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• 51. [Article] Impact of artificial flooding on farm profits and streamflow in Echo Meadows, Oregon

  Competition for water both from within the irrigation community and from outside interests has been a major source of conflict in the West. In the Umatilla Basin of central Oregon, Umatilla River water ...

  Citation × Citation Citation Abstract Copy Title: Impact of artificial flooding on farm profits and streamflow in Echo Meadows, Oregon Author: Seely, Harold E Competition for water both from within the irrigation community and from outside interests has been a major source of conflict in the West. In the Umatilla Basin of central Oregon, Umatilla River water is diverted to irrigate a variety of crops, while instream flows have value in salmonid production. Historically, the Umatilla Basin supported runs of fall and spring Chinook as well as steelhead and resident trout but native fish populations have largely disappeared from the river system. The decline in salmonid production has been blamed, in part, on a combination of low streamflow and high water temperatures in the summer months resulting from diversions by agricultural users. This thesis examines a proposed project designed to increase streamflow in the lower Umatilla River during the summer months by artificially flooding selected agricultural land in the Echo Meadows area of the basin during the late winter. The thesis also examines alternative options to increase streamflow. Estimates of the economic and hydrologic impacts of winter water spreading and other options provides information to policy-makers and irrigators on the costs and benefits associated with various project management alternatives. Using information on agricultural production and water supply in the lower Umatilla Basin, this thesis constructs a mathematical optimization model of representative farms in the area. In addition, because return flows represent an important component of streamflow in summer months, water applications determined by the representative farm models are used to assess the impacts of the artificial flooding project on streamflow in the Umatilla River below the study area. The results of the representative farm models indicate that the artificial flooding project increases farm profits by $37,620 and streamflow by 18.58 cubic feet per second. Alternative techniques to obtain similar increases in streamflow are more costly and would have negative effects on the agricultural community. Title: Impact of artificial flooding on farm profits and streamflow in Echo Meadows, Oregon Author: Seely, Harold E Competition for water both from within the irrigation community and from outside interests has been a major source of conflict in the West. In the Umatilla Basin of central Oregon, Umatilla River water is diverted to irrigate a variety of crops, while instream flows have value in salmonid production. Historically, the Umatilla Basin supported runs of fall and spring Chinook as well as steelhead and resident trout but native fish populations have largely disappeared from the river system. The decline in salmonid production has been blamed, in part, on a combination of low streamflow and high water temperatures in the summer months resulting from diversions by agricultural users. This thesis examines a proposed project designed to increase streamflow in the lower Umatilla River during the summer months by artificially flooding selected agricultural land in the Echo Meadows area of the basin during the late winter. The thesis also examines alternative options to increase streamflow. Estimates of the economic and hydrologic impacts of winter water spreading and other options provides information to policy-makers and irrigators on the costs and benefits associated with various project management alternatives. Using information on agricultural production and water supply in the lower Umatilla Basin, this thesis constructs a mathematical optimization model of representative farms in the area. In addition, because return flows represent an important component of streamflow in summer months, water applications determined by the representative farm models are used to assess the impacts of the artificial flooding project on streamflow in the Umatilla River below the study area. The results of the representative farm models indicate that the artificial flooding project increases farm profits by $37,620 and streamflow by 18.58 cubic feet per second. Alternative techniques to obtain similar increases in streamflow are more costly and would have negative effects on the agricultural community. Close

• 52. [Article] Community perceptions of flooding, water quality, and riparian habitat in Thomas Creek watershed of Oregon

  The complexity of human/riverine systems has led to an increasing focus on land use patterns and policy. My goal is to understand the dynamics of a coupled human and natural system. The central question ...

