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• 241. [Article] Short-term relationship of timber management and Pacific giant salamander populations, and the response of larval stream amphibian to predators under differing sediment levels

  In the Pacific Northwest, multiple studies have found negative effects of timber harvest on stream amphibians, but the results have been highly variable and region-specific. In this collection of studies, ...

  Citation × Citation Citation Abstract Copy Title: Short-term relationship of timber management and Pacific giant salamander populations, and the response of larval stream amphibian to predators under differing sediment levels Author: Leuthold, Niels C. In the Pacific Northwest, multiple studies have found negative effects of timber harvest on stream amphibians, but the results have been highly variable and region-specific. In this collection of studies, I examined the short term effect of timber harvest using a field study, and used lab work to examine a potential mechanism for timber harvest effect. Over the last 30 years forest management practices have changed substantially, yet little work examines how modern forest management relates to the abundance or density of stream amphibians. I examined the influences of contemporary forest practices on Pacific giant salamanders as part of the Hinkle Creek paired watershed study. I used a mark-recapture analysis to estimate Pacific giant salamander density at 100 1-m segments spread throughout the basin and then used extended linear models that accounted for correlation resulting from the repeated surveys at sites across years. Density was positively associated with substrate, negatively associate with upstream area drained, and had a weak positive association with fish density, but I found no evidence of an effect of harvest. A Monte Carlo analysis suggested that our results were not sensitive to missing captures at sites with no captures. Pacific Northwest stream amphibians are often negatively associated with sedimentation, but the mechanism underlying this relationship is not clear. One hypothesized mechanism is that the reduced interstitial space that results from sedimentation increases susceptibility of amphibians to predation. I used laboratory mesocosms to test this hypothesis and examine the response of larval Pacific giant salamanders and tailed frogs to cutthroat trout and adult Pacific giant salamander presence under three different levels of sediment. I found amphibian larvae were more visible as sediment level increased and some evidence that larvae were less visible in the presence of fish. Movement decreased in the presence of cutthroat trout, though for tailed frog larvae this effect was marginally significant (p = 0.066). Larvae did not respond to presence of adult Pacific giant salamanders. These patterns are consistent with the hypothesis that sediment affects larval stream amphibians by increasing vulnerability to predation. While both species of larvae actively sought cover in response to fish, I found little evidence that this behavior mitigates the effects of increasing sediment. Title: Short-term relationship of timber management and Pacific giant salamander populations, and the response of larval stream amphibian to predators under differing sediment levels Author: Leuthold, Niels C. In the Pacific Northwest, multiple studies have found negative effects of timber harvest on stream amphibians, but the results have been highly variable and region-specific. In this collection of studies, I examined the short term effect of timber harvest using a field study, and used lab work to examine a potential mechanism for timber harvest effect. Over the last 30 years forest management practices have changed substantially, yet little work examines how modern forest management relates to the abundance or density of stream amphibians. I examined the influences of contemporary forest practices on Pacific giant salamanders as part of the Hinkle Creek paired watershed study. I used a mark-recapture analysis to estimate Pacific giant salamander density at 100 1-m segments spread throughout the basin and then used extended linear models that accounted for correlation resulting from the repeated surveys at sites across years. Density was positively associated with substrate, negatively associate with upstream area drained, and had a weak positive association with fish density, but I found no evidence of an effect of harvest. A Monte Carlo analysis suggested that our results were not sensitive to missing captures at sites with no captures. Pacific Northwest stream amphibians are often negatively associated with sedimentation, but the mechanism underlying this relationship is not clear. One hypothesized mechanism is that the reduced interstitial space that results from sedimentation increases susceptibility of amphibians to predation. I used laboratory mesocosms to test this hypothesis and examine the response of larval Pacific giant salamanders and tailed frogs to cutthroat trout and adult Pacific giant salamander presence under three different levels of sediment. I found amphibian larvae were more visible as sediment level increased and some evidence that larvae were less visible in the presence of fish. Movement decreased in the presence of cutthroat trout, though for tailed frog larvae this effect was marginally significant (p = 0.066). Larvae did not respond to presence of adult Pacific giant salamanders. These patterns are consistent with the hypothesis that sediment affects larval stream amphibians by increasing vulnerability to predation. While both species of larvae actively sought cover in response to fish, I found little evidence that this behavior mitigates the effects of increasing sediment. Close

• 242. [Article] Biology and management of Meloidogyne chitwoodi using oxamyl on potato in the western United States

  Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season ...

