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• 1. [Article] 2005 Diamond Lake Submersed Aquatic Vegetation Survey

  Diamond Lake is a large natural lake having a surface area of some 3214 acres (1300.7 hectares) and a maximum depth of 52 feet (15.8 meters). It is located within the Umpqua National Forest in the Southern ...

  Citation × Citation Citation Abstract Copy Title: 2005 Diamond Lake Submersed Aquatic Vegetation Survey Author: Sytsma, Mark D., Pfauth, Mary Year: 2006 Diamond Lake is a large natural lake having a surface area of some 3214 acres (1300.7 hectares) and a maximum depth of 52 feet (15.8 meters). It is located within the Umpqua National Forest in the Southern Cascade Mountains of Oregon, at an elevation of over 5000 feet (>1524 meters). Diamond Lake is a high-use waterbody that supports angling, public campgrounds, recreational boating, swimming, and water skiing. The human activity associated with the lake has been a significant contributor to the economy of southern Oregon since the early part of the twentieth century. Historically Diamond Lake was fishless but since 1910 the lake has been managed as a popular trophy trout fishery. The unauthorized introduction of the tui chub (Gila bicolor) into the lake in the 1930s caused disruption of the food web and a decline in the fishery. In 1954, the Oregon Game Commission constructed a canal near the Lake Creek outlet, lowered the lake level, and treated Diamond Lake with rotenone, to eradicate tui chub. The lake was restocked with trout following the successful rotenone treatment and a fishery was maintained for several decades. In 1992, tui chub were reintroduced, through accidental introduction or intentional illegal stocking, and again caused a decline in the trout fishery. Originally mesotrophic, Diamond Lake Diamond Lake productivity increased over the last century to a eutrophic state, and is currently included on the Oregon Department of Environmental Quality (ODEQ) 303(d) list of water quality limited water bodies for pH and algae. The lake had severe blooms of the cyanobacteria (blue-green algae) Anabaena flos-aquae, which produce neurotoxins, in the summers of 2001, 2002, and 2003. Microcystis aeruginosa, another toxin producing cyanobacterium species, was also present in the 2003 bloom. Diamond Lake was closed to some public uses (wading, swimming, water skiing, and boating) during portions of all three summers due to public health and safety concerns. Algae blooms and declining trout fishery have been attributed to alteration of the food web by the tui chubs. The chubs spawn early and consume the zooplankton in the lake, which reduces grazing pressure on phytoplankton. Since the lake is nitrogen limited, nitrogen-fixing cyanobacteria dominate the phytoplankton community. Therefore, the chubs reduce the quality of the trout fishery by reducing food available for trout and impact water quality by facilitating cyanobacteria blooms, which can be toxic. In response to the impact of the tui chub on Diamond Lake the US Forest Service and Oregon Department of Fish and Wildlife are collaborating in a tui chub eradication effort. The eradication plan includes a 2.4-m (8 ft) drawdown of the lake in the winter and spring of 2006 and a rotenone treatment of remaining lake volume in 2006 to kill any remaining fish. The US Forest Service prepared an EIS for the drawdown and rotenone treatment. Potential impacts of the drawdown on littoral aquatic plant communities were identified in the EIS. The US Forest Service conducted a qualitative survey to develop a species list for the lake. The survey described here provides a quantitative, pretreatment measure of cover and biomass of aquatic plants in Diamond Lake. Follow-up sampling, using similar methods, will permit assessment of changes in the plant community following drawdown and refilling of the lake. Title: 2005 Diamond Lake Submersed Aquatic Vegetation Survey Author: Sytsma, Mark D., Pfauth, Mary Year: 2006 Diamond Lake is a large natural lake having a surface area of some 3214 acres (1300.7 hectares) and a maximum depth of 52 feet (15.8 meters). It is located within the Umpqua National Forest in the Southern Cascade Mountains of Oregon, at an elevation of over 5000 feet (>1524 meters). Diamond Lake is a high-use waterbody that supports angling, public campgrounds, recreational boating, swimming, and water skiing. The human activity associated with the lake has been a significant contributor to the economy of southern Oregon since the early part of the twentieth century. Historically Diamond Lake was fishless but since 1910 the lake has been managed as a popular trophy trout fishery. The unauthorized introduction of the tui chub (Gila bicolor) into the lake in the 1930s caused disruption of the food web and a decline in the fishery. In 1954, the Oregon Game Commission constructed a canal near the Lake Creek outlet, lowered the lake level, and treated Diamond Lake with rotenone, to eradicate tui chub. The lake was restocked with trout following the successful rotenone treatment and a fishery was maintained for several decades. In 1992, tui chub were reintroduced, through accidental introduction or intentional illegal stocking, and again caused a decline in the trout fishery. Originally mesotrophic, Diamond Lake Diamond Lake productivity increased over the last century to a eutrophic state, and is currently included on the Oregon Department of Environmental Quality (ODEQ) 303(d) list of water quality limited water bodies for pH and algae. The lake had severe blooms of the cyanobacteria (blue-green algae) Anabaena flos-aquae, which produce neurotoxins, in the summers of 2001, 2002, and 2003. Microcystis aeruginosa, another toxin producing cyanobacterium species, was also present in the 2003 bloom. Diamond Lake was closed to some public uses (wading, swimming, water skiing, and boating) during portions of all three summers due to public health and safety concerns. Algae blooms and declining trout fishery have been attributed to alteration of the food web by the tui chubs. The chubs spawn early and consume the zooplankton in the lake, which reduces grazing pressure on phytoplankton. Since the lake is nitrogen limited, nitrogen-fixing cyanobacteria dominate the phytoplankton community. Therefore, the chubs reduce the quality of the trout fishery by reducing food available for trout and impact water quality by facilitating cyanobacteria blooms, which can be toxic. In response to the impact of the tui chub on Diamond Lake the US Forest Service and Oregon Department of Fish and Wildlife are collaborating in a tui chub eradication effort. The eradication plan includes a 2.4-m (8 ft) drawdown of the lake in the winter and spring of 2006 and a rotenone treatment of remaining lake volume in 2006 to kill any remaining fish. The US Forest Service prepared an EIS for the drawdown and rotenone treatment. Potential impacts of the drawdown on littoral aquatic plant communities were identified in the EIS. The US Forest Service conducted a qualitative survey to develop a species list for the lake. The survey described here provides a quantitative, pretreatment measure of cover and biomass of aquatic plants in Diamond Lake. Follow-up sampling, using similar methods, will permit assessment of changes in the plant community following drawdown and refilling of the lake. Close

