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• 1. [Article] Toward More Robust Extreme Flood Prediction by Bayesian Hierarchical and Multimodeling

  Flood information, especially extreme flood, is necessary for any large hydraulic structure design and flood risk management. Flood mitigation also requires a comprehensive assessment of flood risk and ...

  Citation × Citation Citation Abstract Copy Title: Toward More Robust Extreme Flood Prediction by Bayesian Hierarchical and Multimodeling Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2016 Flood information, especially extreme flood, is necessary for any large hydraulic structure design and flood risk management. Flood mitigation also requires a comprehensive assessment of flood risk and an explicit quantification of the flood uncertainty. In the present study, we use a multimodel ensemble approach based on Bayesian model averaging (BMA) method to account for model structure and distribution uncertainties. The usefulness of this approach is assessed by a case study over the Willamette River Basin (WRB) in Pacific Northwest, USA. Besides the standard log-Pearson Type III distribution, we also identified that the generalized extreme value and three-parameter lognormal distributions were both potential distributions in WRB. Three different statistical models, including the Bulletin-17B quantile model, index-flood model, and spatial Bayesian hierarchical model, were considered in the study. The BMA method is then used to assign weights to different models, where better performing model receives higher weights. It was found that the major uncertainty in extreme flood prediction is contributed by model structure, while the choice of distribution plays a lesser important role in quantification of flood uncertainty. The BMA approach provides a more robust extreme flood prediction than any single model. Title: Toward More Robust Extreme Flood Prediction by Bayesian Hierarchical and Multimodeling Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2016 Flood information, especially extreme flood, is necessary for any large hydraulic structure design and flood risk management. Flood mitigation also requires a comprehensive assessment of flood risk and an explicit quantification of the flood uncertainty. In the present study, we use a multimodel ensemble approach based on Bayesian model averaging (BMA) method to account for model structure and distribution uncertainties. The usefulness of this approach is assessed by a case study over the Willamette River Basin (WRB) in Pacific Northwest, USA. Besides the standard log-Pearson Type III distribution, we also identified that the generalized extreme value and three-parameter lognormal distributions were both potential distributions in WRB. Three different statistical models, including the Bulletin-17B quantile model, index-flood model, and spatial Bayesian hierarchical model, were considered in the study. The BMA method is then used to assign weights to different models, where better performing model receives higher weights. It was found that the major uncertainty in extreme flood prediction is contributed by model structure, while the choice of distribution plays a lesser important role in quantification of flood uncertainty. The BMA approach provides a more robust extreme flood prediction than any single model. Close

• 2. [Article] Ancient Cataclysmic Floods in the Pacific Northwest: Ancestors to the Missoula Floods

  Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et ...

  Citation × Citation Citation Abstract Copy Title: Ancient Cataclysmic Floods in the Pacific Northwest: Ancestors to the Missoula Floods Author: Medley, Erica Year: 2012 Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et al., 2009). All previously studied ancient sites were visited (14) and new sites (11) were found; four Missoula Flood quarries were also visited; a total of 29 sites were studied in this thesis. The use of calcrete paleosols to provide relative age dates for flood deposits was analyzed in this thesis. Missoula Flood gravel pits were sampled in order to examine the degree of calcrete development in flood deposits of known ages. All of the Missoula Flood deposits tested contain Stage 1 calcrete soil development. Calcrete paleosols at sites with evidence for older floods were all analyzed. Eight sites have paleosols with Stage II development (3-12% CaCO3): Rulo Outcrop, Potholes Coulee, Leslie Road, Benge, E. Callaway Road, Collier Coulee, Palouse, and Connell. Five sites have paleosols with Stage II+ development (12-17% CaCO3): Brown Road, Leslie Road, Benge, Reese Coulee, and Connell. Fourteen sites have paleosols with Stage III development (17-35% CaCO3): The Dalles, Rulo Outcrop, Winans Road 1, Poplar Heights, Yakima Bluffs, Canal Outcrop, Othello Canal, Reese Coulee, Potholes Coulee, E. Callaway Road, Frenchmen Coulee, Macall, Ritzville, and East Connell. One site has a paleosol with Stage III+ development (35-50% CaCO3): Othello Canal. Ancient Cataclysmic flooding initiated in the Early Pleistocene, at least 1.5 Ma. Sixteen field sites show evidence for Early Pleistocene flooding, preserved in all six provinces: Othello Channels, Columbia River Gorge, Cheney-Palouse Scabland, Quincy Basin, Pasco Basin, and the Walla Walla Valley. There are 26 field sites with evidence for Middle Pleistocene flooding, present in all regions except Othello Channels. Eleven of those 26 sites also show evidence for Early Pleistocene floods. Evidence for Early and Middle Pleistocene floods is present over a wide distribution of elevations from 117 to 524 meters. Title: Ancient Cataclysmic Floods in the Pacific Northwest: Ancestors to the Missoula Floods Author: Medley, Erica Year: 2012 Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et al., 2009). All previously studied ancient sites were visited (14) and new sites (11) were found; four Missoula Flood quarries were also visited; a total of 29 sites were studied in this thesis. The use of calcrete paleosols to provide relative age dates for flood deposits was analyzed in this thesis. Missoula Flood gravel pits were sampled in order to examine the degree of calcrete development in flood deposits of known ages. All of the Missoula Flood deposits tested contain Stage 1 calcrete soil development. Calcrete paleosols at sites with evidence for older floods were all analyzed. Eight sites have paleosols with Stage II development (3-12% CaCO3): Rulo Outcrop, Potholes Coulee, Leslie Road, Benge, E. Callaway Road, Collier Coulee, Palouse, and Connell. Five sites have paleosols with Stage II+ development (12-17% CaCO3): Brown Road, Leslie Road, Benge, Reese Coulee, and Connell. Fourteen sites have paleosols with Stage III development (17-35% CaCO3): The Dalles, Rulo Outcrop, Winans Road 1, Poplar Heights, Yakima Bluffs, Canal Outcrop, Othello Canal, Reese Coulee, Potholes Coulee, E. Callaway Road, Frenchmen Coulee, Macall, Ritzville, and East Connell. One site has a paleosol with Stage III+ development (35-50% CaCO3): Othello Canal. Ancient Cataclysmic flooding initiated in the Early Pleistocene, at least 1.5 Ma. Sixteen field sites show evidence for Early Pleistocene flooding, preserved in all six provinces: Othello Channels, Columbia River Gorge, Cheney-Palouse Scabland, Quincy Basin, Pasco Basin, and the Walla Walla Valley. There are 26 field sites with evidence for Middle Pleistocene flooding, present in all regions except Othello Channels. Eleven of those 26 sites also show evidence for Early Pleistocene floods. Evidence for Early and Middle Pleistocene floods is present over a wide distribution of elevations from 117 to 524 meters. Close

• 3. [Article] Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota

  Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow ...

  Citation × Citation Citation Abstract Copy Title: Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota Author: Harden, Tessa M. Year: 2012 Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow rates substantially larger than those gaged historically. Flood-frequency analyses for the study reaches account for 29 paleofloods inferred from interpretation of stratigraphic records locally extending back 1,000 to almost 2,000 years. The addition of paleoflood data to the gaged and historical data significantly reduced uncertainties related to flood-frequency. For all study reaches the 95-percent confidence intervals about the low-probability quantile estimates (100-, 200-, and 500-year recurrence-intervals) were reduced by at least 78 percent relative to those for the gaged records only. In some cases, 95-percent uncertainty intervals were reduced by 99 percent or more. Additionally, a stratigraphic record of 35 large paleofloods and four large historical floods during the last 2,000 years (including several floods not used in the frequency analyses due to age constraints) reveal four flooding episodes at A.D.: 130-40, 640-670, 900-1290, and 1410 to present. During the Medieval Climate Anomaly (~A.D. 900-1300) the Black Hills experienced 13 large floods compared to nine large floods in the previous 800 years. This high concentration of large flooding events were likely caused by: 1) instability of air masses caused by stronger than normal westerlies; 2) larger or more frequent hurricanes in the Gulf of Mexico and Atlantic Ocean; and/or 3) reduced land covering vegetation and an increase in forest fires caused by the severe drought. By examining the response of streamflow to the MCA, it seems likely that if severe long-term drought conditions persist for the Black Hills region, an increase in the frequency and magnitude of large floods can be expected. The Black Hills paleofloods represent some of the largest known floods, relative to drainage area, for the United States. Many of the other largest known United States floods are in areas with physiographic and climatologic conditions broadly similar to the Black Hills--semi-arid and rugged landscapes that intercept and focus heavy precipitation from convective storm systems. Title: Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota Author: Harden, Tessa M. Year: 2012 Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow rates substantially larger than those gaged historically. Flood-frequency analyses for the study reaches account for 29 paleofloods inferred from interpretation of stratigraphic records locally extending back 1,000 to almost 2,000 years. The addition of paleoflood data to the gaged and historical data significantly reduced uncertainties related to flood-frequency. For all study reaches the 95-percent confidence intervals about the low-probability quantile estimates (100-, 200-, and 500-year recurrence-intervals) were reduced by at least 78 percent relative to those for the gaged records only. In some cases, 95-percent uncertainty intervals were reduced by 99 percent or more. Additionally, a stratigraphic record of 35 large paleofloods and four large historical floods during the last 2,000 years (including several floods not used in the frequency analyses due to age constraints) reveal four flooding episodes at A.D.: 130-40, 640-670, 900-1290, and 1410 to present. During the Medieval Climate Anomaly (~A.D. 900-1300) the Black Hills experienced 13 large floods compared to nine large floods in the previous 800 years. This high concentration of large flooding events were likely caused by: 1) instability of air masses caused by stronger than normal westerlies; 2) larger or more frequent hurricanes in the Gulf of Mexico and Atlantic Ocean; and/or 3) reduced land covering vegetation and an increase in forest fires caused by the severe drought. By examining the response of streamflow to the MCA, it seems likely that if severe long-term drought conditions persist for the Black Hills region, an increase in the frequency and magnitude of large floods can be expected. The Black Hills paleofloods represent some of the largest known floods, relative to drainage area, for the United States. Many of the other largest known United States floods are in areas with physiographic and climatologic conditions broadly similar to the Black Hills--semi-arid and rugged landscapes that intercept and focus heavy precipitation from convective storm systems. Close

• 4. [Article] A Validated Tropical-Extratropical Flood Hazard Assessment for New York Harbor

  Recent studies of flood risk at New York Harbor (NYH) have shown disparate results for the 100 year storm tide, providing an uncertain foundation for the flood mitigation response after Hurricane Sandy. ...

  Citation × Citation Citation Abstract Copy Title: A Validated Tropical-Extratropical Flood Hazard Assessment for New York Harbor Author: Orton, Philip M., Hall, T. M., Talke, Stefan A., Blumberg, Alan F., Georgas, Nickitas, Vinogradov, S. Year: 2016 Recent studies of flood risk at New York Harbor (NYH) have shown disparate results for the 100 year storm tide, providing an uncertain foundation for the flood mitigation response after Hurricane Sandy. Here we present a flood hazard assessment that improves confidence in our understanding of the region's present-day potential for flooding, by separately including the contribution of tropical cyclones (TCs) and extratropical cyclones (ETCs), and validating our modeling study at multiple stages against historical observations. The TC assessment is based on a climatology of 606 synthetic storms developed from a statistical-stochastic model of North Atlantic TCs. The ETC assessment is based on simulations of historical storms with many random tide scenarios. Synthetic TC landfall rates and the final TC and ETC flood exceedance curves are all shown to be consistent with curves computed using historical data, within 95% confidence ranges. Combining the ETC and TC results together, the 100 year return period storm tide at NYH is 2.70 m (2.51–2.92 at 95% confidence), and Hurricane Sandy's storm tide of 3.38 m was a 260 year (170–420) storm tide. Deeper analyses of historical flood reports from estimated Category-3 hurricanes in 1788 and 1821 lead to new estimates and reduced uncertainties for their floods and show that Sandy's storm tide was the largest at NYH back to at least 1700. The flood exceedance curves for ETCs and TCs have sharply different slopes due to their differing meteorology and frequency, warranting separate treatment in hazard assessments. Title: A Validated Tropical-Extratropical Flood Hazard Assessment for New York Harbor Author: Orton, Philip M., Hall, T. M., Talke, Stefan A., Blumberg, Alan F., Georgas, Nickitas, Vinogradov, S. Year: 2016 Recent studies of flood risk at New York Harbor (NYH) have shown disparate results for the 100 year storm tide, providing an uncertain foundation for the flood mitigation response after Hurricane Sandy. Here we present a flood hazard assessment that improves confidence in our understanding of the region's present-day potential for flooding, by separately including the contribution of tropical cyclones (TCs) and extratropical cyclones (ETCs), and validating our modeling study at multiple stages against historical observations. The TC assessment is based on a climatology of 606 synthetic storms developed from a statistical-stochastic model of North Atlantic TCs. The ETC assessment is based on simulations of historical storms with many random tide scenarios. Synthetic TC landfall rates and the final TC and ETC flood exceedance curves are all shown to be consistent with curves computed using historical data, within 95% confidence ranges. Combining the ETC and TC results together, the 100 year return period storm tide at NYH is 2.70 m (2.51–2.92 at 95% confidence), and Hurricane Sandy's storm tide of 3.38 m was a 260 year (170–420) storm tide. Deeper analyses of historical flood reports from estimated Category-3 hurricanes in 1788 and 1821 lead to new estimates and reduced uncertainties for their floods and show that Sandy's storm tide was the largest at NYH back to at least 1700. The flood exceedance curves for ETCs and TCs have sharply different slopes due to their differing meteorology and frequency, warranting separate treatment in hazard assessments. Close

• 5. [Article] State space approach to flood stage estimation

  A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with ...

  Citation × Citation Citation Abstract Copy Title: State space approach to flood stage estimation Author: Jones, Gregory Allen Year: 1984 A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with the output being an optimal estimate of stage given known inputs of streamflow. These equations are developed in state space and the Kalman filter is employed to estimate the flow and river stage. The model is applied to the Toutle and Cowlitz Rivers in the State of Washington, where the stage is affected by a shifting bed elevation. With the deterministic inputs at Mayfield Dam on the Cowlitz and Tower Road on the Toutle, the optimal output of stage is predicted at Castle Rock on the Cowlitz River. Addition of the Kalman Filter improves stage prediction based on an application to an observed storm event. Title: State space approach to flood stage estimation Author: Jones, Gregory Allen Year: 1984 A flood routing and stage prediction model is developed using the techniques of State Space and Kalman filtering. The governing equation is the physically based hydrologic method of flood routing with the output being an optimal estimate of stage given known inputs of streamflow. These equations are developed in state space and the Kalman filter is employed to estimate the flow and river stage. The model is applied to the Toutle and Cowlitz Rivers in the State of Washington, where the stage is affected by a shifting bed elevation. With the deterministic inputs at Mayfield Dam on the Cowlitz and Tower Road on the Toutle, the optimal output of stage is predicted at Castle Rock on the Cowlitz River. Addition of the Kalman Filter improves stage prediction based on an application to an observed storm event. Close

• 6. [Article] The Influence of Floodplain Restoration on Flow and Sediment Dynamics in an Urban River

  A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two-dimensional hydro-morphodynamic model for predicting flow and suspended-sediment dynamics in the ...

  Citation × Citation Citation Abstract Copy Title: The Influence of Floodplain Restoration on Flow and Sediment Dynamics in an Urban River Author: Ahilan, Sangaralingam, Guan, Mingfu, Sleigh, Andrew, Wright, Nigel G., Chang, Heejun Year: 2016 A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two-dimensional hydro-morphodynamic model for predicting flow and suspended-sediment dynamics in the downstream of Johnson Creek, the East Lents reach, where the bank of the river has been reconfigured to reconnect to a restored floodplain on a 0.26 km2 (26-ha) site. The simulation scenarios include 10-, 50-, 100- and 500-year event-based deposition modelling of flood events and long-term modelling using the 64 historical flood events between 1941 and 2014. Simulation results showed that the restored floodplain significantly attenuates the upstream flood peak by up to 25% at the downstream. Results also indicated that approximately 20%–30% of sediment from the upstream is deposited on the East Lents floodplain. Furthermore, deposited sediment over the simulated period (1941–2014) is approximately 0.1% of the basin's flood storage capacity; however, the reduction in the storage does not offset the overall flood resilience impact of the flood basin. The sediment conservation at the East Lents flood basin as predicted by the model reduces the annual sediment loading of the Johnson Creek by 1% at the confluence with Willamette River, providing both improved water quality and flood resilience further downstream. Title: The Influence of Floodplain Restoration on Flow and Sediment Dynamics in an Urban River Author: Ahilan, Sangaralingam, Guan, Mingfu, Sleigh, Andrew, Wright, Nigel G., Chang, Heejun Year: 2016 A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two-dimensional hydro-morphodynamic model for predicting flow and suspended-sediment dynamics in the downstream of Johnson Creek, the East Lents reach, where the bank of the river has been reconfigured to reconnect to a restored floodplain on a 0.26 km2 (26-ha) site. The simulation scenarios include 10-, 50-, 100- and 500-year event-based deposition modelling of flood events and long-term modelling using the 64 historical flood events between 1941 and 2014. Simulation results showed that the restored floodplain significantly attenuates the upstream flood peak by up to 25% at the downstream. Results also indicated that approximately 20%–30% of sediment from the upstream is deposited on the East Lents floodplain. Furthermore, deposited sediment over the simulated period (1941–2014) is approximately 0.1% of the basin's flood storage capacity; however, the reduction in the storage does not offset the overall flood resilience impact of the flood basin. The sediment conservation at the East Lents flood basin as predicted by the model reduces the annual sediment loading of the Johnson Creek by 1% at the confluence with Willamette River, providing both improved water quality and flood resilience further downstream. Close

• 7. [Article] Potential Impacts of Climate Change on Flood-Induced Travel Disruptions: A Case Study of Portland, Oregon, USA

  This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland, Oregon, metropolitan area. We used ensemble climate ...

