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• 31. [Article] Factors influencing pool morphology in Oregon coastal streams

  Pool morphology was surveyed in 19 stream sections within the central Oregon Coast Range. Pool locations, sizes, spacings, numbers, and factors affecting pool formation were determined for each stream ...

  Citation × Citation Citation Abstract Copy Title: Factors influencing pool morphology in Oregon coastal streams Author: Stack, William Robert Pool morphology was surveyed in 19 stream sections within the central Oregon Coast Range. Pool locations, sizes, spacings, numbers, and factors affecting pool formation were determined for each stream section. All sections were underlain by sedimentary rocks, had drainage areas ranging from 1.3 to 17.3 km², and had average water surface slopes from 0.5 to 5.6%. Stream sections were divided into two categories: (1) low timber harvest (<20% of watershed area harvested) and (2) high timber harvest (>45% of watershed area harvested). A "Rapid Bed Profile" (REP) technique was developed to measure residual pool characteristics in each stream section. The REP technique is a survey method that requires only thalweg depths and the average reach gradient. The technique was effective for classifying pools since it is objective, independent of flow, accurate, and time-efficient. Residual pool size characteristics (e.g., volume) for the low timber harvest stream sections were positively correlated to a power function of drainage area. Stream sections with beaver dams, especially those with at least 10% of their reach length in beaver-caused pools, typically had larger residual pools. Pool size characteristics for high timber harvest stream sections were not different from low timber harvest stream sections. The average spacing between residual pools was positively correlated to a power function of drainage area for the low timber harvest stream sections (a negative correlation was found between the number of pools and drainage area). High timber harvest stream sections may be associated with an increased spacing and a decreased number of pools for larger watersheds (i.e., greater than 8 km²). However, the potential effects of previous large storms, changes in timber management practices, and/or the small number of streams surveyed precluded a definitive conclusion. The frequency of occurrence of pool forming processes (e.g., plunge, deflection) was correlated with average water surface slope for the low timber harvest stream sections. The percentage of plunge and impoundment processes increased as water surface slope increased while the percentage of deflection and underflow processes decreased. Two high timber harvest streams had a higher percentage of plunge pools than expected based on the relationships established for the low timber harvest streams. The frequency of occurrence of wood and boulder pool forming elements was correlated with an index of stream power (drainage area times average water slope) for the low timber harvest stream sections. As the stream power index increased, the relative frequency of wood-formed pools decreased while boulder-formed pools increased. Wood and boulder combined, generally, made up 80% of the pool forming elements. The frequency of occurrence of pool forming elements was not different between low and high timber harvest stream sections. Title: Factors influencing pool morphology in Oregon coastal streams Author: Stack, William Robert Pool morphology was surveyed in 19 stream sections within the central Oregon Coast Range. Pool locations, sizes, spacings, numbers, and factors affecting pool formation were determined for each stream section. All sections were underlain by sedimentary rocks, had drainage areas ranging from 1.3 to 17.3 km², and had average water surface slopes from 0.5 to 5.6%. Stream sections were divided into two categories: (1) low timber harvest (<20% of watershed area harvested) and (2) high timber harvest (>45% of watershed area harvested). A "Rapid Bed Profile" (REP) technique was developed to measure residual pool characteristics in each stream section. The REP technique is a survey method that requires only thalweg depths and the average reach gradient. The technique was effective for classifying pools since it is objective, independent of flow, accurate, and time-efficient. Residual pool size characteristics (e.g., volume) for the low timber harvest stream sections were positively correlated to a power function of drainage area. Stream sections with beaver dams, especially those with at least 10% of their reach length in beaver-caused pools, typically had larger residual pools. Pool size characteristics for high timber harvest stream sections were not different from low timber harvest stream sections. The average spacing between residual pools was positively correlated to a power function of drainage area for the low timber harvest stream sections (a negative correlation was found between the number of pools and drainage area). High timber harvest stream sections may be associated with an increased spacing and a decreased number of pools for larger watersheds (i.e., greater than 8 km²). However, the potential effects of previous large storms, changes in timber management practices, and/or the small number of streams surveyed precluded a definitive conclusion. The frequency of occurrence of pool forming processes (e.g., plunge, deflection) was correlated with average water surface slope for the low timber harvest stream sections. The percentage of plunge and impoundment processes increased as water surface slope increased while the percentage of deflection and underflow processes decreased. Two high timber harvest streams had a higher percentage of plunge pools than expected based on the relationships established for the low timber harvest streams. The frequency of occurrence of wood and boulder pool forming elements was correlated with an index of stream power (drainage area times average water slope) for the low timber harvest stream sections. As the stream power index increased, the relative frequency of wood-formed pools decreased while boulder-formed pools increased. Wood and boulder combined, generally, made up 80% of the pool forming elements. The frequency of occurrence of pool forming elements was not different between low and high timber harvest stream sections. Close

