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• 1. [Article] Water Quality in the Long Tom River Watershed 1999-2003

  Abstract -- The report contains: introduction, background on the watershed: land use, water use, precipitation, fish and amphibians, study design and methods: training, parameters and sampling frequency, ...

  Citation × Citation Citation Abstract Copy Title: Water Quality in the Long Tom River Watershed 1999-2003 Abstract -- The report contains: introduction, background on the watershed: land use, water use, precipitation, fish and amphibians, study design and methods: training, parameters and sampling frequency, methods, quality assurance and control, results: comparison to state water quality standards, sub-watershed conditions, water quality and land use, and conclusions. Title: Water Quality in the Long Tom River Watershed 1999-2003 Abstract -- The report contains: introduction, background on the watershed: land use, water use, precipitation, fish and amphibians, study design and methods: training, parameters and sampling frequency, methods, quality assurance and control, results: comparison to state water quality standards, sub-watershed conditions, water quality and land use, and conclusions. Close

• 2. [Article] Little Deschutes Subbasin Watershed Assessment

  Abstract -- Many of the impacts to fish and wildlife habitat and water quality in the Little Deschutes River Subbasin are concentrated in the areas of housing, roads, and other human development. Most ...

  Citation × Citation Citation Abstract Copy Title: Little Deschutes Subbasin Watershed Assessment Abstract -- Many of the impacts to fish and wildlife habitat and water quality in the Little Deschutes River Subbasin are concentrated in the areas of housing, roads, and other human development. Most of the human population in the subbasin is concentrated around the community centers of La Pine, Gilchrist, Crescent, and Crescent Lake. There is significant dispersed development along the lower reaches of the Little Deschutes River between the communities of Sunriver and La Pine -an area characterized by gentle topography and depressions with forested wetlands, marshes and shallow lakes. Streams in this area, as illustrated by the Little Deschutes River , are low gradient and originate in the high elevation areas in the southwest portion of the watershed where there is higher precipitation. This ownership pattern has significant implications for natural resource management, as lower gradient floodplain areas tend to provide important wetland, fish, and wildlife habitat. Key Findings Fuel Loading: Having homes safe from wildfires is a concern for many residents. Fire suppression has increased the amount of dry wood in the area, creating a ready source for major wildfires. Riparian Areas and Wetlands: Loss of wetland and riparian areas , especially in the lower areas along the Little Deschutes River , has affected a number of resources. Water quality has been affected by the reduced wetlands that act as filters of nitrogen; the loss of streamside trees and other vegetation reduces shade that helps to cool water temperatures. Finally, loss ofwetlands and riparian vegetation has reduced important fish and wildlife habitats. Wildlife: The growth and development have altered wildlife habitats. Loss of wetlands, streamside vegetation, and other changes in the watershed have reduced important wildlife habitat. Roads and development have impacted migrating mule deer, increasing collisions between deer and cars and altering their migration pathways. Fish: There has been a significant loss of native trout and an increase in introduced brook and brown trout in the Little Deschutes River and tributaries. Loss of native trout is from competition with introduced species and changes in aquatic habitat and water temperatures. Water Quality: A major concern about the water in the river is unusually high temperatures in the summer and the abnormal growth of algae. Other studies indicated that there are problems with groundwater loading ofnitrogen. The high water table (with associated wetlands), and porous pumice soils contributes to increased nitrates, a by-product of septic systems and an indicator of human pathogens. Title: Little Deschutes Subbasin Watershed Assessment Abstract -- Many of the impacts to fish and wildlife habitat and water quality in the Little Deschutes River Subbasin are concentrated in the areas of housing, roads, and other human development. Most of the human population in the subbasin is concentrated around the community centers of La Pine, Gilchrist, Crescent, and Crescent Lake. There is significant dispersed development along the lower reaches of the Little Deschutes River between the communities of Sunriver and La Pine -an area characterized by gentle topography and depressions with forested wetlands, marshes and shallow lakes. Streams in this area, as illustrated by the Little Deschutes River , are low gradient and originate in the high elevation areas in the southwest portion of the watershed where there is higher precipitation. This ownership pattern has significant implications for natural resource management, as lower gradient floodplain areas tend to provide important wetland, fish, and wildlife habitat. Key Findings Fuel Loading: Having homes safe from wildfires is a concern for many residents. Fire suppression has increased the amount of dry wood in the area, creating a ready source for major wildfires. Riparian Areas and Wetlands: Loss of wetland and riparian areas , especially in the lower areas along the Little Deschutes River , has affected a number of resources. Water quality has been affected by the reduced wetlands that act as filters of nitrogen; the loss of streamside trees and other vegetation reduces shade that helps to cool water temperatures. Finally, loss ofwetlands and riparian vegetation has reduced important fish and wildlife habitats. Wildlife: The growth and development have altered wildlife habitats. Loss of wetlands, streamside vegetation, and other changes in the watershed have reduced important wildlife habitat. Roads and development have impacted migrating mule deer, increasing collisions between deer and cars and altering their migration pathways. Fish: There has been a significant loss of native trout and an increase in introduced brook and brown trout in the Little Deschutes River and tributaries. Loss of native trout is from competition with introduced species and changes in aquatic habitat and water temperatures. Water Quality: A major concern about the water in the river is unusually high temperatures in the summer and the abnormal growth of algae. Other studies indicated that there are problems with groundwater loading ofnitrogen. The high water table (with associated wetlands), and porous pumice soils contributes to increased nitrates, a by-product of septic systems and an indicator of human pathogens. Close