  Citation × Citation Citation Abstract Copy Title: Biology and management of Meloidogyne chitwoodi using oxamyl on potato in the western United States Author: David, Nicholas L. Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season potato varieties Russet Norkotah and Russet Nugget (San Luis Valley only). The experiments were located in the San Luis Valley in Colorado, Klamath Basin in Oregon, and southern Columbia Basin in Oregon to represent, cool, warm, and hot growing regions, respectively. M. chitwoodi soil population dynamics were multi-modal in all three regions representing distinct periods of egg hatch and root and tuber infection. M. chitwoodi completed two generations in the cooler production areas of the Klamath Basin and San Luis Valley, and three generations in the hot region of the Columbia Basin. When left uncontrolled, M. chitwoodi infected and caused tuber symptoms in all three regions, but tuber symptoms were significantly reduced with the use of a bi-weekly oxamyl program that began at the hatch of the second generation. Furthermore, augmenting with in-furrow at-planting and crop emergence applications provided better protection. The level of reduction in symptoms using the application schedules outlined in this research was substantially better than that previously observed with this nematicide. Oxamyl did not control M. chitwoodi densities in the soil. For that reason, internal and external symptoms increased when harvest was delayed by three weeks in the Columbia Basin regardless of whether or not oxamyl had been applied. Following harvest in the Columbia Basin and Klamath Basin there is potential for internal symptom development if tubers are stored warm. The percentage of tubers with internal symptoms increased when stored at 21-24°C and more than 740 post-harvest DD5C were accumulated, regardless of whether or not oxamyl was used. However internal symptoms did not increase during long-term cold storage (3-5°C) when no more than 480 – 610 post-harvest DD5C were accumulated. Unlike internal symptoms, there was no increase in external symptoms following harvest even when as many as 1,000 post-harvest DD5C were accumulated. Oxamyl is currently the only chemical that growers can apply during the growing season to suppress tuber damage from M. chitwoodi and reduces symptoms on short-season potato cultivars in both cool and hot growing regions in the western United States. Title: Biology and management of Meloidogyne chitwoodi using oxamyl on potato in the western United States Author: David, Nicholas L. Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season potato varieties Russet Norkotah and Russet Nugget (San Luis Valley only). The experiments were located in the San Luis Valley in Colorado, Klamath Basin in Oregon, and southern Columbia Basin in Oregon to represent, cool, warm, and hot growing regions, respectively. M. chitwoodi soil population dynamics were multi-modal in all three regions representing distinct periods of egg hatch and root and tuber infection. M. chitwoodi completed two generations in the cooler production areas of the Klamath Basin and San Luis Valley, and three generations in the hot region of the Columbia Basin. When left uncontrolled, M. chitwoodi infected and caused tuber symptoms in all three regions, but tuber symptoms were significantly reduced with the use of a bi-weekly oxamyl program that began at the hatch of the second generation. Furthermore, augmenting with in-furrow at-planting and crop emergence applications provided better protection. The level of reduction in symptoms using the application schedules outlined in this research was substantially better than that previously observed with this nematicide. Oxamyl did not control M. chitwoodi densities in the soil. For that reason, internal and external symptoms increased when harvest was delayed by three weeks in the Columbia Basin regardless of whether or not oxamyl had been applied. Following harvest in the Columbia Basin and Klamath Basin there is potential for internal symptom development if tubers are stored warm. The percentage of tubers with internal symptoms increased when stored at 21-24°C and more than 740 post-harvest DD5C were accumulated, regardless of whether or not oxamyl was used. However internal symptoms did not increase during long-term cold storage (3-5°C) when no more than 480 – 610 post-harvest DD5C were accumulated. Unlike internal symptoms, there was no increase in external symptoms following harvest even when as many as 1,000 post-harvest DD5C were accumulated. Oxamyl is currently the only chemical that growers can apply during the growing season to suppress tuber damage from M. chitwoodi and reduces symptoms on short-season potato cultivars in both cool and hot growing regions in the western United States. Close