  Citation × Citation Citation Abstract Copy Title: Potential Impacts of Climate Change on Flood-Induced Travel Disruptions: A Case Study of Portland, Oregon, USA Author: Chang, Heejun, Lafrenz, Martin, Jung, Il-won, Figliozzi, Miguel, Platman, Deena, Pederson, Cindy Year: 2010 This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland, Oregon, metropolitan area. We used ensemble climate change scenarios, a hydrologic model, a stream channel survey, a hydraulic model, and a travel forecast model to develop an integrated impact assessment method. High-resolution climate change scenarios are based on the combinations of two emission scenarios and eight general circulation models. The Precipitation-Runoff Modeling System was calibrated and validated for the historical period of 1988 and 2006 and simulated for determining the probability of floods for 2020 through 2049. We surveyed stream cross-sections at five road crossings for stream channel geometry and determined flood water surface elevations using the Hydrologic Engineering Centers River Analysis System (HEC-RAS) model. Four of the surveyed bridges and roadways were lower in elevation than the current 100-year flood water surface elevation, leading to relatively frequent nuisance flooding. These roadway flooding events will become more frequent under some climate change scenarios in the future, but climate change impacts will depend on local geomorphic conditions. Whereas vehicle miles traveled was not significantly affected by road closure, vehicle hours delay demonstrated a greater impact from road closures, increasing by 10 percent in the Fanno Creek area. Our research demonstrated the usefulness of the integration of top-down and bottom-up approaches in climate change impact assessment and the need for spatially explicit modeling and participatory planning in flood management and transportation planning under increasing climate uncertainty. Title: Potential Impacts of Climate Change on Flood-Induced Travel Disruptions: A Case Study of Portland, Oregon, USA Author: Chang, Heejun, Lafrenz, Martin, Jung, Il-won, Figliozzi, Miguel, Platman, Deena, Pederson, Cindy Year: 2010 This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland, Oregon, metropolitan area. We used ensemble climate change scenarios, a hydrologic model, a stream channel survey, a hydraulic model, and a travel forecast model to develop an integrated impact assessment method. High-resolution climate change scenarios are based on the combinations of two emission scenarios and eight general circulation models. The Precipitation-Runoff Modeling System was calibrated and validated for the historical period of 1988 and 2006 and simulated for determining the probability of floods for 2020 through 2049. We surveyed stream cross-sections at five road crossings for stream channel geometry and determined flood water surface elevations using the Hydrologic Engineering Centers River Analysis System (HEC-RAS) model. Four of the surveyed bridges and roadways were lower in elevation than the current 100-year flood water surface elevation, leading to relatively frequent nuisance flooding. These roadway flooding events will become more frequent under some climate change scenarios in the future, but climate change impacts will depend on local geomorphic conditions. Whereas vehicle miles traveled was not significantly affected by road closure, vehicle hours delay demonstrated a greater impact from road closures, increasing by 10 percent in the Fanno Creek area. Our research demonstrated the usefulness of the integration of top-down and bottom-up approaches in climate change impact assessment and the need for spatially explicit modeling and participatory planning in flood management and transportation planning under increasing climate uncertainty. Close

• 8. [Article] Modeling of Historic Columbia River Flood Impacts Based on Delft 3D Simulations

  Natural and anthropogenic processes over the past 150 years have altered the bathymetry of the Lower Columbia River (LCR) and have changed the long wave propagation of tides and floods. Possible causes ...

  Citation × Citation Citation Abstract Copy Title: Modeling of Historic Columbia River Flood Impacts Based on Delft 3D Simulations Author: Helaire, Lumas Terence Year: 2016 Natural and anthropogenic processes over the past 150 years have altered the bathymetry of the Lower Columbia River (LCR) and have changed the long wave propagation of tides and floods. Possible causes for the increase in tidal amplitudes (+7% in tidal range in Astoria) are decreases in river discharge, lengthening of the river channel due to the construction of jetties at the mouth, dredging and deepening of the shipping channel, and reduction of the tidal prism due to the filling and diking of tidal wetlands. In this study, changes in the characteristics of long waves are elucidated by developing two hydrodynamic models of the LCR which reflect historical and modern bathymetric conditions and forcing. The historic model simulates late 19th century conditions and is extensively validated using recently recovered tide records along the LCR (e.g., Astoria, 1853-1876) and river stage measurements (e.g., Portland, 1876-1964). Results suggest that water levels in Portland at low river discharge are up to 0.5-1.0m lower than in the past. However, historical water levels during a flood scenario based on the 1880 spring freshet are similar to modern water levels. Since tidal range in the modern scenario is persistently higher at all locations, the flood risk in many locations along the LCR has increased for the same boundary conditions. The results are explained by considering the governing equations of momentum and mass-conservation. At low river flow, greater depth leads to reduced frictional effects, producing amplified tidal range and tidal velocities but a decreased river slope (and lower Portland water levels). At high flow, the modern flood is confined by dikes and the loss of wetlands, which counteracts the effect of decreased friction. Nonetheless, the high friction of the historical wooded floodplain also confined the historical flood path. Hence, historical and modern flood heights are surprisingly similar, though scaling analysis suggests that the historical flood wave was more diffusive. Title: Modeling of Historic Columbia River Flood Impacts Based on Delft 3D Simulations Author: Helaire, Lumas Terence Year: 2016 Natural and anthropogenic processes over the past 150 years have altered the bathymetry of the Lower Columbia River (LCR) and have changed the long wave propagation of tides and floods. Possible causes for the increase in tidal amplitudes (+7% in tidal range in Astoria) are decreases in river discharge, lengthening of the river channel due to the construction of jetties at the mouth, dredging and deepening of the shipping channel, and reduction of the tidal prism due to the filling and diking of tidal wetlands. In this study, changes in the characteristics of long waves are elucidated by developing two hydrodynamic models of the LCR which reflect historical and modern bathymetric conditions and forcing. The historic model simulates late 19th century conditions and is extensively validated using recently recovered tide records along the LCR (e.g., Astoria, 1853-1876) and river stage measurements (e.g., Portland, 1876-1964). Results suggest that water levels in Portland at low river discharge are up to 0.5-1.0m lower than in the past. However, historical water levels during a flood scenario based on the 1880 spring freshet are similar to modern water levels. Since tidal range in the modern scenario is persistently higher at all locations, the flood risk in many locations along the LCR has increased for the same boundary conditions. The results are explained by considering the governing equations of momentum and mass-conservation. At low river flow, greater depth leads to reduced frictional effects, producing amplified tidal range and tidal velocities but a decreased river slope (and lower Portland water levels). At high flow, the modern flood is confined by dikes and the loss of wetlands, which counteracts the effect of decreased friction. Nonetheless, the high friction of the historical wooded floodplain also confined the historical flood path. Hence, historical and modern flood heights are surprisingly similar, though scaling analysis suggests that the historical flood wave was more diffusive. Close

• 9. [Article] Hydrodynamic and Water Quality Modeling of the Chehalis River in Washington

  The Chehalis River Basin is located in the southwest region of Washington and is over 125 miles long flowing through agricultural, residential, industrial, and forest land. Four major rivers, many smaller ...

  Citation × Citation Citation Abstract Copy Title: Hydrodynamic and Water Quality Modeling of the Chehalis River in Washington Author: Van Glubt, Sarah, Wells, Scott A., Berger, Chris J. Year: 2017 The Chehalis River Basin is located in the southwest region of Washington and is over 125 miles long flowing through agricultural, residential, industrial, and forest land. Four major rivers, many smaller creeks, five wastewater treatment plants, and groundwater discharge to the Chehalis River. Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen. CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure’s impacts to water quality, as well as river responses to potential climate change scenarios. In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed for the years 2013 and 2014. Once calibration was complete, model scenarios for future climate conditions and dam operating regimes were conducted. Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river. Title: Hydrodynamic and Water Quality Modeling of the Chehalis River in Washington Author: Van Glubt, Sarah, Wells, Scott A., Berger, Chris J. Year: 2017 The Chehalis River Basin is located in the southwest region of Washington and is over 125 miles long flowing through agricultural, residential, industrial, and forest land. Four major rivers, many smaller creeks, five wastewater treatment plants, and groundwater discharge to the Chehalis River. Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen. CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure’s impacts to water quality, as well as river responses to potential climate change scenarios. In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed for the years 2013 and 2014. Once calibration was complete, model scenarios for future climate conditions and dam operating regimes were conducted. Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river. Close

• 10. [Article] A Regional Bayesian Hierarchical Model for Flood Frequency Analysis

  In this study, we propose a regional Bayesian hierarchical model for flood frequency analysis. The Bayesian method is an alternative to the traditional regional flood frequency analysis. Instead of relying ...

  Citation × Citation Citation Abstract Copy Title: A Regional Bayesian Hierarchical Model for Flood Frequency Analysis Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2015 In this study, we propose a regional Bayesian hierarchical model for flood frequency analysis. The Bayesian method is an alternative to the traditional regional flood frequency analysis. Instead of relying on the delineation of implicit homogeneous regions, the Bayesian hierarchical method describes the spatial dependence in its inner structure. Similar to the classical Bayesian hierarchical model, the process layer of our model presents the spatial variability of the parameters by considering different covariates (e.g., drainage area, elevation, precipitation). Beyond the three classical layers (data, process, and prior) of the Bayesian hierarchical model, we add a new layer referred to as the “L-moments layer”. The L-moments layer uses L-moments theory to select the best-fit probability distribution based on the available data. This new layer can overcome the subjective selection of the distribution based on extreme value theory and determine the distribution from the data instead. By adding this layer, we can combine the merits of regional flood frequency and Bayesian methods. A standard process of covariates selection is also proposed in the Bayesian hierarchical model. The performance of the Bayesian model is assessed by a case study over the Willamette River Basin in the Pacific Northwest, U.S. The uncertainty of different flood percentiles can be quantified from the posterior distributions using the Markov Chain Monte Carlo method. Temporal changes for the 100-year flood percentiles are also examined using a 20- and 30-year moving window method. The calculated shifts in flood risk can aid future water resources planning and management. Title: A Regional Bayesian Hierarchical Model for Flood Frequency Analysis Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2015 In this study, we propose a regional Bayesian hierarchical model for flood frequency analysis. The Bayesian method is an alternative to the traditional regional flood frequency analysis. Instead of relying on the delineation of implicit homogeneous regions, the Bayesian hierarchical method describes the spatial dependence in its inner structure. Similar to the classical Bayesian hierarchical model, the process layer of our model presents the spatial variability of the parameters by considering different covariates (e.g., drainage area, elevation, precipitation). Beyond the three classical layers (data, process, and prior) of the Bayesian hierarchical model, we add a new layer referred to as the “L-moments layer”. The L-moments layer uses L-moments theory to select the best-fit probability distribution based on the available data. This new layer can overcome the subjective selection of the distribution based on extreme value theory and determine the distribution from the data instead. By adding this layer, we can combine the merits of regional flood frequency and Bayesian methods. A standard process of covariates selection is also proposed in the Bayesian hierarchical model. The performance of the Bayesian model is assessed by a case study over the Willamette River Basin in the Pacific Northwest, U.S. The uncertainty of different flood percentiles can be quantified from the posterior distributions using the Markov Chain Monte Carlo method. Temporal changes for the 100-year flood percentiles are also examined using a 20- and 30-year moving window method. The calculated shifts in flood risk can aid future water resources planning and management. Close

• 11. [Article] Quantifying Uncertainty in Urban Flooding Analysis Considering Hydro-Climatic Projection and Urban Development Effects

  How will the combined impacts of land use change, climate change, and hydrologic modeling influence changes in urban flood frequency and what is the main uncertainty source of the results? Will such changes ...

  Citation × Citation Citation Abstract Copy Title: Quantifying Uncertainty in Urban Flooding Analysis Considering Hydro-Climatic Projection and Urban Development Effects Author: Jung, Il-Won, Chang, Heejun, Moradkhani, Hamid Year: 2011 How will the combined impacts of land use change, climate change, and hydrologic modeling influence changes in urban flood frequency and what is the main uncertainty source of the results? Will such changes differ by catchment with different degrees of current and future urban development? We attempt to answer these questions in two catchments with different degrees of urbanization, the Fanno catchment with 84% urban land use and the Johnson catchment with 36% urban land use, both located in the Pacific Northwest of the US. Five uncertainty sources – general circulation model (GCM) structures, future greenhouse gas (GHG) emission scenarios, land use change scenarios, natural variability, and hydrologic model parameters – are considered to compare the relative source of uncertainty in flood frequency projections. Two land use change scenarios, conservation and development, representing possible future land use changes are used for analysis. Results show the highest increase in flood frequency under the combination of medium high GHG emission (A1B) and development scenarios, and the lowest increase under the combination of low GHG emission (B1) and conservation scenarios. Although the combined impact is more significant to flood frequency change than individual scenarios, it does not linearly Title: Quantifying Uncertainty in Urban Flooding Analysis Considering Hydro-Climatic Projection and Urban Development Effects Author: Jung, Il-Won, Chang, Heejun, Moradkhani, Hamid Year: 2011 How will the combined impacts of land use change, climate change, and hydrologic modeling influence changes in urban flood frequency and what is the main uncertainty source of the results? Will such changes differ by catchment with different degrees of current and future urban development? We attempt to answer these questions in two catchments with different degrees of urbanization, the Fanno catchment with 84% urban land use and the Johnson catchment with 36% urban land use, both located in the Pacific Northwest of the US. Five uncertainty sources – general circulation model (GCM) structures, future greenhouse gas (GHG) emission scenarios, land use change scenarios, natural variability, and hydrologic model parameters – are considered to compare the relative source of uncertainty in flood frequency projections. Two land use change scenarios, conservation and development, representing possible future land use changes are used for analysis. Results show the highest increase in flood frequency under the combination of medium high GHG emission (A1B) and development scenarios, and the lowest increase under the combination of low GHG emission (B1) and conservation scenarios. Although the combined impact is more significant to flood frequency change than individual scenarios, it does not linearly Close

• 12. [Article] Channel Shallowing as Mitigation of Coastal Flooding

  Here, we demonstrate that reductions in the depth of inlets or estuary channels can be used to reduce or prevent coastal flooding. A validated hydrodynamic model of Jamaica Bay, New York City (NYC), is ...

  Citation × Citation Citation Abstract Copy Title: Channel Shallowing as Mitigation of Coastal Flooding Author: Orton, Philip M., Talke, Stefan A., Jay, David A., Yin, Larry, Blumberg, Alan F., Georgas, Nickitas, Zhao, Haihong, Roberts, Hugh J., MacManus, Kytt Year: 2015 Here, we demonstrate that reductions in the depth of inlets or estuary channels can be used to reduce or prevent coastal flooding. A validated hydrodynamic model of Jamaica Bay, New York City (NYC), is used to test nature-based adaptation measures in ameliorating flooding for NYC’s two largest historical coastal flood events. In addition to control runs with modern bathymetry, three altered landscape scenarios are tested: (1) increasing the area of wetlands to their 1879 footprint and bathymetry, but leaving deep shipping channels unaltered; (2) shallowing all areas deeper than 2 m in the bay to be 2 m below Mean Low Water; (3) shallowing only the narrowest part of the inlet to the bay. These three scenarios are deliberately extreme and designed to evaluate the leverage each approach exerts on water levels. They result in peak water level reductions of 0.3%, 15%, and 6.8% for Hurricane Sandy, and 2.4%, 46% and 30% for the Category-3 hurricane of 1821, respectively (bay-wide averages). These results suggest that shallowing can provide greater flood protection than wetland restoration, and it is particularly effective at reducing "fast-pulse" storm surges that rise and fall quickly over several hours, like that of the 1821 storm. Nonetheless, the goal of flood mitigation must be weighed against economic, navigation, and ecological needs, and practical concerns such as the availability of sediment. Title: Channel Shallowing as Mitigation of Coastal Flooding Author: Orton, Philip M., Talke, Stefan A., Jay, David A., Yin, Larry, Blumberg, Alan F., Georgas, Nickitas, Zhao, Haihong, Roberts, Hugh J., MacManus, Kytt Year: 2015 Here, we demonstrate that reductions in the depth of inlets or estuary channels can be used to reduce or prevent coastal flooding. A validated hydrodynamic model of Jamaica Bay, New York City (NYC), is used to test nature-based adaptation measures in ameliorating flooding for NYC’s two largest historical coastal flood events. In addition to control runs with modern bathymetry, three altered landscape scenarios are tested: (1) increasing the area of wetlands to their 1879 footprint and bathymetry, but leaving deep shipping channels unaltered; (2) shallowing all areas deeper than 2 m in the bay to be 2 m below Mean Low Water; (3) shallowing only the narrowest part of the inlet to the bay. These three scenarios are deliberately extreme and designed to evaluate the leverage each approach exerts on water levels. They result in peak water level reductions of 0.3%, 15%, and 6.8% for Hurricane Sandy, and 2.4%, 46% and 30% for the Category-3 hurricane of 1821, respectively (bay-wide averages). These results suggest that shallowing can provide greater flood protection than wetland restoration, and it is particularly effective at reducing "fast-pulse" storm surges that rise and fall quickly over several hours, like that of the 1821 storm. Nonetheless, the goal of flood mitigation must be weighed against economic, navigation, and ecological needs, and practical concerns such as the availability of sediment. Close

• 13. [Article] It’s an Emergency: The Portland State University Library Flood

  Preservation Librarian Kris Kern discusses flooding at the Portland State University Library and lessons learned to prevent extended damage to the Library collections.

  Citation × Citation Citation Abstract Copy Title: It’s an Emergency: The Portland State University Library Flood Author: Kern, Kristen Year: 2008 Preservation Librarian Kris Kern discusses flooding at the Portland State University Library and lessons learned to prevent extended damage to the Library collections. Title: It’s an Emergency: The Portland State University Library Flood Author: Kern, Kristen Year: 2008 Preservation Librarian Kris Kern discusses flooding at the Portland State University Library and lessons learned to prevent extended damage to the Library collections. Close

• 14. [Article] First season effects of managed flooding on the invasive species Phalaris arundinacea L. and shoreline vegetation communities in an urban wetland

  Recent management efforts in the Smith and Bybee Lakes Wildlife Area (SBL), a 700-ha preserve in north Portland, Oregon, have included using a water control structure to suppress invasive reed canarygrass ...