• 3. [Article] The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models

  The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving ...

  Citation × Citation Citation Abstract Copy Title: The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models Author: Mtundu, Nangantani Davies Godfrey Year: 1987 The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture. Title: The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models Author: Mtundu, Nangantani Davies Godfrey Year: 1987 The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture. Close

• 4. [Article] Map-based Probabilistic Infinite Slope Analysis of the Stephens Creek Watershed, Portland, Oregon

  The Stephens Creek Watershed in southwest Portland, Oregon was chosen by the city as a pilot project for urban stream restoration efforts, and the infiltration of stormwater was identified as a potential ...

  Citation × Citation Citation Abstract Copy Title: Map-based Probabilistic Infinite Slope Analysis of the Stephens Creek Watershed, Portland, Oregon Author: Cole, Ryan Andrew Year: 2013 The Stephens Creek Watershed in southwest Portland, Oregon was chosen by the city as a pilot project for urban stream restoration efforts, and the infiltration of stormwater was identified as a potential restoration strategy. The Stephens Creek Watershed has historically been known to be unstable during high precipitation events (Burns, 1996), and the need to address the response of slope stability to anthropogenically-driven changing groundwater conditions is the focus of this study. Airborne light detection and ranging (LiDAR) and geotechnical data from the City of Portland were employed to create a high resolution (0.84 m2) physics-based probabilistic slope stability model for this watershed, using the map-based probabilistic infinite slope analysis program PISA-m (Haneberg, 2007). Best and worst case models were run using fully dry and fully saturated soil conditions, respectively. Model results indicate that 96.3% of the watershed area had a probability [less than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 for fully dry conditions, compared to 76.4% for fully saturated conditions. Areas that had a probability [greater than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 were found to occur mainly along cut/fill slopes as well as within the deeply incised canyons of Stephens Creek and its tributaries. An infiltration avoidance map was derived to define areas that appear to be unsuitable for infiltration. Based on these results, it is recommended that stormwater continues to be directed to existing sewer infrastructure and that the "storm water disconnect" restoration approach not be used by the city. Title: Map-based Probabilistic Infinite Slope Analysis of the Stephens Creek Watershed, Portland, Oregon Author: Cole, Ryan Andrew Year: 2013 The Stephens Creek Watershed in southwest Portland, Oregon was chosen by the city as a pilot project for urban stream restoration efforts, and the infiltration of stormwater was identified as a potential restoration strategy. The Stephens Creek Watershed has historically been known to be unstable during high precipitation events (Burns, 1996), and the need to address the response of slope stability to anthropogenically-driven changing groundwater conditions is the focus of this study. Airborne light detection and ranging (LiDAR) and geotechnical data from the City of Portland were employed to create a high resolution (0.84 m2) physics-based probabilistic slope stability model for this watershed, using the map-based probabilistic infinite slope analysis program PISA-m (Haneberg, 2007). Best and worst case models were run using fully dry and fully saturated soil conditions, respectively. Model results indicate that 96.3% of the watershed area had a probability [less than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 for fully dry conditions, compared to 76.4% for fully saturated conditions. Areas that had a probability [greater than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 were found to occur mainly along cut/fill slopes as well as within the deeply incised canyons of Stephens Creek and its tributaries. An infiltration avoidance map was derived to define areas that appear to be unsuitable for infiltration. Based on these results, it is recommended that stormwater continues to be directed to existing sewer infrastructure and that the "storm water disconnect" restoration approach not be used by the city. Close

• 5. [Article] Determination of toluene's degradation products under simulated atmospheric conditions

  The reactions of aromatic hydrocarbons represent a major area of uncertainty in urban atmospheric photochemistry. Much effort has been spent studying the simulated atmospheric oxidation chemistry of model ...

