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• 82081. [Image] Recreational use and carrying capacity for the Klamath River

  	ABSTRACT These reports document recreation use and estimate carrying capacities for the Klamath River in northern California. The river section studied runs from Interstate 5 near Yreka to the town of ...
  	Citation × Citation Citation Abstract Copy Title: Recreational use and carrying capacity for the Klamath River Author: Shelby, Bo Year: 1984, 2005 ABSTRACT These reports document recreation use and estimate carrying capacities for the Klamath River in northern California. The river section studied runs from Interstate 5 near Yreka to the town of Orleans, and includes the lower sections of the Scott and Salmon River tributaries. A major highway runs along the river throughout the study area, with numerous; access points. The study covers the summer river running season and the fall salmon/ steel head fishing season. Because of the differences in time periods and activities, the study was done in two separate parts, each with a separate report. This document combines the two. The summer season report is presented first, followed by the fall season report. Each of these is preceeded by its own table of contents, list of tables, and summary of findings, and each is followed by its own appendices. The reports are separated by a colored page for easy reference. Data were collected by sampling, observation, and counting as well as a user questionnaire. Th? study presents a detailed description of river sections and documents recreational use by location and activity type. Carrying capacities are estimated for both river running and fishing activities. Estimates include discussions of ecological, facility, physical, and social carrying capacities, distinguishing descriptive and evaluative components. Limiting factors vary, depending on the activity and location. The more developed setting and the variety of activities and capacities distinguishes this project from earlier river capacity studies. Title: Recreational use and carrying capacity for the Klamath River Author: Shelby, Bo Year: 1984, 2005 ABSTRACT These reports document recreation use and estimate carrying capacities for the Klamath River in northern California. The river section studied runs from Interstate 5 near Yreka to the town of Orleans, and includes the lower sections of the Scott and Salmon River tributaries. A major highway runs along the river throughout the study area, with numerous; access points. The study covers the summer river running season and the fall salmon/ steel head fishing season. Because of the differences in time periods and activities, the study was done in two separate parts, each with a separate report. This document combines the two. The summer season report is presented first, followed by the fall season report. Each of these is preceeded by its own table of contents, list of tables, and summary of findings, and each is followed by its own appendices. The reports are separated by a colored page for easy reference. Data were collected by sampling, observation, and counting as well as a user questionnaire. Th? study presents a detailed description of river sections and documents recreational use by location and activity type. Carrying capacities are estimated for both river running and fishing activities. Estimates include discussions of ecological, facility, physical, and social carrying capacities, distinguishing descriptive and evaluative components. Limiting factors vary, depending on the activity and location. The more developed setting and the variety of activities and capacities distinguishes this project from earlier river capacity studies. Close

• 82082. [Image] The Chemical and biological impact of Klamath Marsh on the Williamson River, Oregon

