Once in a while a scientist emerges who, through sheer power of intellect, curiosity and enthusiasm, transforms an entire field of study and effectively sets the trajectory of inquiry for decades to come. Such is Dr. William “Bill” Dietrich’s contribution to geomorphology — an unrivaled legacy of transformative ideas, insights, initiatives and community leadership.

Bill’s career is distinguished by geomorphic investigations of exceptional breadth and depth, driven by core principles, foremost a physics-based balance-of-forces approach to understanding surficial processes. First proposed by the 19th century geomorphologist G. K. Gilbert, this approach was largely conceptual until Bill brought modern analytical and computational tools to bear, demonstrating how to crack thorny geomorphic problems.

With his students, he was then able to answer fundamental questions in geomorphology: Where do channels begin? What determines where landslides occur? What governs the shape of hillslopes? How does river form reflect both uplift and erosion? And even, is there a topographic signature of life? To answer these questions, Bill formulated what he termed “geomorphic transport laws,” sparking a revolution in landscape modeling and prediction, novel field studies, and new geomorphic tools. Suddenly, virtually all geomorphic processes could be quantitatively explored, modeled and tested against field and laboratory evidence. This work required detailed topographic data, and Bill pioneered applying lidar technology to geomorphic problems.

Bill’s leadership has been generous and transformative. From his role guiding the National Center for Earth-Surface Dynamics to his passionate advocacy for and demonstration of critical zone science and his leading role in guiding the Mars Curiosity mission, his legacy of unselfish leadership is unparalleled. That legacy includes mentoring generations of geomorphologists, many of whom are themselves acknowledged leaders in the field.

Perhaps his most enduring community accomplishment is establishing the “Gilbert Club,” now in its 40th year, following the AGU Fall Meeting. Beginning as a living room salon, it is now the capstone event of the geomorphic community, attracting 300+ researchers worldwide to hear cutting-edge talks, engage in spirited dialogue over pizza and feel themselves part of something larger:

Bill’s career represents a model for what any scientist might aspire to. His work is testimony to the best that science brings us: curiosity as a fundamental drive, a deep sense of place and time, an embrace of how research takes a village, a commitment to lead and innovate for the greater good, and an appreciation for this marvelous planet and universe we live in.

— Gordon Grant
Pacific Northwest Research Station, U.S. Department of Agriculture
Portland, Oregon


— Alan Howard
University of Virginia (emeritus)
Charlottesville, Virginia

First, I thank Gordon Grant and Alan Howard for their exceptionally generous and kind citation. They are two leaders of the many from whom I have learned so much, as colleagues, mentors and companions on the journey of discovery about the thing we love: geomorphology. Tom Dunne and J. Dungan Smith at the University of Washington, my graduate advisers, shared their insights; the joy of field work; the necessity of theory; and the deep value of debate, discussion and collaboration. I joined the faculty at Berkeley in 1982 and had the great fortune of attracting amazing graduate students and postdocs who would attack basic questions, use new tools and teach me about how geomorphic (and hydrologic) processes work. My Berkeley department colleagues have always been supportive, encouraging and collaborative. Participation in the National Science Foundation-supported National Center for Earth-Surface Dynamics and the critical zone observatories programs gave me opportunities to take research risks and learn through further collaborations. Mike Malin invited me to participate in the Mars Science Laboratory (Curiosity mission) well before the rover was built. We have learned much about Mars, but I also have returned to Earth with new questions about how Earth surface processes work. In the 1970s, geomorphology was not commonly found in geology departments. When I arrived in Berkeley, I felt a need to find a way to create a community to focus on important questions that would help advance the field. It occurred to me to take advantage of the AGU annual meeting in San Francisco by offering a Saturday-after gathering not affiliated with AGU, but in its shadow, inviting an audience who chose to stay an extra day. This “Gilbert Club,” mentioned in the citation, was conceived as an opportunity for a growing community to hear major talks, debate new ideas and encourage community-level discussion of issues. The goal is to have faculty, students, government researchers and industry workers meet regularly to spawn collaborations and to encourage friendships. It has always been an open meeting. New tools arrived, including digital elevation models, airborne laser mapping and cosmogenic nuclide data, revolutionizing geomorphic research. AGU has been exceptionally welcoming and supportive as a community grew, initiated the Journal of Geophysical Research: Earth Surface, and eventually formed the Earth and Planetary Surface Processes section. Finally, I must thank Mary Power, Berkeley ecologist, collaborator, my love, my wife, and my best friend of nearly 50 years.— William Eric Dietrich, University of, Berkeley, Berkeley, California

William E. Dietrich received the 2010 G. K. Gilbert Award at the 2010 AGU Fall Meeting, held 13–17 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.”  

