Robert Walter

Education

B.A., Geology, Franklin and Marshall College

Ph.D., Geochemistry, Case Western Reserve University

Post-Doctoral Fellow, Department of Physics (Division of Geophysics) and the Department of Geology, University of Toronto

Biography

Robert Walter is a geologist, geochemist and geochronologist. He has conducted geological explorations and field research in East Africa (calibration of human origins, rift basin analyses, Plio-Pleistocene climate change, and volcanology), North America (Quaternary geology, surface water and groundwater interactions and environmental geology), around the Pacific Rim (neotectonics), and around the world (groundwater exploration). He was elected a Fellow of the California Academy of Science in 1989 and a Fellow of the Geological Society of America in 2011. He was the Chief Geologist for the Institute of Human Origins in Berkeley, California (1987-94) and a Senior Scientist at the University of Toronto Argon Dating Lab and the Jack Satterly Geochronology Laboratory at the Royal Ontario Museum, Toronto (1994-2000). He is a former American Association for the Advancement of Science (AAAS) Diplomacy Fellow and Senior Science Advisor to the U.S. Department of State (INR/HIU, 2003-04), where he conducted research on complex humanitarian emergencies, with a focus on Africa and the Near East. He was a Visiting Professor and Presidential Fellow at Case Western Reserve University (2005-06) and the Allen Cox Visiting Professor at Stanford University (2011-12). In 2011 he and Dorothy Merritts received the Kirk Bryan Award for Outstanding Research in Quaternary Geology and Geomorphology from the Geological Society of America for their 2008 paper in Science, "Natural Streams and the Legacy of Water Powered Mills." Currently, he is the Dr. Earl D. Stage & Mary E. Stage Professor of Geosciences and Chair of the Department of Earth and Environment at Franklin and Marshall College (2006-Present), where his research interests focus on quantitative geochemical analyses of rocks, soils, and water, bedrock fracture analyses, groundwater exploration, water quality analyses, soil-sediment-bedrock-water interactions, and human disturbances of earth surface processes.

He directs the Big Spring Run Restoration Experiment, authored over 90 peer-reviewed publications, and co-wrote and co-directed five short documentary films on human evolution. He is co-founder and Chief Science Officer of Power 7 Inc., a pioneering groundwater exploration company that specializes in discovering fresh groundwater where traditional methods fail to look. In 2021, along with F&M colleagues Dorothy Merritts (ENE) and Patrick Fleming (ECON), he is Co-Director of the Chesapeake Watershed Initiative at F&M, funded by the Richard King Mellon Foundation.

Research Interests

Isotope Geochemistry and Geochronology, Volcanology, Tectonics
Critical Zone Studies, Landscape and Aqueous Geochemistry, Sediment Fingerprinting, Anthropocene Landscape Change, Stream Restoration
Hydrogeology, Water Security, Groundwater Exploration
Science Visualization

Research Gate profile for Bob Walter

Selected Publications

Isotope Geochemistry and Geochronology, Volcanology, Tectonics:

Anders, M.H., Rodgers, D. W., Hemming, S.R., Saltzman, J., DiVinere, V., Hagstrum, J.T., Embree, G.F., and Walter, R.C., 2014. A fixed sub-lithospheric source for the late Neogene track of the Yellowstone hotspot: Implications of the Heise and Picabo Volcanic Fields. J. Geophys. Res., DOI: 10.1002/2013JB010483 (PDF)

Aronson, R.C., Schmitt, T.J., Walter, R.C., Taieb. M., Tiercelin, J-J., Naeser, C.W., and Nairn, A.E.M., 1977, New geochronological and paleomagnetic data for the hominid-bearing Hadar Formation of Ethiopia. Nature, 267, 323-337. (PDF)

Asfaw, B., Beyene, Y., Suwa, G., Walter, R.C., White., T.D., WoldeGabriel, G., Yemane, T., 1992, The Earliest Acheulian from Konso-Gardula, Nature, 360, 732-734. (PDF)

