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• 41. [Article] Diurnal HO₂ cycles at clean air and urban sites in the troposphere

  HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds ...

  Citation × Citation Citation Abstract Copy Title: Diurnal HO₂ cycles at clean air and urban sites in the troposphere Author: Hard, Thomas M., Chan, C. Y., Mehrabzadeh, A. A., O'Brien, Robert J. Year: 1992 HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO₂ was determined during moderately low ozone pollution levels. At both sites, maximum daily [HO₂] was in the range of 1-2times10⁸ cm⁻³ under clear-sky conditions, with an estimated overall uncertainty of 40%. Title: Diurnal HO₂ cycles at clean air and urban sites in the troposphere Author: Hard, Thomas M., Chan, C. Y., Mehrabzadeh, A. A., O'Brien, Robert J. Year: 1992 HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO₂ was determined during moderately low ozone pollution levels. At both sites, maximum daily [HO₂] was in the range of 1-2times10⁸ cm⁻³ under clear-sky conditions, with an estimated overall uncertainty of 40%. Close

• 42. [Article] Carbon monoxide in the antarctic atmosphere: Observations of decreasing concentrations

  Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth's atmosphere (Thompson 1992). In recent ...

  Citation × Citation Citation Abstract Copy Title: Carbon monoxide in the antarctic atmosphere: Observations of decreasing concentrations Author: Khalil, M. A., Rasmussen, R. A. Year: 1994 Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth's atmosphere (Thompson 1992). In recent years, there have been growing concerns that, over the past century and now, human activities may be depleting hydroxyl concentrations by adding huge amounts of carbon monoxide and methane to the atmosphere. Reduction in the hydroxyl concentrations can then indirectly lead to more global warming, stratospheric ozone depletion, and other disturbances in atmospheric chemistry. Carbon monoxide (CO) is a key component in the determination of hydroxyl radical (OH) concentrations: increases of CO would lead to a decline of OH. Global increases of CO had been observed in the 1980s (Khalil and Rasmussen 1985, 1988, 1990), but now it appears that the atmospheric concentrations of CO are falling. Here we will report data from Antarctica that suggest recent decreases in the concentration of CO. Title: Carbon monoxide in the antarctic atmosphere: Observations of decreasing concentrations Author: Khalil, M. A., Rasmussen, R. A. Year: 1994 Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth's atmosphere (Thompson 1992). In recent years, there have been growing concerns that, over the past century and now, human activities may be depleting hydroxyl concentrations by adding huge amounts of carbon monoxide and methane to the atmosphere. Reduction in the hydroxyl concentrations can then indirectly lead to more global warming, stratospheric ozone depletion, and other disturbances in atmospheric chemistry. Carbon monoxide (CO) is a key component in the determination of hydroxyl radical (OH) concentrations: increases of CO would lead to a decline of OH. Global increases of CO had been observed in the 1980s (Khalil and Rasmussen 1985, 1988, 1990), but now it appears that the atmospheric concentrations of CO are falling. Here we will report data from Antarctica that suggest recent decreases in the concentration of CO. Close

• 43. [Article] Intercomparison of Local Hydroxyl Measurements by Radiocarbon and FAGE Techniques

  A direct intercomparison of near-surface tropospheric HO concentration measurements by two different techniques was made in October–November 1992 at a rural site near Pullman, Washington. The atmosphere ...

