Michelle Walvoord
Michelle Walvoord is a Research Hydrologist for the USGS Water Resources Mission Area.
Dr. Michelle A. Walvoord is a hydrogeologist whose current research focuses on understanding hydrologic response to climate variability and wildfire disturbance. With expertise in non-isothermal, multiphase subsurface flow and transport, she has led a variety of process-based vadose zone and groundwater studies in systems ranging from mid-latitude deserts to high-latitude boreal forests. Her research relies on a blend of field, statistical, and physics-based modeling approaches and typically intersects with multiple disciplines including biogeochemistry, ecology, and geophysics.
Professional Experience
Research Hydrologist, USGS Earth System Processes Division, Denver, CO (2017 – present)
Research Hydrologist, USGS National Research Program, Denver, CO (2004-2017)
National Academy of Sciences Postdoctoral Research Associate, Denver, CO (2002-2004)
Education and Certifications
Ph.D. in Earth and Environmental Science, New Mexico Tech
M.S. in Hydrology, New Mexico Tech
B.A. in Geology, Hamilton College
Honors and Awards
O.E. Meinzer Award, Geological Society of America, Hydrogeology Division, 2025
Woo Distinguished Lecture in Hydrology, Canadian Geophysical Union, 2022
Outstanding Woman in Science Award, Geological Society of America, 2005
Langmuir Award for Excellence in Research, New Mexico Tech, 2004
Science and Products
Filter Total Items: 70
Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw
A coupled hydrogeophysical forward and inverse modeling approach is developed to illustrate the ability of frequency-domain airborne electromagnetic (AEM) data to characterize subsurface physical properties associated with sublacustrine permafrost thaw during lake-talik formation. Numerical modeling scenarios are evaluated that consider non-isothermal hydrologic responses to variable...
Authors
Burke Minsley, Tristan Wellman, Michelle Walvoord, Andre Revil
Spatial variability and landscape controls of near-surface permafrost within the Alaskan Yukon River Basin Spatial variability and landscape controls of near-surface permafrost within the Alaskan Yukon River Basin
The distribution of permafrost is important to understand because of permafrost's influence on high-latitude ecosystem structure and functions. Moreover, near-surface (defined here as within 1 m of the Earth's surface) permafrost is particularly susceptible to a warming climate and is generally poorly mapped at regional scales. Subsequently, our objectives were to (1) develop the first...
Authors
Neal Pastick, M. Torre Jorgenson, Bruce Wylie, Joshua Rose, Matthew Rigge, Michelle Walvoord
Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone
A gas-tracer test in a deep arid unsaturated zone demonstrates that standard estimates of effective diffusivity from sediment properties allow a reasonable first-cut assessment of gas contaminant transport. Apparent anomalies in historic transport behavior at this and other waste disposal sites may result from factors other than nonreactive gas transport properties. A natural gradient...
Authors
Michelle Walvoord, Brian Andraski, Christopher Green, David Stonestrom, Robert Striegl
New permafrost is forming around shrinking Arctic lakes, but will it last? New permafrost is forming around shrinking Arctic lakes, but will it last?
Widespread lake shrinkage in cold regions has been linked to climate warming and permafrost thaw. Permafrost aggradation, however, has been observed within the margins of recently receded lakes, in seeming contradiction of climate warming. Here permafrost aggradation dynamics are examined at Twelvemile Lake, a retreating lake in interior Alaska. Observations reveal patches of recently...
Authors
Martin A. Briggs, Michelle Walvoord, Jeffrey McKenzie, Clifford Voss, Frederick Day-Lewis, John Lane
Modeling the hydrogeophysical response of lake talik evolution Modeling the hydrogeophysical response of lake talik evolution
Geophysical methods provide valuable information about subsurface permafrost and its relation to dynamic hydrologic systems. Airborne electromagnetic data from interior Alaska are used to map the distribution of permafrost, geological features, surface water, and groundwater. To validate and gain further insight into these field datasets, we also explore the geophysical response to...