• 243. [Article] Oregon Fish Habitat Distribution - Redband Trout

  Abstract -- These data describe areas of suitable habitat believed to be used currently and historically by redband trout populations. Columbia River redband trout, Oncorhynchus mykiss gairdneri, a subspecies ...

  Citation × Citation Citation Abstract Copy Title: Oregon Fish Habitat Distribution - Redband Trout Abstract -- These data describe areas of suitable habitat believed to be used currently and historically by redband trout populations. Columbia River redband trout, Oncorhynchus mykiss gairdneri, a subspecies of rainbow trout, Oncorhynchus mykiss, is native to the Fraser and Columbia River drainages, east of the Cascade Mountains to barrier falls on the Pend Oreille, Spokane, Snake and Kootenai rivers (Allendorf et al. 1980; Behnke 1992). Northern Great Basin redband trout, Oncorhynchus mykiss newberrii, are found in the closed basins of south-central Oregon as well as the Upper Klamath Lake basin. While Upper Klamath Lake now drains to the ocean, redband trout in the basin had ancestors that came from interior connections to the Great Basin and not from connections to the ocean (Behnke 1992). Redband trout, for the purposes of habitat distribution mapping, are generally defined as stream-resident O. mykiss gairdneri; migration is confined within their natal stream or watershed while steelhead, or the anadromous life form of O.mykiss gairdneri, migrate from their natal stream to the ocean and back. It is recognized, that while redband and steelhead habitat distribution datasets are published separately, overlapping areas represent the same subspecies. The term "currently" is defined as within the past five reproductive cycles. This information is based on sampling, the best professional opinion of Oregon Dept. of Fish and Wildlife or other natural resources agency staff biologists or modeling (see the fhdBasis field). Due to natural variations in run size, water conditions, or other environmental factors, some habitats identified may not be used annually. These data now comply with the Oregon Fish Habitat Distribution Data Standard that was adopted by the Oregon Geographic Information Council in February 2011. The Standard document can be found at: http://gis.oregon.gov/DAS/EISPD/GEO/standards/docs/OregonFishHabitatDistributionDataStandardv2.pdf Key features of the Oregon Fish Habitat Distribution Data include: species, run, life history, habitat use, origin, production, the basis for each record, originator name, originator entity and reference. Habitat distribution data are mapped at a 1:24,000 scale statewide and are based on the Pacific Northwest Framework Hydrography dataset. The data are made available as GIS files in both shapefile and ESRI geodatabase format. The data were developed over an extensive time period ranging from 1996 to 2011. Title: Oregon Fish Habitat Distribution - Redband Trout Abstract -- These data describe areas of suitable habitat believed to be used currently and historically by redband trout populations. Columbia River redband trout, Oncorhynchus mykiss gairdneri, a subspecies of rainbow trout, Oncorhynchus mykiss, is native to the Fraser and Columbia River drainages, east of the Cascade Mountains to barrier falls on the Pend Oreille, Spokane, Snake and Kootenai rivers (Allendorf et al. 1980; Behnke 1992). Northern Great Basin redband trout, Oncorhynchus mykiss newberrii, are found in the closed basins of south-central Oregon as well as the Upper Klamath Lake basin. While Upper Klamath Lake now drains to the ocean, redband trout in the basin had ancestors that came from interior connections to the Great Basin and not from connections to the ocean (Behnke 1992). Redband trout, for the purposes of habitat distribution mapping, are generally defined as stream-resident O. mykiss gairdneri; migration is confined within their natal stream or watershed while steelhead, or the anadromous life form of O.mykiss gairdneri, migrate from their natal stream to the ocean and back. It is recognized, that while redband and steelhead habitat distribution datasets are published separately, overlapping areas represent the same subspecies. The term "currently" is defined as within the past five reproductive cycles. This information is based on sampling, the best professional opinion of Oregon Dept. of Fish and Wildlife or other natural resources agency staff biologists or modeling (see the fhdBasis field). Due to natural variations in run size, water conditions, or other environmental factors, some habitats identified may not be used annually. These data now comply with the Oregon Fish Habitat Distribution Data Standard that was adopted by the Oregon Geographic Information Council in February 2011. The Standard document can be found at: http://gis.oregon.gov/DAS/EISPD/GEO/standards/docs/OregonFishHabitatDistributionDataStandardv2.pdf Key features of the Oregon Fish Habitat Distribution Data include: species, run, life history, habitat use, origin, production, the basis for each record, originator name, originator entity and reference. Habitat distribution data are mapped at a 1:24,000 scale statewide and are based on the Pacific Northwest Framework Hydrography dataset. The data are made available as GIS files in both shapefile and ESRI geodatabase format. The data were developed over an extensive time period ranging from 1996 to 2011. Close