• 32. [Article] Aquatic insect adaptations to different flow regimes

  My thesis explored the effects of environmental variability on population dynamics and community composition of aquatic insects. Environmental variability in the form of flow regime in streams can limit ...

  Citation × Citation Citation Abstract Copy Title: Aquatic insect adaptations to different flow regimes Author: Yamamuro, Asako Melody My thesis explored the effects of environmental variability on population dynamics and community composition of aquatic insects. Environmental variability in the form of flow regime in streams can limit the distribution and life-history traits of aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically different flow regimes to compare aquatic insect community composition (Chapter 2). Runoff-dominated streams were responsive to precipitation events and had high flow events in the winter and dried down in the summer. Spring-fed streams had a relatively steady flow regime year round. Streams categorized as runoff-dominated had distinctly different taxonomic composition of aquatic insects compared to streams designated as having a spring-fed flow regime. Larval Ameletus (order Ephemeroptera) and Calineuria (order Plecoptera) were prominent indicator genera for runoff-dominated streams while Caudatella (order Ephemeroptera) and Yoraperla (order Plecoptera) were prominent indicator genera for spring-fed streams. Additionally, life-history trait indicators for spring-fed streams included semivoltinism, poorly synchronized emergence, and slow seasonal development. These analyses suggested that there were community level differences between seasonally fluctuating and relatively constant flow regimes. My thesis investigated population-level differences in life-history traits of an aquatic insect species that is found in both runoff-dominated and spring-fed streams (Chapter 3). Cohort patterns of Yoraperla nigrisoma were distinctly different between both stream types. At the end of the summer, spring-fed streams had three distinct cohorts, while runoff-dominated streams had two distinct cohorts present. Yoraperla nigrisoma in spring-fed streams have a more consistent growth rate year round, and they emerge at a larger size and have more cohorts present than in runoff-dominated streams. These analyses suggest that flow regime type is highly associated with these life-history differences. My thesis explored whether life-history trait differences at the population level are phenotypically plastic to environmental conditions in the short term (Chapter 4). The variability in sources of phenotypic variation may be due to the presence or lack of phenotyically plastic factors. I conducted a reciprocal transplant experiment to quantify the effects of environment on life-history traits of Yoraperla nigrisoma. Insects from the spring-fed stream that were transferred to the runoff-dominated stream sped up their development, which was measured by change in head width over time. Also, newly-emerged adults showed differences in head width and biomass between treatments, but the small sample sizes associated with these results should be considered. Overall, both phenotypically plastic factors and factors lacking phenotypic plasticity affect life-history traits between the runoff-dominated and spring-fed stream. Title: Aquatic insect adaptations to different flow regimes Author: Yamamuro, Asako Melody My thesis explored the effects of environmental variability on population dynamics and community composition of aquatic insects. Environmental variability in the form of flow regime in streams can limit the distribution and life-history traits of aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically different flow regimes to compare aquatic insect community composition (Chapter 2). Runoff-dominated streams were responsive to precipitation events and had high flow events in the winter and dried down in the summer. Spring-fed streams had a relatively steady flow regime year round. Streams categorized as runoff-dominated had distinctly different taxonomic composition of aquatic insects compared to streams designated as having a spring-fed flow regime. Larval Ameletus (order Ephemeroptera) and Calineuria (order Plecoptera) were prominent indicator genera for runoff-dominated streams while Caudatella (order Ephemeroptera) and Yoraperla (order Plecoptera) were prominent indicator genera for spring-fed streams. Additionally, life-history trait indicators for spring-fed streams included semivoltinism, poorly synchronized emergence, and slow seasonal development. These analyses suggested that there were community level differences between seasonally fluctuating and relatively constant flow regimes. My thesis investigated population-level differences in life-history traits of an aquatic insect species that is found in both runoff-dominated and spring-fed streams (Chapter 3). Cohort patterns of Yoraperla nigrisoma were distinctly different between both stream types. At the end of the summer, spring-fed streams had three distinct cohorts, while runoff-dominated streams had two distinct cohorts present. Yoraperla nigrisoma in spring-fed streams have a more consistent growth rate year round, and they emerge at a larger size and have more cohorts present than in runoff-dominated streams. These analyses suggest that flow regime type is highly associated with these life-history differences. My thesis explored whether life-history trait differences at the population level are phenotypically plastic to environmental conditions in the short term (Chapter 4). The variability in sources of phenotypic variation may be due to the presence or lack of phenotyically plastic factors. I conducted a reciprocal transplant experiment to quantify the effects of environment on life-history traits of Yoraperla nigrisoma. Insects from the spring-fed stream that were transferred to the runoff-dominated stream sped up their development, which was measured by change in head width over time. Also, newly-emerged adults showed differences in head width and biomass between treatments, but the small sample sizes associated with these results should be considered. Overall, both phenotypically plastic factors and factors lacking phenotypic plasticity affect life-history traits between the runoff-dominated and spring-fed stream. Close