  Citation × Citation Citation Abstract Copy Title: Intercomparison of Local Hydroxyl Measurements by Radiocarbon and FAGE Techniques Author: Campbell, Malcolm J., Hall, Brad D., Sheppard, John C., Utley, Philip L., O'Brien, Robert J., Hard, Thomas M., George, Linda Acha Year: 1995 A direct intercomparison of near-surface tropospheric HO concentration measurements by two different techniques was made in October–November 1992 at a rural site near Pullman, Washington. The atmosphere at the site is believed to contain low levels of anthropogenic pollution. The instruments' inlets were located at the same height (3.5 m) above the ground and were separated by 10 m along a line normal to the prevailing wind. Readings of the FAGE3 and radiocarbon instruments showed a high correlation (r² = 0.74) despite HO concentrations that were frequently near the detection limit of the instruments. An unweighted least squares regression shows a slope significantly different from unity, indicating different calibration scales of the two instruments Title: Intercomparison of Local Hydroxyl Measurements by Radiocarbon and FAGE Techniques Author: Campbell, Malcolm J., Hall, Brad D., Sheppard, John C., Utley, Philip L., O'Brien, Robert J., Hard, Thomas M., George, Linda Acha Year: 1995 A direct intercomparison of near-surface tropospheric HO concentration measurements by two different techniques was made in October–November 1992 at a rural site near Pullman, Washington. The atmosphere at the site is believed to contain low levels of anthropogenic pollution. The instruments' inlets were located at the same height (3.5 m) above the ground and were separated by 10 m along a line normal to the prevailing wind. Readings of the FAGE3 and radiocarbon instruments showed a high correlation (r² = 0.74) despite HO concentrations that were frequently near the detection limit of the instruments. An unweighted least squares regression shows a slope significantly different from unity, indicating different calibration scales of the two instruments Close

• 44. [Article] Thiophene Based Molecular Sensors Towards Mercury Detection

  Toxic heavy metals such as mercury have increased in concentration in the environment due to pollution. Inorganic mercury in the environment can be later converted to a more toxic form: methylmercury. ...

  Citation × Citation Citation Abstract Copy Title: Thiophene Based Molecular Sensors Towards Mercury Detection Author: Shigemoto, Austin K., Virca, Carolyn N., Underwood, Sam, Shetterly, Lauren, McCormick, Theresa M. Year: 2016 Toxic heavy metals such as mercury have increased in concentration in the environment due to pollution. Inorganic mercury in the environment can be later converted to a more toxic form: methylmercury. Regular consumption of fish containing methylmercury can lead to several cognitive and motor disorders as well as Minamata disease. The current methods used to detect both methylmercury and inorganic mercury in sea life and drinking water involve long sample preparation and cost. In order to more efficiently track this toxic metal in the environment and identify contaminated food and water sources, a cheaper and faster method of detection is required. Fluorescent molecular sensors offer a more affordable alternative to current methods that would allow for detection and quantification of mercury in the environment. We report on fluorescent molecular sensors designed in our lab based on the organic compound thiophene, that have shown a selective response to mercury. The results show that thiophene containing compounds offer selectivity for mercury. Synthetic variations towards the design of effective sensors will be discussed. Title: Thiophene Based Molecular Sensors Towards Mercury Detection Author: Shigemoto, Austin K., Virca, Carolyn N., Underwood, Sam, Shetterly, Lauren, McCormick, Theresa M. Year: 2016 Toxic heavy metals such as mercury have increased in concentration in the environment due to pollution. Inorganic mercury in the environment can be later converted to a more toxic form: methylmercury. Regular consumption of fish containing methylmercury can lead to several cognitive and motor disorders as well as Minamata disease. The current methods used to detect both methylmercury and inorganic mercury in sea life and drinking water involve long sample preparation and cost. In order to more efficiently track this toxic metal in the environment and identify contaminated food and water sources, a cheaper and faster method of detection is required. Fluorescent molecular sensors offer a more affordable alternative to current methods that would allow for detection and quantification of mercury in the environment. We report on fluorescent molecular sensors designed in our lab based on the organic compound thiophene, that have shown a selective response to mercury. The results show that thiophene containing compounds offer selectivity for mercury. Synthetic variations towards the design of effective sensors will be discussed. Close

• 45. [Article] Then and Now: Vegetative Change Detection on Mount St. Helens 2000-2015

  The 1980 eruption of Mount St. Helens (MSH) proved a dramatic event with many important socio-economic consequences. In addition, this eruption resulted in an array of ecological consequences with subsequent ...