• 244. [Article] Willamette River Basin Temperature TMDL Model: Model Calibration

  The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all ...

  Citation × Citation Citation Abstract Copy Title: Willamette River Basin Temperature TMDL Model: Model Calibration Author: Berger, Chris, McKillip, Michael Lee, Annear, Robert Leslie, Khan, Sher Jamal, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. The river basin model was originally divided into several reaches. Individual models were developed for each reach. The models were set-up for each section of the Willamette basin as described in Annear et al. (2004a), the models were calibrated to field data and management strategies were evaluated as described in Annear et al (2004b). This report outlines the model calibration of each of these model sections or elements for both the calibration time periods. The calibration period for each model section differs due to the availability of boundary condition data. The model management simulation scenarios (Annear et al, 2004b) also required boundary condition data that extended past the calibration periods. Title: Willamette River Basin Temperature TMDL Model: Model Calibration Author: Berger, Chris, McKillip, Michael Lee, Annear, Robert Leslie, Khan, Sher Jamal, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. The river basin model was originally divided into several reaches. Individual models were developed for each reach. The models were set-up for each section of the Willamette basin as described in Annear et al. (2004a), the models were calibrated to field data and management strategies were evaluated as described in Annear et al (2004b). This report outlines the model calibration of each of these model sections or elements for both the calibration time periods. The calibration period for each model section differs due to the availability of boundary condition data. The model management simulation scenarios (Annear et al, 2004b) also required boundary condition data that extended past the calibration periods. Close

• 245. [Article] Willamette River Basin Temperature TMDL Model: Model Scenarios

  The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all ...

  Citation × Citation Citation Abstract Copy Title: Willamette River Basin Temperature TMDL Model: Model Scenarios Author: Annear, Robert Leslie, McKillip, Michael Lee, Khan, Sher Jamal, Berger, Chris, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. Once the models were set-up for each section of the Willamette basin, the model was calibrated to field data and management strategies were evaluated. These are the subjects of two other reports: Annear et al. (2004) and Berger et al. (2004). This report outlines the results of implementing model scenarios for each of the model sections or elements for specific time periods. The model scenario simulation periods used to investigate management scenarios required boundary condition data that extended past the model calibration periods. The model simulation period for year 2001 was from June 1 to October 31 and for year 2002 from April 1 to October 31. Title: Willamette River Basin Temperature TMDL Model: Model Scenarios Author: Annear, Robert Leslie, McKillip, Michael Lee, Khan, Sher Jamal, Berger, Chris, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. Once the models were set-up for each section of the Willamette basin, the model was calibrated to field data and management strategies were evaluated. These are the subjects of two other reports: Annear et al. (2004) and Berger et al. (2004). This report outlines the results of implementing model scenarios for each of the model sections or elements for specific time periods. The model scenario simulation periods used to investigate management scenarios required boundary condition data that extended past the model calibration periods. The model simulation period for year 2001 was from June 1 to October 31 and for year 2002 from April 1 to October 31. Close