  Citation × Citation Citation Abstract Copy Title: First season effects of managed flooding on the invasive species Phalaris arundinacea L. and shoreline vegetation communities in an urban wetland Author: Jenkins, Noah John Year: 2005 Recent management efforts in the Smith and Bybee Lakes Wildlife Area (SBL), a 700-ha preserve in north Portland, Oregon, have included using a water control structure to suppress invasive reed canarygrass (Phalaris arundinacea L.) by flooding during spring and early summer growth periods. For the first year of managed flooding, I sought to determine: (a) the extent and distribution of reed canarygrass at SBL; (b) the effectiveness of the change in water level at suppressing reed canarygrass; and ( c) the effects of the change in water level on other plant species. I established 30 vegetation transects throughout SBL before completion of the water control structure. These transects were randomly distributed, placed perpendicularly to the shorelines of the wetlands, and had a cumulative length of 3.1 km. I measured vegetation on the transects in autumn 2003 and autumn 2004 using the line intercept method at 10-cm intervals. I surveyed the transects to generate elevation profiles, accurate to 0.15 cm, to determine depth and duration of flooding, which I correlated with vegetative changes. I also monitored inundation depth, growth, and phenological response of individual stands of reed canarygrass during the 2004 growing season. Title: First season effects of managed flooding on the invasive species Phalaris arundinacea L. and shoreline vegetation communities in an urban wetland Author: Jenkins, Noah John Year: 2005 Recent management efforts in the Smith and Bybee Lakes Wildlife Area (SBL), a 700-ha preserve in north Portland, Oregon, have included using a water control structure to suppress invasive reed canarygrass (Phalaris arundinacea L.) by flooding during spring and early summer growth periods. For the first year of managed flooding, I sought to determine: (a) the extent and distribution of reed canarygrass at SBL; (b) the effectiveness of the change in water level at suppressing reed canarygrass; and ( c) the effects of the change in water level on other plant species. I established 30 vegetation transects throughout SBL before completion of the water control structure. These transects were randomly distributed, placed perpendicularly to the shorelines of the wetlands, and had a cumulative length of 3.1 km. I measured vegetation on the transects in autumn 2003 and autumn 2004 using the line intercept method at 10-cm intervals. I surveyed the transects to generate elevation profiles, accurate to 0.15 cm, to determine depth and duration of flooding, which I correlated with vegetative changes. I also monitored inundation depth, growth, and phenological response of individual stands of reed canarygrass during the 2004 growing season. Close

• 15. [Article] Future Flooding Impacts on Transportation Infrastructure and Traffic Patterns Resulting from Climate Change

  This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland metropolitan area. We used ensemble climate change ...

  Citation × Citation Citation Abstract Copy Title: Future Flooding Impacts on Transportation Infrastructure and Traffic Patterns Resulting from Climate Change Author: Chang, Heejun, Lafrenz, Martin, Jung, Il-Won, Figliozzi, Miguel A., Melgoza, Rolando, Ruelas, David, Platman, Deena, Pederson, Cindy Year: 2011 This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland metropolitan area. We used ensemble climate change scenarios, a hydrologic model, stream channel survey, a hydraulic model, and a travel forecast model to develop an integrated impact assessment method. High-resolution climate change scenarios are based on the combinations of two emission scenarios and eight general circulation models. The Precipitation-Runoff Modeling System was calibrated and validated for the period 1988-2006, and simulated for determining the probability of floods from 2020-2049. We surveyed stream cross sections at five road crossings for stream channel geometry and determined floodwater surface elevations using the HEC-RAS model. Four of the surveyed bridges and roadways were lower in elevation than the current 100-year floodwater surface elevation, leading to relatively frequent nuisance flooding. These roadway flooding events will become more frequent under some climate change scenarios in the future, but climate change impacts will depend on local geomorphic conditions. While vehicle miles traveled were not significantly affected by road closure, vehicle-hours delay demonstrated a greater impact from road closures, increasing by 10 percent in the Fanno Creek area. Results indicate that any cost analysis is extremely sensitive to the occurrence of human fatalities or injuries and fairly insensitive to delay costs. In addition, this research presents a comprehensive classification of flooding costs, identifies preventative measures, and makes short- and long-term recommendations. Our research demonstrated the usefulness of the integration of top-down and bottom-up approaches in climate change impact assessment, and the need for spatially explicit modeling and participatory planning in flood management and transportation planning under increasing climate uncertainty. Title: Future Flooding Impacts on Transportation Infrastructure and Traffic Patterns Resulting from Climate Change Author: Chang, Heejun, Lafrenz, Martin, Jung, Il-Won, Figliozzi, Miguel A., Melgoza, Rolando, Ruelas, David, Platman, Deena, Pederson, Cindy Year: 2011 This study investigated potential impacts of climate change on travel disruption resulting from road closures in two urban watersheds in the Portland metropolitan area. We used ensemble climate change scenarios, a hydrologic model, stream channel survey, a hydraulic model, and a travel forecast model to develop an integrated impact assessment method. High-resolution climate change scenarios are based on the combinations of two emission scenarios and eight general circulation models. The Precipitation-Runoff Modeling System was calibrated and validated for the period 1988-2006, and simulated for determining the probability of floods from 2020-2049. We surveyed stream cross sections at five road crossings for stream channel geometry and determined floodwater surface elevations using the HEC-RAS model. Four of the surveyed bridges and roadways were lower in elevation than the current 100-year floodwater surface elevation, leading to relatively frequent nuisance flooding. These roadway flooding events will become more frequent under some climate change scenarios in the future, but climate change impacts will depend on local geomorphic conditions. While vehicle miles traveled were not significantly affected by road closure, vehicle-hours delay demonstrated a greater impact from road closures, increasing by 10 percent in the Fanno Creek area. Results indicate that any cost analysis is extremely sensitive to the occurrence of human fatalities or injuries and fairly insensitive to delay costs. In addition, this research presents a comprehensive classification of flooding costs, identifies preventative measures, and makes short- and long-term recommendations. Our research demonstrated the usefulness of the integration of top-down and bottom-up approaches in climate change impact assessment, and the need for spatially explicit modeling and participatory planning in flood management and transportation planning under increasing climate uncertainty. Close

• 16. [Article] Hydrodynamic and Water Quality Modeling of the Chehalis River Using CE-QUAL-W2

  The Chehalis River Basin is located in the southwest region of Washington State, originating in the Olympic Mountains and flowing to Grays Harbor and the Pacific Ocean. The Chehalis River is over 125 miles, ...

  Citation × Citation Citation Abstract Copy Title: Hydrodynamic and Water Quality Modeling of the Chehalis River Using CE-QUAL-W2 Author: Van Glubt, Sarah Year: 2017 The Chehalis River Basin is located in the southwest region of Washington State, originating in the Olympic Mountains and flowing to Grays Harbor and the Pacific Ocean. The Chehalis River is over 125 miles, exists within five counties, and flows through agricultural, residential, industrial, and forest land areas. Four major rivers discharge to the Chehalis River, as well as many smaller creeks, five wastewater treatment plants, and groundwater flows. Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia, with severe consequences for property, safety and transportation. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen, and has had multiple water quality and Total Maximum Daily Load studies beginning in 1990. CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure's impacts to water quality, as well as river responses to potential climate change scenarios. In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed. This involved developing meteorological data, riparian shading data, and flow, temperature, water quality records for all tributaries during the calibration period of January 1, 2013 to December 31, 2014. System cross-sectional geometry data were also required for the model grid. Because of the short travel time in the river, the model was sensitive to boundary condition data, wind speed, bathymetry, nutrient kinetics, and algae, epiphyton, and zooplankton kinetics. Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures also showed impacts to river temperature and water quality. Structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river. As this research continues improvements will be made, particularly to temperature and water quality constituents. Additional data for the system would be beneficial to this process. Model predictions of temperature were sensitive to meteorological data, including cloud cover, which were largely estimated based on solar radiation. Additional meteorological data throughout the basin would be useful to temperature results. Temperature results were also sensitive to the model bathymetry, and additional investigations into segments widths and water depths may improve temperature predictions. Water quality constituent data were largely lacking for the system. Many estimation techniques and approximations were used for input water quality constituents for the model upstream boundary and tributaries when little or no data were available, introducing uncertainty to the model. It was not possible to calibrate pH to field data because alkalinity data were essentially unavailable. However, other constituents had good agreement between model predictions and field data, including dissolved oxygen, nitrates, total phosphorus, and total suspended solids. Title: Hydrodynamic and Water Quality Modeling of the Chehalis River Using CE-QUAL-W2 Author: Van Glubt, Sarah Year: 2017 The Chehalis River Basin is located in the southwest region of Washington State, originating in the Olympic Mountains and flowing to Grays Harbor and the Pacific Ocean. The Chehalis River is over 125 miles, exists within five counties, and flows through agricultural, residential, industrial, and forest land areas. Four major rivers discharge to the Chehalis River, as well as many smaller creeks, five wastewater treatment plants, and groundwater flows. Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia, with severe consequences for property, safety and transportation. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen, and has had multiple water quality and Total Maximum Daily Load studies beginning in 1990. CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure's impacts to water quality, as well as river responses to potential climate change scenarios. In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed. This involved developing meteorological data, riparian shading data, and flow, temperature, water quality records for all tributaries during the calibration period of January 1, 2013 to December 31, 2014. System cross-sectional geometry data were also required for the model grid. Because of the short travel time in the river, the model was sensitive to boundary condition data, wind speed, bathymetry, nutrient kinetics, and algae, epiphyton, and zooplankton kinetics. Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures also showed impacts to river temperature and water quality. Structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river. As this research continues improvements will be made, particularly to temperature and water quality constituents. Additional data for the system would be beneficial to this process. Model predictions of temperature were sensitive to meteorological data, including cloud cover, which were largely estimated based on solar radiation. Additional meteorological data throughout the basin would be useful to temperature results. Temperature results were also sensitive to the model bathymetry, and additional investigations into segments widths and water depths may improve temperature predictions. Water quality constituent data were largely lacking for the system. Many estimation techniques and approximations were used for input water quality constituents for the model upstream boundary and tributaries when little or no data were available, introducing uncertainty to the model. It was not possible to calibrate pH to field data because alkalinity data were essentially unavailable. However, other constituents had good agreement between model predictions and field data, including dissolved oxygen, nitrates, total phosphorus, and total suspended solids. Close

• 17. [Article] Tidal Asymmetry in an Estuarine Pycnocline 2. Transport

  Flood currents in shallow estuaries are driven by an along-channel barotropic and baroclinic pressure gradient that increases monotonically toward the bottom, while friction retards near-bottom currents. ...

  Citation × Citation Citation Abstract Copy Title: Tidal Asymmetry in an Estuarine Pycnocline 2. Transport Author: Jay, David A., Cudaback, Cynthia N. Year: 2001 Flood currents in shallow estuaries are driven by an along-channel barotropic and baroclinic pressure gradient that increases monotonically toward the bottom, while friction retards near-bottom currents. Therefore, in many estuaries there is a middepth maximum in flood currents. We explore this phenomenon using a simple three-layer model in which each layer has vertically uniform currents and constant density. In this model the middle layer is of intermediate density and grows by shear-induced entrainment from the other two layers. This very simple model produces a middepth maximum in flood currents and simulates observed currents in the Columbia River entrance channel within about 10%. There is good qualitative agreement between model salinity transport and observed transport. The model pycnocline rises and falls tidally, in phase with the observed pycnocline, although pycnocline depth and thickness are better simulated using results from a two-layer model Title: Tidal Asymmetry in an Estuarine Pycnocline 2. Transport Author: Jay, David A., Cudaback, Cynthia N. Year: 2001 Flood currents in shallow estuaries are driven by an along-channel barotropic and baroclinic pressure gradient that increases monotonically toward the bottom, while friction retards near-bottom currents. Therefore, in many estuaries there is a middepth maximum in flood currents. We explore this phenomenon using a simple three-layer model in which each layer has vertically uniform currents and constant density. In this model the middle layer is of intermediate density and grows by shear-induced entrainment from the other two layers. This very simple model produces a middepth maximum in flood currents and simulates observed currents in the Columbia River entrance channel within about 10%. There is good qualitative agreement between model salinity transport and observed transport. The model pycnocline rises and falls tidally, in phase with the observed pycnocline, although pycnocline depth and thickness are better simulated using results from a two-layer model Close

• 18. [Article] Effects of urbanization on the hydrologic regime of Johnson Creek, Portland, Oregon

  The Johnson Creek watershed, Portland, Oregon, has undergone urbanization at an increasing rate. Excessive flooding has occurred in the lower portions of the watershed, resulting in an estimated 1.5 million ...

  Citation × Citation Citation Abstract Copy Title: Effects of urbanization on the hydrologic regime of Johnson Creek, Portland, Oregon Author: Clement, William Vandewater Year: 1984 The Johnson Creek watershed, Portland, Oregon, has undergone urbanization at an increasing rate. Excessive flooding has occurred in the lower portions of the watershed, resulting in an estimated 1.5 million dollars worth of flood losses annually. In attempts to mitigate the flooding damages millions of dollars have been spent to channelize the creek, and over 200 thousand dollars has been spent during the last 20 years on preliminary feasibility studies alone. The author saw a need to verify that there has been a change in the rainfall-runoff relationships in the upper Johnson Creek basin since 1941 and to quantify this change through the analysis of key hydrologic parameters. To accomplish this , extensive background research was conducted to gather as much extant information as possible about the climatic and physiographic characteristics that affect the basin hydrology. The watershed was found to have many distinct physiographic sub-areas comprised of different underlying geology, soils, geomorphic areas, slopes, vegetation patterns, and land use types that result in a complex interaction between the watershed input {precipitation) and the watershed output (runoff at the stream gage). Title: Effects of urbanization on the hydrologic regime of Johnson Creek, Portland, Oregon Author: Clement, William Vandewater Year: 1984 The Johnson Creek watershed, Portland, Oregon, has undergone urbanization at an increasing rate. Excessive flooding has occurred in the lower portions of the watershed, resulting in an estimated 1.5 million dollars worth of flood losses annually. In attempts to mitigate the flooding damages millions of dollars have been spent to channelize the creek, and over 200 thousand dollars has been spent during the last 20 years on preliminary feasibility studies alone. The author saw a need to verify that there has been a change in the rainfall-runoff relationships in the upper Johnson Creek basin since 1941 and to quantify this change through the analysis of key hydrologic parameters. To accomplish this , extensive background research was conducted to gather as much extant information as possible about the climatic and physiographic characteristics that affect the basin hydrology. The watershed was found to have many distinct physiographic sub-areas comprised of different underlying geology, soils, geomorphic areas, slopes, vegetation patterns, and land use types that result in a complex interaction between the watershed input {precipitation) and the watershed output (runoff at the stream gage). Close

• 19. [Article] Floodplains: Balancing Nature and Human Needs

  For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River ...

  Citation × Citation Citation Abstract Copy Title: Floodplains: Balancing Nature and Human Needs Author: Shandas, Vivek, Merrick, Meg Year: 2008 For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River between 13 and 17 thousand years ago established the fertile and absorptive landscape of the Willamette Valley. The lush vegetation controlled the regional climate and stabilized the soils, while the thirsty wetlands reduced flood potential, provided habitat, and purified the water. Over geological time, these natural processes have created ideal conditions for humans. The Pacific Northwest was home to some of the most densely populated communities of Native Americans, due partly to mild climate, plentiful water, and abundant sources of food and shelter. In the 19th century, Anglo settlers flooded the region for the same amenities, which continues to create ideal conditions for all that the region is known for today, including hiking, kayaking, and sailing - not to mention the provision of climate, topography, and fertile soils for growing some of the world?s best wines! Land surveys from the 1860s suggest that the current form of the metroscape started to take shape at the end of the 19th century. The conifers, alders, and maples that covered the region were slowly removed to make way for new urban settlements, and wetlands were drained to create farms and agricultural areas. In this atlas, we journey 140 years into the past to examine how and where the metroscape has changed. Our aim is to illustrate historic flooding of the region, and ponder what changes might mean to its future. Title: Floodplains: Balancing Nature and Human Needs Author: Shandas, Vivek, Merrick, Meg Year: 2008 For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River between 13 and 17 thousand years ago established the fertile and absorptive landscape of the Willamette Valley. The lush vegetation controlled the regional climate and stabilized the soils, while the thirsty wetlands reduced flood potential, provided habitat, and purified the water. Over geological time, these natural processes have created ideal conditions for humans. The Pacific Northwest was home to some of the most densely populated communities of Native Americans, due partly to mild climate, plentiful water, and abundant sources of food and shelter. In the 19th century, Anglo settlers flooded the region for the same amenities, which continues to create ideal conditions for all that the region is known for today, including hiking, kayaking, and sailing - not to mention the provision of climate, topography, and fertile soils for growing some of the world?s best wines! Land surveys from the 1860s suggest that the current form of the metroscape started to take shape at the end of the 19th century. The conifers, alders, and maples that covered the region were slowly removed to make way for new urban settlements, and wetlands were drained to create farms and agricultural areas. In this atlas, we journey 140 years into the past to examine how and where the metroscape has changed. Our aim is to illustrate historic flooding of the region, and ponder what changes might mean to its future. Close

• 20. [Article] Temporal Variations of Citizens’ Demands on Flood Damage Mitigation, Streamflow Quantity and Quality in the Korean Urban Watershed

  Sustainable watershed management (SWM) can be achieved through recognition and reflection upon the values of citizens. Collaborative governance consisting of citizens is crucial for successful SWM. Collaborative ...

  Citation × Citation Citation Abstract Copy Title: Temporal Variations of Citizens’ Demands on Flood Damage Mitigation, Streamflow Quantity and Quality in the Korean Urban Watershed Author: Hong, Change-Yu, Chung, Eun-Sung Year: 2016 Sustainable watershed management (SWM) can be achieved through recognition and reflection upon the values of citizens. Collaborative governance consisting of citizens is crucial for successful SWM. Collaborative governance definitely requires an active participatory decision-making process that reflects citizens’ preferences. Citizen preference also tends to substantially change with life pattern and life quality. These shifts can be caused by slight variations in both social priorities and personal preferences for SWM. Therefore, collaborative water governance must be frequently renewed in response to citizens’ values through the participatory framework. The An’yang Stream in South Korea is generally regarded as a representative urban stream restoration case that has been successfully led by collaborative governance. By conducting individual surveys with citizens on-site, this study addresses how citizens’ preferences of the stream’s management have changed between 2005 and 2015. In addition, this study used three quantitative hydrologic vulnerability indices: potential flood damage (PFD), potential streamflow depletion (PSD), and potential water quality deterioration (PWQD). They can spatially quantify citizen preference using the Analytic Hierarchy Process (AHP), which can systematically derive citizens’ subjective relative-weighted preferences. In the end, this study identified critical differences in priorities in regard to vulnerable areas between in 2005 and in 2015. Title: Temporal Variations of Citizens’ Demands on Flood Damage Mitigation, Streamflow Quantity and Quality in the Korean Urban Watershed Author: Hong, Change-Yu, Chung, Eun-Sung Year: 2016 Sustainable watershed management (SWM) can be achieved through recognition and reflection upon the values of citizens. Collaborative governance consisting of citizens is crucial for successful SWM. Collaborative governance definitely requires an active participatory decision-making process that reflects citizens’ preferences. Citizen preference also tends to substantially change with life pattern and life quality. These shifts can be caused by slight variations in both social priorities and personal preferences for SWM. Therefore, collaborative water governance must be frequently renewed in response to citizens’ values through the participatory framework. The An’yang Stream in South Korea is generally regarded as a representative urban stream restoration case that has been successfully led by collaborative governance. By conducting individual surveys with citizens on-site, this study addresses how citizens’ preferences of the stream’s management have changed between 2005 and 2015. In addition, this study used three quantitative hydrologic vulnerability indices: potential flood damage (PFD), potential streamflow depletion (PSD), and potential water quality deterioration (PWQD). They can spatially quantify citizen preference using the Analytic Hierarchy Process (AHP), which can systematically derive citizens’ subjective relative-weighted preferences. In the end, this study identified critical differences in priorities in regard to vulnerable areas between in 2005 and in 2015. Close

• 21. [Article] Overcoming Uncertainty and Barriers to Adoption of Blue-Green Infrastructure for Urban Flood Risk Management

  Blue-Green Infrastructure (BGI) and Sustainable Drainage Systems (SuDS) are increasingly recognised as vital components of urban flood risk management. However, uncertainty regarding their hydrologic performance ...