  Citation × Citation Citation Abstract Copy Title: Determination of toluene's degradation products under simulated atmospheric conditions Author: Dumdei, Bruce E. Year: 1984 The reactions of aromatic hydrocarbons represent a major area of uncertainty in urban atmospheric photochemistry. Much effort has been spent studying the simulated atmospheric oxidation chemistry of model aromatics, such as toluene, in order to delineate their reaction mechanisms. These studies are motivated both by interest in fundamental processes and a desire to discover an aromatic's contribution to the formation of ozone in polluted ambient atmospheres. Previous work on toluene includes both product studies and proposed mechanisms. In all previous studies, the combined product yields are half or less of the initially reacted toluene. A major reason for the poor carbon balances found in these studies in the precipitation of intermediate reaction products from the gas phase to the reaction walls. We have studied the oxidation process by blacklight irradiation of 1-10 ppm each of toluene and oxides of nitrogen in 22-liter pyrex flasks, in zero-air at 50% relative humidity. The products were recovered from the walls by exrtraction with methanol or dichloromethane. Some gas-phase products were recovered in the solvent as well. The extracts were analyzed on a Finnigan MAT triple stage quadrupole mass spectrometer/data system by direct probe injection. Once their molecular weights were determined, the products were fragmented by collision-induced-dissociation (CID) in the middle quadrupole to produce characteristic daughter ions. To assist in the spectral interpretation, toluene in three isomeric forms was subjected to simulated atmospheric reaction. In addition to normal (H8) toluene, methyl-deuterated (D3) and per-deuterated (D8) toluene were used. This study confirmed the existence of a number of products identified in past studies, confirmed the formation of some products which have been hypothesized in several proposed mechanisms for toluene oxidation, identified a number of previously unidentified and unproposed products. Detailed mechanistic steps have been outlined for all reaction products' formation and destruction. Other analytical techniques including GC, GC/MS, and HPLC, have supplemented the MS/MS analysis. These results and the further study of the types of compounds identified should make a significant contribution to the understanding of atmospheric aromatic systems. Title: Determination of toluene's degradation products under simulated atmospheric conditions Author: Dumdei, Bruce E. Year: 1984 The reactions of aromatic hydrocarbons represent a major area of uncertainty in urban atmospheric photochemistry. Much effort has been spent studying the simulated atmospheric oxidation chemistry of model aromatics, such as toluene, in order to delineate their reaction mechanisms. These studies are motivated both by interest in fundamental processes and a desire to discover an aromatic's contribution to the formation of ozone in polluted ambient atmospheres. Previous work on toluene includes both product studies and proposed mechanisms. In all previous studies, the combined product yields are half or less of the initially reacted toluene. A major reason for the poor carbon balances found in these studies in the precipitation of intermediate reaction products from the gas phase to the reaction walls. We have studied the oxidation process by blacklight irradiation of 1-10 ppm each of toluene and oxides of nitrogen in 22-liter pyrex flasks, in zero-air at 50% relative humidity. The products were recovered from the walls by exrtraction with methanol or dichloromethane. Some gas-phase products were recovered in the solvent as well. The extracts were analyzed on a Finnigan MAT triple stage quadrupole mass spectrometer/data system by direct probe injection. Once their molecular weights were determined, the products were fragmented by collision-induced-dissociation (CID) in the middle quadrupole to produce characteristic daughter ions. To assist in the spectral interpretation, toluene in three isomeric forms was subjected to simulated atmospheric reaction. In addition to normal (H8) toluene, methyl-deuterated (D3) and per-deuterated (D8) toluene were used. This study confirmed the existence of a number of products identified in past studies, confirmed the formation of some products which have been hypothesized in several proposed mechanisms for toluene oxidation, identified a number of previously unidentified and unproposed products. Detailed mechanistic steps have been outlined for all reaction products' formation and destruction. Other analytical techniques including GC, GC/MS, and HPLC, have supplemented the MS/MS analysis. These results and the further study of the types of compounds identified should make a significant contribution to the understanding of atmospheric aromatic systems. Close

• 6. [Article] The Development of an Arsenic(V) Selective Electrode

  The object of this research was to develop an arsenic(V) selective electrode. The electrode is based on a solid state membrane prepared by pressing a precipitate of silver arsenate-silver sulfide into ...

