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M. Alisa Mast

Alisa is an hydrologist for the Colorado Water Science Center

Science and Products

link
View of the Dolores River, Paradox Valley, CO

Paradox Valley Total Dissolved Solids (TDS) Regression Equations

The primary objective of the project is to evaluate and update previous regression equations, developed for the USGS streamgages and continuous water-quality records, that describe the relation between specific conductance measured in the Dolores River and calculated total dissolved solids TDS. A secondary objective is to evaluate brine discharge to the river using a previously developed...
By
Colorado Water Science Center
link

Paradox Valley Total Dissolved Solids (TDS) Regression Equations

The primary objective of the project is to evaluate and update previous regression equations, developed for the USGS streamgages and continuous water-quality records, that describe the relation between specific conductance measured in the Dolores River and calculated total dissolved solids TDS. A secondary objective is to evaluate brine discharge to the river using a previously developed...
Learn More
link
Study site locations, major drainages, and areas underlain by Mancos Shale in the lower Uncompahgre River Basin

Selenium Mobilization from Shales

Selenium (Se) and salinity (total dissolved solids) are water-quality concerns in much of the arid western US where agricultural and urban irrigation overlie Cretaceous-age shale. Leaching of Se and salinity from shale can degrade water quality and negatively affect aquatic biota in receiving water bodies. Since 1985 programs In the upper Colorado River Basin have worked to reduce Se and salinity...
By
Colorado Water Science Center
link

Selenium Mobilization from Shales

Selenium (Se) and salinity (total dissolved solids) are water-quality concerns in much of the arid western US where agricultural and urban irrigation overlie Cretaceous-age shale. Leaching of Se and salinity from shale can degrade water quality and negatively affect aquatic biota in receiving water bodies. Since 1985 programs In the upper Colorado River Basin have worked to reduce Se and salinity...
Learn More
link
USGS scientist recording data near alpine waterway

Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed

Loch Vale is an alpine/subalpine watershed in Rocky Mountain National Park where the U.S. Geological Survey has been conducting research since the 1980s. Our research has focused on the effects of climate change and atmospheric pollutants on water, soil, vegetation, and aquatic life. The alpine/subalpine ecosystem in Loch Vale is sensitive to changes in climate and air pollution. Our long-term...
By
Colorado Water Science Center
link

Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed

Loch Vale is an alpine/subalpine watershed in Rocky Mountain National Park where the U.S. Geological Survey has been conducting research since the 1980s. Our research has focused on the effects of climate change and atmospheric pollutants on water, soil, vegetation, and aquatic life. The alpine/subalpine ecosystem in Loch Vale is sensitive to changes in climate and air pollution. Our long-term...
Learn More
link
View of three USGS Visual Identity items

Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States

The Hydrologic Benchmark Network (HBN) was established in 1963 to provide long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities.
By
Colorado Water Science Center
link

Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States

The Hydrologic Benchmark Network (HBN) was established in 1963 to provide long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities.
Learn More

MODFLOW-6 model of variable-density groundwater flow and brine discharge to the Dolores River in the Paradox Valley, Colorado

MODFLOW-6 with the Groundwater Flow (GWF) and Groundwater Transport (GWT) models was used to simulate the geohydrology of the aquifer system of the Paradox Valley in western Colorado. Salinity of the Colorado River is a major concern in both the United States and the Republic of Mexico. The Colorado River and its tributaries supply water for about 40 million people and irrigation of about 5.5 mill
By
Colorado Water Science Center

GIS data and scripts for Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS)

This data release includes GIS datasets supporting the Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS), a web mapping application available at https://geonarrative.usgs.gov/colmlwades/. Water chemistry data were compiled from the U.S. Geological Survey (USGS) National Water Information System (NWIS), U.S. Environmental Protection Agency (EPA) STORET database, and the USGS
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Passive seismic (HVSR) data from Fountain Creek, CO