• 33. [Article] Geomorphic influences on habitat formation, distribution, and development and the classification of upland coastal Oregon streams

  A framework is presented for a more causal explanation and ordering of stream characteristics than traditional means have used. Patterns of stream habitat distribution are related to particular characteristics ...

  Citation × Citation Citation Abstract Copy Title: Geomorphic influences on habitat formation, distribution, and development and the classification of upland coastal Oregon streams Author: Hurley, Michael D. A framework is presented for a more causal explanation and ordering of stream characteristics than traditional means have used. Patterns of stream habitat distribution are related to particular characteristics of the geomorphology of watersheds. Variability in stream characteristics can be explained by the spatial distribution of properties of the watershed and by identifying stages in the development of stream habitat. This has implications for the classification of streams in a geomorphic context, emphasizing the concepts of capacity and genesis. Within the context of a hierarchical watershed classification, stream segment is considered the most useful classification level for understanding habitat distribution and dynamics. Basins in basalt and sandstone geologic formations in the Oregon Coast Range were investigated for stream habitat distribution. In streams flowing through sandstone, repetitive patterns of large-scale valley segments are identified in headwaters to large rivers. Segment boundaries are identified by changes in valley morphology. Alternating patterns of wide valleys and constricted valleys are common in some landtype associations. The formation of these segments is influenced by bedrock stratigraphy and large-scale geomorphic processes such as slump-slides. Valley dimensions are quantified by nondimensional indices of valley width / channel width and the stream gradient index. Pool distribution was intensively analysed in 2.8 kilometers of a fourth order stream that flows through basalt bedrock. The mainstem was stratified by tributary junctions, each of which was further divided into 3 equal zones. Distributional patterns were analyzed by pool spacing, linear nearest neighbor, and by composition of zones. Pool spacing does not conform to the expected normal distribution with a median spacing at 5-7 channel widths. Pool spacing is strongly skewed towards shorter spacings and has a median spacing at 2-3 channel widths. Pools of similar size and type occur locally, which indicates that different areas of the stream have different conditions for habitat formation and development. Habitat distribution and composition is related to valley morphology, hillslope processes, location in relation to tributary junctions, and time since disturbance. Debris torrents are the dominant processes influencing the stream, these supplying sediment and instream structure of wood and boulders, as well as influencing channel slope. A balance between disturbance and recovery exists in unmanaged as well as perturbed watersheds. Effective management of watersheds must maintain the geomorphic integrity of the valley and stream. Classification of the stream and habitat in a geomorphic context enhances explanation and the understanding of the interaction between watershed form and process and characteristics of the stream. Stream habitat formation, distribution, and dynamics are better understood in the context of geomorphic concepts such as sediment storage and dynamics. Title: Geomorphic influences on habitat formation, distribution, and development and the classification of upland coastal Oregon streams Author: Hurley, Michael D. A framework is presented for a more causal explanation and ordering of stream characteristics than traditional means have used. Patterns of stream habitat distribution are related to particular characteristics of the geomorphology of watersheds. Variability in stream characteristics can be explained by the spatial distribution of properties of the watershed and by identifying stages in the development of stream habitat. This has implications for the classification of streams in a geomorphic context, emphasizing the concepts of capacity and genesis. Within the context of a hierarchical watershed classification, stream segment is considered the most useful classification level for understanding habitat distribution and dynamics. Basins in basalt and sandstone geologic formations in the Oregon Coast Range were investigated for stream habitat distribution. In streams flowing through sandstone, repetitive patterns of large-scale valley segments are identified in headwaters to large rivers. Segment boundaries are identified by changes in valley morphology. Alternating patterns of wide valleys and constricted valleys are common in some landtype associations. The formation of these segments is influenced by bedrock stratigraphy and large-scale geomorphic processes such as slump-slides. Valley dimensions are quantified by nondimensional indices of valley width / channel width and the stream gradient index. Pool distribution was intensively analysed in 2.8 kilometers of a fourth order stream that flows through basalt bedrock. The mainstem was stratified by tributary junctions, each of which was further divided into 3 equal zones. Distributional patterns were analyzed by pool spacing, linear nearest neighbor, and by composition of zones. Pool spacing does not conform to the expected normal distribution with a median spacing at 5-7 channel widths. Pool spacing is strongly skewed towards shorter spacings and has a median spacing at 2-3 channel widths. Pools of similar size and type occur locally, which indicates that different areas of the stream have different conditions for habitat formation and development. Habitat distribution and composition is related to valley morphology, hillslope processes, location in relation to tributary junctions, and time since disturbance. Debris torrents are the dominant processes influencing the stream, these supplying sediment and instream structure of wood and boulders, as well as influencing channel slope. A balance between disturbance and recovery exists in unmanaged as well as perturbed watersheds. Effective management of watersheds must maintain the geomorphic integrity of the valley and stream. Classification of the stream and habitat in a geomorphic context enhances explanation and the understanding of the interaction between watershed form and process and characteristics of the stream. Stream habitat formation, distribution, and dynamics are better understood in the context of geomorphic concepts such as sediment storage and dynamics. Close

