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Joel Unema (Former Employee)

Science and Products

Photo of USGS hydrologist collecting quarterly suspended-sediment samples from a kayak at Colorado River below Imperial Dam

Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the...
By
Arizona Water Science Center
Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the...
Learn More
Photograph show the initial energy wave of a flash flood on the Paria River in Arizona.

Grand Canyon Streamflow and Sediment Project

The AZWSC Grand Canyon Streamflow and Sediment project supports the work of Grand Canyon Monitoring and Research Center’s (GCMRC) Discharge, Sediment and Water Quality Project. This support is accomplished by collecting sediment, temperature, and streamflow data from tributaries of the Colorado River in Grand Canyon and by collecting temperature and streamflow data on the main stem of the Colorado...
By
Arizona Water Science Center
Grand Canyon Streamflow and Sediment Project

Grand Canyon Streamflow and Sediment Project

The AZWSC Grand Canyon Streamflow and Sediment project supports the work of Grand Canyon Monitoring and Research Center’s (GCMRC) Discharge, Sediment and Water Quality Project. This support is accomplished by collecting sediment, temperature, and streamflow data from tributaries of the Colorado River in Grand Canyon and by collecting temperature and streamflow data on the main stem of the Colorado...
Learn More
Sediment sampling and surrogates

Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
By
Water Resources Mission Area
Sediment Acoustics

Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
Learn More

Channel and floodplain cross-section and bed-elevation data for the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah Channel and floodplain cross-section and bed-elevation data for the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah

These data were compiled to determine the rate and magnitude of channel-planform change, and the topographic change of the channel and floodplain in Echo, Island, and Rainbow Parks within Dinosaur National Monument between the 1990s and 2019. The objective(s) of our study were to analyze geomorphic change within Echo, Island, and Rainbow Parks to determine the magnitude and style of...
By
Southwest Biological Science Center

Model Archive for indirect discharge computation for a 300-meter reach of Sand Creek, Wyoming, USA, 2023 Model Archive for indirect discharge computation for a 300-meter reach of Sand Creek, Wyoming, USA, 2023

This product includes a model archive using the iRIC-SAC Solver for indirect discharge computation of the spring snowmelt peak flow surveyed on May 27, 2023, and estimated to have occurred in early April 2023. The best-fit discharge for this flood is 3,500 ft3/s. Other data include topographic cross-section data, control points, and high-water marks collected by RTK GPS, and selected...
By
Arizona Water Science Center

Surveyed coordinates and elevations in a 2020 resurvey of previously established cross sections on the Green River between Jensen and Ouray, Utah Surveyed coordinates and elevations in a 2020 resurvey of previously established cross sections on the Green River between Jensen and Ouray, Utah

These data were compiled for/to National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Green River, Utah, in, and upstream, from Ouray National Wildlife Refuge to document changes in channel width, depth, and cross-sectional area. These data represent the 2020 resurvey...
By
Southwest Biological Science Center

Surveyed coordinates and elevations in a 2017 resurvey of previously established cross sections on the Little Snake and Yampa rivers in Lily and Deerlodge parks, Colorado Surveyed coordinates and elevations in a 2017 resurvey of previously established cross sections on the Little Snake and Yampa rivers in Lily and Deerlodge parks, Colorado

These data were compiled for the National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Yampa and Little Snake rivers in the Deerlodge Park area to document changes in channel width, depth, and cross-sectional area. A secondary purpose of this study was to document the...
By
Southwest Biological Science Center

Streamflow measurement and channel cross section data from a synoptic base-flow survey of the Verde River, Arizona, USA January 2021 Streamflow measurement and channel cross section data from a synoptic base-flow survey of the Verde River, Arizona, USA January 2021

These data include a summary of a base flow survey of the Verde River within Verde Valley, a ~65km reach from ~7 km above Clarkdale, AZ to ~5km below the mouth of West Clear Creek. Data include discharge, water temperature, and specific conductance values from 22 sites on the Verde River and its tributaries, including Oak Creek, Beaver Creek, West Clear Creek, and irrigation ditches...
By
Arizona Water Science Center

Water Quality Data from Select Spring and Stream Sites and Water and Sediment Quality Data from the Colorado River and Major Tributaries in Grand Canyon, Northern Arizona (ver. 2.0, April 2024) Water Quality Data from Select Spring and Stream Sites and Water and Sediment Quality Data from the Colorado River and Major Tributaries in Grand Canyon, Northern Arizona (ver. 2.0, April 2024)