Bruggemann, J.H., Buffler, R.T., Guillaume, M.M., Walter, R.C., von Cosel, R., Ghenretensae, N., Berhe, S., 2004. Stratigraphy, paleoenvironments and model for the deposition of the Abdur Reef Limestone: Context for an important archaeological site from the last interglacial on the Red Sea coast of Eritrea. Palaeogeography, Palaeolclimatology, Palaeoecology 203, 179-206. (PDF)

Buffler, R.T., Walter, R.C., Ghebretensae, B.N., Bruggemann, J.H., Guillaume, M.M.M., Berhe, S.M., McIntosh, W., Park, L.E., 2010. Geologic setting of the Abdur Archaeological Site on the Red Sea coast of Eritrea, Africa. Global and Planetary Change 72, 429-450. (PDF)

Chernet, T., Hart, W.K., Aronson, J.L., and Walter, R.C., 1998, New age constraints on the timing of volcanism and tectonism in the northern main Ethiopian Rift-southern Afar transition zone, Journal of Volcanology and Geothermal Research, 80, 267-280 (PDF)

Clark, J.D., Asfaw, B, Assefa, G., Harris, J.W.K., Kurishina, H., Walter, R.C., White, T.D., and Williams, M.A.J., 1984, Paleoanthropological discoveries in the Middle Awash valley. Nature, 307, 423-428. (PDF)

Clark, J.D., de Heinzelin, J., Schick, K.D., Hart, W.K., White, T.D., WoldeGabriel, G., Walter, R.C., Suwa, G., Asfaw, B., Vrba, E., Selassie, Y.H., 1994, African Homo erectus: Old Radiometric Ages and Young Oldowan Assemblages in the Middle Awash, Ethiopia, Science, 264, 1907-1910. (PDF)

Ebinger, C.J., Yemane, T., WoldeGabriel, T., Aronson, J.L., and Walter, R.C., 1993, Late Eocene-Recent volcanism and faulting in the southern main Ethiopian rift, Journal of the Geological Society, London, 150, 99-108. (PDF)

Johanson, D.C., Masao, F., Eck, G., White, T.D., Walter, R.C., Kimbel, W.H., Manega, P., 1987, New partial skeleton of Homo habilis from Olduvai Gorge, Tanzania. Nature, 327, 205-209. (PDF)

Johanson, D.C., Kimbel, W.H., Walter, R.C., Vondra, C., Yemane, T., Aronson, J.L., Eck, G.G., Rak, Y., Hovers, E., Reed, K.E., and Bobe-Quinteros, R., 1995, Fossil collecting; discussion, Science 268, 1113. (PDF)

Johnson, K.M., Snyder, N.P., Castle, S., Hopkins, A.J., Waltner, M., Merritts, D.J. and Walter, R.C., 2019. Legacy sediment storage in New England river valleys: Anthropogenic processes in a postglacial landscape. Geomorphology, 327, pp.417-437. https://doi.org/10.1016/j.geomorph.2018.11.017

Kimbel, W.H., Walter, R.C. and Johanson, D.C., et al., 1996, Late Pliocene Homo and Oldowan tools from the Hadar Formation (Kada Hadar Member). Ethiopia, Journal of Human Evolution, 31, 549-561. (PDF)

Longenecker*, J., T. Bechtel, Z. Chen, N. Goldscheider, T. Liesch, and R. Walter, 2017, Correlating Global Precipitation Measurement satellite data with karst spring hydrographs for rapid catchment delineation, Geophysical Research Letters44, 4926–4932, doi:10.1002/2017GL07379 0. http://onlinelibrary.wiley.com/doi/10.1002/2017GL073790/abstract

Pazzaglia, F.J., Braun, D.D., Pavich, M., Bierman, P., Potter, N., Jr., Merritts, D., Walter, R., and Germanoski, D., 2006, Rivers, glaciers, landscape evolution, and active tectonics of the central Appalachians, Pennsylvania and Maryland, in Pazzaglia, F.J., ed., Excursions in Geology and History: Field Trips in the Middle Atlantic States: Geological Society of America Field Guide 8, p. 169–197, doi: 10.1130/2006.fl d008(09). (PDF)