• 34. [Article] Spatiotemporal dynamics and drivers of stream pCO₂ in a headwater mountain catchment in the Cascade Mountains, Oregon

  We examined the spatial and temporal variability of stream carbon dioxide (CO₂) and the drivers of these variations in a headwater catchment. To examine temporal variation and drivers, we measured stream ...

  Citation × Citation Citation Abstract Copy Title: Spatiotemporal dynamics and drivers of stream pCO₂ in a headwater mountain catchment in the Cascade Mountains, Oregon Author: Dosch, Nicholas T. We examined the spatial and temporal variability of stream carbon dioxide (CO₂) and the drivers of these variations in a headwater catchment. To examine temporal variation and drivers, we measured stream and hyporheic pCO₂ at high temporal resolution over 11 months in a 95.9-ha forested headwater catchment in the Western Cascades of Central Oregon, USA. Stream and hyporheic pCO₂ showed high seasonal and event-scale variability with distinct stream and hyporheic dynamics during storm discharge events. Hyporheic exchange flow exported 37.5 kg-C yr⁻¹ per watershed hectare (confidence interval 4.0-122.3 kg-C ha⁻¹ yr⁻¹) from the riparian zone to the stream. Summing CO₂ evasion and downstream advection suggests that one third of inorganic carbon export originated in the hyporheic zone. Hyporheic exchange flow had greatest influence over stream pCO₂ during low and high baseflow, while CO₂ evasion had greatest influence during storm discharge events. These findings suggest that the hyporheic zone actively participates in carbon cycling in this headwater stream and continuously replenishes stream CO₂. To examine spatial variation and drivers, we measured stream CO₂ at monthly intervals from July 2013 through July 2014 at 38 locations across the 6400-ha HJ Andrews Experimental Forest. Stream pCO₂ was consistently supersaturated with respect to atmospheric concentrations. Stream pCO₂ ranged from atmospheric (~400 μatm) to 20 times atmospheric concentrations (8150 μatm) and exhibited strong spatial and temporal variability. The distribution of pCO₂ over the study period was different in small and large streams within the drainage network. At the watershed scale, pCO₂ decreased with distance downstream. At the reach scale, we did not detect clear patterns in the downstream direction. However, individual transects displayed persistent profile shape, with consistent high and low pCO₂ locations. We found negative relationships between stream pCO₂ and stream discharge, mean velocity and the carbon dioxide gas transfer velocity. Stream pCO₂ exhibited changes over short distances, with large changes in pCO₂ over less than 50 m. Longitudinal variability indicates spatial variability of in-stream controls on pCO₂ at this scale. Stream pCO₂ shows generally higher concentrations during the summer and lower concentrations in the winter, with considerable intrannual variability. Title: Spatiotemporal dynamics and drivers of stream pCO₂ in a headwater mountain catchment in the Cascade Mountains, Oregon Author: Dosch, Nicholas T. We examined the spatial and temporal variability of stream carbon dioxide (CO₂) and the drivers of these variations in a headwater catchment. To examine temporal variation and drivers, we measured stream and hyporheic pCO₂ at high temporal resolution over 11 months in a 95.9-ha forested headwater catchment in the Western Cascades of Central Oregon, USA. Stream and hyporheic pCO₂ showed high seasonal and event-scale variability with distinct stream and hyporheic dynamics during storm discharge events. Hyporheic exchange flow exported 37.5 kg-C yr⁻¹ per watershed hectare (confidence interval 4.0-122.3 kg-C ha⁻¹ yr⁻¹) from the riparian zone to the stream. Summing CO₂ evasion and downstream advection suggests that one third of inorganic carbon export originated in the