William “Bill” Dietrich’s contributions to geomorphology, hydrology, and ecogeomorphology are unequaled in breadth and quality. We are particularly honored to recognize his accomplishments in this inaugural awarding of the G. K. Gilbert Award. Bill exemplifies the depth of insights and breadth of interests that characterized the award’s namesake, G. K. Gilbert. Bill’s status in the scientific community is manifest in his election to the National Academy of Sciences and in several other honors he has received, including AGU’s 2009 Robert E. Horton Medal.

Bill is largely responsible for establishing geomorphology in AGU in its strong present role in the Earth and Planetary Surface Processes (EPSP) focus group. He was instrumental in organizing geomorphology-oriented sessions at the AGU Fall Meeting through his leading role in the Erosion and Sedimentation Subcommittee of the Hydrology section. A very significant part of his success in making AGU a primary outlet for fundamental geomorphologic research was his establishment of the Gilbert Club 25 years ago. This annual gathering immediately follows the AGU Fall Meeting and has become the premier scientific and social gathering for geomorphologists.

Many of the graduate students and postdocs working with Bill have become leading scientists in academic and government organizations. Beyond this traditional mentoring, however, Bill has been unselfish in cooperation and collaboration with the geomorphic community. He serves as a sounding board about research for many of our colleagues, and most of us have seen our theories and conjectures wither in the face of his incisive analysis.

— Alan D. Howard, Department of Environmental Sciences, University of Virginia, Charlottesville

In the early 1980s I started an annual 1-day gathering to discuss geomorphology in Berkeley on the Saturday after the annual AGU Fall Meeting in San Francisco. I whimsically called it the “Gilbert Club” and offered an open invitation to anyone to come join us. The whimsy, of course, was the use of the word a “club,” as there was no organization or affiliation, and in fact no “club”—rather just a deep admiration for G. K. Gilbert. We grew from 7 to nearly 300 attendees, and now “grandstudents” of the meeting are coming, doing pop-up statements, and painting the future for us. Geomorphology is a vibrant community, enabled with new tools, and rich with great unsolved problems. The AGU Earth and Planetary Surface Processes focus group decision to award me its first G. K. Gilbert award was a shock and, as everyone saw at the awards ceremony, left me speechless. It is an exceptionally kind act. I share this award with the fantastic group of students and postdocs at Berkeley with whom I have been lucky enough to work. There are too many individuals to thank for this honor, but I must mention three. I am in this field because when I arrived at the University of Washington hungry to begin my graduate studies, I had the great fortune to be mentored by Tom Dunne and Jim Smith. We worked together in the field, debated at the blackboard, and continued the debate as we wrote papers. The joy of discovery was ever present. I must also thank Alan Howard, who has continuously shared his deep understanding of geomorphology and guided me in many research adventures. Finally, I thank the entire geomorphology community for being what it has become. We are truly fortunate. —William E. Dietrich , Department of Earth and Planetary Science, University of California, Berkeley

William E. Dietrich was awarded the 2009 Robert E. Horton Medal at the AGU Fall Meeting Honors Ceremony, held on 16 December 2009 in San Francisco, Calif. The medal is for “outstanding contributions to hydrology.”  

It is truly a pleasure to introduce William Dietrich of the University of California at Berkeley as the 2009 Horton medalist for his outstanding contributions to the geophysical aspects of hydrology. That citation pales by comparison with Bill’s accomplishments, for no one comes close to the impact Bill has had in modernizing the field of geomorphology. He maintains the same unflagging energy and creativity in research, teaching, and professional service that have earned him international fame as the most productive, diverse, and influential geomorphologist in the world today.