  	A comparative study of the Williamson River (before and after passage through Klamath Marsh) and the Sprague River (which is a major tributary of the Williamson River) in South Central Oregon has provided ...
  	Citation × Citation Citation Abstract Copy Title: The Chemical and biological impact of Klamath Marsh on the Williamson River, Oregon Author: Perdue, Edward M. Year: 1981, 2005 A comparative study of the Williamson River (before and after passage through Klamath Marsh) and the Sprague River (which is a major tributary of the Williamson River) in South Central Oregon has provided substantial insight into the effects of a marsh environment on the transport of iron and aquatic humus in river water. In the Sprague River and in the pre-marsh Williamson River, iron is transported primarily as 0.80 ym suspended particulate material. In Klamath Marsh, this coarse particulate material is "weathered11, yielding iron-aquatic humus "complexes'1. Thus, most iron and aquatic humus in the post-marsh Williamson River are in the 0.025 ?m size fraction. Presumably, other trace metals would be similarly affected. Klamath Marsh serves as an important source of biologically derived solutes such as amino acids and sugars. Fractionation studies have shown that amino acids are almost exclusively humic-bound in the Will-iamson River system, while sugars may be present as either polysacchar-ides (PS) or humic-bound saccharides (HS). The PS/HS ratio may reflect the relative importance of autochthonous and allochthonous sources of sugars. Major solute composition strongly indicates that ground waters flowing into the pre-marsh Williamson River and the Sprague River are derived from a different source than are ground waters which enter the post-marsh Williamson River from Big Springs, Spring Creek, and from unidentified springs below Klamath Marsh. Nutrient concentrations (H4SiO4, NO3, PO43) are significantly higher in spring waters than elsewhere in the system. While nitrate levels (3-11 ?m) were somewhat low, phosphate levels (1-3 ?m) were quite high throughout the Williamson River system. There was some evidence for nitrogen limitation of algal growth in the pre-marsh Williamson River. While Fragilaria construens was dominant throughout the Williamson River system, several Navicula spp. were restricted to the pre-marsh Williamson River and several Fragilaria spp. and Nitzschia, spp. were found only in the post-marsh Williamson River. In Upper Klamath Lake, Stephanodiscus astrea minuta, Fragilaria construens, and Aphanizomenon flos-aquae appeared in succession, with nuisance blooms of the latter organism occurring July-November. The cessation of flow of humic-rich water from Klamath Marsh during the summer months drastically decreased the flux of aquatic humus, iron, amino acids, and other marsh-derived solutes in the post-marsh Williamson River. At the time of cessation of flow from Klamath Marsh, nuisance blooms of Aphanizomenon flos-aquae appeared in Upper Klamath Lake. Furthermore, when flow from the marsh was re-established with the first major winter rains in November or December, Aphanizomenon flos-aquae abruptly ceased to grow in Upper Klamath Lake. Further studies are planned to determine whether this correlation is causal or coincidental. Title: The Chemical and biological impact of Klamath Marsh on the Williamson River, Oregon Author: Perdue, Edward M. Year: 1981, 2005 A comparative study of the Williamson River (before and after passage through Klamath Marsh) and the Sprague River (which is a major tributary of the Williamson River) in South Central Oregon has provided substantial insight into the effects of a marsh environment on the transport of iron and aquatic humus in river water. In the Sprague River and in the pre-marsh Williamson River, iron is transported primarily as 0.80 ym suspended particulate material. In Klamath Marsh, this coarse particulate material is "weathered11, yielding iron-aquatic humus "complexes'1. Thus, most iron and aquatic humus in the post-marsh Williamson River are in the 0.025 ?m size fraction. Presumably, other trace metals would be similarly affected. Klamath Marsh serves as an important source of biologically derived solutes such as amino acids and sugars. Fractionation studies have shown that amino acids are almost exclusively humic-bound in the Will-iamson River system, while sugars may be present as either polysacchar-ides (PS) or humic-bound saccharides (HS). The PS/HS ratio may reflect the relative importance of autochthonous and allochthonous sources of sugars. Major solute composition strongly indicates that ground waters flowing into the pre-marsh Williamson River and the Sprague River are derived from a different source than are ground waters which enter the post-marsh Williamson River from Big Springs, Spring Creek, and from unidentified springs below Klamath Marsh. Nutrient concentrations (H4SiO4, NO3, PO43) are significantly higher in spring waters than elsewhere in the system. While nitrate levels (3-11 ?m) were somewhat low, phosphate levels (1-3 ?m) were quite high throughout the Williamson River system. There was some evidence for nitrogen limitation of algal growth in the pre-marsh Williamson River. While Fragilaria construens was dominant throughout the Williamson River system, several Navicula spp. were restricted to the pre-marsh Williamson River and several Fragilaria spp. and Nitzschia, spp. were found only in the post-marsh Williamson River. In Upper Klamath Lake, Stephanodiscus astrea minuta, Fragilaria construens, and Aphanizomenon flos-aquae appeared in succession, with nuisance blooms of the latter organism occurring July-November. The cessation of flow of humic-rich water from Klamath Marsh during the summer months drastically decreased the flux of aquatic humus, iron, amino acids, and other marsh-derived solutes in the post-marsh Williamson River. At the time of cessation of flow from Klamath Marsh, nuisance blooms of Aphanizomenon flos-aquae appeared in Upper Klamath Lake. Furthermore, when flow from the marsh was re-established with the first major winter rains in November or December, Aphanizomenon flos-aquae abruptly ceased to grow in Upper Klamath Lake. Further studies are planned to determine whether this correlation is causal or coincidental. Close