A total of 119 passive seismic soundings were collected with Tromino (MoHo s.r.l.) 3-axis seismometers in the Fountain Creek area to partially refine alluvial aquifer thickness (depth to bedrock) estimates, particularly over known or suspected paleochannels. Data were collected during June 21-24, 2021 with a team of 4-5 people, each equipped with a Tromino Blu or Tromino 3G passive seismometer.
By
New York Water Science Center

Geospatial datasets developed for a hydrogeologic conceptual model of brine discharge to the Dolores River, Paradox Valley, Colorado

Geospatial datasets were developed to estimate the altitude of the top of bedrock, altitude of the top of the Paradox salt, altitude of the water table in the alluvial aquifer, and the thickness and extent of saturated alluvium in the Paradox Valley in western Colorado. This study was completed by the U.S. Geological Survey (USGS) in cooperation with the Bureau of Reclamation for modeling of brine
By
Colorado Water Science Center

Water quality and discharge data from draining mine tunnels near Silverton, Colorado 1993-2015

The American Tunnel, the Black Hawk mine, the Gold King mine, the Mogul mine, and the Red and Bonita mine are located in the Cement Creek watershed, tributary to the upper Animas River near Silverton, Colorado. All five sites have tunnels that drain groundwater from abandoned underground mine workings to the surface. This draining water has elevated concentrations of metals and degrades water qual
By
Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Near-surface geophysical data collected in the Sunflower Drain study area near Delta, Colorado, March 2018

Near-surface geophysical surveys were conducted during March 2018 in an irrigated agricultural drainage near Delta, Colorado, locally know as Sunflower Drain. This data release presents results of two surveys, one using fiber-optic distributed temperature sensing (FO-DTS) and the second using a horizontal-to-vertical spectral ratio (HVSR) passive seismic method. For the FO-DTS, a temperature sensi
By
Colorado Water Science Center

Raw Data from Continuous Resistivity Profiles and Electromagnetic Surveys Collected in and adjacent to the Dolores River in the Paradox Valley, Colorado (2017)

This data release includes raw and processed (inverted) data for three different geophysical methods, continuous resistivity profiles (CRP), direct current electrical resistivity tomography (ERT), and frequency domain electromagnetic induction (FDEM) data. These surface geophysical methods were used as a proxy for groundwater salinity in the Paradox Valley in western Colorado to investigate tempor
By
Colorado Water Science Center

Calibration datasets and model archive summaries for regression models developed to estimate metal concentrations at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah

This data release supports the following publication: Mast, M. A., 2018, Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah: U.S. Geological Survey Scientific Investigations Report 2018-5116. The U.S. Geological Survey (USGS), in cooperation with the U. S. Environmental Protection Age
By
Colorado Water Science Center

Alteration Map Showing Major Faults and Veins and Associated Water-Quality Signatures of the Animas River Watershed Headwaters Near Silverton, Southwest Colorado

This map was produced to provide hard-copy and digital data for alteration assemblages in the historical mining area centered on the Tertiary San Juan and Silverton calderas. The data have direct application to geoenvironmental and mineral exploration objectives. This dataset represents alteration mapping for the upper Animas River watershed near Silverton, Colorado. The map is based on detaile
No results found.
Filter Total Items: 72

Simulation of groundwater flow and brine discharge to the Dolores River in the Paradox Valley, Montrose County, Colorado

Salinity, or total dissolved solids (TDS), of the Colorado River affects agricultural, municipal, and industrial water users and is an important concern in the Western United States. In the Paradox Valley of southwestern Colorado, natural discharge of sodium-chloride brine to the Dolores River from the underlying core of a salt-valley anticline accounts for about 6 percent of the salinity load to
Authors
Charles E. Heywood, Suzanne S. Paschke, M. Alisa Mast, Kenneth R Watts
By
Water Resources Mission Area, Colorado Water Science Center

Hydrogeologic conceptual model of groundwater occurrence and brine discharge to the Dolores River in the Paradox Valley, Montrose County, Colorado

