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• 1. [Article] Analysis of Dam-Induced Cyclic Patterns on River Flow Dynamics

  This paper investigates the impact of the Hungry Horse Dam on streamflow dynamics in the South Fork of the Flathead River, Montana, USA. To this end, pre- and post-dam periods of raw and naturalized streamflow ...

  Citation × Citation Citation Abstract Copy Title: Analysis of Dam-Induced Cyclic Patterns on River Flow Dynamics Author: Tongal, Hakan, Demirel, Mehmet C., Moradkhani, Hamid Year: 2016 This paper investigates the impact of the Hungry Horse Dam on streamflow dynamics in the South Fork of the Flathead River, Montana, USA. To this end, pre- and post-dam periods of raw and naturalized streamflow data were analysed. Pettitt’s change point analysis indicated a significant change point in streamflow dynamics due to dam construction. Complexities in the pre- and post-dam periods were evaluated by sample and multi-scale entropy analyses, and the entropies of the post-dam period were found to be higher than those of the pre-dam period. Possible reasons for this, unrelated to the natural hydrological cycle caused by the dam, were analysed using wavelet analyses. The wavelet analyses showed a clear change in the phase relationship between precipitation and streamflow. Finally, weak positive trends found in the hydrological variables indicated the effects of human activities (e.g. dam construction). The results also revealed distorted lead times, which can improve the streamflow forecasts for different lead times. Title: Analysis of Dam-Induced Cyclic Patterns on River Flow Dynamics Author: Tongal, Hakan, Demirel, Mehmet C., Moradkhani, Hamid Year: 2016 This paper investigates the impact of the Hungry Horse Dam on streamflow dynamics in the South Fork of the Flathead River, Montana, USA. To this end, pre- and post-dam periods of raw and naturalized streamflow data were analysed. Pettitt’s change point analysis indicated a significant change point in streamflow dynamics due to dam construction. Complexities in the pre- and post-dam periods were evaluated by sample and multi-scale entropy analyses, and the entropies of the post-dam period were found to be higher than those of the pre-dam period. Possible reasons for this, unrelated to the natural hydrological cycle caused by the dam, were analysed using wavelet analyses. The wavelet analyses showed a clear change in the phase relationship between precipitation and streamflow. Finally, weak positive trends found in the hydrological variables indicated the effects of human activities (e.g. dam construction). The results also revealed distorted lead times, which can improve the streamflow forecasts for different lead times. Close

• 2. [Article] Modeling Historic Columbia River Flood Impacts

  The Lower Columbia River Estuary (LCRE) has undergone extensive modifications since the 19th century. Construction of dams, installation of jetties and dikes, dredging of the navigation channel and filling ...

  Citation × Citation Citation Abstract Copy Title: Modeling Historic Columbia River Flood Impacts Author: Helaire, Lumas, Mahedy, Andrew, Talke, Stefan A., Jay, David A Year: 2014 The Lower Columbia River Estuary (LCRE) has undergone extensive modifications since the 19th century. Construction of dams, installation of jetties and dikes, dredging of the navigation channel and filling in of tidal wetlands have all contributed significantly to alterations in tidal dynamics and the flow regime, with consequences for habitat inundation and salinity intrusion. In this talk we discuss the development and implementation of a 19th century flow model for the LCRE, using a digital elevation model based on historic bathymetry. The model has been calibrated with recently rediscovered and digitized tide data from the 19th century. In this research project we look at several river flow scenarios. We are interested in the interaction between river flow and ocean tides, how it has changed in the LCRE since the 19th century and how it affects the river physics. With the model, we focus on the following questions: How has the spatial structure of salinity changed since the 1890's? Has the salinity intrusion length increased or decreased? Is there a change in residual salinity in some of the bays in the estuary? How have changes to the bathymetric structure of the river affected salinity intrusion? For the same flow river flow, how have wetland inundation patterns changed? How have changes to the tidal prism ascertained from a temporal analysis of tidal records, affected the amount of land inundated in a tidal cycle and how long that land remains inundated? Initial results suggest that salinity intrusion patterns have shifted and that wetland inundation patterns have been impacted by the up to 10% increase in the estuary tidal range since the late 19th century. Title: Modeling Historic Columbia River Flood Impacts Author: Helaire, Lumas, Mahedy, Andrew, Talke, Stefan A., Jay, David A Year: 2014 The Lower Columbia River Estuary (LCRE) has undergone extensive modifications since the 19th century. Construction of dams, installation of jetties and dikes, dredging of the navigation channel and filling in of tidal wetlands have all contributed significantly to alterations in tidal dynamics and the flow regime, with consequences for habitat inundation and salinity intrusion. In this talk we discuss the development and implementation of a 19th century flow model for the LCRE, using a digital elevation model based on historic bathymetry. The model has been calibrated with recently rediscovered and digitized tide data from the 19th century. In this research project we look at several river flow scenarios. We are interested in the interaction between river flow and ocean tides, how it has changed in the LCRE since the 19th century and how it affects the river physics. With the model, we focus on the following questions: How has the spatial structure of salinity changed since the 1890's? Has the salinity intrusion length increased or decreased? Is there a change in residual salinity in some of the bays in the estuary? How have changes to the bathymetric structure of the river affected salinity intrusion? For the same flow river flow, how have wetland inundation patterns changed? How have changes to the tidal prism ascertained from a temporal analysis of tidal records, affected the amount of land inundated in a tidal cycle and how long that land remains inundated? Initial results suggest that salinity intrusion patterns have shifted and that wetland inundation patterns have been impacted by the up to 10% increase in the estuary tidal range since the late 19th century. Close