  Citation × Citation Citation Abstract Copy Title: Overcoming Uncertainty and Barriers to Adoption of Blue-Green Infrastructure for Urban Flood Risk Management Author: Thorne, Colin R., Lawson, E. C., Ozawa, Connie P., Hamlin, Samantha, Smith, Leonard A. Year: 2015 Blue-Green Infrastructure (BGI) and Sustainable Drainage Systems (SuDS) are increasingly recognised as vital components of urban flood risk management. However, uncertainty regarding their hydrologic performance and lack of confidence concerning their public acceptability create concerns and challenges that limit their widespread adoption. This paper investigates barriers to implementation of BGI in Portland, Oregon, using the Relevant Dominant Uncertainty (RDU) approach. Two types of RDU are identified: scientific RDUs related to physical processes that affect infrastructure performance and service provision, and socio-political RDUs that reflect a lack of confidence in socio-political structures and public preferences for BGI. We find that socio-political RDUs currently exert the strongest negative influences on BGI decision making in Portland.We conclude that identification and management of both biophysical and socio-political uncertainties are essential to broadening the implementation of BGI and sustainable urban flood risk management solutions that are practical, scientifically sound, and supported by local stakeholders. Title: Overcoming Uncertainty and Barriers to Adoption of Blue-Green Infrastructure for Urban Flood Risk Management Author: Thorne, Colin R., Lawson, E. C., Ozawa, Connie P., Hamlin, Samantha, Smith, Leonard A. Year: 2015 Blue-Green Infrastructure (BGI) and Sustainable Drainage Systems (SuDS) are increasingly recognised as vital components of urban flood risk management. However, uncertainty regarding their hydrologic performance and lack of confidence concerning their public acceptability create concerns and challenges that limit their widespread adoption. This paper investigates barriers to implementation of BGI in Portland, Oregon, using the Relevant Dominant Uncertainty (RDU) approach. Two types of RDU are identified: scientific RDUs related to physical processes that affect infrastructure performance and service provision, and socio-political RDUs that reflect a lack of confidence in socio-political structures and public preferences for BGI. We find that socio-political RDUs currently exert the strongest negative influences on BGI decision making in Portland.We conclude that identification and management of both biophysical and socio-political uncertainties are essential to broadening the implementation of BGI and sustainable urban flood risk management solutions that are practical, scientifically sound, and supported by local stakeholders. Close

• 22. [Article] Ecosystem Recovery in Estuarine Wetlands of the Columbia River Estuary

  In the restoration of tidal wetland ecosystems, potential drivers of plant community development range from biotic controls (e.g. plant competition, seed dispersal) to abiotic controls (e.g. tidal flooding, ...

  Citation × Citation Citation Abstract Copy Title: Ecosystem Recovery in Estuarine Wetlands of the Columbia River Estuary Author: Kidd, Sarah Ann Year: 2017 In the restoration of tidal wetland ecosystems, potential drivers of plant community development range from biotic controls (e.g. plant competition, seed dispersal) to abiotic controls (e.g. tidal flooding, salinity levels). How these controls influence the success of tidal wetland restoration are only partly understood, but have important implications for wetland habitat recovery. Specifically, the extent to which the existing native and non-native seed banks in tidally reconnected wetlands interact with these controls is not clear, yet the potential success of passive restoration methods depends upon this understanding. For a 54-year chronosequence of eleven tidal wetland restoration sites in the Lower Columbia River of western Oregon, USA, it was hypothesized that native plant species and soil properties would show trends approaching reference levels within 3 to 20 years post-restoration and that lower elevation wetland areas within restored sites would exhibit a greater native species abundance and similarity to reference sites, compared with restored high elevation wetland areas. Results indicated that plant species richness, soil organic matter, bulk density, pH, and salinity conditions among the restoration sites reached reference wetland ranges within 3-6 years post-tidal reconnection. The mid-low marsh elevation zones (2.5 m) remained dominated by non-native species Phalaris arundinacea and Juncus effusus subsp. effusus. To investigate the mechanisms driving these non-native plant invasions, it was hypothesized that native and non-native wetland plant community distributions would be reflective both of their abundance in the seed bank and of their germination tolerance to wetland tidal flooding and salinity conditions. Using a factorial study design of three tidal conditions by three salinity levels, these hypotheses were tested in the greenhouse. Overall, non-native seeds were found to significantly outnumber native seeds in both seed banks. In the greenhouse, P. arundinacea and J. effusus were found to germinate more readily out of the seed bank under freshwater high-marsh flooding (1 hour a day) treatments as compared to oligohaline (3 ppt) mid-low marsh flooding (3-6 hours twice a day) treatments and to brackish salinity (10 ppt) treatments. Dominant native wetland species, Carex lyngbyei and Schoenoplectus lacustris, germination were not found to vary significantly among the treatments (p > 0.10). These results indicate that the salinity and flooding gradients within these restored marshes suppress germination of the non-native species in the low-mid marsh but not in the high marsh, where they are likely able to outcompete the native species due to their dominance in the seed bank. The implications of these results for passive tidal wetland restoration efforts are that both seed bank composition and species-specific tolerances to restored tidal flooding and salinity gradients are key mechanisms driving native and non-native plant community development and resilience. Title: Ecosystem Recovery in Estuarine Wetlands of the Columbia River Estuary Author: Kidd, Sarah Ann Year: 2017 In the restoration of tidal wetland ecosystems, potential drivers of plant community development range from biotic controls (e.g. plant competition, seed dispersal) to abiotic controls (e.g. tidal flooding, salinity levels). How these controls influence the success of tidal wetland restoration are only partly understood, but have important implications for wetland habitat recovery. Specifically, the extent to which the existing native and non-native seed banks in tidally reconnected wetlands interact with these controls is not clear, yet the potential success of passive restoration methods depends upon this understanding. For a 54-year chronosequence of eleven tidal wetland restoration sites in the Lower Columbia River of western Oregon, USA, it was hypothesized that native plant species and soil properties would show trends approaching reference levels within 3 to 20 years post-restoration and that lower elevation wetland areas within restored sites would exhibit a greater native species abundance and similarity to reference sites, compared with restored high elevation wetland areas. Results indicated that plant species richness, soil organic matter, bulk density, pH, and salinity conditions among the restoration sites reached reference wetland ranges within 3-6 years post-tidal reconnection. The mid-low marsh elevation zones (2.5 m) remained dominated by non-native species Phalaris arundinacea and Juncus effusus subsp. effusus. To investigate the mechanisms driving these non-native plant invasions, it was hypothesized that native and non-native wetland plant community distributions would be reflective both of their abundance in the seed bank and of their germination tolerance to wetland tidal flooding and salinity conditions. Using a factorial study design of three tidal conditions by three salinity levels, these hypotheses were tested in the greenhouse. Overall, non-native seeds were found to significantly outnumber native seeds in both seed banks. In the greenhouse, P. arundinacea and J. effusus were found to germinate more readily out of the seed bank under freshwater high-marsh flooding (1 hour a day) treatments as compared to oligohaline (3 ppt) mid-low marsh flooding (3-6 hours twice a day) treatments and to brackish salinity (10 ppt) treatments. Dominant native wetland species, Carex lyngbyei and Schoenoplectus lacustris, germination were not found to vary significantly among the treatments (p > 0.10). These results indicate that the salinity and flooding gradients within these restored marshes suppress germination of the non-native species in the low-mid marsh but not in the high marsh, where they are likely able to outcompete the native species due to their dominance in the seed bank. The implications of these results for passive tidal wetland restoration efforts are that both seed bank composition and species-specific tolerances to restored tidal flooding and salinity gradients are key mechanisms driving native and non-native plant community development and resilience. Close

• 23. [Article] Seaside, Oregon, Tsunami Pilot Study : Modernization of FEMA Flood Hazard Maps

  FEMA Flood Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in ...

  Citation × Citation Citation Abstract Copy Title: Seaside, Oregon, Tsunami Pilot Study : Modernization of FEMA Flood Hazard Maps Author: González, Frank I, Geist, Eric L., Synolakis, Costas, Arcas, Diego Rodriguez, Bellomo, Douglas, Carlton, David, Horning, Thomas, Jaffe, Bruce, Johnson, Jeff, Kânoğlu, Utku, Mofjeld, Harold O., Newman, Jean, Parsons, Thomas, Peters, Robert, Peterson, Curt D., Priest, George, Titov, Vasily V., Venturato, Angie J., Weber, Joseph, Wong, Florence L., Yalçıner, Ahmet Year: 2006 FEMA Flood Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in the last two decades; this conclusion is the result of two FEMA-sponsored workshops and the associated Tsunami Focused Study (Chowdhury et al., 2005). Therefore, as part of FEMA's Map Modernization Program, a Tsunami Pilot Study was carried out in the Seaside/Gearhart, Oregon, area to develop an improved Probabilistic Tsunami Hazard Assessment (PTHA) methodology and to provide recommendations for improved tsunami hazard assessment guidelines. The Seaside area was chosen because it is typical of many coastal communities in the section of the Pacific Coast from Cape Mendocino to the Strait of Juan de Fuca, and because State Agencies and local stakeholders expressed considerable interest in mapping the tsunami threat to this area. The study was an interagency effort by FEMA, U.S. Geological Survey, and the National Oceanic and Atmospheric Administration, in collaboration with the University of Southern California, Middle East Technical University, Portland State University, Horning Geoscience, Northwest Hydraulics Consultants, and the Oregon Department of Geological and Mineral Industries. Title: Seaside, Oregon, Tsunami Pilot Study : Modernization of FEMA Flood Hazard Maps Author: González, Frank I, Geist, Eric L., Synolakis, Costas, Arcas, Diego Rodriguez, Bellomo, Douglas, Carlton, David, Horning, Thomas, Jaffe, Bruce, Johnson, Jeff, Kânoğlu, Utku, Mofjeld, Harold O., Newman, Jean, Parsons, Thomas, Peters, Robert, Peterson, Curt D., Priest, George, Titov, Vasily V., Venturato, Angie J., Weber, Joseph, Wong, Florence L., Yalçıner, Ahmet Year: 2006 FEMA Flood Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in the last two decades; this conclusion is the result of two FEMA-sponsored workshops and the associated Tsunami Focused Study (Chowdhury et al., 2005). Therefore, as part of FEMA's Map Modernization Program, a Tsunami Pilot Study was carried out in the Seaside/Gearhart, Oregon, area to develop an improved Probabilistic Tsunami Hazard Assessment (PTHA) methodology and to provide recommendations for improved tsunami hazard assessment guidelines. The Seaside area was chosen because it is typical of many coastal communities in the section of the Pacific Coast from Cape Mendocino to the Strait of Juan de Fuca, and because State Agencies and local stakeholders expressed considerable interest in mapping the tsunami threat to this area. The study was an interagency effort by FEMA, U.S. Geological Survey, and the National Oceanic and Atmospheric Administration, in collaboration with the University of Southern California, Middle East Technical University, Portland State University, Horning Geoscience, Northwest Hydraulics Consultants, and the Oregon Department of Geological and Mineral Industries. Close

• 24. [Article] Residual Circulation in Shallow Estuaries 1. Highly Stratified, Narrow Estuaries

  Long-wave theory and simple turbulence closures have been used to show that three distinct types of circulation (highly stratified, weakly stratified, and partially mixed) arise in narrow, shallow estuaries ...

  Citation × Citation Citation Abstract Copy Title: Residual Circulation in Shallow Estuaries 1. Highly Stratified, Narrow Estuaries Author: Jay, David A., Smith, J. Dungan Year: 1990 Long-wave theory and simple turbulence closures have been used to show that three distinct types of circulation (highly stratified, weakly stratified, and partially mixed) arise in narrow, shallow estuaries from the finite amplitude of the tide and the interaction of stratification with vertical mixing. Each type has a different dominant process causing the vertical exchange of salt and fresh water on the flood, and each gives rise to a characteristic residual circulation. The tidal circulation in highly stratified shallow estuaries, described herein, is the result of a finite amplitude internal motion driven by the barotropic tide; shear instabilities at the interface are the major vertical exchange mechanism. The residual circulation is caused primarily by ebb-flood asymmetry in interface position and thickness. A model based on our theoretical analysis shows that the interface thickness on flood is much less than the depth of flow up to a critical tidal amplitude at which the two-layer flow is destroyed, and correctly predicts the tidal amplitude of the neap-spring transition in the Columbia River Estuary. Tidal frequency internal wave motion is not found in weakly stratified and partially mixed estuaries. Because of the reduced tidal shear, shear instabilities are weak or absent, and the residual circulation assumes a very different character, as described in part 2. Title: Residual Circulation in Shallow Estuaries 1. Highly Stratified, Narrow Estuaries Author: Jay, David A., Smith, J. Dungan Year: 1990 Long-wave theory and simple turbulence closures have been used to show that three distinct types of circulation (highly stratified, weakly stratified, and partially mixed) arise in narrow, shallow estuaries from the finite amplitude of the tide and the interaction of stratification with vertical mixing. Each type has a different dominant process causing the vertical exchange of salt and fresh water on the flood, and each gives rise to a characteristic residual circulation. The tidal circulation in highly stratified shallow estuaries, described herein, is the result of a finite amplitude internal motion driven by the barotropic tide; shear instabilities at the interface are the major vertical exchange mechanism. The residual circulation is caused primarily by ebb-flood asymmetry in interface position and thickness. A model based on our theoretical analysis shows that the interface thickness on flood is much less than the depth of flow up to a critical tidal amplitude at which the two-layer flow is destroyed, and correctly predicts the tidal amplitude of the neap-spring transition in the Columbia River Estuary. Tidal frequency internal wave motion is not found in weakly stratified and partially mixed estuaries. Because of the reduced tidal shear, shear instabilities are weak or absent, and the residual circulation assumes a very different character, as described in part 2. Close

• 25. [Article] Suspended Sediment Fluxes at an Intertidal Flat: The Shifting Influence of Wave, Wind, Tidal, and Freshwater Forcing

  Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and ...

  Citation × Citation Citation Abstract Copy Title: Suspended Sediment Fluxes at an Intertidal Flat: The Shifting Influence of Wave, Wind, Tidal, and Freshwater Forcing Author: Talke, Stefan A., Stacey, Mark T. Year: 2008 Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are dominated by increases in tidally averaged SSC and flow. Runoff and wind-induced circulation contribute to an order of magnitude increase in tidally averaged offshore flow, while waves and seiching motions from wind forcing cause an order of magnitude increase in tidally averaged SSC. Sediment fluxes during calm periods are dominated by asymmetries in SSC over a tidal cycle. Freshwater forcing produces sharp salinity fronts which trap sediment and sweep by the sensors over short (∼30 min) time scales, and occur primarily during the flood. The resulting flood dominance in SSC is magnified or reversed by variations in wind forcing between the flood and ebb. Long-term records show that more than half of wind events (sustained speeds of greater than 5 m/s) occur for 3 h or less, suggesting that asymmetric wind forcing over a tidal cycle commonly occurs. Seiching associated with wind and its variation produces onshore sediment transport. Overall, the changing hydrodynamic and meteorological forcing influence sediment flux at both short (minutes) and long (days) time scales. Title: Suspended Sediment Fluxes at an Intertidal Flat: The Shifting Influence of Wave, Wind, Tidal, and Freshwater Forcing Author: Talke, Stefan A., Stacey, Mark T. Year: 2008 Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are dominated by increases in tidally averaged SSC and flow. Runoff and wind-induced circulation contribute to an order of magnitude increase in tidally averaged offshore flow, while waves and seiching motions from wind forcing cause an order of magnitude increase in tidally averaged SSC. Sediment fluxes during calm periods are dominated by asymmetries in SSC over a tidal cycle. Freshwater forcing produces sharp salinity fronts which trap sediment and sweep by the sensors over short (∼30 min) time scales, and occur primarily during the flood. The resulting flood dominance in SSC is magnified or reversed by variations in wind forcing between the flood and ebb. Long-term records show that more than half of wind events (sustained speeds of greater than 5 m/s) occur for 3 h or less, suggesting that asymmetric wind forcing over a tidal cycle commonly occurs. Seiching associated with wind and its variation produces onshore sediment transport. Overall, the changing hydrodynamic and meteorological forcing influence sediment flux at both short (minutes) and long (days) time scales. Close

• 26. [Article] The Impacts of Natural Flood Management Approaches on In-Channel Sediment Quality

  Natural Flood Management (NFM) techniques aim to reduce downstream flooding by storing and slowing the flow of stormwater to river channels. These techniques include a range of measures, including setback ...