Salinity, or total dissolved solids (TDS), of the Colorado River is a major concern in the southwestern United States where the river provides water to about 40 million people for municipal and industrial use and is used to irrigate about 5.5 million acres of land. Much of the salinity in the Colorado River Basin is derived from natural interactions of surface water and groundwater with various ge
Authors
Suzanne S. Paschke, M. Alisa Mast, Philip M. Gardner, Connor P. Newman, Kenneth R. Watts
By
Water Resources Mission Area, Colorado Water Science Center, Utah Water Science Center

Estimating urban air pollution contribution to South Platte River nitrogen loads with National Atmospheric Deposition Program data and SPARROW model

Air pollution is commonly disregarded as a source of nutrient loading to impaired surface waters managed under the Clean Water Act per states’ 303(d) list programs. The contribution of air pollution to 2017–2018 South Platte River nitrogen (N) loads was estimated from the headwaters to the gage at Weldona, Colorado, USA (100 km downstream of Denver), using data from the National Atmospheric Deposi
Authors
Gregory A. Wetherbee, Michael Wieczorek, Dale M. Robertson, David A. Saad, Jon Novick, M. Alisa Mast
By
Water Resources Mission Area, Upper Midwest Environmental Sciences Center, Colorado Water Science Center, Maryland-Delaware-D.C. Water Science Center, Upper Midwest Water Science Center

Characterization of groundwater quality and discharge with emphasis on selenium in an irrigated agricultural drainage near Delta, Colorado, 2017–19

Selenium is a water-quality constituent of concern for aquatic ecosystems in the lower Gunnison River Basin. Selenium is derived from bedrock of the Mancos Shale and is mobilized and transported to groundwater and surface water by application of irrigation water. Although it is recognized that groundwater contributes an appreciable amount of selenium to surface water, few studies have addressed in
Authors
M. Alisa Mast
By
Water Resources Mission Area, Colorado Water Science Center

Water-quality change following remediation using structural bulkheads in abandoned draining mines, upper Arkansas River and upper Animas River, Colorado USA

Water-quality effects after remediating abandoned draining mine tunnels using structural bulkheads were examined in two study areas in Colorado, USA. A bulkhead was installed in the Dinero mine tunnel in 2009 to improve water quality in Lake Fork Creek, a tributary to the upper Arkansas River. Although bulkhead installation improved pH, and manganese and zinc concentrations and loads at the Dinero
Authors
Katherine Walton-Day, M. Alisa Mast, Robert L. Runkel
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Preferential elution of ionic solutes in melting snowpacks: Improving process understanding through field observations and modeling in the Rocky Mountains

The preferential elution of ions from melting snowpacks is a complex problem that has been linked to temporary acidification of water bodies. However, the understanding of these processes in snowpacks around the world, including the polar regions that are experiencing unprecedented warming and melting, remains limited despite being instrumental in supporting climate change adaptation.In this study
Authors
Diogo Costa, Graham A. Sexstone, J.W. Pomeroy, Donald H. Campbell, David W. Clow, M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Colorado Water Science Center

2017 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park

The Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (EPA) issued the Nitrogen Deposition Reduction Plan (NDRP) in 2007 to address the effects and trends of nitrogen deposition at Rocky Mountain National Park (RMNP). The agencies chose a glidepath approach to reduce wet nitrogen deposition to a level of 1.5
Authors
Kristi Morris, M. Alisa Mast, Gregory A. Wetherbee, Jill S. Baron, Jim Cheatham, Jim Bromberg, Lisa Devore, James Hou, Kristi Gebhart, Mike Bell, David Gay, Michael Olson, Timothy Weinmann, Daniel Bowker
By
Water Resources Mission Area, Colorado Water Science Center

Controls on spatial and temporal variations of brine discharge to the Dolores River in the Paradox Valley, Colorado, 2016–18

The Paradox Valley in southwestern Colorado is a collapsed anticline formed by movement of the salt-rich Paradox Formation at the core of the anticline. The salinity of the Dolores River, a tributary of the Colorado River, increases substantially as it crosses the valley because of discharge of brine-rich groundwater derived from the underlying salts. Although the brine is naturally occurring, it
Authors
M. Alisa Mast, Neil Terry
By
Water Resources Mission Area, Colorado Water Science Center

