SGER: Dam removal and the response of gravel-bed rivers to sediment pulses

这项研究将调查泥沙输移和河道演变的砾石河床riversin响应泥沙脉冲，利用现场规模的实验，将beccreated拆除米尔敦大坝上的克拉克福克的哥伦比亚河，MT。通过收集大坝拆除前后的河道条件和高流量期米尔敦水库推移质和悬移质输移的数据，本研究将解决有关河流演变、泥沙输移和沉积以及大坝拆除的基本问题。几个假设将调查如何脉冲细泥沙infiltrateinto和影响装甲河床的流动性，关于空间和时间模式的泥沙输移和沉积，以及有关有效的流量为输送泥沙脉冲。这项研究将提供一个很好的机会，以评估以前的flumeresearch或小渠道的实地研究，在此基础上，什么是已知的sedimenttransfer和河流过程的相关方面，规模更大的河流。这里收集的数据也将在地貌反应和沉积物地球化学对栖息地和生物过程的影响的背景下进行评估。米尔敦大坝的拆除将于2008年春季开始，并持续到第二个冬天，特别值得注意的是，（1）就可能用于下游运输的水库沉积物的体积而言，这是美国迄今为止最大的大坝拆除（约300万立方米;另外200万立方米正在机械移除）;（2）该大坝位于美国最大的超级基金项目克拉克福克综合体的下游末端，水库沉积物主要由受污染的尾矿组成;（3）该大坝位于一条区域性重要河流上，该河流包括被指定为受联邦政府威胁的物种牛鳟鱼的关键栖息地。因此，对大坝拆除的系统研究将在多个层面上产生更广泛的影响，包括了解与大坝拆除相关的沉积物和金属迁移，为即将到来的大坝拆除计划提供见解，以及为了解砾石驱动器如何应对增加的沉积物通量做出更广泛的贡献。项目还将产生更广泛的影响？该项目具有跨学科性质，将地貌过程、地球化学、水文学和鱼类反应的分析结合起来，以了解大坝拆除对下游的影响。该项目将帮助一名新教师建立河流地貌过程的研究计划，并将直接支持一名研究生和一名本科生。该项目还促进了蒙大拿大学和Salish-Kootenai学院之间正在进行的合作，Salish-Kootenai学院是蒙大拿州巴勃罗的一所部落学院，其学生将在PI的指导下协助现场数据收集和分析。此外，与MilltownDam拆除相关的数据收集和分析将纳入研究生和本科生地貌学和地球化学课程，该项目将促进教学和研究的整合。靠近蒙大拿大学。

This study will investigate sediment transport and channel evolution in gravel-bed riversin response to sediment pulses, taking advantage of the field-scale experiment that will becreated by the removal of Milltown Dam on the Clark Fork of the Columbia River, MT. Throughdata collection on pre- and post-dam removal channel conditions and on bedload and suspendedload transport out of Milltown reservoir during high flow periods, this research will addressfundamental questions about fluvial processes, sediment transport and deposition, and damremoval. Several hypotheses will be investigated about how pulses of fine sediment infiltrateinto and affect the mobility of armored river beds, about spatial and temporal patterns ofsediment transport and deposition, and about effective discharges for transporting sedimentpulses. This research will provide an excellent opportunity to evaluate how previous flumeresearch or field studies of small channels, upon which much of what is known about sedimenttransport and related aspects of fluvial processes is based, scale up to larger rivers. Thedata collected here will also be evaluated in the context of the implications of geomorphicresponses and sediment geochemistry for habitat and biological processes.Removal of Milltown Dam, which will begin in spring 2008 and continue the following winter,is especially notable because (1) it is the largest dam removal to date in the United Statesin terms of the volume of reservoir sediment potentially available for downstream transport(approximately 3 million m3; another 2 million m3 are being mechanically removed); (2) thedam is the downstream end of the largest Superfund site in the United States, the Clark ForkComplex, and reservoir sediments are composed largely of contaminated mine tailings; (3) itis occurring on a regionally important river that includes designated Critical Habitat forbull trout, a federally threatened species. Systematic study of this dam removal will thereforehave broader impacts on multiple levels, including for understanding the sediment and metalstransport associated with a significant dam removal, for the insights it lends to upcomingplanned removals of large dams, and for its broader contribution to understanding how gravel-bedrivers respond to increased sediment fluxes. Broader impacts will also derive from the project?sinterdisciplinary nature, whereby analyses of geomorphic processes, geochemistry, hydrology,and fish response will be combined to understand downstream effects of dam removal.This project will help a new faculty member build a research program in fluvial geomorphicprocesses and will directly support one graduate and one undergraduate student. The projectwill also foster ongoing collaboration efforts between University of Montana and Salish-KootenaiCollege, a tribal college in Pablo, MT, whose students will assist field data collection andanalysis under the guidance of the PI. Further, data collection and analysis related to MilltownDam removal will be incorporated into graduate and undergraduate geomorphology and geochemistrycourses, an integration of teaching and research that will be facilitated by the project?sclose proximity to the University of Montana.