• 246. [Article] Willamette River Basin Temperature TMDL Model: Boundary Conditions and Model Setup

  The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all ...

  Citation × Citation Citation Abstract Copy Title: Willamette River Basin Temperature TMDL Model: Boundary Conditions and Model Setup Author: Annear, Robert Leslie, McKillip, Michael Lee, Khan, Sher Jamal, Berger, Chris, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. Once the models were set-up for each section of the Willamette basin, the model was calibrated to field data and management strategies were evaluated. These are the subjects of two other reports: Annear et al. (2004b) and Berger et al. (2004). This report outlines the model development of each of these model sections or elements for both the calibration time periods and the management scenario time periods. The calibration period for each model section differs due to the availability of boundary condition data. The model simulation periods used to investigate management scenarios (Annear et al, 2004b) also required boundary condition data that extended past the calibration periods. Title: Willamette River Basin Temperature TMDL Model: Boundary Conditions and Model Setup Author: Annear, Robert Leslie, McKillip, Michael Lee, Khan, Sher Jamal, Berger, Chris, Wells, Scott A. Year: 2004 The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations. Once the models were set-up for each section of the Willamette basin, the model was calibrated to field data and management strategies were evaluated. These are the subjects of two other reports: Annear et al. (2004b) and Berger et al. (2004). This report outlines the model development of each of these model sections or elements for both the calibration time periods and the management scenario time periods. The calibration period for each model section differs due to the availability of boundary condition data. The model simulation periods used to investigate management scenarios (Annear et al, 2004b) also required boundary condition data that extended past the calibration periods. Close

• 247. [Article] Seasonal Variability and Estuary-Shelf Interactions in Circulation Dynamics of a River-dominated Estuary

  The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were ...