Science needs for continued development of total nitrogen deposition budgets in the United States

The objectives of this white paper are to describe the state of the science with respect to total Nr deposition budgets in North America and the research needed to improve these budgets from both a measurement and modeling standpoint. The document is intended to serve as a plan for TDep research activities but also, more broadly, to provide program managers, natural resource managers, policy make
Authors
Gregory A. Wetherbee, Pamela H. Templar, Richard V. Pouyat, Stephen M. Decina, Brian M. Kerschner, Thomas H. Whitlow, Pamela E. Padgett, Donna B. Schwede, Jill Baron, David Clow, M. Alisa Mast, Graham A. Sexstone, Kristi H. Morris
By
Ecosystems Mission Area, Water Resources Mission Area, Fort Collins Science Center, Colorado Water Science Center

Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah

The purpose of this report is to evaluate the use of site-specific regression models to estimate metal concentrations at nine U.S. Geological Survey streamflow-gaging stations on the Animas and San Juan Rivers in Colorado, New Mexico, and Utah. Downstream users could use these regression models to determine if metal concentrations are elevated and pose a risk to water supplies, agriculture, and re
Authors
M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States

Transit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in mountains o
Authors
David W. Clow, M. Alisa Mast, James O. Sickman
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes

Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding of the impa
Authors
Leora Nanus, Donald H. Campbell, Christopher M.B. Lehmann, M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS)

This web application, a summarized compilation of central Colorado water chemistry datasets from USGS and EPA, identifies legacy mine sites within the headwaters of central Colorado that could be good candidates for future remediation work based on stream metal concentrations, the number and complexity of mine features, and the potential for high natural background metal concentrations.

By
Mineral Resources Program, Colorado Water Science Center, Geology, Geophysics, and Geochemistry Science Center

Science and Products

link
View of the Dolores River, Paradox Valley, CO

Paradox Valley Total Dissolved Solids (TDS) Regression Equations

The primary objective of the project is to evaluate and update previous regression equations, developed for the USGS streamgages and continuous water-quality records, that describe the relation between specific conductance measured in the Dolores River and calculated total dissolved solids TDS. A secondary objective is to evaluate brine discharge to the river using a previously developed...
By
Colorado Water Science Center
link

Paradox Valley Total Dissolved Solids (TDS) Regression Equations

The primary objective of the project is to evaluate and update previous regression equations, developed for the USGS streamgages and continuous water-quality records, that describe the relation between specific conductance measured in the Dolores River and calculated total dissolved solids TDS. A secondary objective is to evaluate brine discharge to the river using a previously developed...
Learn More
link
Study site locations, major drainages, and areas underlain by Mancos Shale in the lower Uncompahgre River Basin

Selenium Mobilization from Shales

Selenium (Se) and salinity (total dissolved solids) are water-quality concerns in much of the arid western US where agricultural and urban irrigation overlie Cretaceous-age shale. Leaching of Se and salinity from shale can degrade water quality and negatively affect aquatic biota in receiving water bodies. Since 1985 programs In the upper Colorado River Basin have worked to reduce Se and salinity...
By
Colorado Water Science Center
link

Selenium Mobilization from Shales

Selenium (Se) and salinity (total dissolved solids) are water-quality concerns in much of the arid western US where agricultural and urban irrigation overlie Cretaceous-age shale. Leaching of Se and salinity from shale can degrade water quality and negatively affect aquatic biota in receiving water bodies. Since 1985 programs In the upper Colorado River Basin have worked to reduce Se and salinity...
Learn More
link
USGS scientist recording data near alpine waterway

Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed

Loch Vale is an alpine/subalpine watershed in Rocky Mountain National Park where the U.S. Geological Survey has been conducting research since the 1980s. Our research has focused on the effects of climate change and atmospheric pollutants on water, soil, vegetation, and aquatic life. The alpine/subalpine ecosystem in Loch Vale is sensitive to changes in climate and air pollution. Our long-term...
By
Colorado Water Science Center
link

Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed

Loch Vale is an alpine/subalpine watershed in Rocky Mountain National Park where the U.S. Geological Survey has been conducting research since the 1980s. Our research has focused on the effects of climate change and atmospheric pollutants on water, soil, vegetation, and aquatic life. The alpine/subalpine ecosystem in Loch Vale is sensitive to changes in climate and air pollution. Our long-term...
Learn More
link
View of three USGS Visual Identity items

Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States

The Hydrologic Benchmark Network (HBN) was established in 1963 to provide long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities.
By
Colorado Water Science Center
link

Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States

The Hydrologic Benchmark Network (HBN) was established in 1963 to provide long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities.
Learn More

MODFLOW-6 model of variable-density groundwater flow and brine discharge to the Dolores River in the Paradox Valley, Colorado

MODFLOW-6 with the Groundwater Flow (GWF) and Groundwater Transport (GWT) models was used to simulate the geohydrology of the aquifer system of the Paradox Valley in western Colorado. Salinity of the Colorado River is a major concern in both the United States and the Republic of Mexico. The Colorado River and its tributaries supply water for about 40 million people and irrigation of about 5.5 mill
By
Colorado Water Science Center

GIS data and scripts for Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS)

This data release includes GIS datasets supporting the Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS), a web mapping application available at https://geonarrative.usgs.gov/colmlwades/. Water chemistry data were compiled from the U.S. Geological Survey (USGS) National Water Information System (NWIS), U.S. Environmental Protection Agency (EPA) STORET database, and the USGS
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Passive seismic (HVSR) data from Fountain Creek, CO

A total of 119 passive seismic soundings were collected with Tromino (MoHo s.r.l.) 3-axis seismometers in the Fountain Creek area to partially refine alluvial aquifer thickness (depth to bedrock) estimates, particularly over known or suspected paleochannels. Data were collected during June 21-24, 2021 with a team of 4-5 people, each equipped with a Tromino Blu or Tromino 3G passive seismometer.
By
New York Water Science Center

Geospatial datasets developed for a hydrogeologic conceptual model of brine discharge to the Dolores River, Paradox Valley, Colorado

Geospatial datasets were developed to estimate the altitude of the top of bedrock, altitude of the top of the Paradox salt, altitude of the water table in the alluvial aquifer, and the thickness and extent of saturated alluvium in the Paradox Valley in western Colorado. This study was completed by the U.S. Geological Survey (USGS) in cooperation with the Bureau of Reclamation for modeling of brine
By
Colorado Water Science Center

Water quality and discharge data from draining mine tunnels near Silverton, Colorado 1993-2015

The American Tunnel, the Black Hawk mine, the Gold King mine, the Mogul mine, and the Red and Bonita mine are located in the Cement Creek watershed, tributary to the upper Animas River near Silverton, Colorado. All five sites have tunnels that drain groundwater from abandoned underground mine workings to the surface. This draining water has elevated concentrations of metals and degrades water qual
By
Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Near-surface geophysical data collected in the Sunflower Drain study area near Delta, Colorado, March 2018

Near-surface geophysical surveys were conducted during March 2018 in an irrigated agricultural drainage near Delta, Colorado, locally know as Sunflower Drain. This data release presents results of two surveys, one using fiber-optic distributed temperature sensing (FO-DTS) and the second using a horizontal-to-vertical spectral ratio (HVSR) passive seismic method. For the FO-DTS, a temperature sensi
By
Colorado Water Science Center

Raw Data from Continuous Resistivity Profiles and Electromagnetic Surveys Collected in and adjacent to the Dolores River in the Paradox Valley, Colorado (2017)

This data release includes raw and processed (inverted) data for three different geophysical methods, continuous resistivity profiles (CRP), direct current electrical resistivity tomography (ERT), and frequency domain electromagnetic induction (FDEM) data. These surface geophysical methods were used as a proxy for groundwater salinity in the Paradox Valley in western Colorado to investigate tempor
By
Colorado Water Science Center