Shoshani, H., Walter, R.C., Berhe, S., Libsekal, Y. and Abraha, M., 2006., Paleoenvironments of Late Oligocene Gompothere from Dogali, Eritrea. Proceedings of the National Academy of Science. (PDF)

Renne, P.R., Deino, A.L., Walter, R.C., Turrin, B.D., Swisher, C.C., Becker, T.A., Curtis, G.H., Sharp, W.D. and Jaouni, A.-R., 1994, Intercalibration of astronomical and radioisotopic time, Geology 22, 783-786. (PDF)

Walter, R.C., 1989, Applications and limitations of fission-track geochronology to Quaternary tephras, Quaternary International, 1, 35-46. (PDF)

Walter, R.C., 1989, Applications of K/Ar and 40Ar/sAr dating to Quaternary geology. In: S.L. Forman, ed., “Dating Methods Applicable to Quaternary Geological Studies in the Western United States”. Utah Department of Natural Resources Misc. Pub 98-7, 61-66. (PDF)

Walter, R.C., 1989, Tephrostratigraphy and tephrochronology. In: S.L. Forman, ed., “Dating Methods Applicable to Quaternary Geological Studies in the Western United States”. Utah Department of Natural Resources Misc. Pub 98-7, 54-60. (PDF)

Walter, R.C., 1998. Potassium-Argon/Argon-Argon Dating. In: Chronometric and Allied Dating in Archaeology (R.E. Taylor and M. Aitken, eds.), Advances in Archaeology and Museum Science, Plenum Press, 97-127. (PDF)

Walter, R.C. and Aronson, J.L., 1982, Revisions of K/Ar ages for the Hadar hominid site, Ethiopia. Nature, 296, 122-127.

Walter, R.C., 1994, The Age of Lucy and the First Family: Single-Crystal 40Ar/39Ar Dating of the Denen Dora and lower Kada Hadar Members of the Hadar Formation, Ethiopia, Geology, 22, 6-10. (PDF)

Walter, R.C., et. al., 2000, Early human occupation of the Red Sea coast of Eritrea during the last interglacial, Nature 405, 65-69. (PDF)

Walter, R.C., Hart, W.K., and Westgate, J.L., 1987, Petrogenesis of a basalt-rhyolite tephra from the west-central Afar, Ethiopia. Contributions to Mineralogy and Petrology, 95, 462-480. (PDF)

Walter, R.C., Manega, P.C., Hay, R.L., 1992, Tephrochronology of Bed I, Olduvai Gorge: An Application of Laser-fusion 40Ar/39Ar Dating to Calibrating Biological and Climatic Change, Quaternary International, 13/14, 37-46. (PDF)

Walter, R.C., Manega, P.C., Hay, R.L., Drake, R.E., and Curtis, G.H., 1991, Laser-fusion 40Ar/39Ar Dating of Bed I, Olduvai Gorge, Tanzania, Nature, 354, 145-149. (PDF)

Walter, Robert, Merritts, Dorothy, Rahnis, Michael, Langland, Michael, Galeone, Daniel, Gellis, Allen, Hilgartner, William, Bowne, David, Wallace, John, Mayer, Paul, and Forshay, Ken, 2014, Big Spring Run floodplain-wetland aquatic resources restoration project: Report to Pennsylvania Department of Environmental Protection, 78 p (plus figures, data files, GIS shapefiles, and photo archives). link

Walter. R.C., and Aronson, J.L., 1993, Age and Source of the Sidi Hakoma Tuff, Hadar Formation, Ethiopia, Journal of Human Evolution, 25, 229-240. (PDF)

Westgate, J.A., Preece, S.J., Froese, D.G., Walter, R.C., Sandu, A.S., and Scherger, C.E., 2001, Dating Early and Middle (Reid) Pleistocene Glaciations in Central Yukon by Tephrochronology, Quaternary Research 56, 335-348. (PDF)

Westgate, J.A., Walter, R.C., Pearce, W., and Gorton, M.P., 1985, Geochemistry, age and distribution of the Old Crow tephra, Yukon and Alaska. Canadian Journal of Earth Science, 22, 893-906. (PDF)

