David W Clow (Former Employee)
Science and Products
Filter Total Items: 67
Spatial patterns of atmospheric deposition of nitrogen and sulfur using ion-exchange resin collectors in Rocky Mountain National Park, USA
Lakes and streams in Class 1 wilderness areas in the western United States (U.S.) are at risk from atmospheric deposition of nitrogen (N) and sulfur (S), and protection of these resources is mandated under the Federal Clean Air Act and amendments. Assessment of critical loads, which are the maximum exposure to pollution an area can receive without adverse effects on sensitive ecosystems, requires
Authors
David W. Clow, Heidi Roop, Leora Nanus, Mark Fenn, Graham A. Sexstone
2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park
In 2004, multiple agencies including the Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (U.S. EPA) met to address the effects and trends of nitrogen deposition and related air quality issues at Rocky Mountain National Park (RMNP). These agencies signed a Memorandum of Understanding (MOU) to facilitate inte
Authors
Kristi Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill Baron, Curt Taipale, Tamara Blett, David A. Gay, Daniel Bowker
Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range
Long-term patterns of stream nitrate export and atmospheric N deposition were evaluated over three decades in Loch Vale, a high-elevation watershed in the Colorado Front Range. Stream nitrate concentrations increased in the early 1990s, peaked in the mid-2000s, and have since declined by over 40%, coincident with trends in nitrogen oxide emissions over the past decade. Similarities in the timing a
Authors
M. Alisa Mast, David W. Clow, Jill Baron, Gregory A. Wetherbee
Hydrological effects of forest transpiration loss in bark beetle-impacted watersheds
The recent climate-exacerbated mountain pine beetle infestation in the Rocky Mountains of North America has resulted in tree death that is unprecedented in recorded history. The spatial and temporal heterogeneity inherent in insect infestation creates a complex and often unpredictable watershed response, influencing the primary storage and flow components of the hydrologic cycle. Despite the incre
Authors
Lindsay A. Bearup, Reed M. Maxwell, David W. Clow, John E. McCray
Effects of stock use and backpackers on water quality in wilderness in Sequoia and Kings Canyon National Parks, USA
During 2010-2011, a study was conducted in Sequoia and Kings Canyon National Parks (SEKI) to evaluate the influence of pack animals (stock) and backpackers on water quality in wilderness lakes and streams. The study had three main components: (1) a synoptic survey of water quality in wilderness areas of the parks, (2) paired water-quality sampling above and below several areas with differing type
Authors
David W. Clow, Harrison Forrester, Benjamin Miller, Heidi Roop, James O. Sickman, Hodon Ryu, Jorge Santo Domingo
Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response
A current pine beetle infestation has caused extensive mortality of lodgepole pine (Pinus contorta) in forests of Colorado and Wyoming; it is part of an unprecedented multispecies beetle outbreak extending from Mexico to Canada. In United States and European watersheds, where atmospheric deposition of inorganic N is moderate to low (<10 kg⋅ha⋅y), disturbance of forests by timber harvest or violent
Authors
Charles C. Rhoades, James H. Jr McCutchan, Leigh A. Cooper, David W. Clow, Thomas M. Detmer, Jennifer S. Briggs, John D. Stednick, Thomas T. Veblen, Rachel M. Ertz, Gene E. Likens, William M. Jr Lewis
2010 Monitoring and Tracking Wet Nitrogen Deposition at Rocky Mountain National Park
No abstract available.
Authors
Kristi H. Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill S. Baron, Curt Taipale, David Gay, Eric Richer
Evaluation of SNODAS snow depth and snow water equivalent estimates for the Colorado Rocky Mountains, USA
The National Weather Service's Snow Data Assimilation (SNODAS) program provides daily, gridded estimates of snow depth, snow water equivalent (SWE), and related snow parameters at a 1-km2 resolution for the conterminous USA. In this study, SNODAS snow depth and SWE estimates were compared with independent, ground-based snow survey data in the Colorado Rocky Mountains to assess SNODAS accuracy at t
Authors
David W. Clow, Leora Nanus, Kristine L. Verdin, Jeffrey Schmidt
Hydrologic, water-quality, and biological characteristics of the North Fork Flathead River, Montana, water years 2007-2008
In water year 2007, the U.S. Geological Survey, in cooperation with the National Park Service, began a 2-year study to collect hydrologic, water-quality, and biological data to provide a baseline characterization of the North Fork Flathead River from the United States-Canada border to its confluence with the Middle Fork of the Flathead River near Columbia Falls, Montana. Although mining in the Can
Authors
Taylor J. Mills, E. William Schweiger, M. Alisa Mast, David W. Clow
Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA
Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (3 kg N ha−1 yr−1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha−1 yr−1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin c
Authors
Leora Nanus, David W. Clow, Jasmine E. Saros, Verlin C. Stephens, Donald H. Campbell
Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado
Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985–2008. Sulfate concentrations in precipitation decreased at a rate of −0.15 to −0.55 μeq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during
Authors
M. Alisa Mast, John T. Turk, David W. Clow, Donald D. Campbell
Assessing possible visitor-use impacts on water quality in Yosemite National Park, California
There is concern that visitor-use associated activities, such as bathing, dish washing, wastewater production, and stock animal use near lakes and streams, could cause degradation of water quality in Yosemite National Park. A study was conducted during 2004–2007 to assess patterns in nutrient and Escherichia coli (E. coli) concentrations in the Merced and Tuolumne Rivers and characterize natural b
Authors
David W. Clow, Rachael S. Peavler, Jim Roche, Anna K. Panorska, James M. Thomas, Steve Smith
Science and Products