  Citation × Citation Citation Abstract Copy Title: The Development of an Arsenic(V) Selective Electrode Author: Kang, Sandra Gee Year: 1974 The object of this research was to develop an arsenic(V) selective electrode. The electrode is based on a solid state membrane prepared by pressing a precipitate of silver arsenate-silver sulfide into a pellet. After the electrode was made, experiments were designed to check for three general characteristics of the electrodes: dependence of potential on pH for constant arsenic(V) concentration; dependence of potential on arsenic(V) concentrations at constant pH and extent of interference due to phosphate and arsenic(III) ions. From these measurements, it was found that Ag2HAs04 was formed originally in the membranes containing a small fraction of arsenic(V) and that this compound was converted to Ag3As04 on the electrode surface in alkaline solutions. Title: The Development of an Arsenic(V) Selective Electrode Author: Kang, Sandra Gee Year: 1974 The object of this research was to develop an arsenic(V) selective electrode. The electrode is based on a solid state membrane prepared by pressing a precipitate of silver arsenate-silver sulfide into a pellet. After the electrode was made, experiments were designed to check for three general characteristics of the electrodes: dependence of potential on pH for constant arsenic(V) concentration; dependence of potential on arsenic(V) concentrations at constant pH and extent of interference due to phosphate and arsenic(III) ions. From these measurements, it was found that Ag2HAs04 was formed originally in the membranes containing a small fraction of arsenic(V) and that this compound was converted to Ag3As04 on the electrode surface in alkaline solutions. Close

• 7. [Article] Assessing Hydrologic and Water Quality Sensitivities to Precipitation Changes, Urban Growth and Land Management Using SWAT

  Precipitation changes and urban growth are two factors altering the state of water quality. Changes in precipitation will alter the amount and timing of flows, and the corresponding sediment and nutrient ...

  Citation × Citation Citation Abstract Copy Title: Assessing Hydrologic and Water Quality Sensitivities to Precipitation Changes, Urban Growth and Land Management Using SWAT Author: Psaris, Alexander Michael Year: 2014 Precipitation changes and urban growth are two factors altering the state of water quality. Changes in precipitation will alter the amount and timing of flows, and the corresponding sediment and nutrient dynamics. Meanwhile, densification associated with urban growth will create more impervious surfaces which will alter sediment and nutrient loadings. Land and water managers often rely on models to develop possible future scenarios and devise management responses to these projected changes. We use the Soil and Water Assessment Tool (SWAT) to assess the sensitivities of stream flow, sediment, and nutrient loads in two urbanizing watersheds in Northwest Oregon, USA to various climate and urbanization scenarios. We evaluate the spatial patterns climate change and urban growth will have on water, sediment and nutrient yields. We also identify critical source areas (CSAs) and investigate how implementation of vegetative filter strips (VFS) could ameliorate the effects of these changes. Our findings suggest that: 1) Water yield is tightly coupled to precipitation. 2) Large increases in winter and spring precipitation provide enough sub-surface storage to increase summertime water yields despite a moderate decrease in summer precipitation. 3) Expansion of urban areas increases surface runoff and has mixed effects on sediment and nutrients. 4) Implementation of VFS reduces pollutant loads helping overall watershed health. This research demonstrates the usefulness of SWAT in facilitating informed land and water management decisions. Title: Assessing Hydrologic and Water Quality Sensitivities to Precipitation Changes, Urban Growth and Land Management Using SWAT Author: Psaris, Alexander Michael Year: 2014 Precipitation changes and urban growth are two factors altering the state of water quality. Changes in precipitation will alter the amount and timing of flows, and the corresponding sediment and nutrient dynamics. Meanwhile, densification associated with urban growth will create more impervious surfaces which will alter sediment and nutrient loadings. Land and water managers often rely on models to develop possible future scenarios and devise management responses to these projected changes. We use the Soil and Water Assessment Tool (SWAT) to assess the sensitivities of stream flow, sediment, and nutrient loads in two urbanizing watersheds in Northwest Oregon, USA to various climate and urbanization scenarios. We evaluate the spatial patterns climate change and urban growth will have on water, sediment and nutrient yields. We also identify critical source areas (CSAs) and investigate how implementation of vegetative filter strips (VFS) could ameliorate the effects of these changes. Our findings suggest that: 1) Water yield is tightly coupled to precipitation. 2) Large increases in winter and spring precipitation provide enough sub-surface storage to increase summertime water yields despite a moderate decrease in summer precipitation. 3) Expansion of urban areas increases surface runoff and has mixed effects on sediment and nutrients. 4) Implementation of VFS reduces pollutant loads helping overall watershed health. This research demonstrates the usefulness of SWAT in facilitating informed land and water management decisions. Close

• 8. [Article] Quaternary Chronology and Stratigraphy of Mickey Springs, Oregon

  Mickey Springs in the Alvord Desert, southeast Oregon, is analogous to other Basin and Range hydrothermal systems where the requisite conditions of heat source and permeable pathways are met through crustal ...