WoldeGabriel, G, White, T.D., Suwa, G., Semaw, S., Beyene, Y., Asfaw, B., and Walter, R.C., 1992, Kesem-Kebena: A Newly Discovered Paleoanthropology Research Area in Ethiopia, Journal of Field Archaeology, 19, 471-493. (PDF)

WoldeGabriel, G., Aronson, J.L., and Walter, R.C., 1990 Geology, geochronology, and rift development of the central sector of the Main Ethiopian Rift. Geological Society of America Bulletin 102, 439-458. (PDF)

WoldeGabriel, G., Walter, R.C., Aronson, J.L., and Hart, W.K., 1992, Geochronology and Distribution of Silicic Volcanic Rocks of Plio-Pleistocene Age from the Central Sector of the main Ethiopian Rift, Quaternary International, 13/14, 69-76. (PDF)

Critical Zone Studies, Landscape and Aqueous Geochemistry, Sediment Fingerprinting, Anthropocene Landscape Change, Stream Restoration:

In Review:

Walter, R.C., Merritts, D.J, Rahnis, M., et al., Legacies lost and found: Improving stream restoration practice and water quality policies. Environmental Research Letters.

Merritts, D. J., Marshall, J., Walter, R. C., Rahnis, M., Hertzler, N., Ruck, J., Corbett, L. B., Bierman, P. R., Caffee, M. W., Demitroff, M. N. In review. Freeze-Thaw Landscapes: Evidence of LGM continuous permafrost and thaw in the eastern US. Geology.

Forshay, K. J., Weitzman, J. N., Wilhelm, J. F., Merritts, D. J., Hartranft, J., Rahnis, M. A., Walter, R. C., and Mayer, P. M., in review. Restored stream-floodplain connection and legacy sediment removal increases denitrification and nitrate retention, Big Spring Run, PA USA. Biogeochemistry.

Published:

Lewis, E., Inamdar, S., Gold, A.J., Addy, K., Trammell, T.L., Merritts, D., Peipoch, M., Groffman, P.M., Hripto, J., Sherman, M. and Kan, J., 2021. Draining the landscape: How do nitrogen concentrations in riparian groundwater and stream water change following milldam removal? Journal of Geophysical Research: Biogeosciences, p.e2021JG006444. https://doi.org/10.1029/2021JG006444

Inamdar, S., Peipoch, M., Gold, A.J., Lewis, E., Hripto, J., Sherman, M., Addy, K., Merritts, D., Kan, J., Groffman, P.M. and Walter, R., 2021. Ghosts of landuse past: legacy effects of milldams for riparian nitrogen (N) processing and water quality functions. Environmental Research Letters, 16(3), p.035016.

Lewis, E., Inamdar, S., Gold, A.J., Addy, K., Trammell, T.L., Merritts, D., Peipoch, M., Groffman, P.M., Hripto, J., Sherman, M. and Kan, J., 2021. Draining the landscape: How do nitrogen concentrations in riparian groundwater and stream water change following milldam removal? Journal of Geophysical Research: Biogeosciences, p.e2021JG006444. https://doi.org/10.1029/2021JG006444

Inamdar, S., Peipoch, M., Gold, A.J., Lewis, E., Hripto, J., Sherman, M., Addy, K., Merritts, D., Kan, J., Groffman, P.M. and Walter, R., 2021. Ghosts of landuse past: legacy effects of milldams for riparian nitrogen (N) processing and water quality functions. Environmental Research Letters, 16(3), p.035016.

Dow, S., Snyder, N.P., Ouimet, W.B., Martini, A.M., Yellen, B., Woodruff, J.D., Newton, R.M., Merritts, D.J. and Walter, R.C., 2020. Estimating the timescale of fluvial response to anthropogenic disturbance using two generations of dams on the South River, Massachusetts, USA. Earth Surface Processes and Landforms, 45(10), pp.2380-2393.

Fleming, P.M., Merritts, D.J. and Walter, R.C., 2019, Legacy sediment erosion hot spots: A cost-effective approach for targeting water quality improvements: Journal of Soil and Water Conservation, 74(4), pp.67A-73A.