  Citation × Citation Citation Abstract Copy Title: Then and Now: Vegetative Change Detection on Mount St. Helens 2000-2015 Author: Thalacker, Douglas S., Holz, Andrés Year: 2016 The 1980 eruption of Mount St. Helens (MSH) proved a dramatic event with many important socio-economic consequences. In addition, this eruption resulted in an array of ecological consequences with subsequent studies and profound theoretical ramifications. The eruption created a complex gradient in disturbance severity on the northern aspect of MSH3, promoting successional processes from varying starting points and change rates. This study uses a landscape-scale approach to quantify spatio-temporal trends in vegetative responses to the eruption from 2000-2015, relying on Landsat TM and ETM+ imagery focusing on the primary and (i.e. no biological legacies) secondary (i.e. with biological legacies) succession zones that were studied 15 years ago. Title: Then and Now: Vegetative Change Detection on Mount St. Helens 2000-2015 Author: Thalacker, Douglas S., Holz, Andrés Year: 2016 The 1980 eruption of Mount St. Helens (MSH) proved a dramatic event with many important socio-economic consequences. In addition, this eruption resulted in an array of ecological consequences with subsequent studies and profound theoretical ramifications. The eruption created a complex gradient in disturbance severity on the northern aspect of MSH3, promoting successional processes from varying starting points and change rates. This study uses a landscape-scale approach to quantify spatio-temporal trends in vegetative responses to the eruption from 2000-2015, relying on Landsat TM and ETM+ imagery focusing on the primary and (i.e. no biological legacies) secondary (i.e. with biological legacies) succession zones that were studied 15 years ago. Close

• 46. [Article] Effects of Pharmaceuticals and Personal Care Products on Marine Organisms: From Single-Species Studies to an Ecosystem-Based Approach

  Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging concern that are increasing in use and have demonstrated negative effects on aquatic organisms. There is a growing body of ...

  Citation × Citation Citation Abstract Copy Title: Effects of Pharmaceuticals and Personal Care Products on Marine Organisms: From Single-Species Studies to an Ecosystem-Based Approach Author: Prichard, Emma C, Granek, Elise F. Year: 2016 Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging concern that are increasing in use and have demonstrated negative effects on aquatic organisms. There is a growing body of literature reporting the effects of PPCPs on freshwater organisms, but studies on the effects of PPCPs to marine and estuarine organisms are limited. Among effect studies, the vast majority examines subcellular or cellular effects, with far fewer studies examining organismal- and community-level effects. We reviewed the current published literature on marine and estuarine algae, invertebrates, fish, and mammals exposed to PPCPs, in order to expand upon current reviews. This paper builds on previous reviews of PPCP contamination in marine environments, filling prior literature gaps and adding consideration of ecosystem function and level of knowledge across marine habitat types. Finally, we reviewed and compiled data gaps suggested by current researchers and reviewers and propose a multi-level model to expand the focus of current PPCP research beyond laboratory studies. This model includes examination of direct ecological effects including food web and disease dynamics, biodiversity, community composition, and other ecosystem-level indicators of contaminant-driven change. Title: Effects of Pharmaceuticals and Personal Care Products on Marine Organisms: From Single-Species Studies to an Ecosystem-Based Approach Author: Prichard, Emma C, Granek, Elise F. Year: 2016 Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging concern that are increasing in use and have demonstrated negative effects on aquatic organisms. There is a growing body of literature reporting the effects of PPCPs on freshwater organisms, but studies on the effects of PPCPs to marine and estuarine organisms are limited. Among effect studies, the vast majority examines subcellular or cellular effects, with far fewer studies examining organismal- and community-level effects. We reviewed the current published literature on marine and estuarine algae, invertebrates, fish, and mammals exposed to PPCPs, in order to expand upon current reviews. This paper builds on previous reviews of PPCP contamination in marine environments, filling prior literature gaps and adding consideration of ecosystem function and level of knowledge across marine habitat types. Finally, we reviewed and compiled data gaps suggested by current researchers and reviewers and propose a multi-level model to expand the focus of current PPCP research beyond laboratory studies. This model includes examination of direct ecological effects including food web and disease dynamics, biodiversity, community composition, and other ecosystem-level indicators of contaminant-driven change. Close

• 47. [Article] Modeling the effectiveness of riparian restoration on stream shading in the Clackamas River Basin

  Rivers and streams within the Clackamas River Basin are not currently meeting water quality standards in terms of temperature. The Clackamas River Basin Council (CRBC) designed a restoration program to ...