Authors
Burke Minsley, Tristan Wellman, Michelle Walvoord, Andre Revil
Linkages between lake shrinkage/expansion and sublacustrine permafrost distribution determined from remote sensing of interior Alaska, USA Linkages between lake shrinkage/expansion and sublacustrine permafrost distribution determined from remote sensing of interior Alaska, USA
[1] Linkages between permafrost distribution and lake surface-area changes in cold regions have not been previously examined over a large scale because of the paucity of subsurface permafrost information. Here, a first large-scale examination of these linkages is made over a 5150 km2 area of Yukon Flats, Alaska, USA, by evaluating the relationship between lake surface-area changes during...
Authors
Steven Jepsen, Clifford Voss, Michelle Walvoord, Burke Minsley, Jennifer Rover
Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska
Machine-learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at-sensor reflectance, thermal, TM-derived spectral indices, digital...
Authors
Neal Pastick, M. Torre Jorgenson, Bruce Wylie, Burke Minsley, Lei Ji, Michelle Walvoord, Bruce Smith, Jared D. Abraham, Joshua Rose
Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik evolution, Yukon Flats, Alaska (USA) Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik evolution, Yukon Flats, Alaska (USA)
In cold regions, hydrologic systems possess seasonal and perennial ice-free zones (taliks) within areas of permafrost that control and are enhanced by groundwater flow. Simulation of talik development that follows lake formation in watersheds modeled after those in the Yukon Flats of interior Alaska (USA) provides insight on the coupled interaction between groundwater flow and ice...
Authors
Tristan Wellman, Clifford Voss, Michelle Walvoord
Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge
Groundwater discharge to rivers has increased in recent decades across the circumpolar region and has been attributed to thawing permafrost in arctic and subarctic watersheds. Permafrost-driven changes in groundwater discharge will alter the flux of dissolved organic carbon (DOC) in rivers, yet little is known about the chemical composition and reactivity of dissolved organic matter (DOM...
Authors
Jonathan O’Donnell, George Aiken, Michelle Walvoord, Kenna Butler
Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States
Understanding the role of permafrost in controlling groundwater flow paths and fluxes is central in studies aimed at assessing potential climate change impacts on vegetation, species habitat, biogeochemical cycling, and biodiversity. Recent field studies in interior Alaska show evidence of hydrologic changes hypothesized to result from permafrost degradation. This study assesses the...
Authors
Michelle Walvoord, Clifford Voss, Tristan P. Wellman
Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA) Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)
Many lakes in northern high latitudes have undergone substantial changes in surface area over the last four decades, possibly as a result of climate warming. In the discontinuous permafrost of Yukon Flats, interior Alaska (USA), these changes have been non-uniform across adjacent watersheds, suggesting local controls on lake water budgets. Mechanisms that could explain the decreasing...
Authors
S.M. Jepsen, C.I. Voss, Michelle Walvoord, J.R. Rose, B. J. Minsley, B. Smith
Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011 Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011
A series of ground-based observations were made between September 2010 and August 2011 near Twelvemile Lake, 19 kilometers southwest of Fort Yukon, Alaska, for use in ongoing hydrological analyses of watersheds in this region of discontinuous permafrost. Measurements include depth to ground ice, depth to water table, soil texture, soil moisture, soil temperature, and water pressure above...
Authors
Steven Jepsen, Joshua Koch, Joshua Rose, Clifford Voss, Michelle Walvoord
Non-USGS Publications**
Walvoord, M.A., 2002, A Unifying Conceptual Model to Describe Water, Vapor, and Solute Transport in Deep Arid Vadose Zones, Ph.D. thesis, New Mexico Institute of Mining and Technology, Socorro, NM, 297 p.
Hartsough P.C., S.W. Tyler, J. Sterling, M.A. Walvoord, 2001, A 14.6 kyr record of nitrogen flux from desert soil profiles as inferred from vadose zone pore waters, Geophysical Research Letters, 28, 15, 2955 - 2958.