Johnson, K.M., Snyder, N.P., Castle, S., Hopkins, A.J., Waltner, M., Merritts, D.J. and Walter, R.C., 2019. Legacy sediment storage in New England river valleys: Anthropogenic processes in a postglacial landscape. Geomorphology, 327, pp.417-437. https://doi.org/10.1016/j.geomorph.2018.11.017

Inamdar, S., Johnson, E., Rowland, R., Warner, D., Walter, R. and Merritts, D., 2017, Freeze–thaw processes and intense rainfall: the one-two punch for high sediment and nutrient loads from mid- Atlantic watersheds. Biogeochemistry. https://doi.org/10.1007/s10533-017-0417-7

Brantley, S., Menonigal, P., Scatena, F., Balogh-Brunstad, Z., Barnes, R., Bruns, M., Van Cappelen, P., Dontsova., K., Hartnett, H., Hartshorn, T., Heismath, A., Herndon, E., Jin, L., Keller, C., Leake, J., McDowell, W., Meinzer, F., Mozdzer, T., Petsch, S., Pett-Ridge, J., Pregitzer, K., Raymond, P., Riebe, C., Shumaker, K., Sutton-Grier, A., Walter, R., Yoo, K., 2011, Twelve testable hypothesis on the geobiology of weathering. Geobiology. DOI: 10.1111/j.1472-4669.2010.00264.x (PDF)

Elliott, S.J., Wilf, P., Walter, R.C., Merritts, D.J., 2013, Subfossil Leaves Reveal a New Upland Hardwood Component of the Pre-European Piedmont Landscape, Lancaster County, Pennsylvania. PLoS ONE 8(11): e79317. doi: 10.1371/journal.pone.0079317 (PDF)

Elliott, Sara J., Grettenberger, Christen L., Donovan, Michael P., Wilf, Peter, Walter, Robert C., and Merritts, Dorothy J. 2016. Riparian and valley-margin hardwood species of pre-colonial Piedmont forests: A preliminary study of subfossil leaves from White Clay Creek, southeastern Pennsylvania, USA. Palaeontologia Electronica 19.1.2A: 1-26 (PDF)

Fleming, P.M., Merritts, D.J., and Walter, R.C., in press, Legacy sediment erosion hot spots: A cost-effective approach for targeting water quality improvements. Journal of Soil and Water Conservation. doi:10.2489/jswc.74.4.67AHall, C.M., Walter, R.C., Westgate, J.A., and York, D., 1984, The Cindery Tuff in Pliocene hominid-bearing sediments of the Middle Awash, Ethiopia: Geochronology, stratigraphy and geochemistry. Nature, 308, 26-31. (PDF)

Hartranft, J , Merritts, D., Walter, R., and and Rahnis, M., 2011, The Big Spring Run Restoration Experiment: Geomorphology, Aquatic Ecosystems, and Policy in the Big Spring Run Watershed, Lancaster County, PA. Sustain 24, 24-31. (PDF)

Inamdar, S., Johnson, E., Rowland, R., Warner, D., Walter, R. and Merritts, D., 2017, Freeze–thaw processes and intense rainfall: the one-two punch for high sediment and nutrient loads from mid- Atlantic watersheds. Biogeochemistry.https://doi.org/10.1007/s10533-017-0417-7

Merritts, D., Walter, R., and Rhanis, M., 2010, Sediment and nutrient loads from stream corridor erosion along breached millponds. Pennsylvania Department of Environmental Protection Report, 147p. (PDF)

Merritts, D., Walter, R., Rahnis, M., Hartranft, J., Cox, S., Potter, N., Hilgartner, W., Langland, M., Manion, L.*, Lippincott, C.*, Siddiqui, S.*, Rehman, Z.*, Scheid, C.*, Kratz, L.*, Shilling, A.*, Jenschke, M.*, Datin, K.*, Cranmer, E.*, Reed, A.*, Matuszewski, D.*, Voli, M.*, Ohlson, E.*, Deng, W.*, Neugebauer, A.*, Ahamed., A.*, Neal, C.*, Winter, A.*, and Becker, S.*, 2011. Anthropocene Streams: Human Agents in Base-Level Forcing, Philosophical Transactions of the Royal Society of London 369, 976-1009. (PDF)