  Citation × Citation Citation Abstract Copy Title: Modeling the effectiveness of riparian restoration on stream shading in the Clackamas River Basin Author: Barksdale, Rachel Year: 2017 Rivers and streams within the Clackamas River Basin are not currently meeting water quality standards in terms of temperature. The Clackamas River Basin Council (CRBC) designed a restoration program to address the thermal loading on behalf of Portland General Electric (PGE) in which native trees and shrubs are planted along streams to restore riparian canopy cover. Solar radiation can be blocked by restoring canopy cover and is an effective way to provide shade, as well as providing ancillary environmental benefits such as enhanced wildlife habitat and erosion control. Stream and vegetation data were collected at nine sites to model the increase in shade from the restoration plantings. Using DEQ’s Shade-a-lator model, shade was predicted in future scenarios at 10, 20, and 50 years compared to the current baseline condition. Modeling results suggest increases in shade at each site, which will help to mitigate excessive thermal inputs. The predicted scenarios provide a framework to evaluate the effectiveness of CRBC’s restoration program. Title: Modeling the effectiveness of riparian restoration on stream shading in the Clackamas River Basin Author: Barksdale, Rachel Year: 2017 Rivers and streams within the Clackamas River Basin are not currently meeting water quality standards in terms of temperature. The Clackamas River Basin Council (CRBC) designed a restoration program to address the thermal loading on behalf of Portland General Electric (PGE) in which native trees and shrubs are planted along streams to restore riparian canopy cover. Solar radiation can be blocked by restoring canopy cover and is an effective way to provide shade, as well as providing ancillary environmental benefits such as enhanced wildlife habitat and erosion control. Stream and vegetation data were collected at nine sites to model the increase in shade from the restoration plantings. Using DEQ’s Shade-a-lator model, shade was predicted in future scenarios at 10, 20, and 50 years compared to the current baseline condition. Modeling results suggest increases in shade at each site, which will help to mitigate excessive thermal inputs. The predicted scenarios provide a framework to evaluate the effectiveness of CRBC’s restoration program. Close

• 48. [Article] Elution Tailing of Nonaqueous Phase Liquids in Porous Media

  A variety of porous media were studied to characterize contaminant dispersion over time. This work looked at a compilation of previously published studies to investigate the dependence of long term elution ...

  Citation × Citation Citation Abstract Copy Title: Elution Tailing of Nonaqueous Phase Liquids in Porous Media Author: Orr, Louisa Year: 2017 A variety of porous media were studied to characterize contaminant dispersion over time. This work looked at a compilation of previously published studies to investigate the dependence of long term elution tailing trends on particular soil characteristics. Recession curve analysis was conducted on existing dispersed contaminant literature, to yeild the low-concentration recession constant (K). The R2 values correlating the soil properties to contaminant concentration ranged from 0.12494 to 0.95429. The low-concentration recession constant (K) values ranged from 0.9745407 0.9999988. The relationship between K and the soil properties porosity, organic carbon, and fines fraction is increasing. Bulk density and the partitioning coefficient exhibit a decreasing relationship with K. The observed trends may serve as a take off for further research. Title: Elution Tailing of Nonaqueous Phase Liquids in Porous Media Author: Orr, Louisa Year: 2017 A variety of porous media were studied to characterize contaminant dispersion over time. This work looked at a compilation of previously published studies to investigate the dependence of long term elution tailing trends on particular soil characteristics. Recession curve analysis was conducted on existing dispersed contaminant literature, to yeild the low-concentration recession constant (K). The R2 values correlating the soil properties to contaminant concentration ranged from 0.12494 to 0.95429. The low-concentration recession constant (K) values ranged from 0.9745407 0.9999988. The relationship between K and the soil properties porosity, organic carbon, and fines fraction is increasing. Bulk density and the partitioning coefficient exhibit a decreasing relationship with K. The observed trends may serve as a take off for further research. Close

• 49. [Article] Effect of Reducing Maximum Cycle Length on Roadside Air Quality and Travel Times on a Corridor in Portland, OR

  The Sydney Coordinated Adaptive Traffic System (SCATS), an adaptive signal system designed to reduce congestion, has been installed on a heavily trafficked roadway in Portland, OR. In addition to traffic ...