• 82083. [Image] Klamath River Basin Conservation Area Restoration Program: limited assurance regarding the federal funding requirements: report to congressional requesters

  	Includes bibliographical references; "GAO-05-804"
  	Citation × Citation Citation Abstract Copy Title: Klamath River Basin Conservation Area Restoration Program: limited assurance regarding the federal funding requirements: report to congressional requesters Author: United States. Government Accountability Office Year: 2005, 2006 Includes bibliographical references; "GAO-05-804" Title: Klamath River Basin Conservation Area Restoration Program: limited assurance regarding the federal funding requirements: report to congressional requesters Author: United States. Government Accountability Office Year: 2005, 2006 Includes bibliographical references; "GAO-05-804" Close

• 82084. [Image] Federal Register - Endangered and Threatened Wildlife and Plants; Determination of Endangered Status of the Shortnose Sucker and the Lost River Sucker

  	The Service determines endangered status for the shortnose sucker [Chasmistes brevirostris) and Lost River sucker [Deltistes luxatus), fishes restricted to the Klamath Basin of south-central Oregon and ...
  	Citation × Citation Citation Abstract Copy Title: Federal Register - Endangered and Threatened Wildlife and Plants; Determination of Endangered Status of the Shortnose Sucker and the Lost River Sucker Author: Williams, Jack E. Year: 1988, 2008, 2005 The Service determines endangered status for the shortnose sucker [Chasmistes brevirostris) and Lost River sucker [Deltistes luxatus), fishes restricted to the Klamath Basin of south-central Oregon and north-central California. Dams, draining of marshes, diversion of rivers and dredging of lakes have reduced the range and numbers of both species by more than 95 percent. Remaining populations are composed of older individuals with little or no successful recruitment for many years. Both species are jeopardized by continued loss of habitat, hybridization with more common closely related species, competition and predation by exotic species, and insularization of remaining habitats. This rule implements the protection provided by the Endangered Species Act of 1973, as amended, for the shortnose sucker and Lost River sucker Title: Federal Register - Endangered and Threatened Wildlife and Plants; Determination of Endangered Status of the Shortnose Sucker and the Lost River Sucker Author: Williams, Jack E. Year: 1988, 2008, 2005 The Service determines endangered status for the shortnose sucker [Chasmistes brevirostris) and Lost River sucker [Deltistes luxatus), fishes restricted to the Klamath Basin of south-central Oregon and north-central California. Dams, draining of marshes, diversion of rivers and dredging of lakes have reduced the range and numbers of both species by more than 95 percent. Remaining populations are composed of older individuals with little or no successful recruitment for many years. Both species are jeopardized by continued loss of habitat, hybridization with more common closely related species, competition and predation by exotic species, and insularization of remaining habitats. This rule implements the protection provided by the Endangered Species Act of 1973, as amended, for the shortnose sucker and Lost River sucker Close

• 82085. [Image] Land use and vegetation community changes at Beswick Ranch, Klamath River Canyon, California from 1955 to 2003 : focus on relationship between the irrigation and the vegetation and the land use cover