Merritts, D.J., Walter, R.C., Rahnis, M., Hartranft, J, Cox, S., Scheid, C., Potter, N., Jenschke, M., Reed, A., Matuszewski, D., Kratz, L., Manion, L., Shilling, A., Datin, K., 2013, The rise and fall of Mid-Atlantic streams: Millpond sedimentation, milldam breaching, channel incision, and stream bank erosion. in DeGraff, J.V., and Evans, J.E., eds., The Challenges of Dam Removal and River Restoration: Geological Society of America Reviews in Engineering Geology, v. XXI, p. 183–203, doi:10.1130/2013.4021(14). (PDF)

Walter R.C. and Merritts, D.J., 2008. Natural Streams and the Legacy of Water-Powered Mills. Science 319, 299-304. (PDF)

Walter, R., Merritts, D. Patapova, M., Hilgartner, W., Bowne, D., Johnson, R., Moore, J., 2017, Wetland Program Development in Support of Pennsylvania’s Aquatic Resource Protection and Management Action Plan, Program Focus Area 3: Headwater Aquatic Resource Restoration Monitoring: Report to the Pennsylvania Department of Environmental Protection, 67 p (plus figures, data files and photo/video archives). (PDF)

Walter, Robert, Merritts, Dorothy, Rahnis, Michael, Langland, Michael, Galeone, Daniel, Gellis, Allen, Hilgartner, William, Bowne, David, Wallace, John, Mayer, Paul, and Forshay, Ken, 2014, Big Spring Run floodplain-wetland aquatic resources restoration project: Report to Pennsylvania Department of Environmental Protection, 78 p (plus figures, data files, GIS shapefiles, and photo archives). link

Walter, R.C. and Merritts, D.J., 2008. Dammed You Say. Science Online. (PDF 1 PDF2)

Walter, R.C. and Merritts, D.J., 2008. What to do About these Dammed Streams. Science, 321, 911-912. (PDF 1 PDF 2)

Walter, Merritts and Rahnis, 2007: Estimating Volume, Nutrient Content and Rates of Stream Bank Erosion of Legacy Sediment in the Piedmont and Valley and Ridge Physiographic Provinces, Southeastern and Central PA. PADEP Final Report. 103p. (PDF)

Weitzman, J., Forshay, K., Kaye, J., Mayer, P., Koval, J., Walter, R., 2014, Potential nitrogen and carbon processing in a landscape rich in mill-dam legacy sediment. Biogeochemistry. DOI 10.1007/s10533-014-0003-1 (PDF)

Hydrogeology, Water Security, Groundwater Exploration

Faure, H., Walter, R.C. and Grant, D.E., 2002, The coastal oasis: Ice Age springs on emerged continental shelves, Global and Planetary Change, 33/1-2, 47-56. (PDF)

Longenecker, J., T. Bechtel, Z. Chen, N. Goldscheider, T. Liesch, and R. Walter, 2017, Correlating Global Precipitation Measurement satellite data with karst spring hydrographs for rapid catchment delineation, Geophys. Research Letters, 44, 4926–4932, doi:10.1002/2017GL073790.

Course Information

Main Course Sequence

GEO (ENE) 110 – The Dynamic Earth
GEO (ENE) 273 - Earth Materials
GEO (ENE) 350 – Landscape Geochemistry
GEO (ENE) 480 – Geoscience Capstone Seminar – Global Tectonics

Elective Courses:

GEO (ENE) 170 – The Geopolitics of Afghanistan
GEO (ENE) 171 - The Geopolitics of Humanitarian Crises
GEO (ENE)/TDS 370 – Visual Design for Scientists (co-taught with Dirk Eitzen, TDS)
GEO (ENE) 375 – Karst Hydrogeology (co-taught with Tim Bechtel, ENE)
ENE/CLS 27x (in prep) – The Last Days of Pompeii (will co-teach with Shawn O’Bryhim, CLS)