This USGS Data Release represents water and sediment quality data collected in the Grand Canyon region of northern Arizona. There are 4 separate datasets associated with this Data Release: Water quality data from major Colorado River tributary monitoring sites in and near Grand Canyon from 2015 through 2022. Sediment quality data from the Colorado River and major tributary monitoring...
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Arizona Water Science Center

Channel and floodplain cross-section and bed-elevation analyses of the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah Channel and floodplain cross-section and bed-elevation analyses of the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah

This report by the U.S. Geological Survey focuses on describing geomorphic changes in the alluvial segments of the Green River within Echo, Island, and Rainbow Parks of Dinosaur National Monument, between the 1990s and 2019. Substantial channel change occurred within these meandering alluvial segments following the construction and closure of Flaming Gorge Dam in 1962. Geomorphic...
Authors
David J. Dean, Paul E. Grams, Shannon Leigh Sartain, Christy M. Leonard, Ronald E. Griffiths, Joel A. Unema, David J. Topping, John C. Schmidt
By
Ecosystems Mission Area, Southwest Biological Science Center

Controls on sediment transport and storage in the Little Snake, Yampa, and Green Rivers in the vicinities of Dinosaur National Monument and Ouray National Wildlife Refuge, Colorado and Utah, with implications for fish habitat in the middle Green River Controls on sediment transport and storage in the Little Snake, Yampa, and Green Rivers in the vicinities of Dinosaur National Monument and Ouray National Wildlife Refuge, Colorado and Utah, with implications for fish habitat in the middle Green River

The transport of sand and finer sediment in the Yampa and Green river network is typically in disequilibrium with the local sediment supply because of the partial decoupling of the sources of water and sediment: most of the water is supplied farther upstream than most of the sediment. This decoupling leads to sand being transported in the main-stem rivers as elongating sand waves...
Authors
David J. Topping, Ronald E. Griffiths, Joel A. Unema, David J. Dean
By
Ecosystems Mission Area, Southwest Biological Science Center

Changes in sand storage in the Colorado River in Grand Canyon National Park from July 2017 through June 2020 Changes in sand storage in the Colorado River in Grand Canyon National Park from July 2017 through June 2020

Changes in the quantity of sand stored within river segments can affect aquatic and riparian habitat, archeological resources, and recreation. Since summer to fall of 2002, gaging stations on the Colorado River in Grand Canyon National Park and on its major tributaries and selected lesser tributaries have measured the mass of sand transported past each station, which allows for changes...
Authors
Ronald E. Griffiths, David J. Topping, Joel A. Unema
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

Resurvey of cross sections on the Yampa and Little Snake Rivers in Lily and Deerlodge Parks, Colorado Resurvey of cross sections on the Yampa and Little Snake Rivers in Lily and Deerlodge Parks, Colorado

Resurveys of seven geomorphologic cross sections located in the Lily Park and Deerlodge Park, Colorado, reaches of the Yampa and Little Snake Rivers were conducted in October 2017. These cross sections extend from Lily Park, at the confluence of the two rivers, to Deerlodge Park within Dinosaur National Monument. Four cross sections were first surveyed in 1983 and then resurveyed in 1997...
Authors
Ronald E. Griffiths, David J. Topping, Christina Leonard, Joel A. Unema
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

Historical floods and geomorphic change in the lower Little Colorado River during the late 19th to early 21st centuries Historical floods and geomorphic change in the lower Little Colorado River during the late 19th to early 21st centuries

The Little Colorado River is a major tributary to the Colorado River with a confluence at the boundary between Marble and Grand Canyons within Grand Canyon National Park, Arizona. The bedrock gorge of the lower Little Colorado River is home to the largest known population of Gila cypha (humpback chub), an endangered fish endemic to the Colorado River Basin. Channel conditions might...
Authors
Joel A. Unema, David J. Topping, Keith Kohl, Michael J. Pillow, Joshua J. Caster
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

An assessment of uranium in groundwater in the Grand Canyon region An assessment of uranium in groundwater in the Grand Canyon region

The Grand Canyon region in northern Arizona is a home or sacred place of origin for many Native Americans and is visited by over 6 million tourists each year. Most communities in the area depend upon groundwater for all water uses. Some of the highest-grade uranium ore in the United States also is found in the Grand Canyon region. A withdrawal of over 1 million acres of Federal land in...
Authors
Fred D. Tillman, Kimberly R. Beisner, Jessica R. Anderson, Joel A. Unema
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Arizona Water Science Center, New Mexico Water Science Center

Science and Products

Photo of USGS hydrologist collecting quarterly suspended-sediment samples from a kayak at Colorado River below Imperial Dam

Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the...
By
Arizona Water Science Center
Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam

Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the...
Learn More
Photograph show the initial energy wave of a flash flood on the Paria River in Arizona.