  Citation × Citation Citation Abstract Copy Title: Community perceptions of flooding, water quality, and riparian habitat in Thomas Creek watershed of Oregon Author: Doolittle, Lisa The complexity of human/riverine systems has led to an increasing focus on land use patterns and policy. My goal is to understand the dynamics of a coupled human and natural system. The central question is how people in the community of Scio, Oregon perceive flooding, water quality, and riparian habitat. I use the concept of cognitive models to identify and describe individual models of the environment, while cultural models explain and describe shared models of the environment. I utilize the ethnographic techniques of 22 semi-structured interviews, six months of participant observation, and a review of secondary data to identify cognitive and cultural models. I developed two hypotheses in order to approach the question of how people perceive flooding, water quality, and riparian habitat. The first hypothesis is that landowners who have high levels of risk perception and adaptability are more likely to respond to flooding, water quality, and riparian habitat. I found that even though landowners had high levels of risk perception the variable did not necessarily translate into action in the form of adaptability. The second hypothesis is that cognitive models have a pattern of variation that can be identified by land use. Although land use is a small-scale pattern, I found the more prevalent pattern of two shared cultural models to exist in the community of Scio, Oregon. The first model is characterized as human-centered, particularistic, short-term, locally relevant, stewardship focused, rural-oriented, and informed by experience. The second model is characterized as wildlife-centered, holistic, long-term, and informed by science. Local residents overwhelmingly aligned with the first model while agencies and scientists aligned with the second model. The pattern suggests a wide division between the understanding of local and scientific knowledge, therefore, I recommend a multi-objective management solution that mediates between local and scientific knowledge. Title: Community perceptions of flooding, water quality, and riparian habitat in Thomas Creek watershed of Oregon Author: Doolittle, Lisa The complexity of human/riverine systems has led to an increasing focus on land use patterns and policy. My goal is to understand the dynamics of a coupled human and natural system. The central question is how people in the community of Scio, Oregon perceive flooding, water quality, and riparian habitat. I use the concept of cognitive models to identify and describe individual models of the environment, while cultural models explain and describe shared models of the environment. I utilize the ethnographic techniques of 22 semi-structured interviews, six months of participant observation, and a review of secondary data to identify cognitive and cultural models. I developed two hypotheses in order to approach the question of how people perceive flooding, water quality, and riparian habitat. The first hypothesis is that landowners who have high levels of risk perception and adaptability are more likely to respond to flooding, water quality, and riparian habitat. I found that even though landowners had high levels of risk perception the variable did not necessarily translate into action in the form of adaptability. The second hypothesis is that cognitive models have a pattern of variation that can be identified by land use. Although land use is a small-scale pattern, I found the more prevalent pattern of two shared cultural models to exist in the community of Scio, Oregon. The first model is characterized as human-centered, particularistic, short-term, locally relevant, stewardship focused, rural-oriented, and informed by experience. The second model is characterized as wildlife-centered, holistic, long-term, and informed by science. Local residents overwhelmingly aligned with the first model while agencies and scientists aligned with the second model. The pattern suggests a wide division between the understanding of local and scientific knowledge, therefore, I recommend a multi-objective management solution that mediates between local and scientific knowledge. Close

• 53. [Article] Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest

  Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role ...

  Citation × Citation Citation Abstract Copy Title: Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest Author: Storck, Pascal Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role of forest maturity on snow accumulation and melt. To address this need, a multi-scale field and modeling study of the effects of forest canopies on snow accumulation and melt was conducted. Over a three year period, weighing lysimeters and cut-tree experiments were used to measure the process controlling snow interception and its fate at a site in the Umpqua National Forest, OR (elevation 1200 m). Continuous observations of below-canopy snowpack evolution were made over the same period. Over the study period, approximately 60 percent of annual snowfall was intercepted by the canopy (up to a maximum of 40 mm water equivalent). Approximately 72 percent and 28 percent of the intercepted snow was removed as meltwater drip and large snow masses, respectively. Apparent average sublimation rates from the intercepted snow were less than 1 mm per day and totaled approximately 100 mm per winter season. Title: Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest Author: Storck, Pascal Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role of forest maturity on snow accumulation and melt. To address this need, a multi-scale field and modeling study of the effects of forest canopies on snow accumulation and melt was conducted. Over a three year period, weighing lysimeters and cut-tree experiments were used to measure the process controlling snow interception and its fate at a site in the Umpqua National Forest, OR (elevation 1200 m). Continuous observations of below-canopy snowpack evolution were made over the same period. Over the study period, approximately 60 percent of annual snowfall was intercepted by the canopy (up to a maximum of 40 mm water equivalent). Approximately 72 percent and 28 percent of the intercepted snow was removed as meltwater drip and large snow masses, respectively. Apparent average sublimation rates from the intercepted snow were less than 1 mm per day and totaled approximately 100 mm per winter season. Close

