Sediment Pulse Behaviour Following Dam Removal in Gravel-Bed Rivers

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• 作者：Kylie Marie Pace ; Desiree Tullos ; Cara Walter ; Stephen Lancaster and Catalina Segura
• 刊名：River Research and Applications
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：33
• 期：1
• 页码：102-112
• 全文大小：291K
• ISSN：1535-1467

文摘

As dams approach the end of their useful life, there is need to predict where and how accumulated sediment will move following dam removal to estimate and mitigate the impacts of this process on aquatic habitat and infrastructure. Flume studies suggest that sediment pulses disperse in place for most dams, but it is hypothesized that certain conditions (e.g., low Froude number, fine pulse grain size, small pulse sizes, and large peak discharge) may characterize pulses that translate downstream. However, quantitative analyses of sediment pulse behavior have not been widely conducted in field settings. We thus analyzed bathymetric data from four field sites in Oregon to investigate the reliability of flume-derived hypotheses (1) whether dispersion or translation dominates across a range of dam removal physiographies using multiple methods of evaluation and (2) if Froude number, pulse material grain size, relative pulse size, and discharge can predict reservoir sediment movement mode. Results indicated that dispersion generally dominated pulse behavior in the field setting, with some limited evidence of translational movement in individual years. The Froude number appeared to be the most reliable for anticipating pulse behavior. Further work is needed to link generalized sediment pulse behavior to sediment mobilization and transport processes. Copyright