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• 1. [Article] Structuring expert input for a knowledge-based approach to watershed condition assessment for the Northwest Forest Plan, USA

  Assessments of watershed condition for aquatic and riparian species often have to rely on expert opinion because of the complexity of establishing statistical relationships among the many factors involved. ...

  Citation × Citation Citation Abstract Copy Title: Structuring expert input for a knowledge-based approach to watershed condition assessment for the Northwest Forest Plan, USA Author: Gordon, Sean N, Gallo, Kirsten Year: 2011 Assessments of watershed condition for aquatic and riparian species often have to rely on expert opinion because of the complexity of establishing statistical relationships among the many factors involved. Such expert-based assessments can be difficult to document and apply consistently over time and space. We describe and reflect on the process of developing a computer-based decision support application from expert judgments for assessing aquatic and riparian conditions over the 100,000 km2 managed by the US federal government under the Northwest Forest Plan. The decision support system helped structure and document the assessment process and provided consistency and transparency to the evaluation methodology. However, many decisions and trade-offs were required in the expert engagement and model-building processes. Knowledge elicitation in an interactive group had a number of benefits over nominal group or Delphi processes, but efficient knowledge capture required considerable planning and expertise in the subject matter and modeling process. Communicating model results for validation was problematic and only effectively accomplished via in-person workshops. The choice to use different expert groups for each biophysical province provided more opportunities for participation and promoted greater ownership in the assessment, but it also led to increased variation among the resulting model structures. We propose three possible approaches for better managing the consistency of assessment models when multiple expert groups are involved. Title: Structuring expert input for a knowledge-based approach to watershed condition assessment for the Northwest Forest Plan, USA Author: Gordon, Sean N, Gallo, Kirsten Year: 2011 Assessments of watershed condition for aquatic and riparian species often have to rely on expert opinion because of the complexity of establishing statistical relationships among the many factors involved. Such expert-based assessments can be difficult to document and apply consistently over time and space. We describe and reflect on the process of developing a computer-based decision support application from expert judgments for assessing aquatic and riparian conditions over the 100,000 km2 managed by the US federal government under the Northwest Forest Plan. The decision support system helped structure and document the assessment process and provided consistency and transparency to the evaluation methodology. However, many decisions and trade-offs were required in the expert engagement and model-building processes. Knowledge elicitation in an interactive group had a number of benefits over nominal group or Delphi processes, but efficient knowledge capture required considerable planning and expertise in the subject matter and modeling process. Communicating model results for validation was problematic and only effectively accomplished via in-person workshops. The choice to use different expert groups for each biophysical province provided more opportunities for participation and promoted greater ownership in the assessment, but it also led to increased variation among the resulting model structures. We propose three possible approaches for better managing the consistency of assessment models when multiple expert groups are involved. Close

• 2. [Article] Watershed Data Organization and Project Prioritization

  The Oregon Coastal Salmon Restoration Initiative (OCSRI) (1197) is the first of several documents that have come to be known as the Oregon Plan for Salmon and watersheds (OPSW). The OCSRI indicates that ...

  Citation × Citation Citation Abstract Copy Title: Watershed Data Organization and Project Prioritization Author: Darling, Joshua Year: 2003 The Oregon Coastal Salmon Restoration Initiative (OCSRI) (1197) is the first of several documents that have come to be known as the Oregon Plan for Salmon and watersheds (OPSW). The OCSRI indicates that protection and restoration of salmonid stocks and improvement in water quality are the main roles for state agencies within the Oregon Plan (EO09-01: 1(b)). The Oregon Plan specifies particular actions that state agencies must take to aid in salmon recovery and also directs the Governors Watershed Enhancement Board (GWEB) to help create and organize watershed councils responsible for assessing conditions and determining priorities for watershed health. Title: Watershed Data Organization and Project Prioritization Author: Darling, Joshua Year: 2003 The Oregon Coastal Salmon Restoration Initiative (OCSRI) (1197) is the first of several documents that have come to be known as the Oregon Plan for Salmon and watersheds (OPSW). The OCSRI indicates that protection and restoration of salmonid stocks and improvement in water quality are the main roles for state agencies within the Oregon Plan (EO09-01: 1(b)). The Oregon Plan specifies particular actions that state agencies must take to aid in salmon recovery and also directs the Governors Watershed Enhancement Board (GWEB) to help create and organize watershed councils responsible for assessing conditions and determining priorities for watershed health. Close

• 3. [Article] Green River CE-QUAL-W2 Project: A Hydrodynamic and Water Quality Study of the Green River King County, Washington

  This report describes the data processing and model calibration performed for a hydrodynamic and water quality model of the Green River, located in King County, Washington. Figure 1 shows the location ...