  Citation × Citation Citation Abstract Copy Title: Quaternary Chronology and Stratigraphy of Mickey Springs, Oregon Author: Mowbray, Leslie Allen Year: 2015 Mickey Springs in the Alvord Desert, southeast Oregon, is analogous to other Basin and Range hydrothermal systems where the requisite conditions of heat source and permeable pathways are met through crustal thinning due to normal faulting. This study examines the morphology and lifespan of near-surface spring features through use of ground penetrating radar, thermoluminescence (TL) dating, and elevation modeling. Duration of hydrothermal activity at Mickey Springs has not previously been determined, and age determinations of sinter at the site are conflicting. The reason for and timing of this change in silica saturation in the hydrothermal fluid has not been resolved. Three morphologies of silica sinter deposition have been identified at Mickey Springs. These are (1) well-sorted, fine-grained sandstone with ripple marks, cross beds and preserved root casts, to poorly-sorted conglomerate of primarily basalt clasts, both cemented by coeval silica deposition, (2) large depressions (12-32 m diameter) rimmed with sinter, characterized by fine silt and clay blanketing a sinter apron and infilling the central depression, and (3) quaquaversal sinter mounds identified by outcropping pool-edge sinter typically surrounding a shallow depression of loose sediment. Silica-cemented sandstone and conglomerate were the first features formed by coeval hydrothermal processes at the site, and were emplaced prior to 30 kya as suggested by structural and stratigraphic relationships. Structure between two interacting fault tips may have constrained the extent of silica cementation. By 30 kya, a left-stepping fault oriented roughly north/south further constrained the near-surface permeable zone. TL dates from sediment stratigraphically below and above sinter aprons around mounds and depressions (former spring vents) indicate sinter deposition between 30 and 20 kya. Location of these features was dictated by development of the left-stepping fault. As pluvial Lake Alvord filled at the end of the Pleistocene, lake sediment filled most vents, which were largely inactive, with fine-grained silt and clay. Today, hydrothermal activity persists in two modes: (1) The current high-temperature springs, steam vents and mudpots concentrated in a 50 x 50 m area south of the sinter mounds and depressions, and (2) scattered springs and steam vents that exploit previous permeable pathways that once provided the hydrothermal fluid which precipitated the sinter aprons. Currently there is no active silica sinter deposition at Mickey Springs. Structures and stratigraphic relationships identified through this study favor a transport-limited and structurally controlled model of fluid transport. Sinter deposition is determined to have occurred before the most recent highstand of pluvial Lake Alvord. A climate driven model, where groundwater recharge from pluvial Lake Alvord circulates to a deep heat source and enhances spring discharge, is not supported by these findings, as no evidence was found for sinter precipitation after the drying of the lake. Future studies of other hydrothermal systems in the Basin and Range may reveal that permeable pathways along local structures are the primary drivers in this region. Title: Quaternary Chronology and Stratigraphy of Mickey Springs, Oregon Author: Mowbray, Leslie Allen Year: 2015 Mickey Springs in the Alvord Desert, southeast Oregon, is analogous to other Basin and Range hydrothermal systems where the requisite conditions of heat source and permeable pathways are met through crustal thinning due to normal faulting. This study examines the morphology and lifespan of near-surface spring features through use of ground penetrating radar, thermoluminescence (TL) dating, and elevation modeling. Duration of hydrothermal activity at Mickey Springs has not previously been determined, and age determinations of sinter at the site are conflicting. The reason for and timing of this change in silica saturation in the hydrothermal fluid has not been resolved. Three morphologies of silica sinter deposition have been identified at Mickey Springs. These are (1) well-sorted, fine-grained sandstone with ripple marks, cross beds and preserved root casts, to poorly-sorted conglomerate of primarily basalt clasts, both cemented by coeval silica deposition, (2) large depressions (12-32 m diameter) rimmed with sinter, characterized by fine silt and clay blanketing a sinter apron and infilling the central depression, and (3) quaquaversal sinter mounds identified by outcropping pool-edge sinter typically surrounding a shallow depression of loose sediment. Silica-cemented sandstone and conglomerate were the first features formed by coeval hydrothermal processes at the site, and were emplaced prior to 30 kya as suggested by structural and stratigraphic relationships. Structure between two interacting fault tips may have constrained the extent of silica cementation. By 30 kya, a left-stepping fault oriented roughly north/south further constrained the near-surface permeable zone. TL dates from sediment stratigraphically below and above sinter aprons around mounds and depressions (former spring vents) indicate sinter deposition between 30 and 20 kya. Location of these features was dictated by development of the left-stepping fault. As pluvial Lake Alvord filled at the end of the Pleistocene, lake sediment filled most vents, which were largely inactive, with fine-grained silt and clay. Today, hydrothermal activity persists in two modes: (1) The current high-temperature springs, steam vents and mudpots concentrated in a 50 x 50 m area south of the sinter mounds and depressions, and (2) scattered springs and steam vents that exploit previous permeable pathways that once provided the hydrothermal fluid which precipitated the sinter aprons. Currently there is no active silica sinter deposition at Mickey Springs. Structures and stratigraphic relationships identified through this study favor a transport-limited and structurally controlled model of fluid transport. Sinter deposition is determined to have occurred before the most recent highstand of pluvial Lake Alvord. A climate driven model, where groundwater recharge from pluvial Lake Alvord circulates to a deep heat source and enhances spring discharge, is not supported by these findings, as no evidence was found for sinter precipitation after the drying of the lake. Future studies of other hydrothermal systems in the Basin and Range may reveal that permeable pathways along local structures are the primary drivers in this region. Close