Filter Total Items: 67
Spatial patterns of atmospheric deposition of nitrogen and sulfur using ion-exchange resin collectors in Rocky Mountain National Park, USA
Lakes and streams in Class 1 wilderness areas in the western United States (U.S.) are at risk from atmospheric deposition of nitrogen (N) and sulfur (S), and protection of these resources is mandated under the Federal Clean Air Act and amendments. Assessment of critical loads, which are the maximum exposure to pollution an area can receive without adverse effects on sensitive ecosystems, requires
Authors
David W. Clow, Heidi Roop, Leora Nanus, Mark Fenn, Graham A. Sexstone
2013 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park
In 2004, multiple agencies including the Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (U.S. EPA) met to address the effects and trends of nitrogen deposition and related air quality issues at Rocky Mountain National Park (RMNP). These agencies signed a Memorandum of Understanding (MOU) to facilitate inte
Authors
Kristi Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill Baron, Curt Taipale, Tamara Blett, David A. Gay, Daniel Bowker
Links between N deposition and nitrate export from a high-elevation watershed in the Colorado Front Range
Long-term patterns of stream nitrate export and atmospheric N deposition were evaluated over three decades in Loch Vale, a high-elevation watershed in the Colorado Front Range. Stream nitrate concentrations increased in the early 1990s, peaked in the mid-2000s, and have since declined by over 40%, coincident with trends in nitrogen oxide emissions over the past decade. Similarities in the timing a
Authors
M. Alisa Mast, David W. Clow, Jill Baron, Gregory A. Wetherbee
Hydrological effects of forest transpiration loss in bark beetle-impacted watersheds
The recent climate-exacerbated mountain pine beetle infestation in the Rocky Mountains of North America has resulted in tree death that is unprecedented in recorded history. The spatial and temporal heterogeneity inherent in insect infestation creates a complex and often unpredictable watershed response, influencing the primary storage and flow components of the hydrologic cycle. Despite the incre
Authors
Lindsay A. Bearup, Reed M. Maxwell, David W. Clow, John E. McCray
Effects of stock use and backpackers on water quality in wilderness in Sequoia and Kings Canyon National Parks, USA
During 2010-2011, a study was conducted in Sequoia and Kings Canyon National Parks (SEKI) to evaluate the influence of pack animals (stock) and backpackers on water quality in wilderness lakes and streams. The study had three main components: (1) a synoptic survey of water quality in wilderness areas of the parks, (2) paired water-quality sampling above and below several areas with differing type
Authors
David W. Clow, Harrison Forrester, Benjamin Miller, Heidi Roop, James O. Sickman, Hodon Ryu, Jorge Santo Domingo
Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response
A current pine beetle infestation has caused extensive mortality of lodgepole pine (Pinus contorta) in forests of Colorado and Wyoming; it is part of an unprecedented multispecies beetle outbreak extending from Mexico to Canada. In United States and European watersheds, where atmospheric deposition of inorganic N is moderate to low (<10 kg⋅ha⋅y), disturbance of forests by timber harvest or violent
Authors
Charles C. Rhoades, James H. Jr McCutchan, Leigh A. Cooper, David W. Clow, Thomas M. Detmer, Jennifer S. Briggs, John D. Stednick, Thomas T. Veblen, Rachel M. Ertz, Gene E. Likens, William M. Jr Lewis
2010 Monitoring and Tracking Wet Nitrogen Deposition at Rocky Mountain National Park
No abstract available.
Authors
Kristi H. Morris, M. Alisa Mast, David W. Clow, Gregory A. Wetherbee, Jill S. Baron, Curt Taipale, David Gay, Eric Richer
Evaluation of SNODAS snow depth and snow water equivalent estimates for the Colorado Rocky Mountains, USA
The National Weather Service's Snow Data Assimilation (SNODAS) program provides daily, gridded estimates of snow depth, snow water equivalent (SWE), and related snow parameters at a 1-km2 resolution for the conterminous USA. In this study, SNODAS snow depth and SWE estimates were compared with independent, ground-based snow survey data in the Colorado Rocky Mountains to assess SNODAS accuracy at t
Authors
David W. Clow, Leora Nanus, Kristine L. Verdin, Jeffrey Schmidt
Hydrologic, water-quality, and biological characteristics of the North Fork Flathead River, Montana, water years 2007-2008
In water year 2007, the U.S. Geological Survey, in cooperation with the National Park Service, began a 2-year study to collect hydrologic, water-quality, and biological data to provide a baseline characterization of the North Fork Flathead River from the United States-Canada border to its confluence with the Middle Fork of the Flathead River near Columbia Falls, Montana. Although mining in the Can
Authors
Taylor J. Mills, E. William Schweiger, M. Alisa Mast, David W. Clow
Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA
Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (3 kg N ha−1 yr−1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha−1 yr−1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin c
Authors
Leora Nanus, David W. Clow, Jasmine E. Saros, Verlin C. Stephens, Donald H. Campbell
Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado
Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985–2008. Sulfate concentrations in precipitation decreased at a rate of −0.15 to −0.55 μeq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during
Authors
M. Alisa Mast, John T. Turk, David W. Clow, Donald D. Campbell
Assessing possible visitor-use impacts on water quality in Yosemite National Park, California
There is concern that visitor-use associated activities, such as bathing, dish washing, wastewater production, and stock animal use near lakes and streams, could cause degradation of water quality in Yosemite National Park. A study was conducted during 2004–2007 to assess patterns in nutrient and Escherichia coli (E. coli) concentrations in the Merced and Tuolumne Rivers and characterize natural b
Authors
David W. Clow, Rachael S. Peavler, Jim Roche, Anna K. Panorska, James M. Thomas, Steve Smith