  Citation × Citation Citation Abstract Copy Title: Green River CE-QUAL-W2 Project: A Hydrodynamic and Water Quality Study of the Green River King County, Washington Author: Kraft, Tim, Annear, Robert Leslie, Berger, Chris, Wells, Scott A. Year: 2004 This report describes the data processing and model calibration performed for a hydrodynamic and water quality model of the Green River, located in King County, Washington. Figure 1 shows the location of the river, and the limits of the section of river that was modeled. The Green River flows from its headwaters in the Cascade Mountain foothills through the King County, Washington communities of Auburn, Kent, and Tukwila before discharging into the Duwamish River. Two sections of the river were modeled in this project. The Middle Green River begins in the Cascade Mountain foothills east of Tacoma, and continues downstream to the city of Auburn, WA. The Lower Green River continues from Auburn to the confluence with the Duwamish River, in the town of Tukwila. The Green/Duwamish River system is unique in that it flows through a heavily urbanized and industrialized environment yet supports a large salmon population (Green/Duwamish Ecosystem Restoration Study, 2003). To protect the river and its prime salmon habitat, King County and the US Army Corps of Engineers have joined together on a study to identify and implement strategies for restoring and protecting the Green/Duwamish River System and its tributaries (Green/Duwamish Ecosystem Restoration Study, 2003). As part of the Green-Duwamish Watershed Water Quality Assessment Program, King County contracted with Portland State University to develop a hydrodynamic and water quality model for the Lower and Middle Green River. This model will be used in Total Maximum Daily Load (TMDL) development, in assessing current water quality conditions in the river, and as a planning tool for evaluating the impacts of future development in the basin. Title: Green River CE-QUAL-W2 Project: A Hydrodynamic and Water Quality Study of the Green River King County, Washington Author: Kraft, Tim, Annear, Robert Leslie, Berger, Chris, Wells, Scott A. Year: 2004 This report describes the data processing and model calibration performed for a hydrodynamic and water quality model of the Green River, located in King County, Washington. Figure 1 shows the location of the river, and the limits of the section of river that was modeled. The Green River flows from its headwaters in the Cascade Mountain foothills through the King County, Washington communities of Auburn, Kent, and Tukwila before discharging into the Duwamish River. Two sections of the river were modeled in this project. The Middle Green River begins in the Cascade Mountain foothills east of Tacoma, and continues downstream to the city of Auburn, WA. The Lower Green River continues from Auburn to the confluence with the Duwamish River, in the town of Tukwila. The Green/Duwamish River system is unique in that it flows through a heavily urbanized and industrialized environment yet supports a large salmon population (Green/Duwamish Ecosystem Restoration Study, 2003). To protect the river and its prime salmon habitat, King County and the US Army Corps of Engineers have joined together on a study to identify and implement strategies for restoring and protecting the Green/Duwamish River System and its tributaries (Green/Duwamish Ecosystem Restoration Study, 2003). As part of the Green-Duwamish Watershed Water Quality Assessment Program, King County contracted with Portland State University to develop a hydrodynamic and water quality model for the Lower and Middle Green River. This model will be used in Total Maximum Daily Load (TMDL) development, in assessing current water quality conditions in the river, and as a planning tool for evaluating the impacts of future development in the basin. Close

• 4. [Article] Type and Timing of Stream Flow Changes in Urbanizing Watersheds in the Eastern U.S.

  Linking the type and timing of hydrologic changes with patterns of urban growth is essential to identifying the underlying mechanisms that drive declines in urban aquatic ecosystems. In six urbanizing ...