• 9. [Article] The Biology of Eastern Kingbirds at Malheur National Wildlife Refuge: Survival, Reproduction, and Testosterone Secretion

  This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern ...

  Citation × Citation Citation Abstract Copy Title: The Biology of Eastern Kingbirds at Malheur National Wildlife Refuge: Survival, Reproduction, and Testosterone Secretion Author: Redmond, Lucas J. Year: 2015 This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern Oregon from 2003 to 2009. Kingbirds are long-distance migratory songbirds that breed across much of North America. This species is socially monogamous but, via frequent extra-pair copulations, is genetically polygamous. Kingbirds exhibit relatively high breeding site fidelity, often returning to the same tree to nest in subsequent years. Both members of a pair provide parental care, but there are often specific duties performed by both male and female kingbirds. For example, males typically perform much of the vigilant nest defense that this species is well known for and contribute, to an extent, to the feeding of nestlings. Females, on the other hand, are entirely responsible for incubating and brooding. Beginning in 2002, most adults within the population of kingbirds at Malheur had been banded with a unique combination of three colored plastic leg bands and an aluminum USFWS band. Also, as many nests were located in each year as possible, and any young that survived to fledging age were banded with a unique combination of leg bands. Considerable effort was then spent each year to locate as many banded individuals as possible, which allowed me to document adult and juvenile survival. Annual survival rates of adult male and female kingbirds in the population at Malheur did not differ and were relatively high at approximately 0.65. Juvenile survival rate was approximately 0.29, indicating that slightly less than one-third of nestlings survive the interval between fledging and their first potential breeding season. Resighting probability was high for both sexes, although higher for adult males (0.94) than for adult female (0.84). The latter finding is consistent with the higher site fidelity of males than of females. Resighting probabilities for juveniles were much lower at 0.68 and 0.40 for males and females, respectively. Again, this was expected because natal site fidelity is typically much lower than breeding site fidelity. Compared to most other reports, resighting probability and return rates of juvenile kingbirds was high, presumably because the riparian habitats where kingbirds breed at Malheur function as an ecological island surrounded by, for kingbirds, unsuitable high desert habitat. Thus, unless they disperse very long distances, the only option for juvenile kingbirds is to begin nesting on the refuge. The collection of blood samples from birds has become an increasingly common practice in ornithology. The data that can be gained from these samples allow a number of interesting questions to be asked such as understanding the genetic mating system of a species, patterns of hormone secretion, and discerning migratory pathways via stable isotope analysis. The volume of blood collected is usually small and was assumed to cause no long-term negative effects on sampled individuals. However, few studies have rigorously examined the effect of blood sampling on survival. I used a multistate mark-recapture analysis to assess the effect blood sampling on annual survival of kingbirds by combining the annual survival data described above with whether or not individuals were subjected to blood sample collection. The results of this analysis indicated that blood sampling had no effect on annual survival rates of kingbirds. Whether or not this is the case for other species remains to be seen. However, my results support the assumption that when done correctly, blood sampling has little to no long-term negative effects on birds. Comparative analyses of many bird species show that testosterone secretion exhibits fairly predictable patterns among breeding birds of different mating systems. Monogamous species reach a peak during mate attraction and the period of female fertility which is then followed by a sharp decline when young are in the nest. By contrast, males of polygynous species tend to maintain higher levels of testosterone throughout the breeding season to, presumably, maximize opportunities for acquiring additional mates. Kingbirds are socially monogamous but cryptically polygamous. However, because of high rates of extra-pair paternity, variation in reproductive success among males is much higher than what is expected for a monogamous species, and, instead, is similar to what has been reported for polygynous species. Therefore from 2005 to 2009 I measured testosterone concentrations from the blood samples collected from male kingbirds to determine the breeding season profile of testosterone secretion in kingbirds and to understand the factors that influence testosterone variation among individuals. Contrary to expected for a monogamous species, the testosterone profile of kingbirds did not exhibit the brief peak in testosterone followed by a precipitous decline. Testosterone peaked early in the season, but declined very slowly as the nest cycle progressed. I attributed this gradual decline in testosterone to the cryptically polygynous nature of the kingbird extra-pair mating system. I also found substantial variation in testosterone concentration among male kingbirds and was able to identify several factors contributing to this variation. As expected, testosterone declined as the breeding season progressed (independent of stage in nest cycle) and nest density increased, while increases in testosterone were correlated with the number of fertile females within the population. This suggests that male kingbirds were capable of modulating testosterone concentrations to both cope with