• 2. [Article] Final Report: Evaluation of the Morphoedaphic Index and Sediment Diatoms for Inference of Pre-European Settlement Total Phosphorus Concentration in EPA Region 10 Lakes

  Water quality in many Northwest lakes has declined over the past century due, in part, to increased anthropogenic nutrient loading (Edmonson and Lehman, 1981). Under the Clean Water Act, resource managers ...

  Citation × Citation Citation Abstract Copy Title: Final Report: Evaluation of the Morphoedaphic Index and Sediment Diatoms for Inference of Pre-European Settlement Total Phosphorus Concentration in EPA Region 10 Lakes Author: Miller, Rich, Hook, Aaron, Petersen, Richard, Sytsma, Mark D. Year: 2005 Water quality in many Northwest lakes has declined over the past century due, in part, to increased anthropogenic nutrient loading (Edmonson and Lehman, 1981). Under the Clean Water Act, resource managers such as the Washington Department of Ecology, Oregon Department of Environmental Quality, and tribes are responsible for restoring and protecting the integrity of these waters. Targets for restoration or criteria for impairment are not well defined, however, and may naturally vary by geology, hydrology, morphometry, and climate. One way to determine whether lakes are impaired and to identify restoration targets is to assess lake reference conditions (EPA 2000). Reference conditions are the water quality conditions that would exist in the absence of anthropogenic perturbation. Reference conditions are not nutrient criteria but can be useful in establishing realistic criteria that reflect natural regional variations in water quality. The EPA suggests three general approaches for assessing reference conditions (EPA 2000): Observation of reference lake or entire lake population distributions Paleolimnological reconstruction of past conditions. Estimation of past conditions from mass balance nutrient loading models, morphoedaphic index models, or other mathematical models. The lake population distribution approach involves observing data from either a set of lakes that are relatively unimpacted or from a random selection of all lakes in a region. The lower percentile of each population distribution is assumed to represent reference conditions. The lower 75th percentile of the relatively unimpacted population distribution has been used as a cutoff for reference conditions while the 25th percentile has been used for the lake population distribution as a whole. The Washington Department of Ecology has used this approach to develop phosphorus criteria (Moore and Hicks 2004). This approach assumes that the percentiles in a distribution represent reference conditions. Paleolimnological models are based on the observation that sediments continually incorporate information from the overlying water column and that sediment cores provide a history of past conditions. Sedimented diatom-based water quality reconstructions are based on two main observations (Hall and Smol 1992): (1) individual diatom species have restricted nutrient requirements and are sensitive indicators of lake trophic status, and (2) the cell walls of diatoms are abundant and well preserved in most lake sediments and can usually be identified to a specific or subspecific level. Weighted-averaging and calibration statistical models have been used to relate sediment surface diatom assemblages to contemporary water quality parameters. These speciesenvironment relationships, known as transfer functions, can then be used to infer past water quality conditions from diatom remains preserved deep in sediments. This approach has been successfully applied in several geographic regions including the northeastern United States (Dixit et al. 1999), Minnesota (Ramstack et al. 2003), and British Columbia (Reavie et al. 1995). The morphoedaphic index (MEI) was originally developed to predict fisheries yield in lakes based on lake morphometry and alkalinity or conductivity (Ryder 1965). Vighi and Chiaudani (1985) suggested the utility of the index for inferring natural background phosphorus levels in lakes. Their major assumption was that human activities have not altered lake morphometry and ionic strength to the degree that the same activities have increased nutrient loading. While the model is simple, it has been successfully used in to infer background phosphorus concentration in