  Citation × Citation Citation Abstract Copy Title: Type and Timing of Stream Flow Changes in Urbanizing Watersheds in the Eastern U.S. Author: Hopkins, Kristina G., Morse, Nathaniel B., Bain, Daniel J., Bettez, Neil D., Grimm, Nancy B., Morse, Jennifer L., Palta, Monica M. Year: 2015 Linking the type and timing of hydrologic changes with patterns of urban growth is essential to identifying the underlying mechanisms that drive declines in urban aquatic ecosystems. In six urbanizing watersheds surrounding three U.S. cities (Baltimore, MD, Boston, MA, and Pittsburgh, PA), we reconstructed the history of development patterns since 1900 and assessed the magnitude and timing of stream flow changes during watershed development. Development reconstructions indicated that the majority of watershed development occurred during a period of peak population growth, typically between 1950 and 1970. Stream flow records indicated significant increases in annual frequency of high-flow events in all six watersheds and increases in annual runoff efficiency in five watersheds. Annual development intensity during the peak growth period had the strongest association with the magnitude of changes in high-flow frequency from the pre- to post-development periods. Results suggest the timing of the peak growth period is particularly important to understanding hydrologic changes, because it can set the type of stormwater infrastructure installed within a watershed. In three watersheds there was a rapid (~10-15 years) shift toward more frequent high-flow events, and in four watersheds there was a shift toward higher runoff efficiency. Breakpoint analyses indicated these shifts occurred between 1969 and 1976 for high-flow frequency and between 1962 and 1984 for runoff efficiency. Results indicated that the timing of high-flow changes were mainly driven by the development trajectory of each watershed, whereas the timing of runoff-efficiency changes were driven by a combination of development trajectories and extreme weather events. Our results underscore the need to refine the causes of urban stream degradation to incorporate the impact of gradual versus rapid urbanization on hydrologic changes and aquatic ecosystem function, as well as to recognize that the dominant drivers of hydrologic changes are heterogeneous among urban watersheds and vary over time. Title: Type and Timing of Stream Flow Changes in Urbanizing Watersheds in the Eastern U.S. Author: Hopkins, Kristina G., Morse, Nathaniel B., Bain, Daniel J., Bettez, Neil D., Grimm, Nancy B., Morse, Jennifer L., Palta, Monica M. Year: 2015 Linking the type and timing of hydrologic changes with patterns of urban growth is essential to identifying the underlying mechanisms that drive declines in urban aquatic ecosystems. In six urbanizing watersheds surrounding three U.S. cities (Baltimore, MD, Boston, MA, and Pittsburgh, PA), we reconstructed the history of development patterns since 1900 and assessed the magnitude and timing of stream flow changes during watershed development. Development reconstructions indicated that the majority of watershed development occurred during a period of peak population growth, typically between 1950 and 1970. Stream flow records indicated significant increases in annual frequency of high-flow events in all six watersheds and increases in annual runoff efficiency in five watersheds. Annual development intensity during the peak growth period had the strongest association with the magnitude of changes in high-flow frequency from the pre- to post-development periods. Results suggest the timing of the peak growth period is particularly important to understanding hydrologic changes, because it can set the type of stormwater infrastructure installed within a watershed. In three watersheds there was a rapid (~10-15 years) shift toward more frequent high-flow events, and in four watersheds there was a shift toward higher runoff efficiency. Breakpoint analyses indicated these shifts occurred between 1969 and 1976 for high-flow frequency and between 1962 and 1984 for runoff efficiency. Results indicated that the timing of high-flow changes were mainly driven by the development trajectory of each watershed, whereas the timing of runoff-efficiency changes were driven by a combination of development trajectories and extreme weather events. Our results underscore the need to refine the causes of urban stream degradation to incorporate the impact of gradual versus rapid urbanization on hydrologic changes and aquatic ecosystem function, as well as to recognize that the dominant drivers of hydrologic changes are heterogeneous among urban watersheds and vary over time. Close

• 5. [Article] Engineering a Healthier Watershed: Middle School Students Use Engineering Design to Lessen the Impact of Their Campus' Impervious Surfaces on Their Local Watershed

  It is important that students understand not only how their local watershed functions, but also how it is being impacted by impervious surfaces. Additionally, students need experience exploring the scientific ...