• 54. [Article] Effects of input and redistribution processes on in-stream wood abundance and arrangement in Lookout Creek, western Cascades Range, Oregon

  This study explored how selected input and redistribution processes affect the amount and arrangement of in-stream wood within the 64 km2 Lookout Creek watershed in the Andrews Forest, western Cascade ...

  Citation × Citation Citation Abstract Copy Title: Effects of input and redistribution processes on in-stream wood abundance and arrangement in Lookout Creek, western Cascades Range, Oregon Author: Dreher, David Marshall This study explored how selected input and redistribution processes affect the amount and arrangement of in-stream wood within the 64 km2 Lookout Creek watershed in the Andrews Forest, western Cascade Range, Oregon. A longitudinal inventory of in-stream wood was conducted over approximately 20 km of stream length in 2nd to 5th-order channels along with reconnaissance activities in stream sections that had originally been mapped in 1970's. The study had two major parts. The first focused on patterns of in-stream wood amount and arrangement within the study watershed. Flood transport capability of inventoried stream segments was assigned based on channel width. Historical observations of debris flows and earthflow activity over the 50-year period prior to our study were used to delineate influence of those processes on inventoried channel segments. Wood amounts decreased with increases in channel transport capability. As channel transport capability increased the number of wood accumulations also decreased and there was a higher proportion of accumulations created by floods. These observations signal an increase in influence of fluvial transport of wood in the downstream direction. There were lower than expected amounts of wood at locations where debris flows entered mainstem channels and where earthflows were in contact with mainstem channels. This is attributed to the relatively high mobilization capability of channels in these locations. Congested wood break flood pulses is thought to be responsible for observed differences in wood conditions among segments affected by these processes and segments affected by floods only during the last fifty years. Some evidence exists to support the idea that debris flow entry to mainstem channels and dam-break flood pulses may promote a several decade period of increased wood input as a result of damage and disruption to trees in and adjacent to the channel in disturbed area. However, analysis of the effects of debris flows and earthflow activity on wood amount and arrangement was limited by small sample sizes. The second part of the study examined relative changes in wood amount and arrangement as well as changes to individual wood accumulations over a 25-year period within 5 stream reaches that had been mapped in detail in the early 1 970s. The effect of channel size, input and redistribution processes, piece size, as well as arrangement and location of pieces with respect to the active channel on changes in wood conditions were analyzed. Overall, changes in in-stream wood amount and arrangement were greater in larger channels than in smaller channels. In-stream wood changes resulting from fluvial redistribution also increased with channel size while decomposition and toppling were the processes responsible for most changes in smaller basins. In-stream wood changes were greater among small pieces than large pieces, although substantial changes in large pieces did occur in larger channels as a result of fluvial transport and in smaller channels as a result of toppling. In-stream wood changes were greater among single pieces than pieces in accumulations. Flood transport probably reduced the number of single pieces by collecting them in accumulations. Significant changes in in-stream wood occurred among pieces located both in and out of the channel suggesting that recent flooding, particularly in larger basins, was able to affect wood located along the margins of the channel. Changes in accumulations were generally minor in all sites except the 5th-order channel site. Title: Effects of input and redistribution processes on in-stream wood abundance and arrangement in Lookout Creek, western Cascades Range, Oregon Author: Dreher, David Marshall This study explored how selected input and redistribution processes affect the amount and arrangement of in-stream wood within the 64 km2 Lookout Creek watershed in the Andrews Forest, western Cascade Range, Oregon. A longitudinal inventory of in-stream wood was conducted over approximately 20 km of stream length in 2nd to 5th-order channels along with reconnaissance activities in stream sections that had originally been mapped in 1970's. The study had two major parts. The first focused on patterns of in-stream wood amount and arrangement within the study watershed. Flood transport capability of inventoried stream segments was assigned based on channel width. Historical observations of debris flows and earthflow activity over the 50-year period prior to our study were used to delineate influence of those processes on inventoried channel segments. Wood amounts decreased with increases in channel transport capability. As channel transport capability increased the number of wood accumulations also decreased and there was a higher proportion of accumulations created by floods. These observations signal an increase in influence of fluvial transport of wood in the downstream direction. There were lower than expected amounts of wood at locations where debris flows entered mainstem channels and where earthflows were in contact with mainstem channels. This is attributed to the relatively high mobilization capability of channels in these locations. Congested wood break flood pulses is thought to be responsible for observed differences in wood conditions among segments affected by these processes and segments affected by floods only during the last fifty years. Some evidence exists to support the idea that debris flow entry to mainstem channels and dam-break flood pulses may promote a several decade period of increased wood input as a result of damage and disruption to trees in and adjacent to the channel in disturbed area. However, analysis of the effects of debris flows and earthflow activity on wood amount and arrangement was limited by small sample sizes. The second part of the study examined relative changes in wood amount and arrangement as well as changes to individual wood accumulations over a 25-year period within 5 stream reaches that had been mapped in detail in the early 1 970s. The effect of channel size, input and redistribution processes, piece size, as well as arrangement and location of pieces with respect to the active channel on changes in wood conditions were analyzed. Overall, changes in in-stream wood amount and arrangement were greater in larger channels than in smaller channels. In-stream wood changes resulting from fluvial redistribution also increased with channel size while decomposition and toppling were the processes responsible for most changes in smaller basins. In-stream wood changes were greater among small pieces than large pieces, although substantial changes in large pieces did occur in larger channels as a result of fluvial transport and in smaller channels as a result of toppling. In-stream wood changes were greater among single pieces than pieces in accumulations. Flood transport probably reduced the number of single pieces by collecting them in accumulations. Significant changes in in-stream wood occurred among pieces located both in and out of the channel suggesting that recent flooding, particularly in larger basins, was able to affect wood located along the margins of the channel. Changes in accumulations were generally minor in all sites except the 5th-order channel site. Close