hyporheic zone. Hyporheic exchange flow had greatest influence over stream pCO₂ during low and high baseflow, while CO₂ evasion had greatest influence during storm discharge events. These findings suggest that the hyporheic zone actively participates in carbon cycling in this headwater stream and continuously replenishes stream CO₂. To examine spatial variation and drivers, we measured stream CO₂ at monthly intervals from July 2013 through July 2014 at 38 locations across the 6400-ha HJ Andrews Experimental Forest. Stream pCO₂ was consistently supersaturated with respect to atmospheric concentrations. Stream pCO₂ ranged from atmospheric (~400 μatm) to 20 times atmospheric concentrations (8150 μatm) and exhibited strong spatial and temporal variability. The distribution of pCO₂ over the study period was different in small and large streams within the drainage network. At the watershed scale, pCO₂ decreased with distance downstream. At the reach scale, we did not detect clear patterns in the downstream direction. However, individual transects displayed persistent profile shape, with consistent high and low pCO₂ locations. We found negative relationships between stream pCO₂ and stream discharge, mean velocity and the carbon dioxide gas transfer velocity. Stream pCO₂ exhibited changes over short distances, with large changes in pCO₂ over less than 50 m. Longitudinal variability indicates spatial variability of in-stream controls on pCO₂ at this scale. Stream pCO₂ shows generally higher concentrations during the summer and lower concentrations in the winter, with considerable intrannual variability. Close

• 35. [Article] Stream temperature and streamside cover 14-17 years after clearcutting along small forested streams, western Oregon

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Society of American Foresters and can be found at: http://www.safnet.org/public...

  Citation × Citation Citation Abstract Copy Title: Stream temperature and streamside cover 14-17 years after clearcutting along small forested streams, western Oregon Author: Newton, Mike, Cole, Liz This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Society of American Foresters and can be found at: http://www.safnet.org/publications/western/index.cfm. Title: Stream temperature and streamside cover 14-17 years after clearcutting along small forested streams, western Oregon Author: Newton, Mike, Cole, Liz This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Society of American Foresters and can be found at: http://www.safnet.org/publications/western/index.cfm. Close

• 36. [Article] Diurnal timing of warmer air under climate change affects magnitude, timing and duration of stream temperature change

  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 John Wiley ...

  Citation × Citation Citation Abstract Copy Title: Diurnal timing of warmer air under climate change affects magnitude, timing and duration of stream temperature change Author: Haggerty, Roy, Wondzell, Steven M., Diabat, Mousa 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 John Wiley & Sons Ltd. and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-1085. Title: Diurnal timing of warmer air under climate change affects magnitude, timing and duration of stream temperature change Author: Haggerty, Roy, Wondzell, Steven M., Diabat, Mousa 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 John Wiley & Sons Ltd. and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-1085. Close

• 37. [Article] Influence of biologically stabilized kraft mill effluent on the food relations and production of juvenile chinook salmon in laboratory streams

  This thesis reports the results of a study on the influence of biologically stabilized kraft mill effluent (SKME) on the food relations and production of juvenile chinook salmon, Oncorhynchus tschawytscha (Walbaum), ...