  Citation × Citation Citation Abstract Copy Title: Engineering a Healthier Watershed: Middle School Students Use Engineering Design to Lessen the Impact of Their Campus' Impervious Surfaces on Their Local Watershed Author: Gardner, Elizabeth Claire Year: 2015 It is important that students understand not only how their local watershed functions, but also how it is being impacted by impervious surfaces. Additionally, students need experience exploring the scientific and engineering practices that are necessary for a strong STEM background. With this knowledge students can be empowered to tackle this real and local problem using engineering design, a powerful practice gaining momentum and clarity through its prominence in the recent Framework for K-12 Science Education. Twenty classes of suburban sixth-graders participated in a new five-week Watershed Engineering Design Unit taught by their regular science teachers. Students engaged in scientific inquiry to learn about the structure, function, and health of their local watersheds, focusing on the effects of impervious surfaces. In small groups, students used the engineering design process to propose solutions to lessen the impact of runoff from their school campuses. The goal of this evaluation was to determine the effectiveness of the curriculum in terms of student gains in understanding of (1) watershed function, (2) the impact of impervious surfaces, and (3) the engineering design process. To determine the impact of this curriculum on their learning, students took multiple-choice pre- and post-assessments made up of items covering the three categories above. This data was analyzed for statistical significance using a lower-tailed paired sample t-test. All three objectives showed statistically significant learning gains and the results were used to recommend improvements to the curriculum and the assessment instrument for future iterations. Title: Engineering a Healthier Watershed: Middle School Students Use Engineering Design to Lessen the Impact of Their Campus' Impervious Surfaces on Their Local Watershed Author: Gardner, Elizabeth Claire Year: 2015 It is important that students understand not only how their local watershed functions, but also how it is being impacted by impervious surfaces. Additionally, students need experience exploring the scientific and engineering practices that are necessary for a strong STEM background. With this knowledge students can be empowered to tackle this real and local problem using engineering design, a powerful practice gaining momentum and clarity through its prominence in the recent Framework for K-12 Science Education. Twenty classes of suburban sixth-graders participated in a new five-week Watershed Engineering Design Unit taught by their regular science teachers. Students engaged in scientific inquiry to learn about the structure, function, and health of their local watersheds, focusing on the effects of impervious surfaces. In small groups, students used the engineering design process to propose solutions to lessen the impact of runoff from their school campuses. The goal of this evaluation was to determine the effectiveness of the curriculum in terms of student gains in understanding of (1) watershed function, (2) the impact of impervious surfaces, and (3) the engineering design process. To determine the impact of this curriculum on their learning, students took multiple-choice pre- and post-assessments made up of items covering the three categories above. This data was analyzed for statistical significance using a lower-tailed paired sample t-test. All three objectives showed statistically significant learning gains and the results were used to recommend improvements to the curriculum and the assessment instrument for future iterations. Close

• 6. [Article] Northwest Forest Plan The First 20 Years (1994-2013): Watershed Condition Status and Trend

  We used two data sets to evaluate stream and upslope/riparian condition for sixth-field watersheds in each aquatic province within the Northwest Forest Plan (NWFP) area. The stream evaluation was based ...

  Citation × Citation Citation Abstract Copy Title: Northwest Forest Plan The First 20 Years (1994-2013): Watershed Condition Status and Trend Author: Miller, Stephanie A., Gordon, Sean N, Eldred, Peter, Beloin, Ronald M., Wilcox, Steve, Raggon, Mark, Andersen, Heidi, Muldoon, Ariel Year: 2015 We used two data sets to evaluate stream and upslope/riparian condition for sixth-field watersheds in each aquatic province within the Northwest Forest Plan (NWFP) area. The stream evaluation was based on stream sampling data collected from 2002 to the 2013 (214 watersheds) as part of an eight year repeating (rotating) sample design. We are currently halfway through our second rotation of stream sampling, and have repeated 110 watersheds since the second rotation began in 2009. The analysis presented in this report uses roughly half the number of watersheds as was originally intended by the sample design since re-visitation will not be completed until 2017. In the meantime, we compare the first rotation of visits (2002-2009) to the first four years of the second rotation (2010-2013) giving us a general idea of current patterns. To evaluate stream condition we used a reference condition nearest neighbor statistical approach to calculate the stream physical habitat scores based on substrate, wood, and pool metrics for each watershed. Macroinvertebrates and water temperature were analyzed separately from physical habitat and provide additional assessment of overall watershed condition. Scores for both stream and upslope/riparian conditions were normalized to fall between 0 (poor) and 100 (good). Title: Northwest Forest Plan The First 20 Years (1994-2013): Watershed Condition Status and Trend Author: Miller, Stephanie A., Gordon, Sean N, Eldred, Peter, Beloin, Ronald M., Wilcox, Steve, Raggon, Mark, Andersen, Heidi, Muldoon, Ariel Year: 2015 We used two data sets to evaluate stream and upslope/riparian condition for sixth-field watersheds in each aquatic province within the Northwest Forest Plan (NWFP) area. The stream evaluation was based on stream sampling data collected from 2002 to the 2013 (214 watersheds) as part of an eight year repeating (rotating) sample design. We are currently halfway through our second rotation of stream sampling, and have repeated 110 watersheds since the second rotation began in 2009. The analysis presented in this report uses roughly half the number of watersheds as was originally intended by the sample design since re-visitation will not be completed until 2017. In the meantime, we compare the first rotation of visits (2002-2009) to the first four years of the second rotation (2010-2013) giving us a general idea of current patterns. To evaluate stream condition we used a reference condition nearest neighbor statistical approach to calculate the stream physical habitat scores based on substrate, wood, and pool metrics for each watershed. Macroinvertebrates and water temperature were analyzed separately from physical habitat and provide additional assessment of overall watershed condition. Scores for both stream and upslope/riparian conditions were normalized to fall between 0 (poor) and 100 (good). Close