• 55. [Article] Effects of timing and duration of flooding on phosphorus release in four restored wetlands around Agency and Upper Klamath Lakes, Oregon

  Upper Klamath Lake (UKL) and Agency Lake in south-central Oregon are hypereutrophic due to phosphorus (P) loading from both geologic and agricultural sources in the watershed. Restoring historic lake-fringe ...

  Citation × Citation Citation Abstract Copy Title: Effects of timing and duration of flooding on phosphorus release in four restored wetlands around Agency and Upper Klamath Lakes, Oregon Author: Stevens, Carla J. Upper Klamath Lake (UKL) and Agency Lake in south-central Oregon are hypereutrophic due to phosphorus (P) loading from both geologic and agricultural sources in the watershed. Restoring historic lake-fringe wetlands to provide P sinks around the lakes has been accepted as a favorable means of reducing lake P levels and loading. Hydrologic management strategies differ in their timing of wetland filling and draining, and they may have significantly different outcomes on P forms and concentrations released to the lakes. To evaluate the effects of hydrologic management on P loading to the lakes, we investigated the biotic and abiotic mechanisms of P release related to timing and duration of inundation of wetland soils from four restoration sites through a laboratory and field study. More specifically, we evaluated four hypotheses related to hydrologic management and P release in the restored wetlands: 1) timing (temperature) of inundation affects the concentrations and forms of P released in study wetlands, 2) the nature of P dynamics in the study wetlands releases primarily soluble reactive phosphorus (SRP), as opposed to organic P, 3) abiotic factors including dissolved oxygen, pH, redox, organic matter, and bulk density levels influence P release, and 4) soil P fractions change over time with different flooding regimes. These hypotheses were investigated in a lab experiment in which dry wetland soil cores were flooded for 56 days and included sampling of total phosphorus (TP), SRP, dissolved oxygen (DO), pH, redox, and CO2. Measurements were also taken on soil cores when dry, flooded for one day, after experiment flooding, and after flooding in the field for soil pH, organic matter, bulk density, total P, microbial P, and inorganic P fractions. Higher release rates of TP were found in summer temperature treatments in all wetlands while release of SRP varied more with temperature and abiotic factors. Low DO and redox levels also influenced greater release of P from soil cores. Soil solution pH upon flooding resulted in dissolution of inorganic P fractions, leading to release of SRP to the water column. After dissolution, wetlands with mineral soils had greater capacities of adsorbing SRP into P fractions than the wetlands with organic soils. Microbial P was also a factor in SRP release; saturated biological demand resulted in higher mineralization than immobilization rates in two wetlands. Our data indicate that wetlands with hydrologic connectivity to the lakes and mineral soils released the lowest concentrations of TP, while SRP was variable. Further, our data provide evidence for determining best management strategies for wetlands to lower P loading to the lakes, which should be based upon soil type, how inorganic P is held in soil fractions, microbial activity, and the effect of abiotic factors such as temperature, DO, redox, and pH. Title: Effects of timing and duration of flooding on phosphorus release in four restored wetlands around Agency and Upper Klamath Lakes, Oregon Author: Stevens, Carla J. Upper Klamath Lake (UKL) and Agency Lake in south-central Oregon are hypereutrophic due to phosphorus (P) loading from both geologic and agricultural sources in the watershed. Restoring historic lake-fringe wetlands to provide P sinks around the lakes has been accepted as a favorable means of reducing lake P levels and loading. Hydrologic management strategies differ in their timing of wetland filling and draining, and they may have significantly different outcomes on P forms and concentrations released to the lakes. To evaluate the effects of hydrologic management on P loading to the lakes, we investigated the biotic and abiotic mechanisms of P release related to timing and duration of inundation of wetland soils from four restoration sites through a laboratory and field study. More specifically, we evaluated four hypotheses related to hydrologic management and P release in the restored wetlands: 1) timing (temperature) of inundation affects the concentrations and forms of P released in study wetlands, 2) the nature of P dynamics in the study wetlands releases primarily soluble reactive phosphorus (SRP), as opposed to organic P, 3) abiotic factors including dissolved oxygen, pH, redox, organic matter, and bulk density levels influence P release, and 4) soil P fractions change over time with different flooding regimes. These hypotheses were investigated in a lab experiment in which dry wetland soil cores were flooded for 56 days and included sampling of total phosphorus (TP), SRP, dissolved oxygen (DO), pH, redox, and CO2. Measurements were also taken on soil cores when dry, flooded for one day, after experiment flooding, and after flooding in the field for soil pH, organic matter, bulk density, total P, microbial P, and inorganic P fractions. Higher release rates of TP were found in summer temperature treatments in all wetlands while release of SRP varied more with temperature and abiotic factors. Low DO and redox levels also influenced greater release of P from soil cores. Soil solution pH upon flooding resulted in dissolution of inorganic P fractions, leading to release of SRP to the water column. After dissolution, wetlands with mineral soils had greater capacities of adsorbing SRP into P fractions than the wetlands with organic soils. Microbial P was also a factor in SRP release; saturated biological demand resulted in higher mineralization than immobilization rates in two wetlands. Our data indicate that wetlands with hydrologic connectivity to the lakes and mineral soils released the lowest concentrations of TP, while SRP was variable. Further, our data provide evidence for determining best management strategies for wetlands to lower P loading to the lakes, which should be based upon soil type, how inorganic P is held in soil fractions, microbial activity, and the effect of abiotic factors such as temperature, DO, redox, and pH. Close

• 56. [Article] Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial

  Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the ...

  Citation × Citation Citation Abstract Copy Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Close

• 57. [Article] Impact of floods versus routing events on the thermohaline circulation

  This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl/.

  Citation × Citation Citation Abstract Copy Title: Impact of floods versus routing events on the thermohaline circulation Author: Meissner, Katrin J., Clark, Peter U. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl/. Title: Impact of floods versus routing events on the thermohaline circulation Author: Meissner, Katrin J., Clark, Peter U. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl/. Close

• 58. [Article] Continuous Hydrologic Simulation of Johnson Creek Basin

  Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR.