Grand Canyon Streamflow and Sediment Project

The AZWSC Grand Canyon Streamflow and Sediment project supports the work of Grand Canyon Monitoring and Research Center’s (GCMRC) Discharge, Sediment and Water Quality Project. This support is accomplished by collecting sediment, temperature, and streamflow data from tributaries of the Colorado River in Grand Canyon and by collecting temperature and streamflow data on the main stem of the Colorado...
By
Arizona Water Science Center
Grand Canyon Streamflow and Sediment Project

Grand Canyon Streamflow and Sediment Project

The AZWSC Grand Canyon Streamflow and Sediment project supports the work of Grand Canyon Monitoring and Research Center’s (GCMRC) Discharge, Sediment and Water Quality Project. This support is accomplished by collecting sediment, temperature, and streamflow data from tributaries of the Colorado River in Grand Canyon and by collecting temperature and streamflow data on the main stem of the Colorado...
Learn More
Sediment sampling and surrogates

Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
By
Water Resources Mission Area
Sediment Acoustics

Sediment Acoustics

The U.S. Geological Survey recognizes the need to provide sediment acoustic training and to develop standardized techniques and practices.
Learn More

Channel and floodplain cross-section and bed-elevation data for the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah Channel and floodplain cross-section and bed-elevation data for the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah

These data were compiled to determine the rate and magnitude of channel-planform change, and the topographic change of the channel and floodplain in Echo, Island, and Rainbow Parks within Dinosaur National Monument between the 1990s and 2019. The objective(s) of our study were to analyze geomorphic change within Echo, Island, and Rainbow Parks to determine the magnitude and style of...
By
Southwest Biological Science Center

Model Archive for indirect discharge computation for a 300-meter reach of Sand Creek, Wyoming, USA, 2023 Model Archive for indirect discharge computation for a 300-meter reach of Sand Creek, Wyoming, USA, 2023

This product includes a model archive using the iRIC-SAC Solver for indirect discharge computation of the spring snowmelt peak flow surveyed on May 27, 2023, and estimated to have occurred in early April 2023. The best-fit discharge for this flood is 3,500 ft3/s. Other data include topographic cross-section data, control points, and high-water marks collected by RTK GPS, and selected...
By
Arizona Water Science Center

Surveyed coordinates and elevations in a 2020 resurvey of previously established cross sections on the Green River between Jensen and Ouray, Utah Surveyed coordinates and elevations in a 2020 resurvey of previously established cross sections on the Green River between Jensen and Ouray, Utah

These data were compiled for/to National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Green River, Utah, in, and upstream, from Ouray National Wildlife Refuge to document changes in channel width, depth, and cross-sectional area. These data represent the 2020 resurvey...
By
Southwest Biological Science Center

Surveyed coordinates and elevations in a 2017 resurvey of previously established cross sections on the Little Snake and Yampa rivers in Lily and Deerlodge parks, Colorado Surveyed coordinates and elevations in a 2017 resurvey of previously established cross sections on the Little Snake and Yampa rivers in Lily and Deerlodge parks, Colorado

These data were compiled for the National Park Service and Upper Colorado River Endangered Fish Recovery Program. Objective(s) of our study were to resurvey previously established cross sections on the Yampa and Little Snake rivers in the Deerlodge Park area to document changes in channel width, depth, and cross-sectional area. A secondary purpose of this study was to document the...
By
Southwest Biological Science Center

Streamflow measurement and channel cross section data from a synoptic base-flow survey of the Verde River, Arizona, USA January 2021 Streamflow measurement and channel cross section data from a synoptic base-flow survey of the Verde River, Arizona, USA January 2021

These data include a summary of a base flow survey of the Verde River within Verde Valley, a ~65km reach from ~7 km above Clarkdale, AZ to ~5km below the mouth of West Clear Creek. Data include discharge, water temperature, and specific conductance values from 22 sites on the Verde River and its tributaries, including Oak Creek, Beaver Creek, West Clear Creek, and irrigation ditches...
By
Arizona Water Science Center

Water Quality Data from Select Spring and Stream Sites and Water and Sediment Quality Data from the Colorado River and Major Tributaries in Grand Canyon, Northern Arizona (ver. 2.0, April 2024) Water Quality Data from Select Spring and Stream Sites and Water and Sediment Quality Data from the Colorado River and Major Tributaries in Grand Canyon, Northern Arizona (ver. 2.0, April 2024)