  Citation × Citation Citation Abstract Copy Title: The Impacts of Natural Flood Management Approaches on In-Channel Sediment Quality Author: Janes, Victoria, Grabowski, Robert, Mant, J., Allen, Deonie Year: 2017 Natural Flood Management (NFM) techniques aim to reduce downstream flooding by storing and slowing the flow of stormwater to river channels. These techniques include a range of measures, including setback stormwater outfalls and the physical restoration of channels and floodplains, to improve the natural functioning of catchments. An additional benefit of NFM measures is the potential reduction in sediment and pollutant delivery to the channel. Urban development releases a variety of heavy metal and nutrient pollutants that enter rivers through stormwater outfalls with adverse effects on the aquatic ecosystem. In this study, the influence of channel modification and quality of the river habitat on the sediment quality surrounding stormwater outfalls was assessed. Sediment samples were taken at several outfalls within the Johnson Creek catchment, Oregon, USA, and analysed for a variety of urban pollutants. The level of river habitat quality and modification at each site were assessed using a semi-quantitative scoring methodology. Significant increases in pollutant levels were observed at outfalls, with a greater and more variable increase at direct compared to setback outfalls. Removal efficiency of certain pollutants was found to be significantly correlated to the level of habitat quality or modification (for Fe, Ba, Sn, Mg, P, K) indicating that more natural reaches had greater potential for pollutant removal. The findings highlight the multiple benefits associated with NFM and river restoration approaches in relation to sediment quality and pollutant content. Title: The Impacts of Natural Flood Management Approaches on In-Channel Sediment Quality Author: Janes, Victoria, Grabowski, Robert, Mant, J., Allen, Deonie Year: 2017 Natural Flood Management (NFM) techniques aim to reduce downstream flooding by storing and slowing the flow of stormwater to river channels. These techniques include a range of measures, including setback stormwater outfalls and the physical restoration of channels and floodplains, to improve the natural functioning of catchments. An additional benefit of NFM measures is the potential reduction in sediment and pollutant delivery to the channel. Urban development releases a variety of heavy metal and nutrient pollutants that enter rivers through stormwater outfalls with adverse effects on the aquatic ecosystem. In this study, the influence of channel modification and quality of the river habitat on the sediment quality surrounding stormwater outfalls was assessed. Sediment samples were taken at several outfalls within the Johnson Creek catchment, Oregon, USA, and analysed for a variety of urban pollutants. The level of river habitat quality and modification at each site were assessed using a semi-quantitative scoring methodology. Significant increases in pollutant levels were observed at outfalls, with a greater and more variable increase at direct compared to setback outfalls. Removal efficiency of certain pollutants was found to be significantly correlated to the level of habitat quality or modification (for Fe, Ba, Sn, Mg, P, K) indicating that more natural reaches had greater potential for pollutant removal. The findings highlight the multiple benefits associated with NFM and river restoration approaches in relation to sediment quality and pollutant content. Close

• 27. [Article] Holgate Lake Study: An Examination of the Issues Associated with Groundwater Flooding

  This project examines Holgate Lake. Despite its natural hazard characteristics, the Holgate Lake area has not been immune to development pressure. Holgate Lake is an intermittent water body that forms ...

  Citation × Citation Citation Abstract Copy Title: Holgate Lake Study: An Examination of the Issues Associated with Groundwater Flooding Author: Lynch, John J., Jr., Mader, Heidi A., McCann, Mark Year: 1999 This project examines Holgate Lake. Despite its natural hazard characteristics, the Holgate Lake area has not been immune to development pressure. Holgate Lake is an intermittent water body that forms when groundwater levels rise. Historical accounts show that the lake has formed at many different times in the last century. Because the lake fluctuates with the groundwater level, it is not necessarily present from year to year. As the area has developed, more and more people built in the location of the natural lakebed when the water was not present. When the lake level returned in the 1960's flooding of homes in the area became a significant concern. The water remained for up to three months at a time, causing people to leave their homes and belongings behind. A period of dry weather persisted through the 1970's and 1980's, which lowered the level of concern about the lake's potential impacts. Due in part to the lower level 0 concern, development continued to occur in the area. However, the concerns returned in 1996 and 1997 when the lake level rose and inundated the area. These events refocused the City of Portland's attention on this area and its flooding issues. Title: Holgate Lake Study: An Examination of the Issues Associated with Groundwater Flooding Author: Lynch, John J., Jr., Mader, Heidi A., McCann, Mark Year: 1999 This project examines Holgate Lake. Despite its natural hazard characteristics, the Holgate Lake area has not been immune to development pressure. Holgate Lake is an intermittent water body that forms when groundwater levels rise. Historical accounts show that the lake has formed at many different times in the last century. Because the lake fluctuates with the groundwater level, it is not necessarily present from year to year. As the area has developed, more and more people built in the location of the natural lakebed when the water was not present. When the lake level returned in the 1960's flooding of homes in the area became a significant concern. The water remained for up to three months at a time, causing people to leave their homes and belongings behind. A period of dry weather persisted through the 1970's and 1980's, which lowered the level of concern about the lake's potential impacts. Due in part to the lower level 0 concern, development continued to occur in the area. However, the concerns returned in 1996 and 1997 when the lake level rose and inundated the area. These events refocused the City of Portland's attention on this area and its flooding issues. Close

• 28. [Article] Emissions of Anaerobically Produced Methane by Trees

  Recent studies indicate that plants may be a previously overlooked but significant source of atmospheric CH₄, though there is considerable disagreement on the mechanism of production. Our work sought to ...

  Citation × Citation Citation Abstract Copy Title: Emissions of Anaerobically Produced Methane by Trees Author: Rice, Andrew L., Butenhoff, Christopher Lee, Shearer, Martha J., Teama, Doaa, Rosenstiel, Todd N., Khalil, M. A. K. Year: 2010 Recent studies indicate that plants may be a previously overlooked but significant source of atmospheric CH₄, though there is considerable disagreement on the mechanism of production. Our work sought to verify that woody deciduous trees grown under inundated conditions had the capacity for transporting CH₄ from an anaerobic subsurface to the atmosphere and to consider if such a source could be important globally. Here, we report results from a greenhouse mesocosm study that indicate significant emissions of anaerobically produced CH₄ transmitted to the atmosphere through broadleaf riparian tree species grown under flooded conditions. Using a leaf area normalized mean emission rate (0.7 ± 0.3 μg cm⁻² hr⁻¹), results were scaled globally for flooded forest regions and estimated to be 60 ± 20 Tg year⁻¹, ~10% of the global CH₄ source. The carbon isotopic composition of CH4 emitted was found to be significantly enriched compared with expectations (δ13C ~ −54‰) and provided an important isotopic constraint on the global source which coincides with the mean of the globally scaled greenhouse-based estimate. Title: Emissions of Anaerobically Produced Methane by Trees Author: Rice, Andrew L., Butenhoff, Christopher Lee, Shearer, Martha J., Teama, Doaa, Rosenstiel, Todd N., Khalil, M. A. K. Year: 2010 Recent studies indicate that plants may be a previously overlooked but significant source of atmospheric CH₄, though there is considerable disagreement on the mechanism of production. Our work sought to verify that woody deciduous trees grown under inundated conditions had the capacity for transporting CH₄ from an anaerobic subsurface to the atmosphere and to consider if such a source could be important globally. Here, we report results from a greenhouse mesocosm study that indicate significant emissions of anaerobically produced CH₄ transmitted to the atmosphere through broadleaf riparian tree species grown under flooded conditions. Using a leaf area normalized mean emission rate (0.7 ± 0.3 μg cm⁻² hr⁻¹), results were scaled globally for flooded forest regions and estimated to be 60 ± 20 Tg year⁻¹, ~10% of the global CH₄ source. The carbon isotopic composition of CH4 emitted was found to be significantly enriched compared with expectations (δ13C ~ −54‰) and provided an important isotopic constraint on the global source which coincides with the mean of the globally scaled greenhouse-based estimate. Close

• 29. [Article] The effect of human activity on the middle course of the Tualatin River, Oregon

  A diurnal study of biological, chemical, and physical parameters was made on the middle course of the, Tualatin River, which drains a 1840 km2 (711 mi2) basin adjacent to metropolitan Portland, Oregon. ...

  Citation × Citation Citation Abstract Copy Title: The effect of human activity on the middle course of the Tualatin River, Oregon Author: Carter, Lolita M. Year: 1975 A diurnal study of biological, chemical, and physical parameters was made on the middle course of the, Tualatin River, which drains a 1840 km2 (711 mi2) basin adjacent to metropolitan Portland, Oregon. This portion of the river lies along land in transition of use from rural agriculture to highly urbanized development. There is no nutrient loading of the river from farming practices because there was no return of water from summer, sprinkler irrigation of commercial crops. However, irrigation significantly reduces the volume of water in the river in the summers. Effluents from sewage treatment plants flowing into the tributaries that drain the highly urbanized eastern areas of the river basin are the main cause of degraded water quality and algal biomass in the lower reaches of the river. The Tualatin River above the mouth of Rock Creek is relatively unpolluted, but downstream from Rock Creek the river is highly eutrophic and during the periods of low flow in the summer serves as a sewage oxidation channel. In this same portion of the river there is also evidence that nitrification occurs. Winter floods leach nitrate-nitrogen from the basin, but in the summer the possibility exists. that nitrate-nitrogen may be a limiting nutrient for algal productivity in the river above Hillsboro. The principal source of poly-phosphates is from sewage treatment plant effluents, but concentrations of poly-phosphates in the middle reaches of the river indicate that there is a natural source of poly- and/or ortho-phosphates in the watershed. Removal of phosphorous compounds from the effluents probably would not affect the large algal blooms occurring in the river below Hillsboro. Trace metal analyses indicated that iron, potassium, nickel, zinc, lead, copper, cobalt, and chromium concentrations were higher during flooding. Turbidity readings suggest that these trace elements are deposited on the floodplain. Melted snow water, which caused one of the winter floods, contained concentrations of zinc, ·copper, and lead greater than those found in the river during the flood. Greater concentrations of arsenic and zinc came from farmland than from urban areas. Diversities of the net plankton as measured by the Shannon-Weaver Index did not change from season to season, nor with downstream flow. Species in the net plankton were benthic forms at the upper stations and planktonic forms downstream from Hillsboro, especially in the summer when the reduced flow caused the river to pond. The enriched effluents from Rock Creek did not affect the diversity of the organisms downstream, but supported a larger biomass. By rating the diversities with other studies it was found that the middle course of the Tualatin River is eutrophic but not heavily polluted. A diurnal study was especially valuable from April to September, inclusive, when insolation and temperatures favored biological activities such as photosynthesis and decomposition. From November to January little diurnal change in the water quality was found. Farming had its greatest impact in the quantity of water and municipalities had a more serious impact on the water quality in the middle course of the Tualatin River. Even with the reduced flow from agricultural irrigation, the river can maintain relatively good water quality, except when effluents from sewage plants caused highly eutrophic conditions. Title: The effect of human activity on the middle course of the Tualatin River, Oregon Author: Carter, Lolita M. Year: 1975 A diurnal study of biological, chemical, and physical parameters was made on the middle course of the, Tualatin River, which drains a 1840 km2 (711 mi2) basin adjacent to metropolitan Portland, Oregon. This portion of the river lies along land in transition of use from rural agriculture to highly urbanized development. There is no nutrient loading of the river from farming practices because there was no return of water from summer, sprinkler irrigation of commercial crops. However, irrigation significantly reduces the volume of water in the river in the summers. Effluents from sewage treatment plants flowing into the tributaries that drain the highly urbanized eastern areas of the river basin are the main cause of degraded water quality and algal biomass in the lower reaches of the river. The Tualatin River above the mouth of Rock Creek is relatively unpolluted, but downstream from Rock Creek the river is highly eutrophic and during the periods of low flow in the summer serves as a sewage oxidation channel. In this same portion of the river there is also evidence that nitrification occurs. Winter floods leach nitrate-nitrogen from the basin, but in the summer the possibility exists. that nitrate-nitrogen may be a limiting nutrient for algal productivity in the river above Hillsboro. The principal source of poly-phosphates is from sewage treatment plant effluents, but concentrations of poly-phosphates in the middle reaches of the river indicate that there is a natural source of poly- and/or ortho-phosphates in the watershed. Removal of phosphorous compounds from the effluents probably would not affect the large algal blooms occurring in the river below Hillsboro. Trace metal analyses indicated that iron, potassium, nickel, zinc, lead, copper, cobalt, and chromium concentrations were higher during flooding. Turbidity readings suggest that these trace elements are deposited on the floodplain. Melted snow water, which caused one of the winter floods, contained concentrations of zinc, ·copper, and lead greater than those found in the river during the flood. Greater concentrations of arsenic and zinc came from farmland than from urban areas. Diversities of the net plankton as measured by the Shannon-Weaver Index did not change from season to season, nor with downstream flow. Species in the net plankton were benthic forms at the upper stations and planktonic forms downstream from Hillsboro, especially in the summer when the reduced flow caused the river to pond. The enriched effluents from Rock Creek did not affect the diversity of the organisms downstream, but supported a larger biomass. By rating the diversities with other studies it was found that the middle course of the Tualatin River is eutrophic but not heavily polluted. A diurnal study was especially valuable from April to September, inclusive, when insolation and temperatures favored biological activities such as photosynthesis and decomposition. From November to January little diurnal change in the water quality was found. Farming had its greatest impact in the quantity of water and municipalities had a more serious impact on the water quality in the middle course of the Tualatin River. Even with the reduced flow from agricultural irrigation, the river can maintain relatively good water quality, except when effluents from sewage plants caused highly eutrophic conditions. Close

• 30. [Article] Sedimentologic changes in the deposits of an evolving lahar-flood in 2006, Hood River Basin, Mount Hood, Oregon

  Over a span of six days from November 2nd -- 7th, 2006 approximately 43 cm of precipitation fell over the Hood River Basin in Oregon. A lahar was initiated on the Eliot Branch of the Middle Fork Hood River ...

  Citation × Citation Citation Abstract Copy Title: Sedimentologic changes in the deposits of an evolving lahar-flood in 2006, Hood River Basin, Mount Hood, Oregon Author: Poole, Matthew Ray Year: 2016 Over a span of six days from November 2nd -- 7th, 2006 approximately 43 cm of precipitation fell over the Hood River Basin in Oregon. A lahar was initiated on the Eliot Branch of the Middle Fork Hood River by two or more landslides that occurred on the lateral moraines of the Eliot Glacier on the early part of November 7th, 2006. The Eliot Branch lahar was embedded within the larger regional flood that was occurring in the Hood River Basin and traveled a total of 48 km from the initiation points on the north flank of Mount Hood to the Hood Rivers confluence with the Columbia River. The initiating landslides abruptly transformed into a debris flow upon mixing with flood waters of the Eliot Branch. The debris flow traveled a distance of ~28 km at which point it was transformed first to a hyperconcentrated flow and then to water flow via selective deposition of coarse sediment and progressive dilution by channel flow waters from the East and West Fork Hood Rivers. The transformation from debris flow to hyperconcentrated streamflow was recorded by a thickening wedge of hyperconcentrated streamflow sediments found above and below progressively fining debris flow sediments over a reach of 22 km. Finally, the hyperconcentrated-flow phase of the lahar transformed to water flow and then traveled an additional 20 km to the Hood River delta. Upon reaching the apex of the Hood River delta, depositing sediments led to an expansion of the delta. Debris-flow sediments were predominantly gravel (36.0-69.7% by wt.) with sand (22.1-55.9% by wt.) and fines (4.7-7.8% by wt.). Hyperconcentrated flow deposits contained a larger sand fraction of (66.8-99.2% by wt.) with few gravel clasts (0-26.0% by wt.) and fines (0-8.8% by wt.). Water flow deposits averaged 90.5% (wt.) sand with 6.0% (wt.) gravel and 3.0% (wt.) fines. Sorting was a key factor in flow identification and showed progressive improvement downstream from the initiation point. Sorting values for the flow types are as follows: debris flow deposits ranged from 3.3Φ (very poorly sorted) to 1.8Φ (poorly sorted), hyperconcentrated flow deposits ranged from 2.4Φ (very poorly sorted) to 0.8Φ (moderately sorted), and water flood deposits ranged between 1.4Φ (poorly sorted) to 0.6Φ (moderately sorted). Title: Sedimentologic changes in the deposits of an evolving lahar-flood in 2006, Hood River Basin, Mount Hood, Oregon Author: Poole, Matthew Ray Year: 2016 Over a span of six days from November 2nd -- 7th, 2006 approximately 43 cm of precipitation fell over the Hood River Basin in Oregon. A lahar was initiated on the Eliot Branch of the Middle Fork Hood River by two or more landslides that occurred on the lateral moraines of the Eliot Glacier on the early part of November 7th, 2006. The Eliot Branch lahar was embedded within the larger regional flood that was occurring in the Hood River Basin and traveled a total of 48 km from the initiation points on the north flank of Mount Hood to the Hood Rivers confluence with the Columbia River. The initiating landslides abruptly transformed into a debris flow upon mixing with flood waters of the Eliot Branch. The debris flow traveled a distance of ~28 km at which point it was transformed first to a hyperconcentrated flow and then to water flow via selective deposition of coarse sediment and progressive dilution by channel flow waters from the East and West Fork Hood Rivers. The transformation from debris flow to hyperconcentrated streamflow was recorded by a thickening wedge of hyperconcentrated streamflow sediments found above and below progressively fining debris flow sediments over a reach of 22 km. Finally, the hyperconcentrated-flow phase of the lahar transformed to water flow and then traveled an additional 20 km to the Hood River delta. Upon reaching the apex of the Hood River delta, depositing sediments led to an expansion of the delta. Debris-flow sediments were predominantly gravel (36.0-69.7% by wt.) with sand (22.1-55.9% by wt.) and fines (4.7-7.8% by wt.). Hyperconcentrated flow deposits contained a larger sand fraction of (66.8-99.2% by wt.) with few gravel clasts (0-26.0% by wt.) and fines (0-8.8% by wt.). Water flow deposits averaged 90.5% (wt.) sand with 6.0% (wt.) gravel and 3.0% (wt.) fines. Sorting was a key factor in flow identification and showed progressive improvement downstream from the initiation point. Sorting values for the flow types are as follows: debris flow deposits ranged from 3.3Φ (very poorly sorted) to 1.8Φ (poorly sorted), hyperconcentrated flow deposits ranged from 2.4Φ (very poorly sorted) to 0.8Φ (moderately sorted), and water flood deposits ranged between 1.4Φ (poorly sorted) to 0.6Φ (moderately sorted). Close

• 31. [Article] Climate Change Impact on the Spatio-Temporal Variability of Hydro-Climate Extremes

  The rising temperature of the earth due to climate change has shown to alter the variations of hydro-climate variables, including their intensities, frequencies and durations. Extreme events such as floods ...