  Citation × Citation Citation Abstract Copy Title: Influence of biologically stabilized kraft mill effluent on the food relations and production of juvenile chinook salmon in laboratory streams Author: Seim, W. K. (Wayne K.) This thesis reports the results of a study on the influence of biologically stabilized kraft mill effluent (SKME) on the food relations and production of juvenile chinook salmon, Oncorhynchus tschawytscha (Walbaum), in laboratory streams. Experiments were conducted at the Oak Creek Fisheries Research Laboratory, Oregon State University, during 1967 and 1968. Kraft mill effluent used in this study was either collected raw and biologically stabilized at the laboratory, or collected already treated from a mill operating a stabilization pond. Stabilization of wastes was accomplished at the laboratory by sewage bacteria under constant aeration and with the addition of nitrogen and phosphorus. One aspect of this study dealt with the relationship between salmon production and salmon biomass in streams stocked with salmon at different densities in three control and three streams receiving 1.5 percent SKME by volume. This design permitted an analysis of the relationships between the abundance of the food organisms and the growth rate and biomass of salmon. Another aspect of the study dealt with the production of fish stocked at similar densities in two control streams and four streams each of which received a different concentration of SKME. In experiments conducted during the spring and fall periods, salmon production was lower in streams receiving a 1.5 percent SKME concentration than in control streams. This difference was attributed to a direct effect of SKME since no reduction in the abundance of food organisms or in the basic capacity of the streams to produce food organisms could be demonstrated. In experiments during the summer salmon production was found to be greater in streams receiving up to 4.0 percent SKME than in control streams. Salmon production was greatest at a 1.0 percent concentration and declined at concentrations of 2.0 and 4.0 percent SKME. The increase in production can probably be attributed to an increase in the numerical density of the major food organism, an amphipod identified as Crangonyx sp. The decline in salmon production at concentrations above 1.0 percent suggested that SKME was directly effecting salmon growth rates during summer experiments also, although this influence may have been small in relation to beneficial effects on food abundance. Amphipod biomass was related to the biomass of organic material in the laboratory streams. Title: Influence of biologically stabilized kraft mill effluent on the food relations and production of juvenile chinook salmon in laboratory streams Author: Seim, W. K. (Wayne K.) This thesis reports the results of a study on the influence of biologically stabilized kraft mill effluent (SKME) on the food relations and production of juvenile chinook salmon, Oncorhynchus tschawytscha (Walbaum), in laboratory streams. Experiments were conducted at the Oak Creek Fisheries Research Laboratory, Oregon State University, during 1967 and 1968. Kraft mill effluent used in this study was either collected raw and biologically stabilized at the laboratory, or collected already treated from a mill operating a stabilization pond. Stabilization of wastes was accomplished at the laboratory by sewage bacteria under constant aeration and with the addition of nitrogen and phosphorus. One aspect of this study dealt with the relationship between salmon production and salmon biomass in streams stocked with salmon at different densities in three control and three streams receiving 1.5 percent SKME by volume. This design permitted an analysis of the relationships between the abundance of the food organisms and the growth rate and biomass of salmon. Another aspect of the study dealt with the production of fish stocked at similar densities in two control streams and four streams each of which received a different concentration of SKME. In experiments conducted during the spring and fall periods, salmon production was lower in streams receiving a 1.5 percent SKME concentration than in control streams. This difference was attributed to a direct effect of SKME since no reduction in the abundance of food organisms or in the basic capacity of the streams to produce food organisms could be demonstrated. In experiments during the summer salmon production was found to be greater in streams receiving up to 4.0 percent SKME than in control streams. Salmon production was greatest at a 1.0 percent concentration and declined at concentrations of 2.0 and 4.0 percent SKME. The increase in production can probably be attributed to an increase in the numerical density of the major food organism, an amphipod identified as Crangonyx sp. The decline in salmon production at concentrations above 1.0 percent suggested that SKME was directly effecting salmon growth rates during summer experiments also, although this influence may have been small in relation to beneficial effects on food abundance. Amphipod biomass was related to the biomass of organic material in the laboratory streams. Close

• 38. [Article] Flow characteristics of co-flowing, laminar streams in a rectangular microchannel

  The effects of varying flow rate ratio and Reynolds number on the momentum diffusion and flow development of two co-flowing, laminar streams in a rectangular microchannel are presented. The microchannel ...