  	Humans have altered the Klamath River Canyon in many ways. This study focuses on the years from 1955 to 2003. One substantial alteration is the conversion of terraces into irrigated pastures for agriculture ...
  	Citation × Citation Citation Abstract Copy Title: Land use and vegetation community changes at Beswick Ranch, Klamath River Canyon, California from 1955 to 2003 : focus on relationship between the irrigation and the vegetation and the land use cover Author: Bilka, Monika N. Year: 2002, 2005 Humans have altered the Klamath River Canyon in many ways. This study focuses on the years from 1955 to 2003. One substantial alteration is the conversion of terraces into irrigated pastures for agriculture and cattle ranching. This research project explains the relationships between the irrigation network and the vegetation and land use cover patterns that existed in the past and that exist today at Beswick Ranch. Data sources such as aerial photographs, maps, and other historical information are used to create Geographic Information System (GIS) maps and models of the area. Due to time constraints, the final maps and models are not complete at this time. However, the completed models were synthesized with observational data to come to preliminary conclusions. While the ditches of Shovel Creek Pasture have undergone little to no change at all since 1955, ranchers have added ditches to Faye Pasture. Ranch workers have also increased the amount of agricultural land use cover and decreased in tree cover of Faye Pasture. Conversely, ranchers increased the tree cover and non-agricultural land cover, and they have decreased the agricultural cover. The GIS coverages of Shovel Pasture remain in the preliminary stage, and further analyses of the calculated areas of land use cover and ditch lengths are needed to complete this study. In partnership with PacifiCorp and the BLM, this project aims to provide information about the impacts of the current and historical irrigation systems used on the pastures and riparian zones within this reach of the Klamath River Canyon from 1955 to 2003. Even at this stage, the preliminary coverages provide insight into the relationships between irrigation, vegetation communities, and land use cover that have occurred during the study period. Title: Land use and vegetation community changes at Beswick Ranch, Klamath River Canyon, California from 1955 to 2003 : focus on relationship between the irrigation and the vegetation and the land use cover Author: Bilka, Monika N. Year: 2002, 2005 Humans have altered the Klamath River Canyon in many ways. This study focuses on the years from 1955 to 2003. One substantial alteration is the conversion of terraces into irrigated pastures for agriculture and cattle ranching. This research project explains the relationships between the irrigation network and the vegetation and land use cover patterns that existed in the past and that exist today at Beswick Ranch. Data sources such as aerial photographs, maps, and other historical information are used to create Geographic Information System (GIS) maps and models of the area. Due to time constraints, the final maps and models are not complete at this time. However, the completed models were synthesized with observational data to come to preliminary conclusions. While the ditches of Shovel Creek Pasture have undergone little to no change at all since 1955, ranchers have added ditches to Faye Pasture. Ranch workers have also increased the amount of agricultural land use cover and decreased in tree cover of Faye Pasture. Conversely, ranchers increased the tree cover and non-agricultural land cover, and they have decreased the agricultural cover. The GIS coverages of Shovel Pasture remain in the preliminary stage, and further analyses of the calculated areas of land use cover and ditch lengths are needed to complete this study. In partnership with PacifiCorp and the BLM, this project aims to provide information about the impacts of the current and historical irrigation systems used on the pastures and riparian zones within this reach of the Klamath River Canyon from 1955 to 2003. Even at this stage, the preliminary coverages provide insight into the relationships between irrigation, vegetation communities, and land use cover that have occurred during the study period. Close