  Citation × Citation Citation Abstract Copy Title: Climate Change Impact on the Spatio-Temporal Variability of Hydro-Climate Extremes Author: Najafi, Mohammad Reza Year: 2013 The rising temperature of the earth due to climate change has shown to alter the variations of hydro-climate variables, including their intensities, frequencies and durations. Extreme events such as floods are, in particular, susceptible to any disturbances in climate cycles. As such it is important to provide policymakers with sufficient knowledge about the probable impacts of climate change on hydrologic extremes and most importantly on floods, which have the highest impacts on the societies. For this reason analysis of hydro-climate extremes is commonly performed using data at each site (or grid cell), however due to the limited number of extreme events, these analyses are not robust. Current methods, such as the regional frequency analysis, which combine data from different locations are incapable of incorporating the spatial structure of the data as well as other explanatory variables, and do not explicitly, assess the uncertainties. In this thesis the spatial hierarchical Bayesian model is proposed for hydro-climate extreme analyses using data recorded at each site or grid. This method combines limited number of data from different locations, estimates the uncertainties in different stages of the hierarchy, incorporates additional explanatory variables (covariates), and can be used to estimate extreme events at un-gaged sites. The first project develops a spatial hierarchical Bayesian method to model the extreme runoffs over two spatial domains in the Columbia River Basin, U.S. The model is also employed to estimate floods with different return levels within time slices of fifteen years in order to detect possible trends in runoff extremes. Continuing on the extreme analysis, the impact of climate change on runoff extremes is investigated over the whole Pacific Northwest (PNW). This study aims to address the question of how the runoff extremes will change in the future compared to the historical time period, investigate the different behaviors of the regional climate models (RCMs) regarding the runoff extremes, and assess the seasonal variations of runoff extremes. Given the increasing number of climate model simulations the goal of the third project is to provide a multi-model ensemble average of hydro-climate extremes and characterize the inherent uncertainties. Outputs from several regional climate models provided by NARCCAP are considered for the analysis in all seasons. Three combination scenarios are defined and compared for multi-modeling of extreme runoffs. The biases of each scenario are calculated and the scenario with the least bias is selected for projecting seasonal runoff extremes. The aim of the fourth project is to quantify and compare the uncertainties regarding global climate models to the ones from the hydrologic model structures in climate change impact studies. Various methods have been proposed to downscale the coarse resolution General Circulation Model (GCM) climatological variables to the fine scale regional variables; however fewer studies have been focused on the selection of GCM predictors. Additionally, the results obtained from one downscaling technique may not be robust and the uncertainties related to the downscaling scheme are not realized. To address these issues, in the fifth study we employed Independent Component Analysis (ICA) for predictor selection which determines spatially independent GCM variables (as discussed in Appendix A). Cross validation of the independent components is employed to find the predictor combination that describes the regional precipitation over the upper Willamette basin with minimum error. These climate variables along with the observed precipitation are used to calibrate three downscaling models: Multi Linear Regression (MLR), Support Vector Machine (SVM) and Adaptive-Network-Based Fuzzy Inference System (ANFIS). Title: Climate Change Impact on the Spatio-Temporal Variability of Hydro-Climate Extremes Author: Najafi, Mohammad Reza Year: 2013 The rising temperature of the earth due to climate change has shown to alter the variations of hydro-climate variables, including their intensities, frequencies and durations. Extreme events such as floods are, in particular, susceptible to any disturbances in climate cycles. As such it is important to provide policymakers with sufficient knowledge about the probable impacts of climate change on hydrologic extremes and most importantly on floods, which have the highest impacts on the societies. For this reason analysis of hydro-climate extremes is commonly performed using data at each site (or grid cell), however due to the limited number of extreme events, these analyses are not robust. Current methods, such as the regional frequency analysis, which combine data from different locations are incapable of incorporating the spatial structure of the data as well as other explanatory variables, and do not explicitly, assess the uncertainties. In this thesis the spatial hierarchical Bayesian model is proposed for hydro-climate extreme analyses using data recorded at each site or grid. This method combines limited number of data from different locations, estimates the uncertainties in different stages of the hierarchy, incorporates additional explanatory variables (covariates), and can be used to estimate extreme events at un-gaged sites. The first project develops a spatial hierarchical Bayesian method to model the extreme runoffs over two spatial domains in the Columbia River Basin, U.S. The model is also employed to estimate floods with different return levels within time slices of fifteen years in order to detect possible trends in runoff extremes. Continuing on the extreme analysis, the impact of climate change on runoff extremes is investigated over the whole Pacific Northwest (PNW). This study aims to address the question of how the runoff extremes will change in the future compared to the historical time period, investigate the different behaviors of the regional climate models (RCMs) regarding the runoff extremes, and assess the seasonal variations of runoff extremes. Given the increasing number of climate model simulations the goal of the third project is to provide a multi-model ensemble average of hydro-climate extremes and characterize the inherent uncertainties. Outputs from several regional climate models provided by NARCCAP are considered for the analysis in all seasons. Three combination scenarios are defined and compared for multi-modeling of extreme runoffs. The biases of each scenario are calculated and the scenario with the least bias is selected for projecting seasonal runoff extremes. The aim of the fourth project is to quantify and compare the uncertainties regarding global climate models to the ones from the hydrologic model structures in climate change impact studies. Various methods have been proposed to downscale the coarse resolution General Circulation Model (GCM) climatological variables to the fine scale regional variables; however fewer studies have been focused on the selection of GCM predictors. Additionally, the results obtained from one downscaling technique may not be robust and the uncertainties related to the downscaling scheme are not realized. To address these issues, in the fifth study we employed Independent Component Analysis (ICA) for predictor selection which determines spatially independent GCM variables (as discussed in Appendix A). Cross validation of the independent components is employed to find the predictor combination that describes the regional precipitation over the upper Willamette basin with minimum error. These climate variables along with the observed precipitation are used to calibrate three downscaling models: Multi Linear Regression (MLR), Support Vector Machine (SVM) and Adaptive-Network-Based Fuzzy Inference System (ANFIS). Close

• 32. [Article] Vegetation, Environmental Characteristics, and their Relationships: Variation within the Annually Flooded Riparian Zones of the John Day River Basin, Oregon

  I hypothesized that vegetation and physical environmental characteristics would differ between the upper and lower extents of the annually flooded riparian zone on the John Day River, and that relationships ...

  Citation × Citation Citation Abstract Copy Title: Vegetation, Environmental Characteristics, and their Relationships: Variation within the Annually Flooded Riparian Zones of the John Day River Basin, Oregon Author: Hartsfield, Samuel J. Year: 2009 I hypothesized that vegetation and physical environmental characteristics would differ between the upper and lower extents of the annually flooded riparian zone on the John Day River, and that relationships between species and environmental variables would display differences between these two zones. Vegetation, environmental variables, and relationships between them were assessed for the entire annually flooded riparian zone, and for the proposed upper and lower zones. Data were collected from 60 one-square-meter quadrats: 30 in each the upper and lower zones. Sites were randomly selected and located so that flood duration was roughly equal at all sites within each zone. 34 plant species were encountered: 25 in the upper zone, 27 in the lower zone. Wetland obligate and facultative wetland species groups and eight individual species accounted for statistically different percentages ofquadrat cover between zones. ANOSIM analysis identified two statistically distinct vegetation communities between the two zones. Soil texture averaged 75.85% sand and 20.81% fines. Sand ranged between 36.69% and 95.55%. Fines ranged between 2.54% and 58.84%. A horizon depths and fine soil particle concentrations were greater in the upper zone. Coarser soils with more sand and gravel dominated the lower zone. All enviromnental variables studied, except pH, were highly variable throughout the study area. ANOSIM analysis results suggest that the upper and lower zones have distinct, statistically different physical environments from each other. Regression analyses relating species quadrat cover to physical environmental variables were performed for the total, upper, and lower riparian zones. Numerous differences were identified between the upper and lower riparian zones that the riparian scale analyses did not represent accurately. There were ten instances in which the zone scale analyses identified a relationship in either the upper or lower zone, while the corresponding riparian scale analysis failed to identify any relationship. The results of this study indicate that vegetation and the physical environment are statistically different between the upper and lower zones on this river, and that relationships between a given plant species and environmental variable can vary between zones. Future research and management efforts should consider and address the potential for such between-zone variation. Title: Vegetation, Environmental Characteristics, and their Relationships: Variation within the Annually Flooded Riparian Zones of the John Day River Basin, Oregon Author: Hartsfield, Samuel J. Year: 2009 I hypothesized that vegetation and physical environmental characteristics would differ between the upper and lower extents of the annually flooded riparian zone on the John Day River, and that relationships between species and environmental variables would display differences between these two zones. Vegetation, environmental variables, and relationships between them were assessed for the entire annually flooded riparian zone, and for the proposed upper and lower zones. Data were collected from 60 one-square-meter quadrats: 30 in each the upper and lower zones. Sites were randomly selected and located so that flood duration was roughly equal at all sites within each zone. 34 plant species were encountered: 25 in the upper zone, 27 in the lower zone. Wetland obligate and facultative wetland species groups and eight individual species accounted for statistically different percentages ofquadrat cover between zones. ANOSIM analysis identified two statistically distinct vegetation communities between the two zones. Soil texture averaged 75.85% sand and 20.81% fines. Sand ranged between 36.69% and 95.55%. Fines ranged between 2.54% and 58.84%. A horizon depths and fine soil particle concentrations were greater in the upper zone. Coarser soils with more sand and gravel dominated the lower zone. All enviromnental variables studied, except pH, were highly variable throughout the study area. ANOSIM analysis results suggest that the upper and lower zones have distinct, statistically different physical environments from each other. Regression analyses relating species quadrat cover to physical environmental variables were performed for the total, upper, and lower riparian zones. Numerous differences were identified between the upper and lower riparian zones that the riparian scale analyses did not represent accurately. There were ten instances in which the zone scale analyses identified a relationship in either the upper or lower zone, while the corresponding riparian scale analysis failed to identify any relationship. The results of this study indicate that vegetation and the physical environment are statistically different between the upper and lower zones on this river, and that relationships between a given plant species and environmental variable can vary between zones. Future research and management efforts should consider and address the potential for such between-zone variation. Close

• 33. [Article] Application of Numerical Modeling to Study River Dynamics: Hydro-Geomorphological Evolution Due to Extreme Events in the Sandy River, Oregon

  The Sandy River (OR) is a costal tributary of the Columbia River and has a steep hydroshed 1316 square kilometers which is located on the western side of Mount Hood (elevation range 3 m to 1800 m). The ...

  Citation × Citation Citation Abstract Copy Title: Application of Numerical Modeling to Study River Dynamics: Hydro-Geomorphological Evolution Due to Extreme Events in the Sandy River, Oregon Author: Muhammad, Sarkawt Hamarahim Year: 2017 The Sandy River (OR) is a costal tributary of the Columbia River and has a steep hydroshed 1316 square kilometers which is located on the western side of Mount Hood (elevation range 3 m to 1800 m). The system exhibits highly variable flow: Its average discharge is ~40 m3/s, and the highest recorded discharge was 1739 m3/s in 1964. In this study I model the geomorphic sensitivity of an 1800m reach located the downstream of the former Marmot Dam, which was removed in 2007. The hydro-geomorphic response to major flood has implications for system management and aquatic life. Studying hydro-geomorphic change requires a systematic approach. Here, I define flows and flood hydrographs for specified return interval based on the observed hydrologic record, and then examine potential hydro-geomorphic changes using a numerical model. A Pearson Type III distribution is used to calculate 100, 75, 50, 25, 10, and 2 year return periods. Extreme event hydrographs are derived by fitting derived and observed flood hydrographs to the gamma distribution curve. Sediment transport and geomorphology are then modeled numerically with Nays2DH, a solver that is part of iRIC software. Because the model is computationally intensive, I model the domain with five different spatial grid resolutions, to find proper grid resolution. The grid resolutions used are 1.5 m, 2 m, 3 m, 4 m, and 5 m. We choose 4 m as optimum grid resolution, based on the convergence of model results. The model is run for extreme event hydrographs with six above return periods. For result visualization and analysis, we focus on flow properties and bed elevation at peak flow and at the end of each event. For both times for each event, important flow and sediment transport parameters are visualized for the entire domain in plane form and eight cross-sections at 200 m intervals. Finally, we divide the geomorphic response into areas of erosion and deposition. Linear regression analyses of mean values of erosion and deposition at peak flow for all extreme events yield R2 of 0.981 for erosion and 0.986 for deposition. The mean erosion and deposition depth at the end of the events is modeled by nonlinear regression with correlation coefficient of 0.965 for erosion and 0.998 for deposition. The regression models provide direct understanding of impacts of different floods on the geomorphic response of the river domain. examination of the model as a whole suggest that the amount of erosion and deposition in the bed and banks is a function of channel geometry, bank and bed geology, riparian area condition and strongly depend on the amount of flow through the channel. Title: Application of Numerical Modeling to Study River Dynamics: Hydro-Geomorphological Evolution Due to Extreme Events in the Sandy River, Oregon Author: Muhammad, Sarkawt Hamarahim Year: 2017 The Sandy River (OR) is a costal tributary of the Columbia River and has a steep hydroshed 1316 square kilometers which is located on the western side of Mount Hood (elevation range 3 m to 1800 m). The system exhibits highly variable flow: Its average discharge is ~40 m3/s, and the highest recorded discharge was 1739 m3/s in 1964. In this study I model the geomorphic sensitivity of an 1800m reach located the downstream of the former Marmot Dam, which was removed in 2007. The hydro-geomorphic response to major flood has implications for system management and aquatic life. Studying hydro-geomorphic change requires a systematic approach. Here, I define flows and flood hydrographs for specified return interval based on the observed hydrologic record, and then examine potential hydro-geomorphic changes using a numerical model. A Pearson Type III distribution is used to calculate 100, 75, 50, 25, 10, and 2 year return periods. Extreme event hydrographs are derived by fitting derived and observed flood hydrographs to the gamma distribution curve. Sediment transport and geomorphology are then modeled numerically with Nays2DH, a solver that is part of iRIC software. Because the model is computationally intensive, I model the domain with five different spatial grid resolutions, to find proper grid resolution. The grid resolutions used are 1.5 m, 2 m, 3 m, 4 m, and 5 m. We choose 4 m as optimum grid resolution, based on the convergence of model results. The model is run for extreme event hydrographs with six above return periods. For result visualization and analysis, we focus on flow properties and bed elevation at peak flow and at the end of each event. For both times for each event, important flow and sediment transport parameters are visualized for the entire domain in plane form and eight cross-sections at 200 m intervals. Finally, we divide the geomorphic response into areas of erosion and deposition. Linear regression analyses of mean values of erosion and deposition at peak flow for all extreme events yield R2 of 0.981 for erosion and 0.986 for deposition. The mean erosion and deposition depth at the end of the events is modeled by nonlinear regression with correlation coefficient of 0.965 for erosion and 0.998 for deposition. The regression models provide direct understanding of impacts of different floods on the geomorphic response of the river domain. examination of the model as a whole suggest that the amount of erosion and deposition in the bed and banks is a function of channel geometry, bank and bed geology, riparian area condition and strongly depend on the amount of flow through the channel. Close

• 34. [Article] Portland State Perspective; June 1979

  A quarterly alumni newsletter. In this issue: master plan charts PSU's future; women engineers; anniversary of Vanport flood noted.

  Citation × Citation Citation Abstract Copy Title: Portland State Perspective; June 1979 Author: Portland State University Year: 1979 A quarterly alumni newsletter. In this issue: master plan charts PSU's future; women engineers; anniversary of Vanport flood noted. Title: Portland State Perspective; June 1979 Author: Portland State University Year: 1979 A quarterly alumni newsletter. In this issue: master plan charts PSU's future; women engineers; anniversary of Vanport flood noted. Close

• 35. [Article] Detecting Change in Rainstorm Properties from 1977-2016 and Associated Future Flood Risks in Portland, Oregon

  In response to increased greenhouse gases and global temperatures, changes to the hydrologic cycle are projected to occur and new precipitation characteristics are expected to emerge. The study of these ...

  Citation × Citation Citation Abstract Copy Title: Detecting Change in Rainstorm Properties from 1977-2016 and Associated Future Flood Risks in Portland, Oregon Author: Cooley, Alexis Kirsten Year: 2017 In response to increased greenhouse gases and global temperatures, changes to the hydrologic cycle are projected to occur and new precipitation characteristics are expected to emerge. The study of these characteristics is facilitated by common indices to measure precipitation and temperature developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). These indices can be used to describe the likely consequences of climate change such as increased daily precipitation intensity (SDII) and heavier rainfall events (R95p). This study calculates a subset of these indices from observed and modelled precipitation data in Portland, Oregon. Five rainfall gages from a high resolution rain gage network and projections from three downscaled global climate models including CanESM2, CESM1, CNRM-CM5 are used to calculate precipitation indices. Mann-Kendall's tau is used to detect monotonic trends in indices. The observational record is compared with models for the historic period (1977-2005) and these past trends are compared with projected future trends (2006-2100). The influence of study unit on trend detection is analyzed by computing trends at the annual and monthly scale. Study unit is show to be important for trend detection. When the annual study unit is used, projected future trends towards increased precipitation intensity and event volumes are not observed in the historic data. However, when analyzed with a monthly study unit, trends towards increased precipitation intensity and event volumes are observed in the historic data. These trends are shown to be important for Portland area flooding, as precipitation indices are shown to significantly correlate with 40 maximum peak flow events that occurred during the period of study. Title: Detecting Change in Rainstorm Properties from 1977-2016 and Associated Future Flood Risks in Portland, Oregon Author: Cooley, Alexis Kirsten Year: 2017 In response to increased greenhouse gases and global temperatures, changes to the hydrologic cycle are projected to occur and new precipitation characteristics are expected to emerge. The study of these characteristics is facilitated by common indices to measure precipitation and temperature developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). These indices can be used to describe the likely consequences of climate change such as increased daily precipitation intensity (SDII) and heavier rainfall events (R95p). This study calculates a subset of these indices from observed and modelled precipitation data in Portland, Oregon. Five rainfall gages from a high resolution rain gage network and projections from three downscaled global climate models including CanESM2, CESM1, CNRM-CM5 are used to calculate precipitation indices. Mann-Kendall's tau is used to detect monotonic trends in indices. The observational record is compared with models for the historic period (1977-2005) and these past trends are compared with projected future trends (2006-2100). The influence of study unit on trend detection is analyzed by computing trends at the annual and monthly scale. Study unit is show to be important for trend detection. When the annual study unit is used, projected future trends towards increased precipitation intensity and event volumes are not observed in the historic data. However, when analyzed with a monthly study unit, trends towards increased precipitation intensity and event volumes are observed in the historic data. These trends are shown to be important for Portland area flooding, as precipitation indices are shown to significantly correlate with 40 maximum peak flow events that occurred during the period of study. Close

• 36. [Article] Delivering Green Streets: an Exploration of Changing Perceptions and Behaviours Over Time Around Bioswales in Portland, Oregon

  Green Infrastructure (GI) is an increasingly popular means of dealing with flooding and water quality issues worldwide. This study examines public perceptions of, and behaviour around, bioswales, which ...