• 7. [Article] A Geospatial Tool for Wetland Prioritization at the Watershed Scale

  There is an increasing demand for assessing ecosystem functions for freshwater wetlands, especially when comparing or prioritizing among wetlands at the watershed scale. We estimated the relative potential ...

  Citation × Citation Citation Abstract Copy Title: A Geospatial Tool for Wetland Prioritization at the Watershed Scale Author: Blackmore, Debra Sue, Chang, Heejun Year: 2015 There is an increasing demand for assessing ecosystem functions for freshwater wetlands, especially when comparing or prioritizing among wetlands at the watershed scale. We estimated the relative potential of selected ecosystem functions for freshwater wetlands within a watershed using widely available geospatial data. We developed four functions to estimate 1) flood storage, 2) late season flow, 3) sediment retention and 4) temperature control in four pilot watersheds in Oregon (Tualatin, Coquille, Upper Grande Ronde and Sprague). These watersheds are geographically separated from each other representing diverse ecoregion environments. Spatial analysis and geographic information system (GIS) were designed for maximum re-use, based on publicly-available data, commonly-used software, semi-automated techniques and wetland characterizations that attempt to capture fundamental wetland processes. Our data sources include 30-meter digital elevation models, NRCS soil survey extracts, USGS National Land Cover Data, USGS HUC8 boundaries (polygons) and statewide wetland delineations (polygons) processed within ArcGIS 10.2 and Python 2.7.5 software. Model parameters were compiled using multiple proxy values for size, slope, aspect, proximity, flow path distance, hydrologic gradient, shade, and soil characteristics. WPT characterizations emphasize the multi-faceted value of freshwater wetlands, relating potential within a watershed as well as providing model-based characterizations between watersheds. Our wetland prioritization tool (WPT) provides useful information to estimate and compare the relative potential for selected wetland functions, thereby improving success in wetland conservation, restoration, and mitigation efforts. Title: A Geospatial Tool for Wetland Prioritization at the Watershed Scale Author: Blackmore, Debra Sue, Chang, Heejun Year: 2015 There is an increasing demand for assessing ecosystem functions for freshwater wetlands, especially when comparing or prioritizing among wetlands at the watershed scale. We estimated the relative potential of selected ecosystem functions for freshwater wetlands within a watershed using widely available geospatial data. We developed four functions to estimate 1) flood storage, 2) late season flow, 3) sediment retention and 4) temperature control in four pilot watersheds in Oregon (Tualatin, Coquille, Upper Grande Ronde and Sprague). These watersheds are geographically separated from each other representing diverse ecoregion environments. Spatial analysis and geographic information system (GIS) were designed for maximum re-use, based on publicly-available data, commonly-used software, semi-automated techniques and wetland characterizations that attempt to capture fundamental wetland processes. Our data sources include 30-meter digital elevation models, NRCS soil survey extracts, USGS National Land Cover Data, USGS HUC8 boundaries (polygons) and statewide wetland delineations (polygons) processed within ArcGIS 10.2 and Python 2.7.5 software. Model parameters were compiled using multiple proxy values for size, slope, aspect, proximity, flow path distance, hydrologic gradient, shade, and soil characteristics. WPT characterizations emphasize the multi-faceted value of freshwater wetlands, relating potential within a watershed as well as providing model-based characterizations between watersheds. Our wetland prioritization tool (WPT) provides useful information to estimate and compare the relative potential for selected wetland functions, thereby improving success in wetland conservation, restoration, and mitigation efforts. Close

• 8. [Article] Emerging Pollutants in the Columbia River: A Simple Assessment of Nonpoint Source Zones

  Water quality modeling in the Columbia River Basin was conducted at the confluence of the Willamette and Columbia Rivers, river mile 101. The study area for this research consists of Sauvie Island, OR, ...