• 82086. [Image] Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon

  	We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin ...
  	Citation × Citation Citation Abstract Copy Title: Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon Author: Perkins, David L.; Scoppettone, Gary; Buettner, Mark Year: 2000, 2005 We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin of Oregon and California, from 1984-1997. Lost River suckers had distinct river and lake shoreline spawning stocks, and individuals of both species commonly spawned in consecutive years. In the Williamson River and lower Sprague River, spawning migration by both species occurred mainly during a 5-week period that started within the first three weeks of April and peaked between mid April and early May, although a separate, earlier (mid March) run of Lost River suckers may also spawn in the upper Sprague River. Migration of both species was several times higher at dawn (0500-0730 h) and evening (1800-2200 h) than other times of the day. Peak migrations almost always corresponded to peaks in water temperature, usually at 10-15°C. Lost River suckers were captured at springs along the east shore of the lake from late February through mid May, with peak spawning usually in mid March to mid April. Shortnose suckers were generally captured at the springs from late March through late May, but the time of peak spawning was not determined. Size and age at maturity was determined by recruitment from a strong year class (1991). Male Lost River suckers began recruitment into the adult population at age 4+ (375-475 mm). Substantial recruitment of females did not begin until age 7+ (510-560 mm). Male and female shortnose suckers began recruitment at age 4+, with the majority offish recruited by age 5+. Males recruited at 270-370 mm; females recruited at 325-425 mm. Fecundity estimates were quite variable ranging from 44,000-236,000 eggs per female Lost River sucker and 18,000-72,000 eggs per female shortnose sucker. In 1984 and 1985, the spawning populations of both species were dominated by large, old individuals, with little indication of recent adult recruitment. In the next 13 years, only one strong year class (1991) recruited into the spawning populations of both species. This year class temporarily boosted population numbers, but annual fish kills from 1995 to 1997 eliminated most adults of both species. Associated with poor water quality caused by the proliferation and decay of blue-green algae Aphanizomenonflos-aquae, these fish kills raise concern that alterations to the lake ecosystem over the past several decades have Perkins et al. Lost River and shortnose suckers 5 increased the magnitude and frequency of poor water quality. As a result, mortality rates of all life stages may have increased, thereby disrupting the species' life history pattern and potentially decreasing long-term population viability. Introduction The Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris are large, long-lived suckers endemic to the upper Klamath Basin of Oregon and California. Both species are typically lake dwelling but migrate to tributaries or shoreline springs to spawn (Moyle 1976, Scoppettone and Vinyard 1991). Once extremely abundant (Cope 1884, Gilbert 1898), both species have experienced severe population declines and were federally listed as endangered in 1988 (USFWS 1988). Much of the original habitat of these suckers has been destroyed or altered by conversion of lake areas to agriculture, dams, instream flow diversions, and water quality problems associated with timber harvest, loss of riparian vegetation, livestock grazing, and agricultural practices (USFWS 1988). Knowledge of the life history of Lost River and shortnose suckers is fundamental to recovery of these species. The objective of this report was to present the results of studies conducted from 1987-1998 on the reproductive biology and demographics of Lost River and shortnose suckers, and to compare these results with earlier unpublished data. Study Sites Studies were conducted on Upper Klamath Lake and the lower Williamson-Sprague river system (Figure 1). These waters form the upper portion of the Klamath River Basin in south-central Oregon and represent most remaining native habitat of Lost River and shortnose suckers. Upper Klamath Lake is a remnant of pluvial Lake Modoc that included eight major basins and encompassed 2,839 km2 (Dicken 1980). Today, Upper Klamath Lake serves as a storage reservoir that provides water for agricultural irrigation, waterfowl refuges, instream flow requirements of anadromous fish, and hydroelectric power generation. At full capacity, the lake covers approximately 360 km2 and has an average depth of 2.4 m. Most deeper water (3-12 m) is restricted to narrow trenches along the western shore. Lake elevation is controlled at the outlet by