  Citation × Citation Citation Abstract Copy Title: Seasonal Variability and Estuary-Shelf Interactions in Circulation Dynamics of a River-dominated Estuary Author: Chawla, Arun, Jay, David A., Baptista, Antonio M., Wilkin, Michael, Seaton, Charles Year: 2008 The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were determined from four Acoustic Doppler Profilers (ADP) and several conductivity-temperature sensors placed in the two main channels. Because of the very strong river discharge, baroclinic processes play a crucial role in the circulation dynamics, and the interaction of the tidal and subtidal baroclinic pressure gradients plays a major role in structuring the velocity field. The input of river flow and the resulting low-frequency flow dynamics in the two channels are quite distinct. Current and salinity data were analyzed on two time scales?subtidal (or residual) and tidal (both diurnal and semidiurnal components). The residual currents in both channels usually showed a classical two-layer baroclinic circulation system with inflow at the bottom and outflow near the surface. However, this two-layer system is transient and breaks down under strong discharge and tidal conditions because of enhanced vertical mixing. Influence of shelf winds on estuarine processes was also observed via the interactions with upwelling and downwelling processes and coastal plume transport. The transient nature of residual inflow affects the long-term transport characteristics of the estuary. Effects of vertical mixing could also be seen at the tidal time scale. Tidal velocities were separated into their diurnal and semidiurnal components using continuous wavelet transforms to account for the nonstationary nature of velocity amplitudes. The vertical structure of velocity amplitudes were considerably altered by baroclinic gradients. This was particularly true for the diurnal components, where tidal asymmetry led to stronger tidal velocities near the bottom. Title: Seasonal Variability and Estuary-Shelf Interactions in Circulation Dynamics of a River-dominated Estuary Author: Chawla, Arun, Jay, David A., Baptista, Antonio M., Wilkin, Michael, Seaton, Charles Year: 2008 The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were determined from four Acoustic Doppler Profilers (ADP) and several conductivity-temperature sensors placed in the two main channels. Because of the very strong river discharge, baroclinic processes play a crucial role in the circulation dynamics, and the interaction of the tidal and subtidal baroclinic pressure gradients plays a major role in structuring the velocity field. The input of river flow and the resulting low-frequency flow dynamics in the two channels are quite distinct. Current and salinity data were analyzed on two time scales?subtidal (or residual) and tidal (both diurnal and semidiurnal components). The residual currents in both channels usually showed a classical two-layer baroclinic circulation system with inflow at the bottom and outflow near the surface. However, this two-layer system is transient and breaks down under strong discharge and tidal conditions because of enhanced vertical mixing. Influence of shelf winds on estuarine processes was also observed via the interactions with upwelling and downwelling processes and coastal plume transport. The transient nature of residual inflow affects the long-term transport characteristics of the estuary. Effects of vertical mixing could also be seen at the tidal time scale. Tidal velocities were separated into their diurnal and semidiurnal components using continuous wavelet transforms to account for the nonstationary nature of velocity amplitudes. The vertical structure of velocity amplitudes were considerably altered by baroclinic gradients. This was particularly true for the diurnal components, where tidal asymmetry led to stronger tidal velocities near the bottom. Close

• 248. [Article] Lake Whatcom Water Quality Model

  A water quality model of Lake Whatcom, Washington was developed as part of a Total Maximum Daily Load Study for the Washington Department of Ecology. Lake Whatcom is a large natural lake which is listed ...

  Citation × Citation Citation Abstract Copy Title: Lake Whatcom Water Quality Model Author: Berger, Chris Year: 2005 A water quality model of Lake Whatcom, Washington was developed as part of a Total Maximum Daily Load Study for the Washington Department of Ecology. Lake Whatcom is a large natural lake which is listed on the 1998 Washington State 303(d) list of waterbodies which do not meet the criterion for dissolved oxygen. Located next to the city of Bellingham, it is approximately 10 miles long and has a surface area of approximately 5000 acres and a maximum depth of over 100 meters. Eutrophication processes in the lake have been accelerated in recent years perhaps by the availability of nutrients from tributary discharges to the basin. Many of these tributaries have accelerated their nutrient loading to the system as a result of development in the watershed. The lake is being modeled using the Corps of Engineer’s model CE-QUAL-W2, which is a two-dimensional, hydrodynamic and water quality model. The project is managed by the Washington Department of Ecology which plans to make recommendations for reduction and allocation of pollutant loads. The objectives of this study were then to develop a hydrodynamic and water quality model of Lake Whatcom, calibrate the model to field data collected from February 2002 through December 2003, and use the model to evaluate strategies for water quality improvement. Title: Lake Whatcom Water Quality Model Author: Berger, Chris Year: 2005 A water quality model of Lake Whatcom, Washington was developed as part of a Total Maximum Daily Load Study for the Washington Department of Ecology. Lake Whatcom is a large natural lake which is listed on the 1998 Washington State 303(d) list of waterbodies which do not meet the criterion for dissolved oxygen. Located next to the city of Bellingham, it is approximately 10 miles long and has a surface area of approximately 5000 acres and a maximum depth of over 100 meters. Eutrophication processes in the lake have been accelerated in recent years perhaps by the availability of nutrients from tributary discharges to the basin. Many of these tributaries have accelerated their nutrient loading to the system as a result of development in the watershed. The lake is being modeled using the Corps of Engineer’s model CE-QUAL-W2, which is a two-dimensional, hydrodynamic and water quality model. The project is managed by the Washington Department of Ecology which plans to make recommendations for reduction and allocation of pollutant loads. The objectives of this study were then to develop a hydrodynamic and water quality model of Lake Whatcom, calibrate the model to field data collected from February 2002 through December 2003, and use the model to evaluate strategies for water quality improvement. Close

