Thomas Dunne was awarded the 2016 Robert E. Horton Medal at the AGU Fall Meeting Honors Ceremony, held on 14 December 2016 in San Francisco, Calif. The medal is for “outstanding contributions to hydrology.”  

This is an award that is long overdue. Tom Dunne has been a major influence in hydrology and geomorphology for the past 40 years in a variety of environments, from Vermont to East Africa, the Andes, and the Amazon. Tom’s methodology has been instructive regardless of the domain of his research. During a period when there has been a tendency for researchers to concentrate either on experiments or on computer models, he has always, like Robert Horton, aimed to transfer the knowledge obtained from careful field experiments to the appropriate representation of processes in models. Tom has done this in an exemplary way: runoff generation mechanisms (from hillslopes to the entire Amazon); channel networks (landscape evolution and river habitat); weathering, hillslope erosion, sediment routing, and sediment budgets; river mechanics, meandering, and floodplain depositional processes; and watershed management and river restoration. He has done so at scales from small plots to the Amazon. At times his methods have been unorthodox, such as his approach to simulating the effects of cattle on infiltration rates in East Africa (which makes for a highly entertaining seminar that inspires students).

Tom is a true research scientist, but that has not meant that he has neglected the application of the science to practical problems—that is essentially what his book with Luna Leopold, Water in Environmental Planning, is all about. He has also been prepared to devote time to the wider interests of the hydrological and geomorphological communities, serving on numerous national and international committees, including working for the United Nations.

All of the supporting letters refer to Tom’s inspiring influence on his students and younger colleagues. In his case, it can really be said that he has nurtured them through his intellectual curiosity, by his active contribution to their fieldwork, and via the weekly paper discussion (or dissection) sessions at his home. Many of those students have, of course, gone on to be outstanding hydrologists, geomorphologists, and ecohydrologists in their own right.

Tom’s name is already linked to that of Horton through the descriptions of Horton and Dunne overland flow mechanisms in hydrological textbooks. As Bill Dietrich expressed in his supporting letter, “He took up the charge of Horton’s ‘hydrophysical’ approach and contributed many fundamental insights about surface processes and landscapes. Our understanding of hydrology and geomorphology has been greatly advanced by both his scholarly publications and his intellectual leadership.”

—Keith Bevin, Lancaster University, Lancaster, U.K.

Thank you to Keith Beven and the other supporters of this nomination for providing me with such an honor, and to the audience for letting me enjoy it with you. The heartwarming aspect of the award is that it reminds me of the influences of the communities and institutions in which I have been fortunate to participate. The geography departments at Cambridge and Johns Hopkins impressed on me the importance of constructing theory based on field investigations (working on what Keith frequently emphasizes are our epistemic uncertainties about how landscapes function), and of spending at least a portion of one’s research efforts on topics of societal value. Nairobi and McGill Universities exposed me to the subarctic and tropics, expanding my appreciation of the environmental range of Earth. And in the multidepartmental communities at the Universities of Washington and of California, Santa Barbara colleagues strengthened my geophysical education and expanded the geographical range and time depth of my studies and also my interest in hydrologic and geomorphic contributions to environmental conservation and restoration from the Pacific Northwest to the Amazon Basin. I am mindful that it was possible to learn new things in all the roles I had in these institutions from undergraduate to aging professor. I learned that diversity of scientific approaches and of geographical exposure is valuable and enriching. But this is also a night to reflect on Robert Horton. He has guided me since my undergraduate days when I was taught that his hydrophysical approach was the key to understanding the fluid mechanical processes driving the formation and hydrological functioning of landscapes. I had to be informed later of the roles that Earth plays in providing the material properties, boundary conditions, and time frames in which those landforms and those functions evolve. But Horton has broader lessons for all of us. He distilled his working engineer’s experience as an observer of nature and his multi­lingual reading into foundational studies across the processes and scales of the hydrologic cycle. In the 1930s, he published a scientific agenda for hydrology and was a ­­­co-­founder of the Hydrology section of AGU in the face of considerable early skepticism about whether hydrology was truly a scientific field. For that, we should be particularly grateful to Robert Horton for providing us with this community and with an opportunity to ask continually whether our own work supports his optimistic vision of what we might accomplish. —Thomas Dunne, Bren School of Environmental Science and Management, University of California, Santa Barbara