Link River Title: Reproductive biology and demographics of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon Author: Perkins, David L.; Scoppettone, Gary; Buettner, Mark Year: 2000, 2005 We analyzed the reproductive biology and demographics of the Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris, two endangered species endemic to the upper Klamath Basin of Oregon and California, from 1984-1997. Lost River suckers had distinct river and lake shoreline spawning stocks, and individuals of both species commonly spawned in consecutive years. In the Williamson River and lower Sprague River, spawning migration by both species occurred mainly during a 5-week period that started within the first three weeks of April and peaked between mid April and early May, although a separate, earlier (mid March) run of Lost River suckers may also spawn in the upper Sprague River. Migration of both species was several times higher at dawn (0500-0730 h) and evening (1800-2200 h) than other times of the day. Peak migrations almost always corresponded to peaks in water temperature, usually at 10-15°C. Lost River suckers were captured at springs along the east shore of the lake from late February through mid May, with peak spawning usually in mid March to mid April. Shortnose suckers were generally captured at the springs from late March through late May, but the time of peak spawning was not determined. Size and age at maturity was determined by recruitment from a strong year class (1991). Male Lost River suckers began recruitment into the adult population at age 4+ (375-475 mm). Substantial recruitment of females did not begin until age 7+ (510-560 mm). Male and female shortnose suckers began recruitment at age 4+, with the majority offish recruited by age 5+. Males recruited at 270-370 mm; females recruited at 325-425 mm. Fecundity estimates were quite variable ranging from 44,000-236,000 eggs per female Lost River sucker and 18,000-72,000 eggs per female shortnose sucker. In 1984 and 1985, the spawning populations of both species were dominated by large, old individuals, with little indication of recent adult recruitment. In the next 13 years, only one strong year class (1991) recruited into the spawning populations of both species. This year class temporarily boosted population numbers, but annual fish kills from 1995 to 1997 eliminated most adults of both species. Associated with poor water quality caused by the proliferation and decay of blue-green algae Aphanizomenonflos-aquae, these fish kills raise concern that alterations to the lake ecosystem over the past several decades have Perkins et al. Lost River and shortnose suckers 5 increased the magnitude and frequency of poor water quality. As a result, mortality rates of all life stages may have increased, thereby disrupting the species' life history pattern and potentially decreasing long-term population viability. Introduction The Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris are large, long-lived suckers endemic to the upper Klamath Basin of Oregon and California. Both species are typically lake dwelling but migrate to tributaries or shoreline springs to spawn (Moyle 1976, Scoppettone and Vinyard 1991). Once extremely abundant (Cope 1884, Gilbert 1898), both species have experienced severe population declines and were federally listed as endangered in 1988 (USFWS 1988). Much of the original habitat of these suckers has been destroyed or altered by conversion of lake areas to agriculture, dams, instream flow diversions, and water quality problems associated with timber harvest, loss of riparian vegetation, livestock grazing, and agricultural practices (USFWS 1988). Knowledge of the life history of Lost River and shortnose suckers is fundamental to recovery of these species. The objective of this report was to present the results of studies conducted from 1987-1998 on the reproductive biology and demographics of Lost River and shortnose suckers, and to compare these results with earlier unpublished data. Study Sites Studies were conducted on Upper Klamath Lake and the lower Williamson-Sprague river system (Figure 1). These waters form the upper portion of the Klamath River Basin in south-central Oregon and represent most remaining native habitat of Lost River and shortnose suckers. Upper Klamath Lake is a remnant of pluvial Lake Modoc that included eight major basins and encompassed 2,839 km2 (Dicken 1980). Today, Upper Klamath Lake serves as a storage reservoir that provides water for agricultural irrigation, waterfowl refuges, instream flow requirements of anadromous fish, and hydroelectric power generation. At full capacity, the lake covers approximately 360 km2 and has an average depth of 2.4 m. Most deeper water (3-12 m) is restricted to narrow trenches along the western shore. Lake elevation is controlled at the outlet by Link River Close