  Citation × Citation Citation Abstract Copy Title: Continuous Hydrologic Simulation of Johnson Creek Basin Author: Shimota, Richard J., Hadley, Hans R. Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Title: Continuous Hydrologic Simulation of Johnson Creek Basin Author: Shimota, Richard J., Hadley, Hans R. Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Close

• 59. [Article] Geology, flooding & human activities : establishing a hierarchy of influence for controls on historic channel change, Willamette River, Oregon

  Channel evolution and influences of changing floodplain characteristics, heterogenous bank materials, and altered flow regimes were examined along the Willamette River, a large alluvial river in northwestern Oregon. ...

  Citation × Citation Citation Abstract Copy Title: Geology, flooding & human activities : establishing a hierarchy of influence for controls on historic channel change, Willamette River, Oregon Author: Wallick, Jennifer Rose Channel evolution and influences of changing floodplain characteristics, heterogenous bank materials, and altered flow regimes were examined along the Willamette River, a large alluvial river in northwestern Oregon. The Willamette River is composed of a series of geomorphically diverse reaches, which have each evolved uniquely in the century following Euro-American settlement. The river was divided into three large (30-50 km) alluvial reaches according to physiographic characteristics. The historically anastomosing and relatively steep McKenzie Reach (uppermost study reach), extends between the confluences of the McKenzie and Long Tom Rivers. The Willamette along the lower-gradient Santiam Reach (between the confluences of the Santiam and Yamhill Rivers is primarily contained within a single channel and has experienced lower rates of erosion than upper reaches. The Long Tom Reach (extending between the confluences of the Long Tom and Santiam Rivers), acts as a transition between the upper and lower Willamette, as it is here that the channel adopts a single-thread planform and becomes more stable. To assess the role of bank materials on bank-erosion rates, a method for detecting relative differences in erodibility between bank materials along large floodplains was developed. Coupling historic patterns of channel change with a simple model of bank erodibility enabled tracking of relative changes in bank erodibility among time intervals and bank materials. The analysis was applied to the McKenzie Reach for three time periods: 1850-1895, 1895-1932, and 1972-1995, and relative differences in bank erodibility were calculated for Holocene alluvium, partially cemented Pleistocene gravels, and revetments constructed in the 20th century. This simple model of bank erodibility reveals that, for all three periods, banks composed of Holocene alluvium were at least 2-5 times more erodible than banks composed of Pleistocene gravels. Revetment installed in the twentieth century was highly resistant to erosion and was at least 10 times less erodible than Pleistocene gravels. To examine larger-scale controls of geology, flooding, and human intervention on channel stability, rates and styles of historic channel change were determined for the McKenzie, Long Tom and Santiam Reaches and were linked with events or factors that may have triggered the observed patterns of channel change. Effects of anthropogenic activities on channel change were assessed by reviewing historic documents describing settlement patterns, riparian deforestation, channel improvements, and other actions. The role of flooding was assessed by compiling gauge records, anecdotal accounts of flooding, and by comparing stream-power distributions of large historic floods against smaller, post-dam floods with a 2-D flood model. Analyses of these larger-scale controls revealed that between 1850 and 1895, a period marked by the 3 largest floods of record, all reaches experienced numerous avulsions, increases in channel width, and decreases in centerline length. During the interval 1895-1932, a period with frequent, moderate-sized floods, migration rates increased by 50-300%, sinuosity increased and channel width decreased. The interval 1932-1995 was initially marked by