Thomas Dunne received the 2011 G. K. Gilbert Award at the 2011 AGU Fall Meeting, held 5–9 December in San Francisco, Calif. The award recognizes “a scientist who has either made a single significant advance or sustained significant contributions to the field of Earth and planetary surface processes, and who has in addition promoted an environment of unselfish cooperation in research and the inclusion of young scientists into the field.”  

The emergence of a strong community of geomorphologists in the past 40 years owes much of its existence to the inspiring intellectual leadership of Tom Dunne. At the University of Washington and the University of California, Santa Barbara, Tom has taught generations of students. He has done this through inspiring lectures, field-based class exercises, reading seminars, joyful discussions with individual students and colleagues, and close collaboration in the field on research projects. His deeply penetrating scholarly publications (including no fewer than 18 book chapters and two books, Rapid Sediment Budgets with Leslie Reid and Water in Environmental Planning with Luna Leopold) reach the entire community.

Tom really is responsible for what could be called a school of thought that helped lead geomorphology from the backwaters of Earth science in the 1950s and 1960s to the success and excitement it now enjoys. One can easily keep busy in science. Tom asks us to do something significant, or at least try to, and have fun trying. He asks for good scholarship, fundamental questions, field observations, experimentation (field and laboratory), process understanding, and theory.

Tom discovered and explained saturation overland flow. The process goes by many names, including the Dunne mechanism. Call it what you will, its discovery, quantification, and explanation by Tom constitute a cornerstone of our understanding of runoff hydrology. Tom has now worked with over 35 graduate students on a wide range of topics, including channel networks, weathering, hillslope erosion, sediment routing and sediment budgets, river mechanics, meandering and floodplain depositional processes, and watershed management and river restoration.

For over 40 years, Tom has shaped the field of geomorphology through key discoveries, intellectual leadership, and mentorship of generations of young geomorphologists. For this leadership he is awarded the 2011 G. K. Gilbert Award of the Earth and Planetary Surface Processes Focus Group of the American Geophysical Union.

— William E. Dietrich, University of California, Berkeley

Thanks, Bill, for the generous introduction and to those who compiled and evaluated the nomination. It’s a reminder of how helpful we all are to one another in organizations like AGU and how energizing such support is in creating and disseminating new knowledge. I never expected to be linked to Gilbert when I was introduced to his theoretical literature and exotic field adventures 50 years ago in Richard Chorley’s revolutionary geomorphology classes at Cambridge. Chorley used Gilbert to illustrate the goal of developing general theory about landscape evolution through the functioning of surface processes. That interdisciplinary goal led directly to the Earth and Planetary Surface Processes Focus Group. This new community required a few other developments. The first was guidance from important mentors, such as Ron Shreve, Peter Eagleson, and Jim Smith, who demonstrated how to transform the study of surface processes into a geophysical science formalizing the analysis of entire evolving landforms and landscapes. Our earlier quantitative approaches were learned, for example, from agricultural and geotechnical engineering, which, however valuable, limited us to small scales of time and space and unidirectional causality. Geophysics enlarged our perspective and allowed us to study the coevolution of landscapes and processes but still promoted rigor of theory and method. Then, as geophysics itself diversified by assimilating chemical and biological studies, our field participated. We also profited from technological advances allowing measurements of Davis’s landforming triad of process, material properties, and time. Most important and promising of all, the field is being transformed by young people with modern scientific training entering the field and utilizing novel methods to study the part of Earth that affects people most immediately as well as other planetary landscapes that inspire our curiosity. It’s a wonderful prospect; this community is working very well. Gilbert, the pioneer, would have approved. — Thomas Dunne, University of California, Santa Barbara