• 82087. [Image] Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency Lakes, Oregon

  	Two maps digitized separately; Includes bibliographical references (p. 44-49)
  	Citation × Citation Citation Abstract Copy Title: Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency Lakes, Oregon Author: Snyder, Daniel T. Year: 1997, 2005, 2004 Two maps digitized separately; Includes bibliographical references (p. 44-49) Title: Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency Lakes, Oregon Author: Snyder, Daniel T. Year: 1997, 2005, 2004 Two maps digitized separately; Includes bibliographical references (p. 44-49) Close

• 82088. [Image] Klamath River fish die-off, September 2002 : causative factors of mortality

  	Executive Summary This report provides information describing the biological, hydrological, meteorological, and water quality conditions associated with the die-off of an estimated 34,056 fish in the Klamath ...
  	Citation × Citation Citation Abstract Copy Title: Klamath River fish die-off, September 2002 : causative factors of mortality Author: Guillen, George Year: 2003, 2005, 2004 Executive Summary This report provides information describing the biological, hydrological, meteorological, and water quality conditions associated with the die-off of an estimated 34,056 fish in the Klamath River, California in September 2002. The proximate cause of death was heavy infections of two fish pathogens, Ich and columnaris. However, given that these ubiquitous pathogens are normally found in the Klamath River, additional factors must have played a role for them to have become lethal. It is our conclusion based on multiple lines of evidence that the fish die-off in the lower Klamath River in 2002 was a result of a combination of factors that began with an early peak in the return of a large run of fall Chinook salmon. Low river discharges apparently did not provide suitable attraction flows for migrating adult salmon, resulting in large numbers of fish congregating in the warm waters of the lower River. The high density offish, low discharges, warm water temperatures, and possible extended residence time of salmon created optimal conditions for parasite proliferation and precipitated an epizootic of Ich and columnaris. Based on a review of available literature and historical records, this was the largest known pre-spawning adult salmonid die-off recorded for the Klamath River and possibly the Pacific coast. Title: Klamath River fish die-off, September 2002 : causative factors of mortality Author: Guillen, George Year: 2003, 2005, 2004 Executive Summary This report provides information describing the biological, hydrological, meteorological, and water quality conditions associated with the die-off of an estimated 34,056 fish in the Klamath River, California in September 2002. The proximate cause of death was heavy infections of two fish pathogens, Ich and columnaris. However, given that these ubiquitous pathogens are normally found in the Klamath River, additional factors must have played a role for them to have become lethal. It is our conclusion based on multiple lines of evidence that the fish die-off in the lower Klamath River in 2002 was a result of a combination of factors that began with an early peak in the return of a large run of fall Chinook salmon. Low river discharges apparently did not provide suitable attraction flows for migrating adult salmon, resulting in large numbers of fish congregating in the warm waters of the lower River. The high density offish, low discharges, warm water temperatures, and possible extended residence time of salmon created optimal conditions for parasite proliferation and precipitated an epizootic of Ich and columnaris. Based on a review of available literature and historical records, this was the largest known pre-spawning adult salmonid die-off recorded for the Klamath River and possibly the Pacific coast. Close

• 82089. [Image] An assessment of ecosystem components in the interior Columbia Basin and portions of the Klamath and Great Basins [volume 2]