  Citation × Citation Citation Abstract Copy Title: Effect of Reducing Maximum Cycle Length on Roadside Air Quality and Travel Times on a Corridor in Portland, OR Author: Kendrick, Christine M., Urowsky, David, Rotich, Willie, Koonce, Peter, George, Linda Acha Year: 2014 The Sydney Coordinated Adaptive Traffic System (SCATS), an adaptive signal system designed to reduce congestion, has been installed on a heavily trafficked roadway in Portland, OR. In addition to traffic performance metrics, we are investigating how this system affects roadway emissions of air pollutants. A twenty-second reduction to maximum cycle length was proposed for the SCATS system to address pedestrian delay concerns. A two-week trial period with this reduced cycle length was implemented. Travel times and roadside air pollution concentrations were monitored throughout this study period and compared to before and after periods with the current maximum cycle length. Average travel times were found to be significantly higher during the reduced maximum cycle length, but with a mean difference of only 4-5 seconds for travel time. Assessment of travel time for this roadway suggests that a twenty second decrease in maximum cycle length to help shorten pedestrian delay can be made without significant consequences to travel time. Total traffic volumes were consistent for all four weeks of the study. Meteorological conditions were similar for the first two weeks comparing maximum cycle lengths. A shift in ambient temperature led the second two weeks of the cycle length comparison to have more similar meteorological conditions versus the first two weeks. Average NO and NO2 concentrations were not significantly different for the first half of the study. However, NO and NO2 concentrations were significantly higher during the reduced maximum cycle length for the second half of the study. When there was a significant difference based on t-test statistics, the measurements did show an increase in roadside concentrations during the shorter maximum cycle length. Preliminary results are unclear if changes to air quality (as assessed by NO and NO2 concentrations) occur or not due to the reduced maximum cycle length. Results require further comparative analysis in which meteorology and traffic conditions are controlled for so that any difference in air quality due to maximum cycle length alone can be quantified. Title: Effect of Reducing Maximum Cycle Length on Roadside Air Quality and Travel Times on a Corridor in Portland, OR Author: Kendrick, Christine M., Urowsky, David, Rotich, Willie, Koonce, Peter, George, Linda Acha Year: 2014 The Sydney Coordinated Adaptive Traffic System (SCATS), an adaptive signal system designed to reduce congestion, has been installed on a heavily trafficked roadway in Portland, OR. In addition to traffic performance metrics, we are investigating how this system affects roadway emissions of air pollutants. A twenty-second reduction to maximum cycle length was proposed for the SCATS system to address pedestrian delay concerns. A two-week trial period with this reduced cycle length was implemented. Travel times and roadside air pollution concentrations were monitored throughout this study period and compared to before and after periods with the current maximum cycle length. Average travel times were found to be significantly higher during the reduced maximum cycle length, but with a mean difference of only 4-5 seconds for travel time. Assessment of travel time for this roadway suggests that a twenty second decrease in maximum cycle length to help shorten pedestrian delay can be made without significant consequences to travel time. Total traffic volumes were consistent for all four weeks of the study. Meteorological conditions were similar for the first two weeks comparing maximum cycle lengths. A shift in ambient temperature led the second two weeks of the cycle length comparison to have more similar meteorological conditions versus the first two weeks. Average NO and NO2 concentrations were not significantly different for the first half of the study. However, NO and NO2 concentrations were significantly higher during the reduced maximum cycle length for the second half of the study. When there was a significant difference based on t-test statistics, the measurements did show an increase in roadside concentrations during the shorter maximum cycle length. Preliminary results are unclear if changes to air quality (as assessed by NO and NO2 concentrations) occur or not due to the reduced maximum cycle length. Results require further comparative analysis in which meteorology and traffic conditions are controlled for so that any difference in air quality due to maximum cycle length alone can be quantified. Close

• 50. [Article] 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake

  The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included ...