an increase in conspecific density, but also to ready themselves for times when extra-pair copulations were more likely. Title: The Biology of Eastern Kingbirds at Malheur National Wildlife Refuge: Survival, Reproduction, and Testosterone Secretion Author: Redmond, Lucas J. Year: 2015 This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern Oregon from 2003 to 2009. Kingbirds are long-distance migratory songbirds that breed across much of North America. This species is socially monogamous but, via frequent extra-pair copulations, is genetically polygamous. Kingbirds exhibit relatively high breeding site fidelity, often returning to the same tree to nest in subsequent years. Both members of a pair provide parental care, but there are often specific duties performed by both male and female kingbirds. For example, males typically perform much of the vigilant nest defense that this species is well known for and contribute, to an extent, to the feeding of nestlings. Females, on the other hand, are entirely responsible for incubating and brooding. Beginning in 2002, most adults within the population of kingbirds at Malheur had been banded with a unique combination of three colored plastic leg bands and an aluminum USFWS band. Also, as many nests were located in each year as possible, and any young that survived to fledging age were banded with a unique combination of leg bands. Considerable effort was then spent each year to locate as many banded individuals as possible, which allowed me to document adult and juvenile survival. Annual survival rates of adult male and female kingbirds in the population at Malheur did not differ and were relatively high at approximately 0.65. Juvenile survival rate was approximately 0.29, indicating that slightly less than one-third of nestlings survive the interval between fledging and their first potential breeding season. Resighting probability was high for both sexes, although higher for adult males (0.94) than for adult female (0.84). The latter finding is consistent with the higher site fidelity of males than of females. Resighting probabilities for juveniles were much lower at 0.68 and 0.40 for males and females, respectively. Again, this was expected because natal site fidelity is typically much lower than breeding site fidelity. Compared to most other reports, resighting probability and return rates of juvenile kingbirds was high, presumably because the riparian habitats where kingbirds breed at Malheur function as an ecological island surrounded by, for kingbirds, unsuitable high desert habitat. Thus, unless they disperse very long distances, the only option for juvenile kingbirds is to begin nesting on the refuge. The collection of blood samples from birds has become an increasingly common practice in ornithology. The data that can be gained from these samples allow a number of interesting questions to be asked such as understanding the genetic mating system of a species, patterns of hormone secretion, and discerning migratory pathways via stable isotope analysis. The volume of blood collected is usually small and was assumed to cause no long-term negative effects on sampled individuals. However, few studies have rigorously examined the effect of blood sampling on survival. I used a multistate mark-recapture analysis to assess the effect blood sampling on annual survival of kingbirds by combining the annual survival data described above with whether or not individuals were subjected to blood sample collection. The results of this analysis indicated that blood sampling had no effect on annual survival rates of kingbirds. Whether or not this is the case for other species remains to be seen. However, my results support the assumption that when done correctly, blood sampling has little to no long-term negative effects on birds. Comparative analyses of many bird species show that testosterone secretion exhibits fairly predictable patterns among breeding birds of different mating systems. Monogamous species reach a peak during mate attraction and the period of female fertility which is then followed by a sharp decline when young are in the nest. By contrast, males of polygynous species tend to maintain higher levels of testosterone throughout the breeding season to, presumably, maximize opportunities for acquiring additional mates. Kingbirds are socially monogamous but cryptically polygamous. However, because of high rates of extra-pair paternity, variation in reproductive success among males is much higher than what is expected for a monogamous species, and, instead, is similar to what has been reported for polygynous species. Therefore from 2005 to 2009 I measured testosterone concentrations from the blood samples collected from male kingbirds to determine the breeding season profile of testosterone secretion in kingbirds and to understand the factors that influence testosterone variation among individuals. Contrary to expected for a monogamous species, the testosterone profile of kingbirds did not exhibit the brief peak in testosterone followed by a precipitous decline. Testosterone peaked early in the season, but declined very slowly as the nest cycle progressed. I attributed this gradual decline in testosterone to the cryptically polygynous nature of the kingbird extra-pair mating system. I also found substantial variation in testosterone concentration among male kingbirds and was able to identify several factors contributing to this variation. As expected, testosterone declined as the breeding season progressed (independent of stage in nest cycle) and nest density increased, while increases in testosterone were correlated with the number of fertile females within the population. This suggests that male kingbirds were capable of modulating testosterone concentrations to both cope with an increase in conspecific density, but also to ready themselves for times when extra-pair copulations were more likely. Close