Calibration datasets and model archive summaries for regression models developed to estimate metal concentrations at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah

This data release supports the following publication: Mast, M. A., 2018, Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah: U.S. Geological Survey Scientific Investigations Report 2018-5116. The U.S. Geological Survey (USGS), in cooperation with the U. S. Environmental Protection Age
By
Colorado Water Science Center

Alteration Map Showing Major Faults and Veins and Associated Water-Quality Signatures of the Animas River Watershed Headwaters Near Silverton, Southwest Colorado

This map was produced to provide hard-copy and digital data for alteration assemblages in the historical mining area centered on the Tertiary San Juan and Silverton calderas. The data have direct application to geoenvironmental and mineral exploration objectives. This dataset represents alteration mapping for the upper Animas River watershed near Silverton, Colorado. The map is based on detaile
No results found.
Filter Total Items: 72

Simulation of groundwater flow and brine discharge to the Dolores River in the Paradox Valley, Montrose County, Colorado

Salinity, or total dissolved solids (TDS), of the Colorado River affects agricultural, municipal, and industrial water users and is an important concern in the Western United States. In the Paradox Valley of southwestern Colorado, natural discharge of sodium-chloride brine to the Dolores River from the underlying core of a salt-valley anticline accounts for about 6 percent of the salinity load to
Authors
Charles E. Heywood, Suzanne S. Paschke, M. Alisa Mast, Kenneth R Watts
By
Water Resources Mission Area, Colorado Water Science Center

Hydrogeologic conceptual model of groundwater occurrence and brine discharge to the Dolores River in the Paradox Valley, Montrose County, Colorado

Salinity, or total dissolved solids (TDS), of the Colorado River is a major concern in the southwestern United States where the river provides water to about 40 million people for municipal and industrial use and is used to irrigate about 5.5 million acres of land. Much of the salinity in the Colorado River Basin is derived from natural interactions of surface water and groundwater with various ge
Authors
Suzanne S. Paschke, M. Alisa Mast, Philip M. Gardner, Connor P. Newman, Kenneth R. Watts
By
Water Resources Mission Area, Colorado Water Science Center, Utah Water Science Center

Estimating urban air pollution contribution to South Platte River nitrogen loads with National Atmospheric Deposition Program data and SPARROW model

Air pollution is commonly disregarded as a source of nutrient loading to impaired surface waters managed under the Clean Water Act per states’ 303(d) list programs. The contribution of air pollution to 2017–2018 South Platte River nitrogen (N) loads was estimated from the headwaters to the gage at Weldona, Colorado, USA (100 km downstream of Denver), using data from the National Atmospheric Deposi
Authors
Gregory A. Wetherbee, Michael Wieczorek, Dale M. Robertson, David A. Saad, Jon Novick, M. Alisa Mast
By
Water Resources Mission Area, Upper Midwest Environmental Sciences Center, Colorado Water Science Center, Maryland-Delaware-D.C. Water Science Center, Upper Midwest Water Science Center

Characterization of groundwater quality and discharge with emphasis on selenium in an irrigated agricultural drainage near Delta, Colorado, 2017–19

Selenium is a water-quality constituent of concern for aquatic ecosystems in the lower Gunnison River Basin. Selenium is derived from bedrock of the Mancos Shale and is mobilized and transported to groundwater and surface water by application of irrigation water. Although it is recognized that groundwater contributes an appreciable amount of selenium to surface water, few studies have addressed in
Authors
M. Alisa Mast
By
Water Resources Mission Area, Colorado Water Science Center

Water-quality change following remediation using structural bulkheads in abandoned draining mines, upper Arkansas River and upper Animas River, Colorado USA

Water-quality effects after remediating abandoned draining mine tunnels using structural bulkheads were examined in two study areas in Colorado, USA. A bulkhead was installed in the Dinero mine tunnel in 2009 to improve water quality in Lake Fork Creek, a tributary to the upper Arkansas River. Although bulkhead installation improved pH, and manganese and zinc concentrations and loads at the Dinero
Authors
Katherine Walton-Day, M. Alisa Mast, Robert L. Runkel
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Colorado Water Science Center