Walvoord, M., P. Pegram, F. Phillips, M. Person, T. Kieft, J. Fredrickson, J. McKinley, J. Swenson, 1999, Groundwater flow and geochemistry in the southeastern San Juan Basin: Implications for microbial transport and activity, Water Resources Research, 35, 1409 – 1425.
Walvoord, M., 1998, Characterization of Groundwater Flow in the Southeastern San Juan Basin: Implications for Microbial Origins in the Deep Subsurface Near Cerro Negro, New Mexico, MS thesis, New Mexico Tech, Socorro, NM, 142 p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 70
Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw
A coupled hydrogeophysical forward and inverse modeling approach is developed to illustrate the ability of frequency-domain airborne electromagnetic (AEM) data to characterize subsurface physical properties associated with sublacustrine permafrost thaw during lake-talik formation. Numerical modeling scenarios are evaluated that consider non-isothermal hydrologic responses to variable...
Authors
Burke Minsley, Tristan Wellman, Michelle Walvoord, Andre Revil
Spatial variability and landscape controls of near-surface permafrost within the Alaskan Yukon River Basin Spatial variability and landscape controls of near-surface permafrost within the Alaskan Yukon River Basin
The distribution of permafrost is important to understand because of permafrost's influence on high-latitude ecosystem structure and functions. Moreover, near-surface (defined here as within 1 m of the Earth's surface) permafrost is particularly susceptible to a warming climate and is generally poorly mapped at regional scales. Subsequently, our objectives were to (1) develop the first...
Authors
Neal Pastick, M. Torre Jorgenson, Bruce Wylie, Joshua Rose, Matthew Rigge, Michelle Walvoord
Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone Field-scale sulfur hexafluoride tracer experiment to understand long distance gas transport in the deep unsaturated zone
A gas-tracer test in a deep arid unsaturated zone demonstrates that standard estimates of effective diffusivity from sediment properties allow a reasonable first-cut assessment of gas contaminant transport. Apparent anomalies in historic transport behavior at this and other waste disposal sites may result from factors other than nonreactive gas transport properties. A natural gradient...
Authors
Michelle Walvoord, Brian Andraski, Christopher Green, David Stonestrom, Robert Striegl
New permafrost is forming around shrinking Arctic lakes, but will it last? New permafrost is forming around shrinking Arctic lakes, but will it last?
Widespread lake shrinkage in cold regions has been linked to climate warming and permafrost thaw. Permafrost aggradation, however, has been observed within the margins of recently receded lakes, in seeming contradiction of climate warming. Here permafrost aggradation dynamics are examined at Twelvemile Lake, a retreating lake in interior Alaska. Observations reveal patches of recently...
Authors
Martin A. Briggs, Michelle Walvoord, Jeffrey McKenzie, Clifford Voss, Frederick Day-Lewis, John Lane
Modeling the hydrogeophysical response of lake talik evolution Modeling the hydrogeophysical response of lake talik evolution
Geophysical methods provide valuable information about subsurface permafrost and its relation to dynamic hydrologic systems. Airborne electromagnetic data from interior Alaska are used to map the distribution of permafrost, geological features, surface water, and groundwater. To validate and gain further insight into these field datasets, we also explore the geophysical response to...
Authors
Burke Minsley, Tristan Wellman, Michelle Walvoord, Andre Revil
Linkages between lake shrinkage/expansion and sublacustrine permafrost distribution determined from remote sensing of interior Alaska, USA Linkages between lake shrinkage/expansion and sublacustrine permafrost distribution determined from remote sensing of interior Alaska, USA
[1] Linkages between permafrost distribution and lake surface-area changes in cold regions have not been previously examined over a large scale because of the paucity of subsurface permafrost information. Here, a first large-scale examination of these linkages is made over a 5150 km2 area of Yukon Flats, Alaska, USA, by evaluating the relationship between lake surface-area changes during...