rapid migration, but channel stabilization and dam building slowed erosion rates, causing the Long Tom and Santiam Reaches to display similar migration rates as those recorded for 1850-1895. Along the upper Willamette (McKenzie Reach), channel change during 1972 to 1995 was primarily limited to lateral migration along areas unrestricted by revetments and occurred at rates similar to 1850-1895 levels. Channel width decreased along all reaches during the 20th century. It is hypothesized that flooding may have been the primary factor responsible for the large-scale straightening and widening that occurred during 1850-1895. Actions taken to reduce streamside wood and side-channels along the McKenzie and Long Tom Reaches may have also contributed to widening. Along some areas of the floodplain, where the largely straightened and widened 1895 channel flowed through Holocene alluvium, the channel developed small bends that subsequently migrated rapidly downstream, and triggered rapid migration of adjacent bends. This concurrence of events and conditions suggests that accelerated erosion during the period 1895-1932 results from a combination of a "primed" planform, highly erodible bank materials, and a highly erosive flow regime with many moderate-sized floods. Migration rates 1895-1932 may have also increased as a result of land clearing and snag removal, as increasing numbers of settlers occupied floodplain lands in this interval. Anthropogenic activities have no clear effect on planform or erosion rates until the 193 D's, when widespread bank stabilization and dam construction resulted in diminished migration rates, fewer avulsions, and channel narrowing. By the late century, 30-45% of each reach was stabilized with revetments, while naturally resistant bank materials bordered an additional 13-30% of the channel length. Results indicate that revetments, naturally resistant bank materials, and flow regulation restrict migration and channel movement along the modern Willamette River. Efforts aiming to increase lateral migration on the Willamette River might consider removing revetment from bends bordered by Holocene alluvium along higher-gradient areas of the floodplain. However, such efforts may not create the suite of floodplain dynamics displayed by the historic Willamette, as much of the rapid migration, side channel maintenance and avulsions were related to flooding, channel change along adjacent bends, and large wood; all of which are largely absent from the modern floodplain. Title: Geology, flooding & human activities : establishing a hierarchy of influence for controls on historic channel change, Willamette River, Oregon Author: Wallick, Jennifer Rose Channel evolution and influences of changing floodplain characteristics, heterogenous bank materials, and altered flow regimes were examined along the Willamette River, a large alluvial river in northwestern Oregon. The Willamette River is composed of a series of geomorphically diverse reaches, which have each evolved uniquely in the century following Euro-American settlement. The river was divided into three large (30-50 km) alluvial reaches according to physiographic characteristics. The historically anastomosing and relatively steep McKenzie Reach (uppermost study reach), extends between the confluences of the McKenzie and Long Tom Rivers. The Willamette along the lower-gradient Santiam Reach (between the confluences of the Santiam and Yamhill Rivers is primarily contained within a single channel and has experienced lower rates of erosion than upper reaches. The Long Tom Reach (extending between the confluences of the Long Tom and Santiam Rivers), acts as a transition between the upper and lower Willamette, as it is here that the channel adopts a single-thread planform and becomes more stable. To assess the role of bank materials on bank-erosion rates, a method for detecting relative differences in erodibility between bank materials along large floodplains was developed. Coupling historic patterns of channel change with a simple model of bank erodibility enabled tracking of relative changes in bank erodibility among time intervals and bank materials. The analysis was applied to the McKenzie Reach for three time periods: 