Sediment routing in gravel-bed rivers following dam removal

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。河流如何应对沉积物供应变化的基本知识对于管理与拆除大坝相关的问题至关重要。大坝拆除也创造了一个机会，了解对大泥沙脉冲的反应，这是规划和河流恢复的关键。 该项目将研究2008年拆除的米尔敦大坝克拉克福克河，MT，开发新的见解沉积和地貌过程，包括如何快速沉积物脉冲通过河流，他们存款，在何种程度上，他们渗透到砾石河床，多远，他们传播，以及他们如何影响通道形态。这将通过以下方式实现：测量推移质运输;对河床物质进行取样，以评估结构变化、渗透动力学和污染物运输;对河床、沙洲和河漫滩地形进行重复调查，以确定沉积物沉积和侵蚀的空间和时间模式。 现场工作将通过沉积物地球化学实验室分析来补充，以识别细沉积物并调查含金属水库沉积物的运输，并模拟水流和沉积物运输过程。这项研究通过开发一个关于大型大坝拆除后地貌反应的综合数据集并将这些结果推广到研究区域以外，将有助于新兴的努力，发展更多的预测科学，为大坝拆除和河流恢复提供信息。这项研究还将代表一个实地规模的实验，以了解砾石床河流中沉积物脉冲的运动和命运，这些实验将用于评估如何将来自水槽和较小河流的理论和数据应用于较大的河流。 考虑到水库沉积物的数量（约300万立方米）和质量（不同程度的采矿污染），此处调查的大坝拆除尤其重要。该项目将建立在米尔敦大坝拆除之前和之后立即收集的数据基础上，这些数据是根据NSF探索性研究小额赠款收集的。外联工作将包括为蒙大拿部落学院的学生和参加大天空科学伙伴关系的K-8教师举办关于河流进程和大坝拆除的讲习班。教育和推广也将通过蒙大拿大学实现？的中心河流科学和流Renaturalization会议和支持研究生和本科生。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Fundamental knowledge of how rivers respond to changes in sediment supply is essential to the management of issues associated with the removal of large dams. Dam removal also creates an opportunity for learning about the response to large sediment pulses, which is critical for planning and stream restoration. This project will examine the 2008 removal of Milltown Dam on the Clark Fork River, MT, to develop new insights into sedimentary and geomorphic processes, including how quickly sediment pulses move through rivers, where they deposit, the extent to which they infiltrate into gravel river beds, how far they propagate, and how they affect channel morphology. This will be achieved through measurements of bedload transport; sampling of bed material to assess textural changes, infiltration dynamics, and contaminant transport; and repeat surveys of river bed, bar and floodplain topography to identify spatial and temporal patterns of sediment deposition and erosion. Field efforts will be complemented by laboratory analysis of sediment geochemistry, to fingerprint fine sediment and investigate transport of metal-laden reservoir sediments, and modeling of flow and sediment transport processes.This research, by developing a comprehensive dataset on geomorphic response to a large dam removal and generalizing those results beyond the study area, will contribute to emerging efforts to develop more predictive science for informing dam removals and river restoration. This research will also represent a field-scale experiment into the movement and fate of sediment pulses in gravel-bed rivers that will be used to evaluate how theory and data from flumes and smaller streams can be applied to larger rivers. The dam removal investigated here is especially significant in light of the quantity (approximately 3 million cubic meters) and quality (varying degrees of mining-derived contamination) of reservoir sediments potentially available for downstream transport. This project will build on data collected immediately before and after the Milltown dam removal under a NSF Small Grant for Exploratory Research. Outreach efforts will include workshops about river processes and dam removal for students from Montana Tribal Colleges and for K-8 teachers participating in the Big Sky Science Partnership. Education and outreach will also be achieved through the University of Montana?s Center for Riverine Science and Stream Renaturalization conferences and support for graduate and undergraduate students.