  Citation × Citation Citation Abstract Copy Title: Delivering Green Streets: an Exploration of Changing Perceptions and Behaviours Over Time Around Bioswales in Portland, Oregon Author: Everett, Glyn, Lamond, Jessica, Morzillo, Anita T., Matsler, Annie Marissa, Chan, Faith Ka Shun Year: 2015 Green Infrastructure (GI) is an increasingly popular means of dealing with flooding and water quality issues worldwide. This study examines public perceptions of, and behaviour around, bioswales, which are a popular GI facility in the United States. Bioswales are highly visible interventions requiring support from residents and policy-makers to be implemented and maintained appropriately. To understand how the residents’ perceptions and attitudes might develop over time, we interviewed residents of Portland, Oregon, living near bioswales installed 1–2, 4–5 and 8–9 years ago, to determine awareness, understanding, and opinions about the devices. We found no consistent patterns across time periods, but did find common issues affecting residents’ appreciation and acceptance: environmental attitudes, awareness and understanding of purpose and function, plant choice and maintenance, and mess and littering. It was apparent that increased public engagement, localised maintenance strategies, and possibly even customising facilities to meet residents’ needs where feasible, might improve acceptance. Title: Delivering Green Streets: an Exploration of Changing Perceptions and Behaviours Over Time Around Bioswales in Portland, Oregon Author: Everett, Glyn, Lamond, Jessica, Morzillo, Anita T., Matsler, Annie Marissa, Chan, Faith Ka Shun Year: 2015 Green Infrastructure (GI) is an increasingly popular means of dealing with flooding and water quality issues worldwide. This study examines public perceptions of, and behaviour around, bioswales, which are a popular GI facility in the United States. Bioswales are highly visible interventions requiring support from residents and policy-makers to be implemented and maintained appropriately. To understand how the residents’ perceptions and attitudes might develop over time, we interviewed residents of Portland, Oregon, living near bioswales installed 1–2, 4–5 and 8–9 years ago, to determine awareness, understanding, and opinions about the devices. We found no consistent patterns across time periods, but did find common issues affecting residents’ appreciation and acceptance: environmental attitudes, awareness and understanding of purpose and function, plant choice and maintenance, and mess and littering. It was apparent that increased public engagement, localised maintenance strategies, and possibly even customising facilities to meet residents’ needs where feasible, might improve acceptance. Close

• 37. [Article] Production, Oxidation, and Emissions of Methane from Rice Fields in China

  Detailed field studies of methane emissions from rice fields show that when nitrogen fertilizers are used with intermittent irrigation the seasonal average flux is about 3 mg/m²/hr. When continuous flooding ...

  Citation × Citation Citation Abstract Copy Title: Production, Oxidation, and Emissions of Methane from Rice Fields in China Author: Khalil, M. A. K., Shearer, Martha J., Rasmussen, R. A., Duan, Chang-Lin, Ren, Lixin Year: 2008 Detailed field studies of methane emissions from rice fields show that when nitrogen fertilizers are used with intermittent irrigation the seasonal average flux is about 3 mg/m²/hr. When continuous flooding and organic material is added to the same fields, the emissions rise to nearly 30 mg/m²/hr. Production rates measured during the two years when both organic material and water were applied to these fields were found to be 60 and 90 mg/m²/hr in consecutive years. The fraction oxidized is calculated to be about 80% one year and 43% the next year. The results suggest that high organic fertilizer increases production, but may affect the emissions more by reducing oxidation. The data show that seasonally averaged emissions vary by up to factor of 2 among adjacent fields but the variability of production is only about 20%. Information obtained from the farmers suggests that there is a trend towards less use of organic manure as nitrogen fertilizers have become available and the occurrence of intermittent flooding has increased for various reasons. These conditions have likely led to decreasing emissions of methane from rice fields in China in the recent decades. Title: Production, Oxidation, and Emissions of Methane from Rice Fields in China Author: Khalil, M. A. K., Shearer, Martha J., Rasmussen, R. A., Duan, Chang-Lin, Ren, Lixin Year: 2008 Detailed field studies of methane emissions from rice fields show that when nitrogen fertilizers are used with intermittent irrigation the seasonal average flux is about 3 mg/m²/hr. When continuous flooding and organic material is added to the same fields, the emissions rise to nearly 30 mg/m²/hr. Production rates measured during the two years when both organic material and water were applied to these fields were found to be 60 and 90 mg/m²/hr in consecutive years. The fraction oxidized is calculated to be about 80% one year and 43% the next year. The results suggest that high organic fertilizer increases production, but may affect the emissions more by reducing oxidation. The data show that seasonally averaged emissions vary by up to factor of 2 among adjacent fields but the variability of production is only about 20%. Information obtained from the farmers suggests that there is a trend towards less use of organic manure as nitrogen fertilizers have become available and the occurrence of intermittent flooding has increased for various reasons. These conditions have likely led to decreasing emissions of methane from rice fields in China in the recent decades. Close

• 38. [Article] Predictive Time Series Analysis Linking Bengal Cholera with Terrestrial Water Storage Measured from Gravity Recovery and Climate Experiment Sensors

  Outbreaks of diarrheal diseases, including cholera, are related to floods and droughts in regions where water and sanitation infrastructure are inadequate or insufficient. However, availability of data ...

  Citation × Citation Citation Abstract Copy Title: Predictive Time Series Analysis Linking Bengal Cholera with Terrestrial Water Storage Measured from Gravity Recovery and Climate Experiment Sensors Author: Jutla, Antarpreet, Akanda, Ali, Unnikrishnan, Avinash, Huq, Anwar, Colwell, Rita Year: 2015 Outbreaks of diarrheal diseases, including cholera, are related to floods and droughts in regions where water and sanitation infrastructure are inadequate or insufficient. However, availability of data on water scarcity and abundance in transnational basins, are a prerequisite for developing cholera forecasting systems. With more than a decade of terrestrial water storage (TWS) data from the Gravity Recovery and Climate Experiment, conditions favorable for predicting cholera occurrence may now be determined. We explored lead–lag relationships between TWS in the Ganges–Brahmaputra–Meghna basin and endemic cholera in Bangladesh. Since bimodal seasonal peaks in cholera in Bangladesh occur during spring and autumn seasons, two separate logistical models between TWS and disease time series (2002–2010) were developed. TWS representing water availability showed an asymmetrical, strong association with cholera prevalence in the spring (τ = −0.53; P < 0.001) and autumn (τ = 0.45; P < 0.001) up to 6 months in advance. One unit (centimeter of water) decrease in water availability in the basin increased odds of above normal cholera by 24% (confidence interval [CI] = 20–31%; P < 0.05) in the spring, while an increase in regional water by 1 unit, through floods, increased odds of above average cholera in the autumn by 29% (CI = 22–33%; P < 0.05). Title: Predictive Time Series Analysis Linking Bengal Cholera with Terrestrial Water Storage Measured from Gravity Recovery and Climate Experiment Sensors Author: Jutla, Antarpreet, Akanda, Ali, Unnikrishnan, Avinash, Huq, Anwar, Colwell, Rita Year: 2015 Outbreaks of diarrheal diseases, including cholera, are related to floods and droughts in regions where water and sanitation infrastructure are inadequate or insufficient. However, availability of data on water scarcity and abundance in transnational basins, are a prerequisite for developing cholera forecasting systems. With more than a decade of terrestrial water storage (TWS) data from the Gravity Recovery and Climate Experiment, conditions favorable for predicting cholera occurrence may now be determined. We explored lead–lag relationships between TWS in the Ganges–Brahmaputra–Meghna basin and endemic cholera in Bangladesh. Since bimodal seasonal peaks in cholera in Bangladesh occur during spring and autumn seasons, two separate logistical models between TWS and disease time series (2002–2010) were developed. TWS representing water availability showed an asymmetrical, strong association with cholera prevalence in the spring (τ = −0.53; P < 0.001) and autumn (τ = 0.45; P < 0.001) up to 6 months in advance. One unit (centimeter of water) decrease in water availability in the basin increased odds of above normal cholera by 24% (confidence interval [CI] = 20–31%; P < 0.05) in the spring, while an increase in regional water by 1 unit, through floods, increased odds of above average cholera in the autumn by 29% (CI = 22–33%; P < 0.05). Close

• 39. [Article] Integrated hydrologic and hydrochemical observations of Hidden Creek Lake jökulhlaups, Kennicott Glacier, Alaska

  Hidden Creek Lake (HCL), an ice-marginal lake impounded by Kennicott Glacier, Wrangell Mountains, Alaska, fills annually to ~20 to 30 x ~10⁶ m³ and then drains subglacially within 2 to 3 days. During the ...

  Citation × Citation Citation Abstract Copy Title: Integrated hydrologic and hydrochemical observations of Hidden Creek Lake jökulhlaups, Kennicott Glacier, Alaska Author: Anderson, Suzanne P., Walder, Joseph S., Anderson, Robert S., Kraal, Erin R., Cunico, Michelle, Fountain, Andrew G., Trabant, Dennis C. Year: 2003 Hidden Creek Lake (HCL), an ice-marginal lake impounded by Kennicott Glacier, Wrangell Mountains, Alaska, fills annually to ~20 to 30 x ~10⁶ m³ and then drains subglacially within 2 to 3 days. During the 1999 and 2000 jökulhlaups, we carried out a series of planned observations around the lake and in the Kennicott River, which drains the glacier. Approximately 20% of the lake volume was contained within a subglacial water ‘‘wedge’’ beneath the ice dam. The entire volume of the lake drains through the wedge; hydraulic head loss through this constriction may be responsible for the fairly symmetrical shape of the HCL outflow hydrographs, deduced from lake level records, basin hypsometry, and collapse of the ice dam. The flood hydrographs in the Kennicott River are similar in shape to the outflow hydrographs, and within error, lake volume matched the river flood volume in both years. Up to 12 x 10⁶ m³ of water was temporarily stored within the glacier during the 2000 jökulhlaup. During the 2000 jökulhlaup the background flow in the Kennicott River shifted to a dilute chemical composition. As the HCL jökulhlaup progressed, Donoho Falls Lake filled with water whose chemistry was closer to that of the background flow in Kennicott River than to HCL water. Comparison of these chemical signals with typical summer variations in Kennicott River chemistry suggests that the jökulhlaup created high subglacial water pressure that impeded normal drainage of solute-rich water from a distributed drainage system into a conduit system at the glacier bed and even caused flow direction locally to reverse. Title: Integrated hydrologic and hydrochemical observations of Hidden Creek Lake jökulhlaups, Kennicott Glacier, Alaska Author: Anderson, Suzanne P., Walder, Joseph S., Anderson, Robert S., Kraal, Erin R., Cunico, Michelle, Fountain, Andrew G., Trabant, Dennis C. Year: 2003 Hidden Creek Lake (HCL), an ice-marginal lake impounded by Kennicott Glacier, Wrangell Mountains, Alaska, fills annually to ~20 to 30 x ~10⁶ m³ and then drains subglacially within 2 to 3 days. During the 1999 and 2000 jökulhlaups, we carried out a series of planned observations around the lake and in the Kennicott River, which drains the glacier. Approximately 20% of the lake volume was contained within a subglacial water ‘‘wedge’’ beneath the ice dam. The entire volume of the lake drains through the wedge; hydraulic head loss through this constriction may be responsible for the fairly symmetrical shape of the HCL outflow hydrographs, deduced from lake level records, basin hypsometry, and collapse of the ice dam. The flood hydrographs in the Kennicott River are similar in shape to the outflow hydrographs, and within error, lake volume matched the river flood volume in both years. Up to 12 x 10⁶ m³ of water was temporarily stored within the glacier during the 2000 jökulhlaup. During the 2000 jökulhlaup the background flow in the Kennicott River shifted to a dilute chemical composition. As the HCL jökulhlaup progressed, Donoho Falls Lake filled with water whose chemistry was closer to that of the background flow in Kennicott River than to HCL water. Comparison of these chemical signals with typical summer variations in Kennicott River chemistry suggests that the jökulhlaup created high subglacial water pressure that impeded normal drainage of solute-rich water from a distributed drainage system into a conduit system at the glacier bed and even caused flow direction locally to reverse. Close

• 40. [Article] Greenhouse Gas Fluxes in Southeastern U.S. Coastal Plain Wetlands Under Contrasting Land Uses

  Whether through sea level rise or wetland restoration, agricultural soils in coastal areas will be inundated at increasing rates, renewing connections to sensitive surface waters and raising critical questions ...

  Citation × Citation Citation Abstract Copy Title: Greenhouse Gas Fluxes in Southeastern U.S. Coastal Plain Wetlands Under Contrasting Land Uses Author: Morse, Jennifer L., Ardón, Marcelo, Bernhardt, Emily S. Year: 2012 Whether through sea level rise or wetland restoration, agricultural soils in coastal areas will be inundated at increasing rates, renewing connections to sensitive surface waters and raising critical questions about environmental trade-offs. Wetland restoration is often implemented in agricultural catchments to improve water quality through nutrient removal. Yet flooding of soils can also increase production of the greenhouse gases nitrous oxide and methane, representing a potential environmental trade-off. Our study aimed to quantify and compare greenhouse gas emissions from unmanaged and restored forested wetlands, as well as actively managed agricultural fields within the North Carolina coastal plain, USA. In sampling conducted once every two months over a two-year comparative study, we found that soil carbon dioxide flux (range: 8000–64 800 kg CO2·ha-1· yr-1) comprised 66–100% of total greenhouse gas emissions from all sites and that methane emissions (range: -6.87 to 197 kg CH4·ha-1·yr-1) were highest from permanently inundated sites, while nitrous oxide fluxes (range: -1.07 to 139 kg N2O·ha-1·yr-1) were highest in sites with lower water tables. Contrary to predictions, greenhouse gas fluxes (as CO2 equivalents) from the restored wetland were lower than from either agricultural fields or unmanaged forested wetlands. In these acidic coastal freshwater ecosystems, the conversion of agricultural fields to flooded young forested wetlands did not result in increases in greenhouse gas emissions. Title: Greenhouse Gas Fluxes in Southeastern U.S. Coastal Plain Wetlands Under Contrasting Land Uses Author: Morse, Jennifer L., Ardón, Marcelo, Bernhardt, Emily S. Year: 2012 Whether through sea level rise or wetland restoration, agricultural soils in coastal areas will be inundated at increasing rates, renewing connections to sensitive surface waters and raising critical questions about environmental trade-offs. Wetland restoration is often implemented in agricultural catchments to improve water quality through nutrient removal. Yet flooding of soils can also increase production of the greenhouse gases nitrous oxide and methane, representing a potential environmental trade-off. Our study aimed to quantify and compare greenhouse gas emissions from unmanaged and restored forested wetlands, as well as actively managed agricultural fields within the North Carolina coastal plain, USA. In sampling conducted once every two months over a two-year comparative study, we found that soil carbon dioxide flux (range: 8000–64 800 kg CO2·ha-1· yr-1) comprised 66–100% of total greenhouse gas emissions from all sites and that methane emissions (range: -6.87 to 197 kg CH4·ha-1·yr-1) were highest from permanently inundated sites, while nitrous oxide fluxes (range: -1.07 to 139 kg N2O·ha-1·yr-1) were highest in sites with lower water tables. Contrary to predictions, greenhouse gas fluxes (as CO2 equivalents) from the restored wetland were lower than from either agricultural fields or unmanaged forested wetlands. In these acidic coastal freshwater ecosystems, the conversion of agricultural fields to flooded young forested wetlands did not result in increases in greenhouse gas emissions. Close

• 41. [Article] Migration Movement

  All†Borders†Are†Temporary "Migration is a phenomenon, not a problem – something that simply is. The right to migrate and to move freely is our human right. When societies restrict or choke off the movements ...

  Citation × Citation Citation Abstract Copy Title: Migration Movement Author: Porte, Robert Year: 2016 All†Borders†Are†Temporary "Migration is a phenomenon, not a problem – something that simply is. The right to migrate and to move freely is our human right. When societies restrict or choke off the movements of their citizens, they end up doing the work of a dam, they generate power and control floods, but in doing so they destroy life and wreck the surrounding space." Justseeds†(excerpt) As the current administration at the time of this writing continues its program of deportation of women and children from the U.S. to their war torn and violent countries of origin, I want not to engage in an art practice that doesn’t consider the sociopolitical climate of our times. Title: Migration Movement Author: Porte, Robert Year: 2016 All†Borders†Are†Temporary "Migration is a phenomenon, not a problem – something that simply is. The right to migrate and to move freely is our human right. When societies restrict or choke off the movements of their citizens, they end up doing the work of a dam, they generate power and control floods, but in doing so they destroy life and wreck the surrounding space." Justseeds†(excerpt) As the current administration at the time of this writing continues its program of deportation of women and children from the U.S. to their war torn and violent countries of origin, I want not to engage in an art practice that doesn’t consider the sociopolitical climate of our times. Close

• 42. [Article] Cleaner Drain

  Water in streets causes several issues, both to our infrastructure and our emotions. The water can harm property by rotting wooden structures. If the water is high enough, it can even stall cars and flood ...

  Citation × Citation Citation Abstract Copy Title: Cleaner Drain Author: Paivarinta, Jonah, Ortiz‐Rojo, Daniel, Klepp, Masson, Likestoskat, Rebekah, Chadney, Macy, Ferrando, Jeremy Year: 2015 Water in streets causes several issues, both to our infrastructure and our emotions. The water can harm property by rotting wooden structures. If the water is high enough, it can even stall cars and flood into buildings. Being forced to walk through or around a puddle can hurt someone's emotional state, which reduces productivity and this affect people around them. It costs about 30 dollars to clean a drain, and there are about 15 thousand drains, which totals to to around$450,000 and if you add in other costs such as employees and street sweeping for a cleaning company it costs around 3.8 million a year. Title: Cleaner Drain Author: Paivarinta, Jonah, Ortiz‐Rojo, Daniel, Klepp, Masson, Likestoskat, Rebekah, Chadney, Macy, Ferrando, Jeremy Year: 2015 Water in streets causes several issues, both to our infrastructure and our emotions. The water can harm property by rotting wooden structures. If the water is high enough, it can even stall cars and flood into buildings. Being forced to walk through or around a puddle can hurt someone's emotional state, which reduces productivity and this affect people around them. It costs about 30 dollars to clean a drain, and there are about 15 thousand drains, which totals to to around$450,000 and if you add in other costs such as employees and street sweeping for a cleaning company it costs around 3.8 million a year. Close

• 43. [Article] Structure and influence of the Tillamook Uplift on the stratigraphy of the Mist area, Oregon

  Fifty three sedimentary samples were analyzed for their minor and trace element concentrations utilizing instrumental neutron activation analysis. Concentrations of Na, K, La, Sm and Sc, and their ratios ...