  Citation × Citation Citation Abstract Copy Title: Flow characteristics of co-flowing, laminar streams in a rectangular microchannel Author: Oak, Jason The effects of varying flow rate ratio and Reynolds number on the momentum diffusion and flow development of two co-flowing, laminar streams in a rectangular microchannel are presented. The microchannel has an aspect ratio of approximately 16 with a width of 1006 μm and a height of 63 μm. A long, thin splitter plate initially separates the two streams such that fully developed flow in each of the two channels is obtained prior to merging. Fluorescent dye imaging and Particle Image Velocimetry (PIV) were utilized to observe the interaction between the streams for a range of flow rate ratios ranging from one to nine while maintaining a chamber Reynolds number of one. Additionally, PIV data was collected for the same flow rate ratios with a chamber Reynolds number of ten. It was found that when there is a velocity difference between the two streams, there is a cross-stream pressure gradient immediately downstream of the splitter plate that causes the faster moving fluid to expand into the slower moving fluid. Despite this rapid expansion, the fluids in two streams do not mix and continue to travel parallel to each other. As expected, the expansion of the faster moving fluid is diminished by the viscous effects present in the flow, although only at higher flow rate ratios. The merged streams eventually recover their fully developed profile although it is shown that existing entrance length relationships do not adequately predict the development length. In addition, the velocity flow characteristics between the streams is illustrated near the end of the splitter plate. As the streams travel past the splitter plate, the flow-wise momentum of the faster moving fluid is converted into a lateral, cross-stream velocity. The presence of an optimum flow rate ratio for obtaining a maximum cross-stream velocity magnitude is suggested. The effect of varying Reynolds number on these observations is also discussed. Title: Flow characteristics of co-flowing, laminar streams in a rectangular microchannel Author: Oak, Jason The effects of varying flow rate ratio and Reynolds number on the momentum diffusion and flow development of two co-flowing, laminar streams in a rectangular microchannel are presented. The microchannel has an aspect ratio of approximately 16 with a width of 1006 μm and a height of 63 μm. A long, thin splitter plate initially separates the two streams such that fully developed flow in each of the two channels is obtained prior to merging. Fluorescent dye imaging and Particle Image Velocimetry (PIV) were utilized to observe the interaction between the streams for a range of flow rate ratios ranging from one to nine while maintaining a chamber Reynolds number of one. Additionally, PIV data was collected for the same flow rate ratios with a chamber Reynolds number of ten. It was found that when there is a velocity difference between the two streams, there is a cross-stream pressure gradient immediately downstream of the splitter plate that causes the faster moving fluid to expand into the slower moving fluid. Despite this rapid expansion, the fluids in two streams do not mix and continue to travel parallel to each other. As expected, the expansion of the faster moving fluid is diminished by the viscous effects present in the flow, although only at higher flow rate ratios. The merged streams eventually recover their fully developed profile although it is shown that existing entrance length relationships do not adequately predict the development length. In addition, the velocity flow characteristics between the streams is illustrated near the end of the splitter plate. As the streams travel past the splitter plate, the flow-wise momentum of the faster moving fluid is converted into a lateral, cross-stream velocity. The presence of an optimum flow rate ratio for obtaining a maximum cross-stream velocity magnitude is suggested. The effect of varying Reynolds number on these observations is also discussed. Close

• 39. [Article] Characteristics of stream low flows in eastern Oregon : their relationship with precipitation and watershed parameters

  Characteristics of low flows of nine streams in eastern Oregon were explored using long-term streamflow records. Year-to-year dependence of low flows is highly significant for streams in the Blue Mountain ...