  Citation × Citation Citation Abstract Copy Title: Emerging Pollutants in the Columbia River: A Simple Assessment of Nonpoint Source Zones Author: Kim, Chulgi Year: 2017 Water quality modeling in the Columbia River Basin was conducted at the confluence of the Willamette and Columbia Rivers, river mile 101. The study area for this research consists of Sauvie Island, OR, and the surrounding areas of Vancouver, WA. Analysis of the region’s watershed and simple hydrologic calculations allowed for estimates of potential sources contributing to PBDEs in the Columbia River along river mile 101. This research included assessment of rainfall patterns and peak discharge rates in the areas along the rivers. A simple model of overland flow for the watershed was applied to estimate the area’s contribution to overall flow in the Columbia River. Potential impacts and possible sources for emerging pollutants in the Columbia River at river mile 101 were inferred from this analysis. Title: Emerging Pollutants in the Columbia River: A Simple Assessment of Nonpoint Source Zones Author: Kim, Chulgi Year: 2017 Water quality modeling in the Columbia River Basin was conducted at the confluence of the Willamette and Columbia Rivers, river mile 101. The study area for this research consists of Sauvie Island, OR, and the surrounding areas of Vancouver, WA. Analysis of the region’s watershed and simple hydrologic calculations allowed for estimates of potential sources contributing to PBDEs in the Columbia River along river mile 101. This research included assessment of rainfall patterns and peak discharge rates in the areas along the rivers. A simple model of overland flow for the watershed was applied to estimate the area’s contribution to overall flow in the Columbia River. Potential impacts and possible sources for emerging pollutants in the Columbia River at river mile 101 were inferred from this analysis. Close

• 9. [Article] Classifying Oregon lake-watershed ecosystems for regional water resources assessment

  Natural lake-watershed ecosystems in Oregon compose a diverse and valuable assemblage of land and water resources. With an increasing demand on lakes for recreation, water supplies, and aesthetic values ...

  Citation × Citation Citation Abstract Copy Title: Classifying Oregon lake-watershed ecosystems for regional water resources assessment Author: Jones, Randall Alan Year: 1987 Natural lake-watershed ecosystems in Oregon compose a diverse and valuable assemblage of land and water resources. With an increasing demand on lakes for recreation, water supplies, and aesthetic values and an increase in available data on Oregon lake systems, there is a need for applicable and timely scientific water management information about lake conditions statewide. This thesis is an attempt to summarize some of the data collected on natural Oregon lake-watershed ecosystems. The purpose of the thesis is to identify the most typical natural systems out of an initial data base of twenty-four variables, measured over ninety-eight lake-watershed ecosystems. The selected variables are reduced to five common factors using principal components factor analysis. K-means cluster analysis is used to create similar groups of lake systems. These groups are compared to ecoregions in Oregon and a typical, representative lake ecosystem is identified for each group. Results show that several lake systems of the state are unique. Title: Classifying Oregon lake-watershed ecosystems for regional water resources assessment Author: Jones, Randall Alan Year: 1987 Natural lake-watershed ecosystems in Oregon compose a diverse and valuable assemblage of land and water resources. With an increasing demand on lakes for recreation, water supplies, and aesthetic values and an increase in available data on Oregon lake systems, there is a need for applicable and timely scientific water management information about lake conditions statewide. This thesis is an attempt to summarize some of the data collected on natural Oregon lake-watershed ecosystems. The purpose of the thesis is to identify the most typical natural systems out of an initial data base of twenty-four variables, measured over ninety-eight lake-watershed ecosystems. The selected variables are reduced to five common factors using principal components factor analysis. K-means cluster analysis is used to create similar groups of lake systems. These groups are compared to ecoregions in Oregon and a typical, representative lake ecosystem is identified for each group. Results show that several lake systems of the state are unique. Close

• 10. [Article] Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed

  Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed A watershed analysis project was undertaken to investigate the impact of urbanization on the water quality with Bronson ...