Authors
Steven Jepsen, Clifford Voss, Michelle Walvoord, Burke Minsley, Jennifer Rover
Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska
Machine-learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at-sensor reflectance, thermal, TM-derived spectral indices, digital...
Authors
Neal Pastick, M. Torre Jorgenson, Bruce Wylie, Burke Minsley, Lei Ji, Michelle Walvoord, Bruce Smith, Jared D. Abraham, Joshua Rose
Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik evolution, Yukon Flats, Alaska (USA) Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik evolution, Yukon Flats, Alaska (USA)
In cold regions, hydrologic systems possess seasonal and perennial ice-free zones (taliks) within areas of permafrost that control and are enhanced by groundwater flow. Simulation of talik development that follows lake formation in watersheds modeled after those in the Yukon Flats of interior Alaska (USA) provides insight on the coupled interaction between groundwater flow and ice...
Authors
Tristan Wellman, Clifford Voss, Michelle Walvoord
Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge
Groundwater discharge to rivers has increased in recent decades across the circumpolar region and has been attributed to thawing permafrost in arctic and subarctic watersheds. Permafrost-driven changes in groundwater discharge will alter the flux of dissolved organic carbon (DOC) in rivers, yet little is known about the chemical composition and reactivity of dissolved organic matter (DOM...
Authors
Jonathan O’Donnell, George Aiken, Michelle Walvoord, Kenna Butler
Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States
Understanding the role of permafrost in controlling groundwater flow paths and fluxes is central in studies aimed at assessing potential climate change impacts on vegetation, species habitat, biogeochemical cycling, and biodiversity. Recent field studies in interior Alaska show evidence of hydrologic changes hypothesized to result from permafrost degradation. This study assesses the...
Authors
Michelle Walvoord, Clifford Voss, Tristan P. Wellman
Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA) Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)
Many lakes in northern high latitudes have undergone substantial changes in surface area over the last four decades, possibly as a result of climate warming. In the discontinuous permafrost of Yukon Flats, interior Alaska (USA), these changes have been non-uniform across adjacent watersheds, suggesting local controls on lake water budgets. Mechanisms that could explain the decreasing...
Authors
S.M. Jepsen, C.I. Voss, Michelle Walvoord, J.R. Rose, B. J. Minsley, B. Smith
Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011 Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011
A series of ground-based observations were made between September 2010 and August 2011 near Twelvemile Lake, 19 kilometers southwest of Fort Yukon, Alaska, for use in ongoing hydrological analyses of watersheds in this region of discontinuous permafrost. Measurements include depth to ground ice, depth to water table, soil texture, soil moisture, soil temperature, and water pressure above...
Authors
Steven Jepsen, Joshua Koch, Joshua Rose, Clifford Voss, Michelle Walvoord
Non-USGS Publications**
Walvoord, M.A., 2002, A Unifying Conceptual Model to Describe Water, Vapor, and Solute Transport in Deep Arid Vadose Zones, Ph.D. thesis, New Mexico Institute of Mining and Technology, Socorro, NM, 297 p.
Hartsough P.C., S.W. Tyler, J. Sterling, M.A. Walvoord, 2001, A 14.6 kyr record of nitrogen flux from desert soil profiles as inferred from vadose zone pore waters, Geophysical Research Letters, 28, 15, 2955 - 2958.
Walvoord, M., P. Pegram, F. Phillips, M. Person, T. Kieft, J. Fredrickson, J. McKinley, J. Swenson, 1999, Groundwater flow and geochemistry in the southeastern San Juan Basin: Implications for microbial transport and activity, Water Resources Research, 35, 1409 – 1425.
Walvoord, M., 1998, Characterization of Groundwater Flow in the Southeastern San Juan Basin: Implications for Microbial Origins in the Deep Subsurface Near Cerro Negro, New Mexico, MS thesis, New Mexico Tech, Socorro, NM, 142 p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.