This influence begins with his superb combination of skill in field observation and his ability to apply mechanistic principles to the analysis of empirical results to construct theories of landscape evolution. His career began with studies of river channel mechanics and of mass wasting in the coastal mountains of Oregon and California. He and his graduate students have extended his discoveries in both of those topics through field studies, laboratory experiments, and analysis of digital topography. They introduced innovations in each field, including high-resolution field measurements of flow and sediment transport, cosmogenic isotope measurement of regolith formation and transport, chemical tracers of floodplain sedimentation patterns, and lidar-resolution measurements of topography. Bill’s group expanded its field, laboratory, and numerical simulation studies to understand regolith formation, runoff processes, sediment transport, channel mechanics, floodplain sedimentation, and bedrock incision by streams and debris flows, typically being the first investigators to demonstrate the utility of a technique for extending landscape theory. Their studies continue to expand into hyperarid landscapes, including Mars.

The novelty and range of Dietrich’s studies begin with his innate curiosity about landscapes and their relevance for humans and other biota. He constantly shares his knowledge openly, and he is relentlessly inquisitive about other disciplines. His friendly demeanor and generosity, especially with young scientists, make him a hero in the discipline, and induce similar behavior among his large and productive group of former graduate students.

Bill is an exemplar of the AGU commitment to “unselfish cooperation in research.” He worked tirelessly within the Erosion and Sedimentation Committee of the Hydrology section to promote geophysical approaches in geomorphology, and to organize special sessions with other sections, leading to seminal interdisciplinary initiatives. These efforts continue and have expanded into other community-building efforts such as the National Center for Earth-surface Dynamics, the National Center for Airborne Laser Mapping, and National Research Council and National Science Foundation committees. His most influential community-building activity must surely lie in organizing the Gilbert Club, an annual gathering of geomorphologists that he established in 1983. At that event, Bill is at his tireless best—reporting scientific results, asking penetrating questions, including specialists from other fields, promoting the role of young researchers, making sure the program runs and that someone has ordered lunch and dinner—essentially driving the field forward with his physical and intellectual energy.

Bill is a model for all we aspire to be as members of this Union, and as worthy a recipient of the Robert Horton Medal as I can imagine.

—THOMAS DUNNE, University of California, Santa Barbara

Robert E. Horton is a hero to all geomorphologists. He lit the candle that guided us to quantitative inquiry. He observed, quantified, analyzed, performed field experiments, and proposed theories linking hydrology, erosion processes, and form. His 1945 Geological Society of America paper is beyond a “classic”—if a “classic” is defined as a paper often cited but never read. Horton’s paper still now, in 2009, deserves reading and rereading. I remember well when I was introduced to Horton’s work and to geomorphology as a whole by Tom Dunne in the early 1970s. Geomorphology was considered by many then as an uncomfortable, backward cousin of Earth science, taught only in introductory classes, and lacking in quantitative accomplishments or rich research opportunities. Tom knew differently and opened the eyes of a generation of students. Things could not be more different now. I have been witness to, and had some hand in, the rediscovery of geomorphology. Our field is populated with generous souls who collaborate closely, share their knowledge, and inspire their students. My colleagues have started new journals, organized new centers, invented new methods of observation, participated in committees and workshops, and written those reports that have created opportunity in our field. The Hydrology section of AGU in particular has been consistently supportive, encouraged new developments, and welcomed this emergence of geomorphology. I must note, too, that the section has been exceptionally kind to me throughout my career. I thank my many collaborators who have continually challenged me, pulled me, and given me opportunities to learn from the best minds. Berkeley is a magnet for ambitious, creative students, and I have had the great fortune of working with many students with exceptional talent. When I opened a door to a room, they would fill it with intellectual furniture beyond my imagination. If chance favors the prepared mind, then I thank in particular Tom Dunne and Jim Smith, my graduate advisors at the University of Washington, for preparing me for what has been a surprising, exciting time of discovery. I share this medal with all of those from whom I have learned so much. And I must also share this medal with Mary Power, my wife, the warm soul who keeps me tethered as I wander this lovely field in search of the new. —WILLIAM E. DIETRICH, Department of Earth and Planetary Science, University of California, Berkeley