This USGS Data Release represents water and sediment quality data collected in the Grand Canyon region of northern Arizona. There are 4 separate datasets associated with this Data Release: Water quality data from major Colorado River tributary monitoring sites in and near Grand Canyon from 2015 through 2022. Sediment quality data from the Colorado River and major tributary monitoring...
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Arizona Water Science Center

Channel and floodplain cross-section and bed-elevation analyses of the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah Channel and floodplain cross-section and bed-elevation analyses of the Green River in Echo, Island, and Rainbow Parks, Dinosaur National Monument, Colorado and Utah

This report by the U.S. Geological Survey focuses on describing geomorphic changes in the alluvial segments of the Green River within Echo, Island, and Rainbow Parks of Dinosaur National Monument, between the 1990s and 2019. Substantial channel change occurred within these meandering alluvial segments following the construction and closure of Flaming Gorge Dam in 1962. Geomorphic...
Authors
David J. Dean, Paul E. Grams, Shannon Leigh Sartain, Christy M. Leonard, Ronald E. Griffiths, Joel A. Unema, David J. Topping, John C. Schmidt
By
Ecosystems Mission Area, Southwest Biological Science Center

Controls on sediment transport and storage in the Little Snake, Yampa, and Green Rivers in the vicinities of Dinosaur National Monument and Ouray National Wildlife Refuge, Colorado and Utah, with implications for fish habitat in the middle Green River Controls on sediment transport and storage in the Little Snake, Yampa, and Green Rivers in the vicinities of Dinosaur National Monument and Ouray National Wildlife Refuge, Colorado and Utah, with implications for fish habitat in the middle Green River

The transport of sand and finer sediment in the Yampa and Green river network is typically in disequilibrium with the local sediment supply because of the partial decoupling of the sources of water and sediment: most of the water is supplied farther upstream than most of the sediment. This decoupling leads to sand being transported in the main-stem rivers as elongating sand waves...
Authors
David J. Topping, Ronald E. Griffiths, Joel A. Unema, David J. Dean
By
Ecosystems Mission Area, Southwest Biological Science Center

Changes in sand storage in the Colorado River in Grand Canyon National Park from July 2017 through June 2020 Changes in sand storage in the Colorado River in Grand Canyon National Park from July 2017 through June 2020

Changes in the quantity of sand stored within river segments can affect aquatic and riparian habitat, archeological resources, and recreation. Since summer to fall of 2002, gaging stations on the Colorado River in Grand Canyon National Park and on its major tributaries and selected lesser tributaries have measured the mass of sand transported past each station, which allows for changes...
Authors
Ronald E. Griffiths, David J. Topping, Joel A. Unema
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

Resurvey of cross sections on the Yampa and Little Snake Rivers in Lily and Deerlodge Parks, Colorado Resurvey of cross sections on the Yampa and Little Snake Rivers in Lily and Deerlodge Parks, Colorado

Resurveys of seven geomorphologic cross sections located in the Lily Park and Deerlodge Park, Colorado, reaches of the Yampa and Little Snake Rivers were conducted in October 2017. These cross sections extend from Lily Park, at the confluence of the two rivers, to Deerlodge Park within Dinosaur National Monument. Four cross sections were first surveyed in 1983 and then resurveyed in 1997...
Authors
Ronald E. Griffiths, David J. Topping, Christina Leonard, Joel A. Unema
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

Historical floods and geomorphic change in the lower Little Colorado River during the late 19th to early 21st centuries Historical floods and geomorphic change in the lower Little Colorado River during the late 19th to early 21st centuries

The Little Colorado River is a major tributary to the Colorado River with a confluence at the boundary between Marble and Grand Canyons within Grand Canyon National Park, Arizona. The bedrock gorge of the lower Little Colorado River is home to the largest known population of Gila cypha (humpback chub), an endangered fish endemic to the Colorado River Basin. Channel conditions might...
Authors
Joel A. Unema, David J. Topping, Keith Kohl, Michael J. Pillow, Joshua J. Caster
By
Water Resources Mission Area, Ecosystems Mission Area, Arizona Water Science Center, Southwest Biological Science Center

An assessment of uranium in groundwater in the Grand Canyon region An assessment of uranium in groundwater in the Grand Canyon region

The Grand Canyon region in northern Arizona is a home or sacred place of origin for many Native Americans and is visited by over 6 million tourists each year. Most communities in the area depend upon groundwater for all water uses. Some of the highest-grade uranium ore in the United States also is found in the Grand Canyon region. A withdrawal of over 1 million acres of Federal land in...
Authors
Fred D. Tillman, Kimberly R. Beisner, Jessica R. Anderson, Joel A. Unema
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Arizona Water Science Center, New Mexico Water Science Center
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