  Citation × Citation Citation Abstract Copy Title: Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed Author: Creech, Jason Cristopher Year: 2003 Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed A watershed analysis project was undertaken to investigate the impact of urbanization on the water quality with Bronson Creek; a small urban stream in the metropolitan area of Portland, Oregon. Total Maximum Daily Loads (TMDLs) have been established for several water quality parameters within the watershed. Water quality data were collected at nine sampling along Bronson Creek by Clean Water Services, a local public utility charged with storm water management and water quality protection duties. Only seven water quality parameters were included in the analysis; they were 1) temperature, 2) total phosphorous, 3) ortho-phosphate, 4) ammonia, 5) total nitrogen, 6) total suspended solids, and 7) E. Coli. Samples were taken approximately twice a month over a 7 year period from 1994 – 2001. Total impervious area (TIA) was used as the indicator of urbanization for the project. Impervious area values (TIA%) were calculated by digitizing aerial photography. Yearly TIA values were calculated for the entire watershed, as well as for its 37 subasins (subcatchement level). Water quality data were analyzed for variations along the stream and for the presence of trends (monotonic changes over time) during seasons of poor water quality. Kendall’s t was also used as the trend test statistic. Data were also analyzed to determine if an association exists between water quality at a sampling site and the upstream imperviousness (TIA%). Kendall’s t was used as the test statistic. Negative trends (improving water quality) were found throughout the watershed with nitrogen exhibiting the largest reduction. Temperature was the only parameter not to exhibit a negative trend at any location within the watershed. Results of the correlation between water quality and TIA% showed similar results, where a parameter experiencing a trend also exhibited a significant Kendall’s correlation with upstream TIA%. As TIA increased, water quality improved at least one site, for all parameters except temperature. One possible cause of the improving water quality within Bronson Creek is the implementation of best management practices within the watershed. Stormwater ponds were located in subcatchments that were adjacent to water quality sampling sites with improving water quality. The Bronson Creek watershed is also part of a pilot program to test the effectiveness of best management practices on improving water quality in the urban environment. Title: Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed Author: Creech, Jason Cristopher Year: 2003 Urbanization and its Relationship to Water Quality within the Bronson Creek Watershed A watershed analysis project was undertaken to investigate the impact of urbanization on the water quality with Bronson Creek; a small urban stream in the metropolitan area of Portland, Oregon. Total Maximum Daily Loads (TMDLs) have been established for several water quality parameters within the watershed. Water quality data were collected at nine sampling along Bronson Creek by Clean Water Services, a local public utility charged with storm water management and water quality protection duties. Only seven water quality parameters were included in the analysis; they were 1) temperature, 2) total phosphorous, 3) ortho-phosphate, 4) ammonia, 5) total nitrogen, 6) total suspended solids, and 7) E. Coli. Samples were taken approximately twice a month over a 7 year period from 1994 – 2001. Total impervious area (TIA) was used as the indicator of urbanization for the project. Impervious area values (TIA%) were calculated by digitizing aerial photography. Yearly TIA values were calculated for the entire watershed, as well as for its 37 subasins (subcatchement level). Water quality data were analyzed for variations along the stream and for the presence of trends (monotonic changes over time) during seasons of poor water quality. Kendall’s t was also used as the trend test statistic. Data were also analyzed to determine if an association exists between water quality at a sampling site and the upstream imperviousness (TIA%). Kendall’s t was used as the test statistic. Negative trends (improving water quality) were found throughout the watershed with nitrogen exhibiting the largest reduction. Temperature was the only parameter not to exhibit a negative trend at any location within the watershed. Results of the correlation between water quality and TIA% showed similar results, where a parameter experiencing a trend also exhibited a significant Kendall’s correlation with upstream TIA%. As TIA increased, water quality improved at least one site, for all parameters except temperature. One possible cause of the improving water quality within Bronson Creek is the implementation of best management practices within the watershed. Stormwater ponds were located in subcatchments that were adjacent to water quality sampling sites with improving water quality. The Bronson Creek watershed is also part of a pilot program to test the effectiveness of best management practices on improving water quality in the urban environment. Close