1850-1895, 1895-1932, and 1972-1995, and relative differences in bank erodibility were calculated for Holocene alluvium, partially cemented Pleistocene gravels, and revetments constructed in the 20th century. This simple model of bank erodibility reveals that, for all three periods, banks composed of Holocene alluvium were at least 2-5 times more erodible than banks composed of Pleistocene gravels. Revetment installed in the twentieth century was highly resistant to erosion and was at least 10 times less erodible than Pleistocene gravels. To examine larger-scale controls of geology, flooding, and human intervention on channel stability, rates and styles of historic channel change were determined for the McKenzie, Long Tom and Santiam Reaches and were linked with events or factors that may have triggered the observed patterns of channel change. Effects of anthropogenic activities on channel change were assessed by reviewing historic documents describing settlement patterns, riparian deforestation, channel improvements, and other actions. The role of flooding was assessed by compiling gauge records, anecdotal accounts of flooding, and by comparing stream-power distributions of large historic floods against smaller, post-dam floods with a 2-D flood model. Analyses of these larger-scale controls revealed that between 1850 and 1895, a period marked by the 3 largest floods of record, all reaches experienced numerous avulsions, increases in channel width, and decreases in centerline length. During the interval 1895-1932, a period with frequent, moderate-sized floods, migration rates increased by 50-300%, sinuosity increased and channel width decreased. The interval 1932-1995 was initially marked by rapid migration, but channel stabilization and dam building slowed erosion rates, causing the Long Tom and Santiam Reaches to display similar migration rates as those recorded for 1850-1895. Along the upper Willamette (McKenzie Reach), channel change during 1972 to 1995 was primarily limited to lateral migration along areas unrestricted by revetments and occurred at rates similar to 1850-1895 levels. Channel width decreased along all reaches during the 20th century. It is hypothesized that flooding may have been the primary factor responsible for the large-scale straightening and widening that occurred during 1850-1895. Actions taken to reduce streamside wood and side-channels along the McKenzie and Long Tom Reaches may have also contributed to widening. Along some areas of the floodplain, where the largely straightened and widened 1895 channel flowed through Holocene alluvium, the channel developed small bends that subsequently migrated rapidly downstream, and triggered rapid migration of adjacent bends. This concurrence of events and conditions suggests that accelerated erosion during the period 1895-1932 results from a combination of a "primed" planform, highly erodible bank materials, and a highly erosive flow regime with many moderate-sized floods. Migration rates 1895-1932 may have also increased as a result of land clearing and snag removal, as increasing numbers of settlers occupied floodplain lands in this interval. Anthropogenic activities have no clear effect on planform or erosion rates until the 193 D's, when widespread bank stabilization and dam construction resulted in diminished migration rates, fewer avulsions, and channel narrowing. By the late century, 30-45% of each reach was stabilized with revetments, while naturally resistant bank materials bordered an additional 13-30% of the channel length. Results indicate that revetments, naturally resistant bank materials, and flow regulation restrict migration and channel movement along the modern Willamette River. Efforts aiming to increase lateral migration on the Willamette River might consider removing revetment from bends bordered by Holocene alluvium along higher-gradient areas of the floodplain. However, such efforts may not create the suite of floodplain dynamics displayed by the historic Willamette, as much of the rapid migration, side channel maintenance and avulsions were related to flooding, channel change along adjacent bends, and large wood; all of which are largely absent from the modern floodplain. Close