  Citation × Citation Citation Abstract Copy Title: Structure and influence of the Tillamook Uplift on the stratigraphy of the Mist area, Oregon Author: Kadri, Moinoddin Murtuzamiya Year: 1982 Fifty three sedimentary samples were analyzed for their minor and trace element concentrations utilizing instrumental neutron activation analysis. Concentrations of Na, K, La, Sm and Sc, and their ratios appear to establish significant trends. The data suggest a major break from a granitic-metamorphic provenance and a volcanic component dominated provenance between the Cowlitz and Keasey Formations respectively. The provenance of the Astoria Formation indicates the presence of flood basalts. Title: Structure and influence of the Tillamook Uplift on the stratigraphy of the Mist area, Oregon Author: Kadri, Moinoddin Murtuzamiya Year: 1982 Fifty three sedimentary samples were analyzed for their minor and trace element concentrations utilizing instrumental neutron activation analysis. Concentrations of Na, K, La, Sm and Sc, and their ratios appear to establish significant trends. The data suggest a major break from a granitic-metamorphic provenance and a volcanic component dominated provenance between the Cowlitz and Keasey Formations respectively. The provenance of the Astoria Formation indicates the presence of flood basalts. Close

• 44. [Article] Periodic Atlas of the Metroscape: Natural Hazards: Are You at Risk

  This edition of the Periodic Atlas of the Metroscape focuses on hazard analysis, and looks at the relative danger of earthquake, flood, landslide, debris flow, lava flow, and radon throughout the Portland ...

  Citation × Citation Citation Abstract Copy Title: Periodic Atlas of the Metroscape: Natural Hazards: Are You at Risk Author: Sanchez, Tom, Burns, Scott, Dorwart, Jon, Merrick, Meg Year: 2002 This edition of the Periodic Atlas of the Metroscape focuses on hazard analysis, and looks at the relative danger of earthquake, flood, landslide, debris flow, lava flow, and radon throughout the Portland area. The maps are printed in 3D format, and the print edition of the Metroscape included special glasses that, when worn, give the maps a 3D appearance. Title: Periodic Atlas of the Metroscape: Natural Hazards: Are You at Risk Author: Sanchez, Tom, Burns, Scott, Dorwart, Jon, Merrick, Meg Year: 2002 This edition of the Periodic Atlas of the Metroscape focuses on hazard analysis, and looks at the relative danger of earthquake, flood, landslide, debris flow, lava flow, and radon throughout the Portland area. The maps are printed in 3D format, and the print edition of the Metroscape included special glasses that, when worn, give the maps a 3D appearance. Close

• 45. [Article] The Columbia River's fate in the twentieth century

  Discusses the history of the Columbia River during the 20th century, emphasizing the image of the river as both a source of industry and an example of wild natural beauty. In 1933 the river was dammed ...

  Citation × Citation Citation Abstract Copy Title: The Columbia River's fate in the twentieth century Author: Lang, William L. Year: 2000 Discusses the history of the Columbia River during the 20th century, emphasizing the image of the river as both a source of industry and an example of wild natural beauty. In 1933 the river was dammed to harness its power for hydroelectricity and control its unpredictable flooding. With the completion of the dams in the 1970's, however, came problems with the edenic vision of the river, especially with the annual salmon run. By the late 20th century, the salmon had all but disappeared, leading to an ongoing conflict between supporters of the dams and conservationists. Title: The Columbia River's fate in the twentieth century Author: Lang, William L. Year: 2000 Discusses the history of the Columbia River during the 20th century, emphasizing the image of the river as both a source of industry and an example of wild natural beauty. In 1933 the river was dammed to harness its power for hydroelectricity and control its unpredictable flooding. With the completion of the dams in the 1970's, however, came problems with the edenic vision of the river, especially with the annual salmon run. By the late 20th century, the salmon had all but disappeared, leading to an ongoing conflict between supporters of the dams and conservationists. Close

• 46. [Article] Interview with Willie Mae Hart

  Interview with Willie Mae Hart by Heather Burmeister and Lisa Donnelly on February 25, 2010, in Portland, Oregon. Willie discusses the many important moments in Oregon history such as the Vanport Flood, ...

  Citation × Citation Citation Abstract Copy Title: Interview with Willie Mae Hart Author: Donnelly, Lisa Chere', Burmeister, Heather Jo Year: 2010 Interview with Willie Mae Hart by Heather Burmeister and Lisa Donnelly on February 25, 2010, in Portland, Oregon. Willie discusses the many important moments in Oregon history such as the Vanport Flood, the debate over the Public Accommodations Act, and presidential candidate John F. Kennedy's campaign visit to Portland in 1960, where he met Willie Mae at an event that she had organized. Title: Interview with Willie Mae Hart Author: Donnelly, Lisa Chere', Burmeister, Heather Jo Year: 2010 Interview with Willie Mae Hart by Heather Burmeister and Lisa Donnelly on February 25, 2010, in Portland, Oregon. Willie discusses the many important moments in Oregon history such as the Vanport Flood, the debate over the Public Accommodations Act, and presidential candidate John F. Kennedy's campaign visit to Portland in 1960, where he met Willie Mae at an event that she had organized. Close

• 47. [Article] Characterization of the Red Bluff Landslide, Greater Cascade Landslide Complex, Columbia River Gorge, Washington

  Located in the Columbia River Gorge, The Red Bluff Landslide (18.8 km2) is one of four large landslides that make up the Cascade Landslide Complex. In its current form, the Red Bluff Landslide is a post-Missoula ...

  Citation × Citation Citation Abstract Copy Title: Characterization of the Red Bluff Landslide, Greater Cascade Landslide Complex, Columbia River Gorge, Washington Author: Randall, James Robert Year: 2012 Located in the Columbia River Gorge, The Red Bluff Landslide (18.8 km2) is one of four large landslides that make up the Cascade Landslide Complex. In its current form, the Red Bluff Landslide is a post-Missoula Flood feature made up of two components: an active upper lobe (8.6 km2) that is translational, creeping to the south at 25 cm/yr and spreading laterally to the east at 6 cm/yr over a semi-fixed portion (10.2 km2) of the Red Bluff Landslide area that has been "smoothed" by Missoula Floods. The upper active lobe is the landslide debris accumulated since Missoula Flood time (~15,000 yr. BP). Five separate collapse events have been identified and rock failures along the main scarp headwalls continue. Two rock avalanches on the Red Bluff Landslide were mapped. The Old Greenleaf Basin Rock Avalanche is estimated to have occurred 100 to 150 years ago, represents the fifth collapse event on the Red Bluff Landslide, and covers an area of 200,000 m2. It has a volume of 4.2 million m3; its length is 748 m and has a width of 215 m. On January 3, 2008, the Greenleaf Basin Rock Avalanche occurred, flowing over the Old Greenleaf Basin Rock Avalanche, covering an area of 100,000 m2 and deposited a volume of about 375,000 m3. Its length is 730 m with an average depth of 1.22 m. It contributed approximately 0.058% of the total volume and 0.01% of the surface area to the active upper lobe portion of the Red Bluff Landslide. The Greenleaf Basin Rock Avalanche was determined to be insignificant in the movement of the active part of the Red Bluff Landslide during the winter of 2007-2008. The original Cascade Landslide Complex map (Wise, 1961) included the Mosley Lakes Landslide which has now been removed because it lacked the characteristics of a landslide like a scarp. The original complex (35.5 km2) has been renamed the "Greater Cascade Landslide Complex" (43.0 km2), with the addition of the adjacent Stevenson Slide and the elimination of the Mosley Lakes Landslide. Title: Characterization of the Red Bluff Landslide, Greater Cascade Landslide Complex, Columbia River Gorge, Washington Author: Randall, James Robert Year: 2012 Located in the Columbia River Gorge, The Red Bluff Landslide (18.8 km2) is one of four large landslides that make up the Cascade Landslide Complex. In its current form, the Red Bluff Landslide is a post-Missoula Flood feature made up of two components: an active upper lobe (8.6 km2) that is translational, creeping to the south at 25 cm/yr and spreading laterally to the east at 6 cm/yr over a semi-fixed portion (10.2 km2) of the Red Bluff Landslide area that has been "smoothed" by Missoula Floods. The upper active lobe is the landslide debris accumulated since Missoula Flood time (~15,000 yr. BP). Five separate collapse events have been identified and rock failures along the main scarp headwalls continue. Two rock avalanches on the Red Bluff Landslide were mapped. The Old Greenleaf Basin Rock Avalanche is estimated to have occurred 100 to 150 years ago, represents the fifth collapse event on the Red Bluff Landslide, and covers an area of 200,000 m2. It has a volume of 4.2 million m3; its length is 748 m and has a width of 215 m. On January 3, 2008, the Greenleaf Basin Rock Avalanche occurred, flowing over the Old Greenleaf Basin Rock Avalanche, covering an area of 100,000 m2 and deposited a volume of about 375,000 m3. Its length is 730 m with an average depth of 1.22 m. It contributed approximately 0.058% of the total volume and 0.01% of the surface area to the active upper lobe portion of the Red Bluff Landslide. The Greenleaf Basin Rock Avalanche was determined to be insignificant in the movement of the active part of the Red Bluff Landslide during the winter of 2007-2008. The original Cascade Landslide Complex map (Wise, 1961) included the Mosley Lakes Landslide which has now been removed because it lacked the characteristics of a landslide like a scarp. The original complex (35.5 km2) has been renamed the "Greater Cascade Landslide Complex" (43.0 km2), with the addition of the adjacent Stevenson Slide and the elimination of the Mosley Lakes Landslide. Close

• 48. [Article] Long-term Responses of Phalaris arundinacea and Columbia River Bottomland Vegetation to Managed Flooding

  I sought to determine the effect of managed flooding on Phalaris arundinacea L. and other plant species distributions in a large wetland complex, Smith and Bybee Wetlands (SBW), in northwestern Oregon. ...

  Citation × Citation Citation Abstract Copy Title: Long-term Responses of Phalaris arundinacea and Columbia River Bottomland Vegetation to Managed Flooding Author: Farrelly, Tina Schantz Year: 2012 I sought to determine the effect of managed flooding on Phalaris arundinacea L. and other plant species distributions in a large wetland complex, Smith and Bybee Wetlands (SBW), in northwestern Oregon. Altered hydrology has reduced historically high spring flow and prematurely initiated the historic summer drying period at SBW. This alteration has increased the coverage of invasive plants (e.g., P. arundinacea) causing a decrease in native plant cover and thus degrading ecological functions. SBW managers installed a water control structure (WCS) between SBW and the Columbia Slough/River system to impound winter rainfall and thus approximate the ecological benefits that natural flooding provided as well as reduce the abundance of P. arundinacea. Prior researchers conducted intensive vegetation and hydrological monitoring in 2003 (during the season immediately before WCS installation) and 2004. I conducted similar analysis in the fifth and sixth years, 2008 and 2009, following establishment of the WCS. Both study years, I determined percent cover of all vegetation on transects established in 2003. The results, including 2004, as well as 2008 and 2009 showed a reduced cover of P. arundinacea in areas experiencing at least 0.6 meters of inundation and an increased cover of native plant communities when compared to the 2003 baseline data. Native Carex aperta Boott. cover increased 7-fold from 0.3% to 2.3%; Polygonum species cover increased from 20.0% to 52.6%; and Salix lucida Muhl. ssp. lasiandra (Benth.) E. Murray cover increased from 10.9% to 15.5% cover. P. arundinacea declined by over one-third from 44.4% to 28.1% cover following water management. Since hydrology management began, the native Polygonum species community replaced P. arundinacea as the dominant species in the emergent zone. The results of this study refined the suggested depth of inundation needed to reduce P. arundinacea cover in such lake-wetland complexes as SBW from 0.85 meters (based on 2004 study results) to 0.6 meters. Shannon Diversity decreased following water management. The findings of this study demonstrated that water management can enhance native bottomland communities, especially those comprised of obligate wetland species, and reduce P. arundinacea cover in areas experiencing at least 0.6 meters of inundation. Title: Long-term Responses of Phalaris arundinacea and Columbia River Bottomland Vegetation to Managed Flooding Author: Farrelly, Tina Schantz Year: 2012 I sought to determine the effect of managed flooding on Phalaris arundinacea L. and other plant species distributions in a large wetland complex, Smith and Bybee Wetlands (SBW), in northwestern Oregon. Altered hydrology has reduced historically high spring flow and prematurely initiated the historic summer drying period at SBW. This alteration has increased the coverage of invasive plants (e.g., P. arundinacea) causing a decrease in native plant cover and thus degrading ecological functions. SBW managers installed a water control structure (WCS) between SBW and the Columbia Slough/River system to impound winter rainfall and thus approximate the ecological benefits that natural flooding provided as well as reduce the abundance of P. arundinacea. Prior researchers conducted intensive vegetation and hydrological monitoring in 2003 (during the season immediately before WCS installation) and 2004. I conducted similar analysis in the fifth and sixth years, 2008 and 2009, following establishment of the WCS. Both study years, I determined percent cover of all vegetation on transects established in 2003. The results, including 2004, as well as 2008 and 2009 showed a reduced cover of P. arundinacea in areas experiencing at least 0.6 meters of inundation and an increased cover of native plant communities when compared to the 2003 baseline data. Native Carex aperta Boott. cover increased 7-fold from 0.3% to 2.3%; Polygonum species cover increased from 20.0% to 52.6%; and Salix lucida Muhl. ssp. lasiandra (Benth.) E. Murray cover increased from 10.9% to 15.5% cover. P. arundinacea declined by over one-third from 44.4% to 28.1% cover following water management. Since hydrology management began, the native Polygonum species community replaced P. arundinacea as the dominant species in the emergent zone. The results of this study refined the suggested depth of inundation needed to reduce P. arundinacea cover in such lake-wetland complexes as SBW from 0.85 meters (based on 2004 study results) to 0.6 meters. Shannon Diversity decreased following water management. The findings of this study demonstrated that water management can enhance native bottomland communities, especially those comprised of obligate wetland species, and reduce P. arundinacea cover in areas experiencing at least 0.6 meters of inundation. Close

• 49. [Article] Nineteenth Century North American and Pacific Tidal Data: Lost or Just Forgotten?

  Tide data are the oldest and longest oceanographic records and comprise one of the few tools for understanding, quantifying, and separating century-scale human and climate impacts on the coastal zone. ...

  Citation × Citation Citation Abstract Copy Title: Nineteenth Century North American and Pacific Tidal Data: Lost or Just Forgotten? Author: Talke, Stefan A., Jay, David A. Year: 2013 Tide data are the oldest and longest oceanographic records and comprise one of the few tools for understanding, quantifying, and separating century-scale human and climate impacts on the coastal zone. Our archival research indicates that continuous measurements of tides began in 1844 in the western Atlantic, 1853 in the Eastern Pacific, and 1858 in the Western Pacific. At least 50 multiyear tide series existed by the year 1900. With few exceptions, however, these 19th and early 20th century measurements have not been analyzed in more than a century and have been forgotten and neglected by the scientific community. This article describes historical tide measurements in the Pacific Ocean and North America, their current status, and ongoing efforts to recover the data. Possible uses of the data include assessing trends in sea level, tidal properties, and river flow, and reanalyzing extreme events such as historical storms and floods. More than 600 years of station data are confirmed to still exist in paper form, out of approximately 1900 years total. Title: Nineteenth Century North American and Pacific Tidal Data: Lost or Just Forgotten? Author: Talke, Stefan A., Jay, David A. Year: 2013 Tide data are the oldest and longest oceanographic records and comprise one of the few tools for understanding, quantifying, and separating century-scale human and climate impacts on the coastal zone. Our archival research indicates that continuous measurements of tides began in 1844 in the western Atlantic, 1853 in the Eastern Pacific, and 1858 in the Western Pacific. At least 50 multiyear tide series existed by the year 1900. With few exceptions, however, these 19th and early 20th century measurements have not been analyzed in more than a century and have been forgotten and neglected by the scientific community. This article describes historical tide measurements in the Pacific Ocean and North America, their current status, and ongoing efforts to recover the data. Possible uses of the data include assessing trends in sea level, tidal properties, and river flow, and reanalyzing extreme events such as historical storms and floods. More than 600 years of station data are confirmed to still exist in paper form, out of approximately 1900 years total. Close

• 50. [Article] Increasing Storm Tides in New York Harbor, 1844–2013

  Three of the nine highest recorded water levels in the New York Harbor region have occurred since 2010 (March 2010, August 2011, and October 2012), and eight of the largest twenty have occurred since 1990. ...

  Citation × Citation Citation Abstract Copy Title: Increasing Storm Tides in New York Harbor, 1844–2013 Author: Talke, Stefan A., Orton, Philip M., Jay, David A. Year: 2014 Three of the nine highest recorded water levels in the New York Harbor region have occurred since 2010 (March 2010, August 2011, and October 2012), and eight of the largest twenty have occurred since 1990. To investigate whether this cluster of high waters is a random occurrence or indicative of intensified storm tides, we recover archival tide gauge data back to 1844 and evaluate the trajectory of the annual maximum storm tide. Approximately half of long-term variance is anticorrelated with decadal-scale variations in the North Atlantic Oscillation, while long-term trends explain the remainder. The 10 year storm tide has increased by 0.28 m. Combined with a 0.44 m increase in local sea level since 1856, the 10 year flood level has increased by approximately 0.72 ± 0.25 m, and magnified the annual probability of overtopping the typical Manhattan seawall from less than 1% to about 20–25%. Title: Increasing Storm Tides in New York Harbor, 1844–2013 Author: Talke, Stefan A., Orton, Philip M., Jay, David A. Year: 2014 Three of the nine highest recorded water levels in the New York Harbor region have occurred since 2010 (March 2010, August 2011, and October 2012), and eight of the largest twenty have occurred since 1990. To investigate whether this cluster of high waters is a random occurrence or indicative of intensified storm tides, we recover archival tide gauge data back to 1844 and evaluate the trajectory of the annual maximum storm tide. Approximately half of long-term variance is anticorrelated with decadal-scale variations in the North Atlantic Oscillation, while long-term trends explain the remainder. The 10 year storm tide has increased by 0.28 m. Combined with a 0.44 m increase in local sea level since 1856, the 10 year flood level has increased by approximately 0.72 ± 0.25 m, and magnified the annual probability of overtopping the typical Manhattan seawall from less than 1% to about 20–25%. Close