Michelle Walvoord
(She/her)Michelle Walvoord is a Research Hydrologist in the Earth System Processes Division of the Water Resources Mission Area.
Dr. Michelle A. Walvoord is a hydrogeologist whose current research focuses on understanding hydrologic response to climate change 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
Affiliations and Memberships*
Affiliate Faculty, Geology and Geological Engineering Dept., Colorado School of Mines (2016 – present)
Graduate Faculty Appointment, Geological Sciences Dept., University of Colorado, Boulder (2016 – present)
Associate Faculty, Université Laval (2021 – present)
Member of the USGS Water Mission Area’s Diversity, Equity, Inclusion, and Accessibility Employee Leadership Team (2022-present)
Member of the American Geophysical Union Hydrology Section’s Justice, Equity, Diversity, and Inclusion committee (2021-present)
Board of Directors, United States Permafrost Association (2021-2022)
Associate Editor, Water Resources Research (2015 – present)
Associate Editor, Hydrogeology Journal (2014-2017)
Member of the Terrestrial Multidisciplinary distributed Observatories for the Study of Arctic Connection (t-MOSAIC) Land-Water Processes Action Group (2019 – present)
Science Steering Committee, Permafrost Action Team for the National Science Foundation’s Study of Environmental Arctic Change Project (SEARCH) (2015 – present)
Science Advisory Board, USGS Powell Center for Analysis and Synthesis (2015 – 2019)
Honors and Awards
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
Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska
Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik evolution, Yukon Flats, Alaska (USA)
Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge
Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw: Example from Yukon Flats Basin, Alaska, United States
Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)
Thermal and hydrological observations near Twelvemile Lake in discontinuous permafrost, Yukon Flats, interior Alaska, September 2010-August 2011
Airborne electromagnetic imaging of discontinuous permafrost
Planning for an uncertain future - Monitoring, integration, and adaptation
Trends in streamflow in the Yukon River Basin from 1944 to 2005 and the influence of the Pacific Decadal Oscillation
On the in situ aqueous alteration of soils on Mars
Susceptibility to enhanced chemical migration from depression-focused preferential flow, High Plains aquifer
Transport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region
Non-USGS Publications**
**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
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Filter Total Items: 64
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 elevation modelAuthorsNeal J. Pastick, M. Torre Jorgenson, Bruce K. Wylie, Burke J. Minsley, Lei Ji, Michelle Ann Walvoord, Bruce D. Smith, Jared D. Abraham, Joshua R. RoseImpacts 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 distribution. ThAuthorsTristan Wellman, Clifford I. Voss, Michelle Ann WalvoordDissolved 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) of grounAuthorsJonathan A. O'Donnell, George R. Aiken, Michelle Ann Walvoord, Kenna D. ButlerInfluence 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 hydrologic conAuthorsMichelle Ann Walvoord, Clifford I. Voss, Tristan P. WellmanSensitivity 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 mass of one lAuthorsS.M. Jepsen, C.I. Voss, Michelle Ann Walvoord, J.R. Rose, B. J. Minsley, B. D. SmithThermal 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 the permaAuthorsSteven M. Jepsen, Joshua C. Koch, Joshua R. Rose, Clifford I. Voss, Michelle Ann WalvoordAirborne electromagnetic imaging of discontinuous permafrost
The evolution of permafrost in cold regions is inextricably connected to hydrogeologic processes, climate, and ecosystems. Permafrost thawing has been linked to changes in wetland and lake areas, alteration of the groundwater contribution to streamflow, carbon release, and increased fire frequency. But detailed knowledge about the dynamic state of permafrost in relation to surface and groundwaterAuthorsB. J. Minsley, J.D. Abraham, B. D. Smith, J. C. Cannia, C.I. Voss, M.T. Jorgenson, Michelle Ann Walvoord, B.K. Wylie, L. Anderson, L.B. Ball, M. Deszcz-Pan, T.P. Wellman, T. A. AgerPlanning for an uncertain future - Monitoring, integration, and adaptation
The 6.7 billion human inhabitants of the earth have the ability to drastically alter ecosystems and the populations of species that have taken eons to evolve. By better understanding how our actions affect the environment, we stand a better chance of designing successful strategies to manage ecosystems sustainably. Toward this end, the Third Interagency Conference on Research in the Watersheds (ICTrends in streamflow in the Yukon River Basin from 1944 to 2005 and the influence of the Pacific Decadal Oscillation
Streamflow characteristics in the Yukon River Basin of Alaska and Canada have changed from 1944 to 2005, and some of the change can be attributed to the two most recent modes of the Pacific Decadal Oscillation (PDO). Seasonal, monthly, and annual stream discharge data from 21 stations in the Yukon River Basin were analyzed for trends over the entire period of record, generally spanning 4-6 decadesAuthorsT. P. Brabets, Michelle Ann WalvoordOn the in situ aqueous alteration of soils on Mars
Early (>3 Gy) wetter climate conditions on Mars have been proposed, and it is thus likely that pedogenic processes have occurred there at some point in the past. Soil and rock chemistry of the Martian landing sites were evaluated to test the hypothesis that in situ aqueous alteration and downward movement of solutes have been among the processes that have transformed these portions of the Mars regAuthorsRonald Amundson, S. Ewing, W. Dietrich, B. Sutter, J. Owen, O. Chadwick, K. Nishiizumi, Michelle Ann Walvoord, C. McKaySusceptibility to enhanced chemical migration from depression-focused preferential flow, High Plains aquifer
Aquifer susceptibility to contamination is controlled in part by the inherent hydrogeologic properties of the vadose zone, which includes preferential-flow pathways. The purpose of this study was to investigate the importance of seasonal ponding near leaky irrigation wells as a mechanism for depression-focused preferential flow and enhanced chemical migration through the vadose zone of the High PlAuthorsJason J. Gurdak, Michelle Ann Walvoord, Peter B. McMahonTransport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region
Mercury contained in buried landfill waste may be released via upward emission to the atmosphere or downward leaching to groundwater. Data from the US Geological Survey’s Amargosa Desert Research Site (ADRS) in arid southwestern Nevada reveal another potential pathway of Hg release: long-distance (102 m) lateral migration of elemental Hg (Hg0) through the unsaturated zone. Gas collected from multiAuthorsMichelle Ann Walvoord, Brian J. Andraski, D. P. Krabbenhoft, Robert G. StrieglNon-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.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government