• 60. [Article] A Remotely Controlled Siphon System for Dynamic Water Storage Management

  This thesis presents an analytical, experimental and numerical study of the initiation of flows in a siphon for rapid and gradual openings of a downstream valve. Three initial water levels in the upstream ...

  Citation × Citation Citation Abstract Copy Title: A Remotely Controlled Siphon System for Dynamic Water Storage Management Author: Alnahit, Ali This thesis presents an analytical, experimental and numerical study of the initiation of flows in a siphon for rapid and gradual openings of a downstream valve. Three initial water levels in the upstream tank and four final positions for the downstream valve were investigated. Two opening times of the downstream valve were also studied. Good agreement between analytical, experimental and numerical results were obtained. The proposed siphon system was found to initiate the flow regardless the downstream valve is opened gradually or rapidly. However, small leakages may lead to air at atmospheric pressure to rush into the top of the siphon and stop the flow. Overall, the proposed siphon system can be an effective and inexpensive method to dynamically manage the storage of ponds and wetlands for flood control. Title: A Remotely Controlled Siphon System for Dynamic Water Storage Management Author: Alnahit, Ali This thesis presents an analytical, experimental and numerical study of the initiation of flows in a siphon for rapid and gradual openings of a downstream valve. Three initial water levels in the upstream tank and four final positions for the downstream valve were investigated. Two opening times of the downstream valve were also studied. Good agreement between analytical, experimental and numerical results were obtained. The proposed siphon system was found to initiate the flow regardless the downstream valve is opened gradually or rapidly. However, small leakages may lead to air at atmospheric pressure to rush into the top of the siphon and stop the flow. Overall, the proposed siphon system can be an effective and inexpensive method to dynamically manage the storage of ponds and wetlands for flood control. Close