Preferential elution of ionic solutes in melting snowpacks: Improving process understanding through field observations and modeling in the Rocky Mountains

The preferential elution of ions from melting snowpacks is a complex problem that has been linked to temporary acidification of water bodies. However, the understanding of these processes in snowpacks around the world, including the polar regions that are experiencing unprecedented warming and melting, remains limited despite being instrumental in supporting climate change adaptation.In this study
Authors
Diogo Costa, Graham A. Sexstone, J.W. Pomeroy, Donald H. Campbell, David W. Clow, M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Colorado Water Science Center

2017 Monitoring and tracking wet nitrogen deposition at Rocky Mountain National Park

The Colorado Department of Public Health and Environment (CDPHE), the National Park Service (NPS), and the U.S. Environmental Protection Agency (EPA) issued the Nitrogen Deposition Reduction Plan (NDRP) in 2007 to address the effects and trends of nitrogen deposition at Rocky Mountain National Park (RMNP). The agencies chose a glidepath approach to reduce wet nitrogen deposition to a level of 1.5
Authors
Kristi Morris, M. Alisa Mast, Gregory A. Wetherbee, Jill S. Baron, Jim Cheatham, Jim Bromberg, Lisa Devore, James Hou, Kristi Gebhart, Mike Bell, David Gay, Michael Olson, Timothy Weinmann, Daniel Bowker
By
Water Resources Mission Area, Colorado Water Science Center

Controls on spatial and temporal variations of brine discharge to the Dolores River in the Paradox Valley, Colorado, 2016–18

The Paradox Valley in southwestern Colorado is a collapsed anticline formed by movement of the salt-rich Paradox Formation at the core of the anticline. The salinity of the Dolores River, a tributary of the Colorado River, increases substantially as it crosses the valley because of discharge of brine-rich groundwater derived from the underlying salts. Although the brine is naturally occurring, it
Authors
M. Alisa Mast, Neil Terry
By
Water Resources Mission Area, Colorado Water Science Center

Science needs for continued development of total nitrogen deposition budgets in the United States

The objectives of this white paper are to describe the state of the science with respect to total Nr deposition budgets in North America and the research needed to improve these budgets from both a measurement and modeling standpoint. The document is intended to serve as a plan for TDep research activities but also, more broadly, to provide program managers, natural resource managers, policy make
Authors
Gregory A. Wetherbee, Pamela H. Templar, Richard V. Pouyat, Stephen M. Decina, Brian M. Kerschner, Thomas H. Whitlow, Pamela E. Padgett, Donna B. Schwede, Jill Baron, David Clow, M. Alisa Mast, Graham A. Sexstone, Kristi H. Morris
By
Ecosystems Mission Area, Water Resources Mission Area, Fort Collins Science Center, Colorado Water Science Center

Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah

The purpose of this report is to evaluate the use of site-specific regression models to estimate metal concentrations at nine U.S. Geological Survey streamflow-gaging stations on the Animas and San Juan Rivers in Colorado, New Mexico, and Utah. Downstream users could use these regression models to determine if metal concentrations are elevated and pose a risk to water supplies, agriculture, and re
Authors
M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States

Transit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in mountains o
Authors
David W. Clow, M. Alisa Mast, James O. Sickman
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes

Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding of the impa
Authors
Leora Nanus, Donald H. Campbell, Christopher M.B. Lehmann, M. Alisa Mast
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Land Change Science Program, Colorado Water Science Center

Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS)

This web application, a summarized compilation of central Colorado water chemistry datasets from USGS and EPA, identifies legacy mine sites within the headwaters of central Colorado that could be good candidates for future remediation work based on stream metal concentrations, the number and complexity of mine features, and the potential for high natural background metal concentrations.

By
Mineral Resources Program, Colorado Water Science Center, Geology, Geophysics, and Geochemistry Science Center
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