• 249. [Article] Using Critical Physical Geography to Map the Unintended Consequences of Conservation Management Programs

  A variety of conservation trends have gained and lost favor throughout the years in agriculture, with U.S. Farm Bills often influencing what conservation practices are implemented by farming communities ...

  Citation × Citation Citation Abstract Copy Title: Using Critical Physical Geography to Map the Unintended Consequences of Conservation Management Programs Author: Malone, Melanie Year: 2017 A variety of conservation trends have gained and lost favor throughout the years in agriculture, with U.S. Farm Bills often influencing what conservation practices are implemented by farming communities throughout the U.S. This dissertation focuses on the unintended consequences of conservation management practices in the Fifteenmile Watershed of Wasco County, Oregon. Specifically, I seek to address how farmer enrollment in various conservation techniques, loosely defined as no-till agriculture, has affected soil and water quality through the increased use of herbicide, and subsequently rendered ecological and human health vulnerable. Using a critical physical geography framework, I address both the biophysical factors and social structures that have co-produced changes in soil and water quality in the study area of this research through intensive physical field data collection, spatial analysis, social surveys, and interviews. I also demonstrate how three neoliberal sets of processes: market-friendly reregulation; state rollback and deregulation; and the creation of self-sufficient individuals and communities, have transformed the human socio-environmental relationship to agriculture. These processes have had significant effects on the policies governing how soil and water quality are managed on both a state and national level, and have created a dependence on enrollment in conservation practices that may ultimately prove counterproductive for long term goals of environmental protection and sustainability. Title: Using Critical Physical Geography to Map the Unintended Consequences of Conservation Management Programs Author: Malone, Melanie Year: 2017 A variety of conservation trends have gained and lost favor throughout the years in agriculture, with U.S. Farm Bills often influencing what conservation practices are implemented by farming communities throughout the U.S. This dissertation focuses on the unintended consequences of conservation management practices in the Fifteenmile Watershed of Wasco County, Oregon. Specifically, I seek to address how farmer enrollment in various conservation techniques, loosely defined as no-till agriculture, has affected soil and water quality through the increased use of herbicide, and subsequently rendered ecological and human health vulnerable. Using a critical physical geography framework, I address both the biophysical factors and social structures that have co-produced changes in soil and water quality in the study area of this research through intensive physical field data collection, spatial analysis, social surveys, and interviews. I also demonstrate how three neoliberal sets of processes: market-friendly reregulation; state rollback and deregulation; and the creation of self-sufficient individuals and communities, have transformed the human socio-environmental relationship to agriculture. These processes have had significant effects on the policies governing how soil and water quality are managed on both a state and national level, and have created a dependence on enrollment in conservation practices that may ultimately prove counterproductive for long term goals of environmental protection and sustainability. Close

• 250. [Article] An a priori process for selecting candidate reference lakes for a national survey

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society ...

  Citation × Citation Citation Abstract Copy Title: An a priori process for selecting candidate reference lakes for a national survey Author: Sullivan, Timothy J., Sobota, Janel Banks, Herlihy, Alan T., McDonnell, Todd C., Tarquinio, Ellen, Lehmann, Sarah To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society for Freshwater Science and can be found at: http://www.freshwater-science.org/. Title: An a priori process for selecting candidate reference lakes for a national survey Author: Sullivan, Timothy J., Sobota, Janel Banks, Herlihy, Alan T., McDonnell, Todd C., Tarquinio, Ellen, Lehmann, Sarah To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society for Freshwater Science and can be found at: http://www.freshwater-science.org/. Close