  Citation × Citation Citation Abstract Copy Title: Characteristics of stream low flows in eastern Oregon : their relationship with precipitation and watershed parameters Author: Zeb, Aurang Characteristics of low flows of nine streams in eastern Oregon were explored using long-term streamflow records. Year-to-year dependence of low flows is highly significant for streams in the Blue Mountain and the southeastern Oregon regions. Low streamflows increased over the period of record for seven of the selected streams. Flow duration curves, flow-date curves and low flow frequency curves were constructed for each stream. Flow per unit area is higher for streams in northeastern Oregon than streams in southeastern Oregon. Forecast equations for streamflow recessions were made for each stream. Forecasts are highly accurate for recession volume and August average flow except for Mill creek and Bridge Creek. Forecasts are poor for the later part of the water year. Even for the later part of the water year, highly accurate results are obtained when forecasts are made for shorter periods (about 40 days). Annual precipitation is fairly well-distributed over the whole year in eastern Oregon with July and August as the driest months. Streams in the Wallowa Mountain and southeastern Oregon regions showed higher trend similarities between summer low flows and precipitation than streams in the Blue Mountain region. Correlations between summer low flows and precipitation were highly significant for the Wallowa Mountain and the southeastern Oregon regions. Correlations between low flows and watershed parameters, as well as average annual precipitation, were found insignificant for all streams. Title: Characteristics of stream low flows in eastern Oregon : their relationship with precipitation and watershed parameters Author: Zeb, Aurang Characteristics of low flows of nine streams in eastern Oregon were explored using long-term streamflow records. Year-to-year dependence of low flows is highly significant for streams in the Blue Mountain and the southeastern Oregon regions. Low streamflows increased over the period of record for seven of the selected streams. Flow duration curves, flow-date curves and low flow frequency curves were constructed for each stream. Flow per unit area is higher for streams in northeastern Oregon than streams in southeastern Oregon. Forecast equations for streamflow recessions were made for each stream. Forecasts are highly accurate for recession volume and August average flow except for Mill creek and Bridge Creek. Forecasts are poor for the later part of the water year. Even for the later part of the water year, highly accurate results are obtained when forecasts are made for shorter periods (about 40 days). Annual precipitation is fairly well-distributed over the whole year in eastern Oregon with July and August as the driest months. Streams in the Wallowa Mountain and southeastern Oregon regions showed higher trend similarities between summer low flows and precipitation than streams in the Blue Mountain region. Correlations between summer low flows and precipitation were highly significant for the Wallowa Mountain and the southeastern Oregon regions. Correlations between low flows and watershed parameters, as well as average annual precipitation, were found insignificant for all streams. Close

• 40. [Article] Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature

  This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data ...

  Citation × Citation Citation Abstract Copy Title: Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature Author: Harewood, Alessandra Greer This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data were gathered at four to seven locations along South Sister Creek in 2006, 2012, and 2013 and were used to explore whether restoration projects (in 2007 to 2011) affected stream temperature. Calculated seven-day maximum temperatures were cooler in post-treatment years (2012 and 2013) than the pre-treatment year (2006) at all four multi-year sites with the greatest differences near the mouth of the creek (4 to 5ºC cooler). While median stream temperature values were highest in 2013 for all four of the multi-year sites, the upper quartiles of measured hourly temperature for 2006 compared to 2012 and 2013 indicated more extreme high temperatures in 2006 than in subsequent years. Cross-correlation between stream and air temperature were used as an indicator of hyporheic flow. All peak CCF coefficients indicated a strong (.70) positive correlation in the early summer period between air and stream temperature, with lags ranging from 3 to 6 hours between peak air temperature and peak stream temperature. In the late summer period, most sites demonstrated lower correlations and longer lag times, patterns consistent with greater groundwater influence during low summer flows. There was no observable difference between pre- and post-treatment air-stream temperature cross correlation relationships. At a sub-reach scale, sites with more in-stream structural complexity -- including designed structures -- displayed greater spatial temperature variability than bedrock dominated reaches with simpler geomorphology. Title: Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature Author: Harewood, Alessandra Greer This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data were gathered at four to seven locations along South Sister Creek in 2006, 2012, and 2013 and were used to explore whether restoration projects (in 2007 to 2011) affected stream temperature. Calculated seven-day maximum temperatures were cooler in post-treatment years (2012 and 2013) than the pre-treatment year (2006) at all four multi-year sites with the greatest differences near the mouth of the creek (4 to 5ºC cooler). While median stream temperature values were highest in 2013 for all four of the multi-year sites, the upper quartiles of measured hourly temperature for 2006 compared to 2012 and 2013 indicated more extreme high temperatures in 2006 than in subsequent years. Cross-correlation between stream and air temperature were used as an indicator of hyporheic flow. All peak CCF coefficients indicated a strong (.70) positive correlation in the early summer period between air and stream temperature, with lags ranging from 3 to 6 hours between peak air temperature and peak stream temperature. In the late summer period, most sites demonstrated lower correlations and longer lag times, patterns consistent with greater groundwater influence during low summer flows. There was no observable difference between pre- and post-treatment air-stream temperature cross correlation relationships. At a sub-reach scale, sites with more in-stream structural complexity -- including designed structures -- displayed greater spatial temperature variability than bedrock dominated reaches with simpler geomorphology. Close