• 10. [Article] Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota

  Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow ...

  Citation × Citation Citation Abstract Copy Title: Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota Author: Harden, Tessa M. Year: 2012 Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow rates substantially larger than those gaged historically. Flood-frequency analyses for the study reaches account for 29 paleofloods inferred from interpretation of stratigraphic records locally extending back 1,000 to almost 2,000 years. The addition of paleoflood data to the gaged and historical data significantly reduced uncertainties related to flood-frequency. For all study reaches the 95-percent confidence intervals about the low-probability quantile estimates (100-, 200-, and 500-year recurrence-intervals) were reduced by at least 78 percent relative to those for the gaged records only. In some cases, 95-percent uncertainty intervals were reduced by 99 percent or more. Additionally, a stratigraphic record of 35 large paleofloods and four large historical floods during the last 2,000 years (including several floods not used in the frequency analyses due to age constraints) reveal four flooding episodes at A.D.: 130-40, 640-670, 900-1290, and 1410 to present. During the Medieval Climate Anomaly (~A.D. 900-1300) the Black Hills experienced 13 large floods compared to nine large floods in the previous 800 years. This high concentration of large flooding events were likely caused by: 1) instability of air masses caused by stronger than normal westerlies; 2) larger or more frequent hurricanes in the Gulf of Mexico and Atlantic Ocean; and/or 3) reduced land covering vegetation and an increase in forest fires caused by the severe drought. By examining the response of streamflow to the MCA, it seems likely that if severe long-term drought conditions persist for the Black Hills region, an increase in the frequency and magnitude of large floods can be expected. The Black Hills paleofloods represent some of the largest known floods, relative to drainage area, for the United States. Many of the other largest known United States floods are in areas with physiographic and climatologic conditions broadly similar to the Black Hills--semi-arid and rugged landscapes that intercept and focus heavy precipitation from convective storm systems. Title: Late-Holocene Flood History, Flood-Frequency, and Paleoclimate Analysis of the Central Black Hills, South Dakota Author: Harden, Tessa M. Year: 2012 Stratigraphic records in four basins in the central Black Hills in combination with hydraulic calculations show that all basins have experienced multiple large floods in the last 2,000 years with flow rates substantially larger than those gaged historically. Flood-frequency analyses for the study reaches account for 29 paleofloods inferred from interpretation of stratigraphic records locally extending back 1,000 to almost 2,000 years. The addition of paleoflood data to the gaged and historical data significantly reduced uncertainties related to flood-frequency. For all study reaches the 95-percent confidence intervals about the low-probability quantile estimates (100-, 200-, and 500-year recurrence-intervals) were reduced by at least 78 percent relative to those for the gaged records only. In some cases, 95-percent uncertainty intervals were reduced by 99 percent or more. Additionally, a stratigraphic record of 35 large paleofloods and four large historical floods during the last 2,000 years (including several floods not used in the frequency analyses due to age constraints) reveal four flooding episodes at A.D.: 130-40, 640-670, 900-1290, and 1410 to present. During the Medieval Climate Anomaly (~A.D. 900-1300) the Black Hills experienced 13 large floods compared to nine large floods in the previous 800 years. This high concentration of large flooding events were likely caused by: 1) instability of air masses caused by stronger than normal westerlies; 2) larger or more frequent hurricanes in the Gulf of Mexico and Atlantic Ocean; and/or 3) reduced land covering vegetation and an increase in forest fires caused by the severe drought. By examining the response of streamflow to the MCA, it seems likely that if severe long-term drought conditions persist for the Black Hills region, an increase in the frequency and magnitude of large floods can be expected. The Black Hills paleofloods represent some of the largest known floods, relative to drainage area, for the United States. Many of the other largest known United States floods are in areas with physiographic and climatologic conditions broadly similar to the Black Hills--semi-arid and rugged landscapes that intercept and focus heavy precipitation from convective storm systems. Close