Midwest lakes (Ramstack et al. 2003). We used the MEI and the sedimented diatom total phosphorus inference models to assess lake reference conditions for Puget Lowlands and Northern Willamette Valley Ecoregion Lakes. Title: Final Report: Evaluation of the Morphoedaphic Index and Sediment Diatoms for Inference of Pre-European Settlement Total Phosphorus Concentration in EPA Region 10 Lakes Author: Miller, Rich, Hook, Aaron, Petersen, Richard, Sytsma, Mark D. Year: 2005 Water quality in many Northwest lakes has declined over the past century due, in part, to increased anthropogenic nutrient loading (Edmonson and Lehman, 1981). Under the Clean Water Act, resource managers such as the Washington Department of Ecology, Oregon Department of Environmental Quality, and tribes are responsible for restoring and protecting the integrity of these waters. Targets for restoration or criteria for impairment are not well defined, however, and may naturally vary by geology, hydrology, morphometry, and climate. One way to determine whether lakes are impaired and to identify restoration targets is to assess lake reference conditions (EPA 2000). Reference conditions are the water quality conditions that would exist in the absence of anthropogenic perturbation. Reference conditions are not nutrient criteria but can be useful in establishing realistic criteria that reflect natural regional variations in water quality. The EPA suggests three general approaches for assessing reference conditions (EPA 2000): Observation of reference lake or entire lake population distributions Paleolimnological reconstruction of past conditions. Estimation of past conditions from mass balance nutrient loading models, morphoedaphic index models, or other mathematical models. The lake population distribution approach involves observing data from either a set of lakes that are relatively unimpacted or from a random selection of all lakes in a region. The lower percentile of each population distribution is assumed to represent reference conditions. The lower 75th percentile of the relatively unimpacted population distribution has been used as a cutoff for reference conditions while the 25th percentile has been used for the lake population distribution as a whole. The Washington Department of Ecology has used this approach to develop phosphorus criteria (Moore and Hicks 2004). This approach assumes that the percentiles in a distribution represent reference conditions. Paleolimnological models are based on the observation that sediments continually incorporate information from the overlying water column and that sediment cores provide a history of past conditions. Sedimented diatom-based water quality reconstructions are based on two main observations (Hall and Smol 1992): (1) individual diatom species have restricted nutrient requirements and are sensitive indicators of lake trophic status, and (2) the cell walls of diatoms are abundant and well preserved in most lake sediments and can usually be identified to a specific or subspecific level. Weighted-averaging and calibration statistical models have been used to relate sediment surface diatom assemblages to contemporary water quality parameters. These speciesenvironment relationships, known as transfer functions, can then be used to infer past water quality conditions from diatom remains preserved deep in sediments. This approach has been successfully applied in several geographic regions including the northeastern United States (Dixit et al. 1999), Minnesota (Ramstack et al. 2003), and British Columbia (Reavie et al. 1995). The morphoedaphic index (MEI) was originally developed to predict fisheries yield in lakes based on lake morphometry and alkalinity or conductivity (Ryder 1965). Vighi and Chiaudani (1985) suggested the utility of the index for inferring natural background phosphorus levels in lakes. Their major assumption was that human activities have not altered lake morphometry and ionic strength to the degree that the same activities have increased nutrient loading. While the model is simple, it has been successfully used in to infer background phosphorus concentration in Midwest lakes (Ramstack et al. 2003). We used the MEI and the sedimented diatom total phosphorus inference models to assess lake reference conditions for Puget Lowlands and Northern Willamette Valley Ecoregion Lakes. Close