  	Abstract Quigley, Thomas M.; Arbelbide, Sylvia J., tech. eds. 1997. An assessment of ecosystem components in the interior Columbia basin and portions of the Klamath and Great Basins: volume 2. Gen. Tech. ...
  	Citation × Citation Citation Abstract Copy Title: An assessment of ecosystem components in the interior Columbia Basin and portions of the Klamath and Great Basins [volume 2] Author: Quigley, Thomas Milton; Arbelbide, S. J. (Sylvia J.) Year: 1997, 2008, 2005 Abstract Quigley, Thomas M.; Arbelbide, Sylvia J., tech. eds. 1997. An assessment of ecosystem components in the interior Columbia basin and portions of the Klamath and Great Basins: volume 2. Gen. Tech. Rep. PNW-GTR-405. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 4 vol. (Quigley, Thomas M., tech. ed.; The Interior Columbia Basin Ecosystem Management Project: Scientific Assessment). The Assessment of Ecosystem Components in the Interior Columbia Basin and Portions of the Klamath and Great Basins provides detailed information about current conditions and trends for the biophysical and social systems within the Basin. This information can be used by land managers to develop broad land management goals and priorities and provides the context for decisions specific to smaller geographic areas. The Assessment area covers about 8 percent of the U.S. land area, 24 percent of the Nations National Forest System lands, 10 percent of the Nations BLM-administered lands, and contains about 1.2 percent of the Nations population. This results in a population density that is less than one-sixth of the U.S. average. The area has experienced recent, rapid population growth and generally has a robust, diverse economy. As compared to historic conditions, the terrestrial, aquatic, forest, and rangeland systems have undergone dramatic changes. Forested landscapes are more susceptible to fire, insect, and disease than under historic conditions. Rangelands are highly susceptible to noxious weed invasion. The disturbance regimes that operate on forest and rangeland have changed substantially, with lethal fires dominating many areas where non-lethal fires were the norm historically. Terrestrial habitats that have experienced the greatest decline include the native grassland, native shrubland, and old forest structures. There are areas within the Assessment area that have higher diversity than others. Aquatic systems are now more fragmented and isolated than historically and the introduction of non-native fish species has complicated current status of native fishes. Core habitat and population centers do remain as building blocks for restoration. Social and economic conditions within the Assessment area vary considerably, depending to a great extent on population, diversity of employment opportunities, and changing demographics. Those counties with the higher population densities and greater diversity of employment opportunities are generally more resilient to economic downturns. This Assessment provides a rich information base, including over 170 mapped themes with associated models and databases, from which future decisions can benefit. Keywords: Columbia basin, biophysical systems, social systems, ecosystem. Title: An assessment of ecosystem components in the interior Columbia Basin and portions of the Klamath and Great Basins [volume 2] Author: Quigley, Thomas Milton; Arbelbide, S. J. (Sylvia J.) Year: 1997, 2008, 2005 Abstract Quigley, Thomas M.; Arbelbide, Sylvia J., tech. eds. 1997. An assessment of ecosystem components in the interior Columbia basin and portions of the Klamath and Great Basins: volume 2. Gen. Tech. Rep. PNW-GTR-405. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 4 vol. (Quigley, Thomas M., tech. ed.; The Interior Columbia Basin Ecosystem Management Project: Scientific Assessment). The Assessment of Ecosystem Components in the Interior Columbia Basin and Portions of the Klamath and Great Basins provides detailed information about current conditions and trends for the biophysical and social systems within the Basin. This information can be used by land managers to develop broad land management goals and priorities and provides the context for decisions specific to smaller geographic areas. The Assessment area covers about 8 percent of the U.S. land area, 24 percent of the Nations National Forest System lands, 10 percent of the Nations BLM-administered lands, and contains about 1.2 percent of the Nations population. This results in a population density that is less than one-sixth of the U.S. average. The area has experienced recent, rapid population growth and generally has a robust, diverse economy. As compared to historic conditions, the terrestrial, aquatic, forest, and rangeland systems have undergone dramatic changes. Forested landscapes are more susceptible to fire, insect, and disease than under historic conditions. Rangelands are highly susceptible to noxious weed invasion. The disturbance regimes that operate on forest and rangeland have changed substantially, with lethal fires dominating many areas where non-lethal fires were the norm historically. Terrestrial habitats that have experienced the greatest decline include the native grassland, native shrubland, and old forest structures. There are areas within the Assessment area that have higher diversity than others. Aquatic systems are now more fragmented and isolated than historically and the introduction of non-native fish species has complicated current status of native fishes. Core habitat and population centers do remain as building blocks for restoration. Social and economic conditions within the Assessment area vary considerably, depending to a great extent on population, diversity of employment opportunities, and changing demographics. Those counties with the higher population densities and greater diversity of employment opportunities are generally more resilient to economic downturns. This Assessment provides a rich information base, including over 170 mapped themes with associated models and databases, from which future decisions can benefit. Keywords: Columbia basin, biophysical systems, social systems, ecosystem. Close

• 82090. [Image] Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001

  	Abstract Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. ...
  	Citation × Citation Citation Abstract Copy Title: Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001 Author: Fisher, Lawrence H. Year: 2004, 2005 Abstract Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Areal release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resus-pension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus was slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 |ig/L/day (micrograms per liter per day) at pH 8, and 0.9 |ug/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance and observed in total phosphorus data collected at individual locations. Title: Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001 Author: Fisher, Lawrence H. Year: 2004, 2005 Abstract Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Areal release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resus-pension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus was slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 |ig/L/day (micrograms per liter per day) at pH 8, and 0.9 |ug/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance and observed in total phosphorus data collected at individual locations. Close