  Citation × Citation Citation Abstract Copy Title: 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake Author: Miller, Rich, Sytsma, Mark D., Brittain, Jeffrey Thomas Year: 2014 The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included in the Project include Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake. The operator of the Project, Portland General Electric (PGE), was issued a license on December 21, 2010 by the Federal Energy Regulatory Commission (FERC) for continued operations and maintenance. The Final Environmental Impact Statement (FEIS) for the license noted that regular surveys for invasive aquatic weed species would be conducted as part of the Project’s Vegetation Management Plan. The term “aquatic weed” is used here to refer to any non-native aquatic plant species. Information from repeated aquatic surveys will help determine native species distributions and the need for treatment of problematic aquatic weed species, particularly hydrilla (Hydrilla verticillata), Brazilian elodea (Egeria densa), and Eurasian watermilfoil (Myriophyllum spicatum). Surveys conducted for PGE by Portland State University (PSU) in Timothy Lake, Lake Harriet, and North Fork Reservoir in 2011 did not locate any problematic submerged or floating leaved aquatic weed species. Earlier surveys of Timothy Lake, and Timothy Lake and Lake Harriet, also indicated the reservoirs were free of aquatic weeds. Heaton et al. (1996) noted that the native species Bidens beckii was present and had the potential to become weedy, however, this species was not found during the 2004 or 2011 surveys. This report covers the results of follow up aquatic vegetation surveys conducted in Lake Harriet, Timothy Lake, and North Fork Reservoir between August 14 and August 21, 2014, as well as new surveys of Faraday Lake and Estacada Lake. Shoreline surveys for emergent invasive species such as yellow flag iris (Iris pseudacorus) and purple loosestrife (Lythrum salicaria) were included in surveys for the first time. Title: 2014 Aquatic Weed Surveys in Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake Author: Miller, Rich, Sytsma, Mark D., Brittain, Jeffrey Thomas Year: 2014 The Clackamas River Hydroelectric Project No. 2195 (Project) is located on the Oak Grove Fork of the Clackamas River and the mainstem of the Clackamas River in Clackamas County, Oregon. Reservoirs included in the Project include Timothy Lake, Lake Harriet, North Fork Reservoir, Faraday Lake, and Estacada Lake. The operator of the Project, Portland General Electric (PGE), was issued a license on December 21, 2010 by the Federal Energy Regulatory Commission (FERC) for continued operations and maintenance. The Final Environmental Impact Statement (FEIS) for the license noted that regular surveys for invasive aquatic weed species would be conducted as part of the Project’s Vegetation Management Plan. The term “aquatic weed” is used here to refer to any non-native aquatic plant species. Information from repeated aquatic surveys will help determine native species distributions and the need for treatment of problematic aquatic weed species, particularly hydrilla (Hydrilla verticillata), Brazilian elodea (Egeria densa), and Eurasian watermilfoil (Myriophyllum spicatum). Surveys conducted for PGE by Portland State University (PSU) in Timothy Lake, Lake Harriet, and North Fork Reservoir in 2011 did not locate any problematic submerged or floating leaved aquatic weed species. Earlier surveys of Timothy Lake, and Timothy Lake and Lake Harriet, also indicated the reservoirs were free of aquatic weeds. Heaton et al. (1996) noted that the native species Bidens beckii was present and had the potential to become weedy, however, this species was not found during the 2004 or 2011 surveys. This report covers the results of follow up aquatic vegetation surveys conducted in Lake Harriet, Timothy Lake, and North Fork Reservoir between August 14 and August 21, 2014, as well as new surveys of Faraday Lake and Estacada Lake. Shoreline surveys for emergent invasive species such as yellow flag iris (Iris pseudacorus) and purple loosestrife (Lythrum salicaria) were included in surveys for the first time. Close