议将提供理论和机制框架，以促进我们对跨尺度和从源到汇的渠道形态动力学的理解，反映控制渠道动力学的气候、地质和地貌因素的多样性。通过跨尺度整合，我们将开发预测工具，帮助减轻未来气候变化和土地利用对景观的影响，并帮助解决许多实际问题，如生态恢复、预测和管理水库和其他水资源基础设施的泥沙输入、洪水缓解和管理，以及诊断和减轻土地利用和气候变化对泥沙的影响。

In the recent geologic past, numerous glaciations sculpted and reorganized the landscapes of BC, redistributing sediment over large areas and often leading to thick deposits of erodible material. These paraglacial valley fill deposits have been identified as a major sediment source to lowland streams. Modern landuse changes and climate change are imposing increasing stresses on BC river ecosystems and leading to their progressive deterioration. Future climate projections predict a warming trend with increased precipitation seasonality, resulting in more extreme floods in the winter/spring and a decreased spring freshet. More frequent landsliding will likely increase the amount of sediment supplied to channels and the likelihood of landslide damming in mountain rivers with resultant changes to channel morphology. How will these probable hydroclimatic shifts impact freshwater ecosystems, most notably rivers and mountain streams? The long-term objective of my research program is to build a more complete knowledge base of river systems in mountainous regions. Over the next five years I plan to focus on four themes covering a wide range of channel morphologies, sediment supply regimes, and landscapes, by analyzing: (1) bedload movement in gravel bed streams under low intensity sediment transport regimes; (2) sediment transport and channel evolution under unsteady conditions; (3) channel response to landslide damming and breaching; and (4) landscape connectivity, sediment sources, storage. To achieve my goals, I propose to conduct flume experiments, theoretical modelling, numerical simulations, and fieldwork. The proposed themes will integrate information across spatial and temporal scales (from the grain scale (Theme 1) to the basin scale (Theme 4)). The proposed projects will generate immediate and ongoing training and research opportunities for graduate students. By working on research questions outlined in this proposal, students will be exposed to a wide range of research topics and will gain valuable experience in state-of-the-art measurement techniques, data analysis procedures, and mathematical and numerical modeling. In total, I envision that this DG will train 22 graduate and undergraduate students. This proposal will provide theoretical and mechanistic frameworks to advance our understanding of channel morphodynamics across scales and from source to sink, reflecting the diversity of climatic, geologic and geomorphic factors that control channel dynamics. By integrating across scales, we will develop predictive tools that help mitigate the future effects of climate change and land use on landscapes, and help solve many practical problems such as ecological restoration, predicting and managing sediment inputs to reservoirs and other water resources infrastructure, flood mitigation and management, and diagnosing and mitigating sediment-related impacts of land use and climate change.